Term
| what are the functions of the GI tract, which are the main functions. explain a little about each |
|
Definition
motility: propell, reduce size, mix, proper rate
secretion: electrolytes, galnds
**digestion: to make molecules absorbable
**absorption: nutrients, electrolytes, water |
|
|
Term
what type of tissue is the mouth
what is the muscle of the lips
what is the vermillion border |
|
Definition
stratified squamous
border between skin of mucosa and face
obricularis oris |
|
|
Term
| what is the tounge covered with, anchored by, and its function |
|
Definition
covered with mucosa and papillae, anchored to hyoid
chewing, swallowing, speech |
|
|
Term
| where are taste buds, what can they taste |
|
Definition
they are nerve cells on pepillae
taste sweet, sour, bitter, salty, and umami |
|
|
Term
|
Definition
|
|
Term
what is the difference between intrinsic and extrinsic salivary glands
what are the extrinsic ones |
|
Definition
intrinsic are in oral mucosa and secrete all the time
extrinsic only secrete around eating. parotid, submandibular, sublingual |
|
|
Term
| what is saliva composed of |
|
Definition
| water, ions, mucous, enzymes |
|
|
Term
| what are the functions of saliva |
|
Definition
| moisten, dissolve food, start digestion, antibacterial, antiviral |
|
|
Term
| how does the pharynx contribute to digestion, what type of tissue is it |
|
Definition
stratified squamous
three constrictor muscles
oropharynx and laryngopharynx are used |
|
|
Term
| how does the esophagus contribute to digestion |
|
Definition
| skeletal muscle controlled by vagus pushes food down, collapses when empty |
|
|
Term
| what are the functions of the stomach |
|
Definition
| temporary storage, mixing, break down protein with pepsin, HCl antimicrobial, absorb water electrolytes asprin alcohol |
|
|
Term
| what are some characteristics of the epithelium / lining of the stomach |
|
Definition
simple columnar
glands open into pits
secrete bicarbonate
rugae: longitudinal folds distentable
muscularis: circular and longitudinal |
|
|
Term
| what are the cell types of the stomach, give a general function |
|
Definition
parietal: secrete HCl and intrinsic factor
Chief: secrete pepsinogen
mucous neck cells |
|
|
Term
| where does the small intestine get blood from, where does it drain |
|
Definition
superior mesenteric arteries
hepatic portal vein |
|
|
Term
| by what structure does the duodenum recieve enzymes from the pancreas |
|
Definition
|
|
Term
| what is the biggest part of the small intestines |
|
Definition
|
|
Term
| what structures help with absorption in intestines |
|
Definition
| circular folds (plicae circularis), villi on simple columnar cells, microvilli, and lacteals (fat absorption) |
|
|
Term
| what are some structural characteristics of the large intestines. beriefly describe them / purpose (cell tyoes, structural markers, tissue characteristics) |
|
Definition
teniae coli: 3 longitudinal muscle strips
haustra: sacs
epiploic ependages: omental folds or eritoneum or fat pouches
cecum: holds symbiotic microbes
ileocecal valve
columnar cells: absorb water and electrolytes
goblet cells: secrete mucous to lubricate
lymphoid tissue: control bacteria
NO villi! |
|
|
Term
| what are the layers of the GI tract and their sublayers from lumen out (10 layers, 6 sub) |
|
Definition
1. lumen
2. mucosal layer :epithelial cells, lamina propria, muscularis mucosae
3. submucosa
4. submucosal / meissner's plexus
5. muscularis externa: circular muscle, myenteric plexus, longutidunal muscle
6. serosa
7. peritoneal cavity |
|
|
Term
| what are the parts of the mucosal layer of the GI tract, what are their functions |
|
Definition
epithelial cells: absorb nutrients, secrete mucous (goblet cells), form barrier
lamina propria: CT, blood, lymph. first line of immune defense (MALT)
muscularis mucosae: contracts locally |
|
|
Term
| what is the submucosa of the GI tract made of, what is its function |
|
Definition
collagen, elastin, glands, vessels
helps regain shape after processing |
|
|
Term
| what is the function of the muscularis externa and the different parts |
|
Definition
peristalsis and segmentation
circular: squeezes
longitudinal: shortens |
|
|
Term
| describe the muscle cells of the GI tract (shape, configuration, function) |
|
Definition
spindle shaped, one nuclri, no striations, in sheets, no sarcomere
slow contraction, fatuge resistant
does not always need nervous signal
stimulated by stretch too |
|
|
Term
| what is another name for the serosa, what type of tissue is it |
|
Definition
| simple squamous epithelium with areolar CT beneath it |
|
|
Term
| what organs are retroperitoneal |
|
Definition
| kidney, ureter, suprarenal gland, great vessels, paired branches |
|
|
Term
| what does the peritoneal cavity contain |
|
Definition
| intestines, stomach, liver |
|
|
Term
| what are the steps in the digestive process, briefly explain each (6) |
|
Definition
1. ingestion
2. propulsion: swallowing, peristalsis
3. mechanical digestion: chew, chrun, mix
4. chemical digestion: enzymes
5. absorption: transport into blood or lymph
6. defecation: elimination via feces |
|
|
Term
| explain the process of defecation |
|
Definition
| wall stretching triggers parasympathetic reflex, contraction of smooth muscle, relaxation of internal anal sphinctor, voluntary relaxation of external anal sphincter (aided by diahragm and abdnominal wall muscles) |
|
|
Term
| what is the extrinsic innervation of the GI tract, general purpose of each part |
|
Definition
autonomic nervous system
parasympathetic: stimulate digestion
sympathetic: stop digestion |
|
|
Term
| what does the parasympathetic part of the vagus nerve innervate in GI tract, what type of innervatin |
|
Definition
upper GI, striated muscle of esophagus
many afferent (mechanoreceptors, chemoreceptors, vasovagal reflexes)
some efferent |
|
|
Term
| what does the phrenic nerve innervate in GI tract |
|
Definition
| lower GI tract (striated muscle of external anal canal too) |
|
|
Term
| where do sympathetic preganglionic cell bodies of extrinsic nervous system synapse |
|
Definition
| celiac, superior mesenteric, inferior mesenteric, and hypogastric ganglia |
|
|
Term
| what neurotransmitters to postganglionic fibers of the extrinsic sympathetic nervous system are there |
|
Definition
| adrenergic release NE and N |
|
|
Term
| where do postganglionic fibers of the extrinsic sympathetic nervous system synapse |
|
Definition
some go to submucosal or myenteric plexuses
some go to smooth myscle, endocrine, or secretory cells |
|
|
Term
| where do the postganglionic parasympathetic fibers of the extrinsic nervous system go, why |
|
Definition
| myenteric and submucosal plexuses to coordinate information |
|
|
Term
| what types of parasympathetic neurons are there for the GI tract, what neurotransmitters do they use |
|
Definition
cholinergic: ACh
peptidergic: substance P, neuropeptide, vasoactive inhibitor peptide (VIP) |
|
|
Term
| where are the cell bodies of the enteric nervous system, what do they control |
|
Definition
submucosal and myenteric plexuses
contractile, secretory, and endocrine functions |
|
|
Term
| what is different about the neurotransmitters of the enteric nervous system |
|
Definition
the release neurocrines/neurochemicals and neuromodulators
nerves may secrete more than one |
|
|
Term
| what and how does the enteric nervous system communicate with |
|
Definition
comminicates with autonomic nervous system
recieves info via chemo and mechanoreceptors and sends info back to GI tract
info is relayed between ganglia by interneurons |
|
|
Term
| what qualifies something to be a hormone |
|
Definition
must be secreted in response to physiologic stimulus, carried in blood to distant site of action, independent function from neural activity
must have been isolated, purified, identified, and synthesized |
|
|
Term
| physically describe the endocrine cells of the mucosa |
|
Definition
single or in small groups dispersed over GI tract
NO glands |
|
|
Term
| what are the types of hormones and almost hormones in the GI tract |
|
Definition
gastrin, CCK, secretin, GIP
almost hormones: motilin, pancreatic polypeptide, enteroglucagon |
|
|
Term
| what are the types of gastrin, explain when each is used. where are they secreted from |
|
Definition
little (G17): in response to meal
big (G34): between meals, more common
C-terminal tetrapeptide: fragment that causes lesser effects
secreted from G (gastrin) cells in the antrum of the stomach |
|
|
Term
| what can signal gastrin release what can turn them off |
|
Definition
peptides, AA (phenyalalnine, tryptophan), distension of stomach, vagal reflexes (GRP/bombesin)
low pH or somatostatin turns them off |
|
|
Term
| what are the actions of gastrin |
|
Definition
cause parietal cells to release H
increase trophic growth of mucosa |
|
|
Term
| what are the types of CCK and its receptors, explain why each are used. where is CCK secreted from |
|
Definition
CCK A receptor: CCK only
CCK B receptor: CCK and gastrin
C-terminal hepatapeptide (CCK-7): smallest part of CCK needed for function
I cells of duodenum and jejum mucosa |
|
|
Term
| what stimulates CCK release |
|
Definition
| peptides, AA, FA (not TG) |
|
|
Term
|
Definition
contraction of gallbladder and relaxation of sphinctor of Oddi to release bile
secreation of pancreatic enzymes and bicarbonate
growth of pancreas and gallbladder
inhibit gastric emptying to help absorb fat |
|
|
Term
| what stimulates secretin release, from where |
|
Definition
pH < 4.5 (H+), Fa
S cells in duodenum |
|
|
Term
|
Definition
secretion of pancreatic and biliary bicarbonate
inhibit gastrin |
|
|
Term
| what stimulates GIP release from where |
|
Definition
FA, AA, oral glucose (only one with all three)
K cells in duodenum and jejunum |
|
|
Term
|
Definition
stmulates B cells in pancreas to release insulin
decrease H secretion |
|
|
Term
| where is moltilin do, where is it secreted from and why |
|
Definition
upper duodenum during fasting
increase motility, initiates inter-digestive myoelecric complexes (90 min intervals) |
|
|
Term
| where is pancreatic polypeptide secreted from and why, what does it do |
|
Definition
pancrease in response to carbs, proteins, and lipids
inhibits pancreas secretion of bicarbonate and enzymes |
|
|
Term
| where is enteroglucagon secreted from and why, what does it do |
|
Definition
intestinal cells in response to decreased blood glucose
tells liver to increase glycogenolysis and gluconeogenesis |
|
|
Term
| what are paracrines, what are the ones in the GI tract, how do they work |
|
Definition
secreted by endocrine cells and act locally unlike hormones
somatostatin and histamine |
|
|
Term
| what is somatostatin secreted by and why, what does it to |
|
Definition
secreted by D cells (endocrine and paracrine) in mucosa in response to low pH
secreted by hypothalamus by delta cells of endocrine pancreas
inhibits H secretion |
|
|
Term
| what makes histamine a paracrine peptide, what does it do for the GI tract |
|
Definition
it is not a peptide.
stimulates H secretion by parietal cells |
|
|
Term
| what are neurocrines, what ones are in the GI tract |
|
Definition
peptides made in neurons
ACh, NE, VIP, GRP, enkephalins, neuropeptide Y, substance P |
|
|
Term
| what does ACh do in the GI tract |
|
Definition
increase contraction in wall, salivation, gastric and pancreas secretion
decrease contraction in sphinctors |
|
|
Term
| what does NE do in the GI tract |
|
Definition
increase sphinctor contraction and salivation
decrease contraction of wall |
|
|
Term
| what does vasoactive intestine peptide do in the GI tract |
|
Definition
increase intestinal and pancreatic secretion
decrease contraction of wall |
|
|
Term
| what does gastrin releasing peptide or bombesin do in the GI tract |
|
Definition
|
|
Term
| what do enkephalins or opiates do in the GI tract |
|
Definition
increase wall contraction
decrease secretion |
|
|
Term
| what does neuropeptide Y do in the Gi tract |
|
Definition
| decrease contraction of wall and secretions |
|
|
Term
| what does substance P do inthe GI tract, how is it released |
|
Definition
co-secreted with ACh
increases contraction of wall and secretions |
|
|
Term
| what is the cause of zollnger-ellison syndrome |
|
Definition
gastrinoma: gasrin secreting tumor
in B cells of pancreas |
|
|
Term
| what are the signs of zollnger-ellison syndrome |
|
Definition
| high H secretion, hypertrophy of gastric mucosa, duodenal ulcers, acidification of lumen deactivates pancreatic lipase, decreased fat digestion, steatorrhea |
|
|
Term
| what is the treatment for zollnger-ellison syndrome |
|
Definition
H2 receptor blockers (cimetidine)
H+ pump inhibitors (omeparazole)
tumor removal
gastric resection |
|
|
Term
| what complication can occur in a gastric resection |
|
Definition
| in antrum is removes, H secretion may over decrease causing gastric mucosa atrophy |
|
|
Term
| what are the other names for heartburn |
|
Definition
| acid reflux, GERD, gastroesophageal reflux disease |
|
|
Term
| what are the causes and effects of heartburn |
|
Definition
abnormal lower esophagel concentration and slow stomach emptying, incomplete closure of LES allowing regurgitation of gastric contents into esophagus, hiatial hernia
effects: wall becomes hyperemic (blood flow increases, iflammation) and white patches are seen (leukoplakia), simple squamous epithelium of low esophagus is replaced by columnar which is at risk for adenocarcinoma, heartburn, regurgitation, nausea, dysphasia (difficult swallowing) |
|
|
Term
| what are the types of hemmhorids, what distinguishes them |
|
Definition
internal: superior to pectinal line
external: inferior to pectinal line |
|
|
Term
| what is the name for the smooth muscle of the GI treat, what makes it unique, where is it located |
|
Definition
it is everywher except the upper 1/3 of the esophagus and external anal sphinctor
connected via gap junctions, low resistance, coordinated
2 muscle components
circular: decreases diametes
longitudinal: shortens length |
|
|
Term
| what are the types of contraction for the smooth muscle of the GI tract: mechanism, location |
|
Definition
phasic: contraction followed by relaxation
in esophagus, gastric antrum, SI, and tissues with mixing and propulsion
tonic: constant level of contraction in orad, lower esophagus, ileocecal, intestinal sphinctor |
|
|
Term
| explain what a slow / myogenic wave is |
|
Definition
| not action potential, slow wave of oscillating depolarization and repolarization that does not cause contraction (EM below threashold) |
|
|
Term
| if slow waves dont cause contraction, how is there contraction in the smooth muscle of GI |
|
Definition
| parasympathetic innervation at the time of plateau of a slow wave gives it enough potential to pass threashold |
|
|
Term
| what is the range of frequencies for slow waves, in what areas is this the slowest and fastest |
|
Definition
| 3 in stomach to 12 in duodenum waves per minute |
|
|
Term
| how if the speed of the slow waves adjusted |
|
Definition
| it isnt, can only modulate product of AP (hormonal or neural) at platau and which adusts strength in contraction, not rate |
|
|
Term
| what is the origin of the slow wave, where is it located, why is it effective |
|
Definition
interstitial cells of cajal in myenteric plexus (between circular and longitudinal muscle)
effective because of spread of waves between low resistance gap junctions |
|
|
Term
| explain the cellular mechanism for slow waves |
|
Definition
depolarization: Ca channels open, Ca moves in
plaeau: membrane potential depolarized all the way until threashold (at this time parasympathetic innervation will do AP)
repolarization: K channels open, K moves out |
|
|
Term
| if there is no parasympathetic input what is the effect of slow waves? what about when there is sympathetic input |
|
Definition
| tonic (basal) contraction, sympathetic does nothing so it stays here |
|
|
Term
| when parasympathetic stimulates the slow wave plateau, explain the contraction |
|
Definition
| phasic, more AP stronger contraction |
|
|
Term
| what is the function of mastication (5) |
|
Definition
| mix food with saliva, reduce size of food particles, enable taste, swallowing, mixing with salivary amalyase to digest carbs |
|
|
Term
| what are the two ways to initiate mastication, how do they work |
|
Definition
• Involuntary: Mechanoreceptors connect to brainstem and make oscillatory pattern of muscle movement
• Voluntary: Can override involuntary chewing at any time |
|
|
Term
| what are the phases of deglutition, are the voluntary or involuntary |
|
Definition
oral: voluntary
pharyngeal: involuntary
esophageal: voluntary |
|
|
Term
| what are the 6 events in the oral phase |
|
Definition
o Tongue voluntarily forces bolus toward pharynx
o Bolus stimulates somatosensory receptors in pharynx
o Vagus and glossopharyngeal nerve send info to medullary swallowing center
o Efferent output to striated muscles of pharynx and upper esophagus stimulated
o Involuntary swallowing reflex initiated
o Lower esophageal sphincter relaxes |
|
|
Term
| what are the 6 events in the pharyngeal phase |
|
Definition
o Soft palate pulls up so food cannot get into nasopharynx (breathing inhibited)
o Epiglottis covers opening to larynx (Adam’s apple)
o larynx moves up against epiglottis to prevent entry into trachea
o Upper esophageal sphincter relaxes
o Peristalsis propels food through
Lower esophageal sphincter closes when peristalsis arrives |
|
|
Term
| in the esophageal phase, what events are under control of the swallowing reflex |
|
Definition
Upper esophageal sphincter closes to prevent reflux
Primary peristaltic wave travels down esophagus
receptive relaxation
sphinctor contracts to resting tone as soon as bolus enters |
|
|
Term
| in the esophageal phase, what events are under control of the enteric nervous system, explain it too |
|
Definition
| secondary peristaltic wave: clearns remaining food at begining point of distension (initiated by un-cleared food) |
|
|
Term
| what is receptive relaxation, how is it initiated |
|
Definition
• Food approaching opens the lower esophageal sphincter causes orad of stomach relaxation, decreasing the pressure to welcome bolus
• Vagus nerve releases VIP relaxing the areas |
|
|
Term
| explain how peristalsis works |
|
Definition
| • As an area closes it creates a high pressure that pushes the bolus |
|
|
Term
| explain the role of intra-thoracic pressure in deglutition, how is this regulated |
|
Definition
Intra-esophageal pressure is equal to intra-thoracic pressure which is lower than atmospheric and abdominal
Makes it hard to keep air out of the top and acid out of the bottom of the esophagus
Upper and lower esophageal sphincters have to take care of this so they are closed unless a bolus is passing |
|
|
Term
|
Definition
| difference between opening and closing of sphincters is a result of the delay of food passage down esophagus |
|
|
Term
| GERD: causes, symptoms, associations |
|
Definition
o Intra-abdominal pressure is increased
o Pregnancy, obesity
o Contents of stomach reflux into esophagus
o Esophageal mucosa damage |
|
|
Term
| what is dysphagia, what are the types |
|
Definition
| difficulty swallowing: oropharyngeal, esophageal |
|
|
Term
| what are the causes of oropharyngeal dysphagia |
|
Definition
| Neurological: bulbar palsy (paralysis), pseudo-bulbar palsy, myasthenia gravis (NMJ disorder, weakness) |
|
|
Term
| what are the causes of esophageal dysphagia |
|
Definition
| • benign (rings, polyps, peptic ulcer), malignant (carcinoma in esophagus, stomach, extrinsic compression), esophagitis (candidias, inflammation), achalasia (can’t relax) |
|
|
Term
| how can a dysphagia be diagnosed |
|
Definition
• endoscopy
• barium sulfate contrast radiology
• esophageal manometry: catheter into nose to stomach, withdrawal to detect pressure changes |
|
|
Term
| what are the 3 necessities for gastric motility |
|
Definition
o Relaxation of orad to receive bolus
o Contractions to reduce size and mix bolus with secretions to digest
o Gastric emptying and propulsion of chyme into SI |
|
|
Term
| what are the muscles of the stomach |
|
Definition
Outer longitudinal
Middle circular
Inner oblique |
|
|
Term
| what are the regions of the stomach, give their main functions |
|
Definition
Fundus
Body: stores food, weak contraction, many oxyntic glands
Antrum: thick muscle, peristalsis, retropulsion of bolus into antrum
Pylorus: regulates passage of chyme into duodenum to a small size |
|
|
Term
| what are the regions of the stomach based on motility. what traditional regions do they contain. what is another difference and function |
|
Definition
o Regions Based on motility
Orad: proximal thin walled. Contains fundus and proximal body
Caudad: distal thick walled. Strong contractions to mix food and propel it into SI. |
|
|
Term
| explain how receptive relaxation works in the stomach |
|
Definition
o Distension of the lower esophagus by food relaxes the lower esophageal sphincter
o Detected by mechanoreceptors
o Vasovagal reflex: afferent and efferent limbs on vagus nerve via VIP
o Reduces pressure and increases volume of orad of stomach |
|
|
Term
| vagotomy: purpose, procedure, results |
|
Definition
eliminates receptive relaxation
cutting of the vagus nerve
reduces stomach acid secretion |
|
|
Term
| how does mixing and digestion occur in stomach, in what direction |
|
Definition
o Waves of contraction begin at mid body and move distally along caudad increasing in strength and veolcity to pylorus
o Mix food and propel into duodenum |
|
|
Term
|
Definition
| Wave of contraction closes pylorus so much chyme is propelled back into the stomach for more mixing than into duodenum |
|
|
Term
| where do slow waves occur in stomach, how often |
|
Definition
| In caudad region at 3-5 per minute |
|
|
Term
| what does parasympathetic innervation do to stomach slow waves, what transmitters |
|
Definition
| • gastrin and motilin increase frequency of AP and force of wave / contraction |
|
|
Term
| what does sympathetic do to stomach slow waves, what transmitters |
|
Definition
| • GIP and secretin decrease frequency of AP and force of contraction |
|
|
Term
| migrating myoelectric complex: 2 functions, locations, regulators, definition, stimulated by, when it happens |
|
Definition
• Moltin causes contractions to occur in 90 minute intervals in fasting
• Regular cycle of waves every 5-10 min initiated by vagal stimulation
• Regulated by VIP, motilin, enkaphalin
• in small intestine and stomach
Functions
o Clear stomach and colon of residue and un-digestible things
o Inhibit colonization of bacteria in the small intestines |
|
|
Term
| gastric emptying: length, what empties faster, requirements for particles, stimulation to end |
|
Definition
o Takes approx. 3 hours
o Liquids and isotonic contents empty faster
o Particles must be 1mm3 or less, retropulsion continues until this is reached |
|
|
Term
| what regulates gastric emptying |
|
Definition
Fat in duodenum stimulates CCK which slows emptying so fat can digest
H+ stimulates mucosa of duodenum and enteric nervous system sends info to the stomach via myenteric plexus to slow emptying so there is more time for H+ to be neutralized by pancreas enzymes |
|
|
Term
| what isthe frequency of slow waves in the small intestine parts |
|
Definition
| 12 in duodenum, 8-9 in ileum |
|
|
Term
| what does parasympathetic and sympathet innervation do to the slow waves of the small intestines. what neurotransmitters |
|
Definition
| parasympathetic: increases contraction. cholinergic and some peptidergic fibers (VIP, encephalin, motilin) |
|
|
Term
| explain segmentation in the small intestines, what controls this movement, what is the function |
|
Definition
enteric NS
• mix cyme and expose it to pancreatic enymes
• bolus in intestinal lumen is split by contraction, the section relaxes and bolus comes back together
• produces no forward movement |
|
|
Term
| explain peristaltic contraction in the small intestines, what neurotransmitters are used |
|
Definition
• propel chyme toward large intestines
• contraction occurs behind bolus (orad) and a portion in front of bolus (caudad) relaxes
• neurotransmitters for contraction are Ach, substance P
• neurotransmitters for relaxation are VIP, NO |
|
|
Term
| what is the afferent portion of the vomitting reflex |
|
Definition
| back of throat and GI tract chemoreceptors carry information on vestibular system triggering zone in 4th ventricle (vomiting center in medulla) |
|
|
Term
| what is the efferent portion of the vomitting reflex |
|
Definition
Reverse peristalsis begins in small intestines
Stomach and pylorus relaxes
Forced inspiration to increase abdominal pressure
Relaxation of lower esophageal sphincter |
|
|
Term
| what movements produce reching |
|
Definition
vomitting reflex with...
Upper esophageal sphincter remains closed
Lower esophageal sphincter is opened and gastric contents return to stomach |
|
|
Term
| what are the contents of the large intestine called |
|
Definition
|
|
Term
| why is there less movement in the large intestines |
|
Definition
| • Less myenteric plexus development and vagus innervation t leads to slower movement |
|
|
Term
| what is the function of the bacteria in the large intestines |
|
Definition
| Bacteria: Make vitamin K and vitamin B complexes |
|
|
Term
| what is the function of mucous in the large intestines |
|
Definition
| • Mucous: holds feces together, alkinity prevents acid attacks to wall |
|
|
Term
| what prevents reflux into the ileum |
|
Definition
|
|
Term
| what types of movements occur in the large intestines |
|
Definition
| segmentation contection, mass movement |
|
|
Term
| where does most of the water absorption in the GI occur, what is the consequence of this |
|
Definition
| distal colon (can make contents difficult to move) |
|
|
Term
| where does large intestine segmentation occur, how |
|
Definition
o Occur in cecum and proximal colon
o Mix contents in haustra (segments) |
|
|
Term
| how often to mass movements occur, why is this diffiuclt, how does it work |
|
Definition
o Occur in colon 1-3 times per day
o Move contents to rectum where it is stored until defecation
o Water absorption occurs (makes contents more difficult to move)
o Longitudinal muscle layer is teniae coli which contract hastura |
|
|
Term
| what reflex controls defecation, what controls it, how does it work |
|
Definition
Rectum filles with feces and smooth muscle of rectum contracts, internal anal sphincter relaxes
External anal sphincter is voluntarily relaxed and smooth muscle of rectum contracts to make pressure (innervated by the pudendal nerve) |
|
|
Term
| what is valsalva, what is the function |
|
Definition
Expiring against closed glottis
Can increase intra-abdominal pressure for additional pressure |
|
|
Term
| what happens if there is an urge to defecate and it does not occur |
|
Definition
Rectum contracts and forces feces back into colon
Urge to defecate can be over ridden by contraction of the external anal sphinctor |
|
|
Term
| explain the ileocecal reflex |
|
Definition
| Distension of ileum causes ileocecal sphincter to relax. Distension of the colon causes ileocecal sphincter to contract |
|
|
Term
| explain the gastroileal reflex |
|
Definition
| produces mass movement shortly after a meal due to action of gastrin and extrinsic autonomic nerves |
|
|
Term
| hirschsprung disease: AKA, cause, effect |
|
Definition
o Chronically constricted colon blocks feces which accumulate and distend colon
o Loss of ganglion cells and low VIP
o bad neural crest migration to make auerbach's plexus in part of colon
o most of the time near the anus |
|
|
Term
|
Definition
o Alternating diarrhea and constipation
o Pain and discomfort with unknown etiology (diffuse or localized to the left iliac fossa)
o relieved by defication
o frequent small stools but patient feels emptying is incomplete
o abdomen distended
o painful spasms, constipation, dirrhea, mucous
o related to stress, sedentary
o relieved by exercise |
|
|
Term
| what are the functions of saliva (13) |
|
Definition
o Initial digestion of starch and lipid
o Dilution and buffering of ingested foods
o Lubrication with mucus to aid in movement
o Hydrating, cleansing, maintenance of mucus
o Antifungal, antibacterial
o Immunity mediator
o Enable swallowing, tasting, and speech articulation |
|
|
Term
| how much saliva is secreted per day |
|
Definition
|
|
Term
| where are glands with serous cells located, what do they secrete |
|
Definition
In Parotid and lingual gland
secrete water, ions and enzymes |
|
|
Term
| where are glands with mucous cells located, what do they secrete |
|
Definition
Secrete Glycoproteins, palatine
In pos-lingual and labial buccal gland |
|
|
Term
| where are glands with serous and mucous cells (mixed) located? which type of cells do these glands have more of? what is the mixed secretion called |
|
Definition
Submaxillary (more mucous) and submandibular glands (more serous)
secrete aqueous fluid and mucus (glycoproteins) |
|
|
Term
| list the branches of the gland in order begining with the most inner part. what cells are in each part |
|
Definition
acinus: acinar cells and myoepithelial cells
intercalated duct: myoepithelial cells
striated duct: ductal cells |
|
|
Term
| what do acinar cells do, what stimulates them |
|
Definition
• make initial saliva
• Innervation is parasympathetic (dominant) and sympathetic both stimulate secretion |
|
|
Term
| what do myoepithelial cells do what stimulates them |
|
Definition
| eject saliva via neural input |
|
|
Term
| what do ductal cells do, what stimulates them |
|
Definition
• modify initial saliva into final saliva by altering enzymes and electrolytes
• Innervation is sympathetic and parasympathetic (dominant) both stimulate secretion |
|
|
Term
| what substances does saliva have in it, what is the tonicity, what are the relative ion concentrations |
|
Definition
Water, lingual lipase, kallikerin, mucus, a-amalyase
Hypotonic to plasma
More K and bicarbonate, low Na and Cl |
|
|
Term
| what is in initial saliva, give a brief function of each |
|
Definition
o water, ions, enzymes, mucus
o a-amalyase: begins digestion of carbs
o lingual lipase: begins digestion of lipids
o mucin glycoproteins: lubricant
o IgA
o Kallikerin: cleaves kininogen to bradykinin which is a vasodilator helping the high salivary blood flow |
|
|
Term
| what anatomical feature allows for an increase in saliva production |
|
Definition
|
|
Term
| what pumps and channels do ductal cells use to modify saliva. what is the overall movement |
|
Definition
• Luminal side: Na/H exchanger, Cl/bicarb exchanger, H/K exchanger
• Blood side: Na/K ATPase pump, Cl channel into blood
• Overall secretion of K and bicarbonate and absorption of Na and Cl
• Net is absorption |
|
|
Term
| how do the ductal cells make saliva hypotonic to plasma |
|
Definition
| they are not permeable to water so pumps are able to create this |
|
|
Term
| where is the highest and lowest flow rate of saliva, what is the rate, what conditions are needed to make these rates |
|
Definition
o Highest rate: 4 mL/min. Final saliva closely resembles plasma, there was less time to modify saliva
o Lowest rate: < 1mL/min. Final saliva is not like plasma, it has lower NaCl and higher K |
|
|
Term
| what is the main determinant of salivary flow rate |
|
Definition
| changes in ionic composition |
|
|
Term
| explain the changes of the flow rate of bicarbonate in saliva, what makes it change |
|
Definition
| o Bicarbonate is lowest at high flow rates and highest at high because it is selectively secreted when saliva production is stimulated by the autonomic nervous system |
|
|
Term
| how does the parasmpathetic nervous system control the secretion of saliva: CN, neurotransmitter, where are receptors, what mechanism causes increased secretion |
|
Definition
| CN VII and IX release ACh which acts on muscarinic receptors of acinar and ductal cells to produce IP3 which increases Ca and causes saliva secretion |
|
|
Term
| how does the sympathetic nervous system regulate secretion of saliva: neurotransmitters, receptors, on what cells, what mechanism |
|
Definition
T1-T3 preganglionics synapse at the superior cervical ganglion
Postganglionics release norepinephrine which acts on B-adrenergic receptors on acinar and ductal cells signaling adenylyl cyclase and cAMP to increase IP3 and Ca |
|
|
Term
| what are the components of gastric juice |
|
Definition
HCl and pepsinogen: initiate protein digestion
Intrinsic factor: a mucoprotein required to absorption of B12 in ileum (only essential component)
Mucus: prevents mucosa from being corroded by HCl and lubricates |
|
|
Term
| what are the types of glands in the body of the stomach, what types of cells are they in, anatomically where are these glands in the mucosa |
|
Definition
oxyntic glands in cheif and parietal cells
secrete contents into openings, or pits, lined with epithelial cells then mucous neck cells, parietial (oxyntic cells), and chief (peptic) cells on the bottom |
|
|
Term
| what do chief cells secrete, what are they controlled by, what is the fate of the secretion |
|
Definition
• Secreted pepsinogen which is converted to pepsin via HCl secreted by parietal cells
• Pepsin breaks down proteins
• Controlled by vagal stimulation so it only releases pepsinogen when pH is low enough to convert it to pepsin |
|
|
Term
| what are parietal cells stimulated by, what precursor or pre-step do they need to function |
|
Definition
• Stimulated by vagus and secrete ACh
o CO2 from aerobic respiration and H2O join via carbonic anhydrase to make H2CO3 which breaks into H+ and HCO3- |
|
|
Term
| what transporters and channels are in a parietal cell |
|
Definition
• Luminal side
o H+/K+ ATPase: secreted H into the lumen
o Cl channel allows Cl into lumen
• Blood side
o Na/K ATPase reabsorbs Na into blood
o HCO3- /K exchanger reabsorbs HCO3- into blood |
|
|
Term
|
Definition
| inhibits H/K ATPase in luminal side of parietal cells to treat ulcers by reducing H |
|
|
Term
|
Definition
| high pH in gastric venous blood after a meal caused by bicarbonate via bicarbonate/K exchanger that reabsorbs bicarbonate into the blood on the blood side of parietal cells |
|
|
Term
| what secretes intrinsic factor, what does a decrease in this cause |
|
Definition
| parietal cells secrete, decrease causes pernnicious anemia |
|
|
Term
| how does ACh regulate gastric secretion: receptor, mechanism in cell |
|
Definition
Released via vagus to M3 receptors in parietal cells
Secondary messenger activating phospholipase C liberating DAG and IP3/Ca, Ca and DAG activate protein kinase, Cells secrete H |
|
|
Term
|
Definition
| block M3 receptors in parietal cells from ACh stimulation |
|
|
Term
| how does histamine regulate gastric secretion: where is it released from, what repceptors, what mechanism in the cell |
|
Definition
Released from enterochromaggin like cells (ECL) via paracrine to parietal cells
H2 receptors stimulate cAMP, adenylyl cyclase, PKA
Secretion of H by parietal cell |
|
|
Term
|
Definition
| blocks H2 receptors stopping histamine stimulation of gastric secretion |
|
|
Term
| how is the rate of gastric secretion regulated |
|
Definition
| Regulated by ACh, histamine, and gastrin independent and together (potentiation: combined response greater) |
|
|
Term
| what is potentiation, what challenges does this create, give an example |
|
Definition
potentiation: combined response greater)
Potentiation makes it difficult for drugs to control H secretion
• Example: Cimetidine blocks histamine and histamine potentiated effects of ACh and gastrin causing greater effect |
|
|
Term
| what glands are in the antrum of the stomach, in what cells, what do they secrete |
|
Definition
Pyloric glands:
: Smaller than oxyntic but with deeper pits
G cells: secrete gastrin into circulation
Mucous cells: secrete bicarb, mucous, and pepsinogen |
|
|
Term
| what are the stages of secretion in stomach |
|
Definition
| cephalic, gastric, intestinal, inhibition |
|
|
Term
| what occurs in the cephalic phase of stomach secretion |
|
Definition
Smell, tasting, chewing, swallowing, and conditioned reflexes in anticipation stimulate
30% of HCl secretion in response to a meal |
|
|
Term
| how is the cephalic stage of secretion initiated / stimulated |
|
Definition
Direct stimulation of parietal cell by vagus nerve which releases ACh
Indirect stimulation of parietal cell by gastrin via GRP released by vagus nerve onto G cells
Local reflexes and vagal stimulation stimulate for chielf cells to secrete pepsinogen |
|
|
Term
| gastric stage of stomach secretion: what is secreted, what stimulates it |
|
Definition
60% of HCl secretion in response to a meal
Distension of the stomach causes vagus to stimulate directly and indirectly
Distension of the stomach antrum initiates local reflexes to stimulate gastrin release
AA and peptides act on G cells to cause gastrin release |
|
|
Term
| what is secreted in the intestinal stage of gastric secretion, what is it mediated by |
|
Definition
10% of HCl secretion
Mediated by protein products of digestion |
|
|
Term
| how is secretion in the stomach inhibited |
|
Definition
HCl is no longer needed to activate pepsinogen so decreased pH stimulates. Food was buffering H but not its done and it becomes acidic
Somatostatin: Direct pathway: binds to parietal cells via G protein stopping adenylyl cyclase antagonizing histamine. Indirect pathway: inhibit histamine and gastrin release
Prostaglandins: Antagonize histamine actions on parietal cells |
|
|
Term
| describe the location of the pancreas |
|
Definition
| LUQ, retroperitoneal, tail touches spleen, sits in curve of duodenum |
|
|
Term
| what are the endocrine cells of the pancreas, also tell each type and what they secrete |
|
Definition
Islets of langerhan cells:
Beta cells: secrete insulin to decrease blood sugar
Alpha cells: secrete glucagon to increase blood sugar
Delta cells: secrete somatostatin
F/PP cells: secrete polypeptides |
|
|
Term
| how much fluid does the axocrine part of the pancreas secrete, what are the two components and their general functions |
|
Definition
o Secrete 1 L / day into the duodenum
o Aqueous component: Bicarbonate neutralizes H from stomach
o Enzymatic component digests carbs, proteins, lipids |
|
|
Term
| what cells does the acinus of the pancreas have, what do they secrete |
|
Definition
| acinar cells, secrete digestive enzymes stored in zymogen granules |
|
|
Term
| what cells are in the ducts of the pancreas, what do they do |
|
Definition
Ductal cells: extend into centroacinar cells into acinus. modify secretions of aqueous component
Centroacinar cells: Secrete bicarbonate, extend into the central acinar portion of the duct |
|
|
Term
| explain the parasympathetic and sympathetic innervation of the pancreas |
|
Definition
o Sympathetic: Postganglionic cells come from superior mesenteric and celiac plexuses. Inhibits secretion
o Parasympathetic: Synapse in enteric nervous system. Stimulates secretion |
|
|
Term
| enzymes of the pancreas: which ones are secreted active, what ones are secreted inactibe, where are they made |
|
Definition
Pancreatic amalyase and lipases are secreted as active enzymes
Pancreatic proteases are secreted as inactive. Pancreas also secretes trypsinogen which turns into trypsin to activate
Made in RER of acinar cells, golgi put them into vacuoles, concentrated into zymogen granules, stored until stimulated |
|
|
Term
| what are the contents of pancreatic juice |
|
Definition
• Isotonic, Na, K, Cl, bicarb
• Cl and bicarbonate concentrations vary with pancreatic flow |
|
|
Term
| how is pancreatic juice formed in general |
|
Definition
Centroacinar and ductal cells make isotonic secretion
Ductal cells modify aqueous component |
|
|
Term
| how do pancreatic ductal cells modify pancreatic juice: transporters on each side, net change |
|
Definition
• Apical side: Cl/bicarbonate exchanger puts Cl into cell
• Basal side: Na/H exchanger puts H into blood, Na/K ATPase puts Na into blood
• CO2 + H2O H2CO3H+ + HCO3-
o overall: Secretion of bicarbonate into pancreatic duct and absorption of H acidifying pancreatic blood |
|
|
Term
| how is the rate of pancreatic secretions regulated: when is it the highest, lowest, what is affected by the change in rate |
|
Definition
o Change in rate only affects Cl/bicarbonate
o High rate: Bicarbonate is high in pancreatic juice. Cl is low
o Low rate: Bicarbonate is low in pancreatic juice |
|
|
Term
| what are the phases of secretion in the pancreas |
|
Definition
| cephalic, gastric, intestinal |
|
|
Term
| cephalic phase of secretion in the pancreas: initiated by, nerves, secreted |
|
Definition
Initiated by smell, taste, and conditioning
Mediated by vagus nerve
Produces mostly enzymes |
|
|
Term
| gastric phase of secretion in the pancreas: initiated by, nerve, produces |
|
Definition
Initiated by smell, taste, and conditioning
Mediated by vagus nerve
Produces mostly enzymes |
|
|
Term
| intestinal phase of secretion in pancreas: stimulation, what cels stimulated |
|
Definition
| enzymes and pancreatic secretion stimulate acinar cells and ductal cells |
|
|
Term
| what do acinar cells do when stimulated in pancreatic secretion: what stimulates them, nerves, secretions |
|
Definition
• I cells stimulated by AA, peptides, and FA release of CCK, phenylalanine, methionine, and tryptophan. CCK stimulates CCKA receptors
• ACh stimulates muscarinic receptors and stimulates CCK via vasovagal reflexes |
|
|
Term
| ductal cells in pancreatic secretion: what stimulats them, what do they release |
|
Definition
o Release by S cells in duodenum in response to H in lumen
o Stimulates bicarbonate secretion to neutralize to pancreatic lipases can work
o Potentiated by CCK and ACh |
|
|
Term
| what are the parts of bile and general function |
|
Definition
o Emulsify lipids and put into a micelle
o Bile salts, bile pigments, lipids, ions, water |
|
|
Term
| what is the anatomical transition from the foregut to the midgut, where is it located |
|
Definition
| o Amoulla of vatar (hepatopancreatic ampulla) at pancreatic and common bile duct junction |
|
|
Term
| what are bile salts made of |
|
Definition
| bile acids, glycine, taurine, cholesterol, phospholipids, bile pigments, electrolytes, water |
|
|
Term
| what are bile acids made of, how is it made |
|
Definition
• Primary bile acids (cholic and cheodeoxycholic acid) are dehydroxylated by intestinal bacteria in intestine to make secondary bile acids (deoxycholic and lighocholic acid)
• Cholic > chenodeoxycholic > deoxycholic > lithocolic |
|
|
Term
| what is conjugation, where does it occur, what is the function |
|
Definition
• Occurs in the liver
• Different acid and glycine or taurine combination allows for 3 different bile salts (glycoholic or taurocholic acid)
o function: To more bile acids more water soluble. pK of 1-4 so they deionize and are soluble |
|
|
Term
| bile salts are conjugated to be amphipathic, what does this allow them do to, how does this contribute to the functions of the GI tract |
|
Definition
o at oil-water interface hydrophilic part dissolves in aqueous phase and hydrophobic part dissolves in oil phase
o allows lipids to be soluble (emulsify) because negative charges surround lipid increasing SA for digestion
o forms micelles around product of lipid digestion |
|
|
Term
| bile pigments / bilirubin: how does this contribute to colors of thigns in the GI system, what is the process of coversion of molecules to create these colors |
|
Definition
yellow color pigment of Hb degradation by reticuloendothelial system
carried in blood on albumin
conjugates with glucronic acid in liver making bilirubin glucuronide
converted to bilirubin and to urobilinogen by intestinal bacteria
some is circulated back into liver, some is oxidized to urobilin and stercobilin (makes poo dark) |
|
|
Term
| how does cholesterol and phospholipids get into bile, what happens to it once secreted |
|
Definition
secreted into bile by hepatocytes
inside micelles with products of lipid digestion
phospholipids are amphipathic aiding in micelle formation |
|
|
Term
| what happens to the electrohytes and water in the bile ducts |
|
Definition
| secretin stimulates ion and water secretion in bile ducts |
|
|
Term
| what do hepatocytes secrete |
|
Definition
| bile salts, cholesterol, phospholipids, bile pigments, ions, and water |
|
|
Term
| what are the functions of the gallbladder |
|
Definition
• Stores bile
• concentrates bile salts: absorbing water and ions by epithelial cells in isosmotic fashion. organic components become concentrated
• ejects bile into duodenum: within 30 min of meal. I cell sense Fa, AA, and peptides and release CCK. CCK contracts gallbladder and relaxes sphincter of Oddi. Bile is ejected in spurts |
|
|
Term
|
Definition
| o Enterohepatic circulation: In terminal part of ileum bile (max digestion) salts are transported to portal blood via Na/bile co-transporter. Portal blood carries bile back to liver. Liver extracts bile salts and adds them to hepatic bile pool |
|
|
Term
| how much bile is lost, where |
|
Definition
| In feces about 600 mg/day |
|
|
Term
| how is bile secretion regulated |
|
Definition
o Bile salts recirculating to the liver stop the rate limiting step in their production, cholesterol 7a-hydroxylase via negative feedback
o When less is recirculated, more bile salts are made
o Choleretic effect: recirculation of bile salts stimulates biliary secretion |
|
|
Term
|
Definition
| fungal infection in the mouth |
|
|
Term
| what is orallichen planus |
|
Definition
|
|
Term
| what is burning mouth syndrome |
|
Definition
| glossodyna: normal appearing mucosa with burning sensation |
|
|
Term
| what is an aphthous ulcer |
|
Definition
|
|
Term
|
Definition
| tooth decay due to bacterial infection |
|
|
Term
| what normally protects the lumen of the stomach |
|
Definition
Mucous neck glands secrete mucous
Gastric epithelial cells secrete bicarbonate which traps in mucous and neutralizes
Prostaglandins, mucosal blood flow, growth factors |
|
|
Term
| what are the causes of peptic ulcer disease |
|
Definition
Lesion of gastric or duodenal mucosa cause by erosion via H and pepsin or H. pylori, NSAIDS, stress, smoking, and alcohol, hyperthyroidism (high Ca stimulates secretion), sollinger ellisons syndrome, ASA, caffiene stimulates gastric acid secretion
Loss of mucous , excessive H or pepsin secretion, or both |
|
|
Term
|
Definition
Usually due to mucous barrier issue
Major cause is H. plyori often in antrum releasing cytotoxins (cagA toxin) breaking down barrier and colonizing with the urease (converts urea to NH3 making it alkaline) |
|
|
Term
| gastric ulcer disease, how do diagnose |
|
Definition
| Diagnosis: drink 13C-urea which is converted to 13CO2 and NH3 in stomach. 13CO2 is absorbed into blood, expired by lungs, and measured in breath test. Secretion of H+ is low because some is secreting into mucosa |
|
|
Term
|
Definition
More common because H+ secretion is higher and can overwhelm bicarbonate
Can also be caused by H.pylori indirectly because. they inhibit somatostatin secretion from D cells in antrum increasing gastrin secretion and H+. they infect duodenum and inhibit bicarbonate secretion
gastrin levels may be normal but release in response to a meal is increased
genetic: no secretion of O blood group antigens into saliva and gastric juice have increased risk |
|
|
Term
| zollinger ellison syndrome (gastrinoma): causes, effect, symptoms, treatment |
|
Definition
highest H+ levels
tumor, usually in pancreas, secretes lots of gastrin
increased H+ secretion in parietal cells and increased parietal cell mass
overpowers bicarbonate and erodes
steatirrhea because pH deactivates pancreatic lipases
not feedback inhibited by H+
treatment: inhibit H+ secretion (cimetidine, omeptrazole), surgical tumor removal |
|
|
Term
| how can you diagnose a peptic ulcer |
|
Definition
urease breath test: drink 13C urea. converted to 13CO2 and NH3 in stomach. 13CO2 is absorbed into the blood and expired into the lungs and measured. Gastric ulcers give lower H than normal because H secreted leaks into damaged mucosa
Endoscopy: Barium meal with contrast x-ray biopsy to show bacterial or malignancy |
|
|
Term
| what medications are used for peptic ulcers |
|
Definition
H. pylori cause: proton pump inhibitor like omeprazole (Prilosec)
Non H. pylori cause: proton pump inhibitors
Cimetidine (tagmet), famotidine (Pepcid), ranitidine(zantac), antacid
histamine H2 antagonist like cimetidien, ranitidine, famotidine, nizatitine inhibit parietal cells
prostaglandin E analouge (misprostol) inhibits gastric acid secretion by inhibiting cAMP in parietal cells
surgery if there are lots of complications |
|
|
Term
| decreased intrinsic factor: cause, why its bad |
|
Definition
o Caused by decreased RBC, removal of stomach
o The only essential secretion |
|
|
Term
| ileal resection: cause, symptoms |
|
Definition
o Removal of ileum
o Recirculation of bile salt is interrupted and much is excreted
o Synthesis of new bile salts is very stimulated but cannot keep up
o Impaired lipid absorption
o Steatorrhea: increased fat in stool |
|
|
Term
| what is bile acid diarrhea, what treats it |
|
Definition
o High bile acids in the intestinal lumen stimulates cAMP dependent Cl secretion in colon epithelial cells. Na and water follow Cl into lumen causing secretory diarrhea
o Cholestyramine treats |
|
|
Term
| how does cholestyramine work |
|
Definition
Treatment bunds bile acids in the colon so they do not stimulate Cl secretion
Does not prevent steatorrhea
Plasma cholesterol is converted to bile acids lowering plasma cholesterol
• Also used for hypercholesterolemia |
|
|
Term
| what are the diseases of the exocrine pancreas |
|
Definition
| cystic fibrosis, acute pancreatitis, chronic pancreatitis, carcinoma of the pancreas |
|
|
Term
| cystic fibrosis: cause, effect, symptoms |
|
Definition
Most common lethal genetic disease
Mucosa secretions are thick and block airway and pancreatic duct
Recurrent pulmonary infection, pancreatic insufficiency, high NaCl in sweat, transmembrane regulator (CFTR) defective, pancreatic duct may have cyst, malabsorption, duct dilation
CF gene on chromome 7 mutated |
|
|
Term
| acute pancreatitis causes |
|
Definition
Inflammation of the pancreas, almost always associated with acinar cell injury
• Metabolic: alcohol, hyperlipoproteinemia, hyperclacemia, drugs
• Mechanical: gall stones, traumatic periperative injury
• Vascular: shock, atherombolism |
|
|
Term
| acute pancreatitis pathology / issues associated |
|
Definition
• Protrolytic destruction of pancreatic substance
• Necrosis of vessels and interstitial hemorrhage
• Fat necrosis by lipolytic enzymes
• Associated acute inflammatory reaction |
|
|
Term
| chronic pancreattis: cause, effects |
|
Definition
Protein hyper secretion (acinar cells)
Protein precipitation forming ductal plugs enlarge to form aggregates |
|
|
Term
| carcinoma of the pancreas: cause, definition, diagnosis, prognosis |
|
Definition
Malignant epithelial neoplasm of exocrine pancreas
Causes: unknown, frequent in smokers
Usually silent until first symptom, obstructive jaundice
1 year survival |
|
|
Term
|
Definition
| a fodm of hirschspring disease that affects people with parkinsonism diabetic neuropathy |
|
|
Term
| constipation: causes, symptoms, treatment |
|
Definition
low fiber in sedentary persons
irregulat defecation
irrational use of laxatives supressing natural reflexes
treatment: increase fiber, walking, suppositories |
|
|
Term
| chagas: how is it aquired |
|
Definition
cause vby trypanosome cruzi a parasite that causes african sleeping sickness
spread by bite from reduvid bugs |
|
|
Term
| how is the lumen protected |
|
Definition
mucous neck glands
gastric epithelial cells secrete bicarbonate trapped in mucous
prostaglandins, mucosal blood flow, growth factors |
|
|
Term
|
Definition
| pain after a meal, worken up with epigastric pain, bleeding from ulcers, uper GI bleeding, hematemesis (vomitting blood or clots), melena (dark, tarry stool, shiny, sticky, foul smelling) |
|
|
Term
| gastritis: definition, classifications, symptoms |
|
Definition
lining of stomach becomes inflammed or swollen
acute, erosive, chronic, non-erosive
symptoms: loss of appetite, nausea, vomiting, pain in upper abdomen, pernicioous anemia |
|
|
Term
|
Definition
alcohol, drugs, (corticosteroids, NSAIDS, ASA)
main cause in antrum: H. pylori leading to loss of parietal cells (achlorhydria), decreased HCl and intrinsic factor |
|
|
Term
| autoimmine / pan gastritis: cause, risks |
|
Definition
autoantibodies to parietal cells
vitamin b12 not absorbed in ileum due to lack of intrinsic factor, pernicious anemia |
|
|
Term
| what is a risk of long term treatment with acid supression drugs |
|
Definition
| mucosal hypertrophy and further rise in acid production with a higher ulcer recurrance rate |
|
|
Term
| what protects the esophagus from the GI mucosa |
|
Definition
clearance mechanisms (UES, LES)
mucosal integrity
LES compliance
gastric emptying |
|
|
Term
|
Definition
No VIP secretion for LES relaxation
Relaxation failure of the LES in response to swallowing due to vomiting and weight loss
No ganglion cells in the myenteric plexus of esophageal wall and LES |
|
|
Term
|
Definition
Food gets stuck because of lack of peristalsis, esophagus dilates, and patient regurgitates
Intermittint dysphagia during meals |
|
|
Term
| achlasia diagnosis methods |
|
Definition
Chest X-ray following barium swallow
Esophagoscopy to exclude milgnancy
Pneumatic bag is placed in LES opening to dilate it
Surgical division of LES in laproscopy
Manometry: evaluation of pressure |
|
|
Term
|
Definition
o LES pressure is often low
o Gastric pouch intra thoracic reservoir
o Diaphragm: no esophageal pinch |
|
|
Term
| leiomyoma: causes symptoms |
|
Definition
Most frequent benign tumor
Tumor of smooth muscle cells
No symptoms unless it ulcerates and bleeds |
|
|
Term
| carcinoma of the stomach: location, classification, risk factors |
|
Definition
Frequently in antrum
Almost always adenocarcinoma
Risk factors: H. pylori, chronic gastritis, atrophia, metaplasia, spicy, salted, smoked food with benzpyren, mitrosamines, blood group A |
|
|
Term
| enterchromaffin cells of the intestine wall carcnoid tumors: secrete, treatment, signs |
|
Definition
Carcnoid tumors that secrete serotonin, bradykinin, histamine, trachykinins, prostaglandins
Octerotide: somatostatin analogue that inhibits excess secretion
Signs: facial flushing, diarrhea |
|
|
Term
| acute GI bleeding: causes, dangers, how to diagnose, signs |
|
Definition
o Occurs in form of hematemesis (vomiting of blood)
o Causes: Peptic ulcer, esophageal varicose veins, gastric carcinoma, infection, polyp
o Dangers: Shock, tachycardia, decreased BP, pallor, Fe deficient anemia
o Examination: Gastroscopy, colonoscopy, enteroscopy |
|
|
Term
| coeliac disease: cause, location |
|
Definition
o Gluten sensitive enteropathy disease
o Duodenal and jejunal mucosa is destroyed via hypersensitivity to gluten |
|
|
Term
| appendicitis: cause, symptoms, treatment |
|
Definition
o Mechanical obstruction dilate until mucosa ulcerates and wall is invaded by bacteria
o Symptoms: Periumbilical or diffuse pain, Sub-febrile, Nausea, vomiting
o Appendectomy: Performed ASAP. Treated with antibiotics first so bacterial spread isn’t helped by surgery |
|
|
Term
| acute peritonitis: cause, symptoms |
|
Definition
o Cause: Perforation. Bacterial infection spreads. Hepatic, alcoholic cirrhosis with portal hypertension
o Symptoms: Sudden, severe pain, high fever, nausea, vomiting, paralytic ileus. Later: septic shock |
|
|
Term
| diverticulosis: defnition, cause, how to diagnose, symptoms, treatment |
|
Definition
o Herniation of mucosa through muscle layers of the colon usually in weak place in gut wall
o Cause: Increased intraluminal pressure. High incidence in inactive persons. Low incidence in vegetarians due to high fiber diet
o Diagnosis via Barium enema
o Symptoms: Disturbed stool habits
o Treatment: mild exercise |
|
|
Term
| colon cancer: cause, risk factors, prevention |
|
Definition
o Related to slow passage of feces with carcinogens that bind to DNA in it
o More frequent in sedentary persons with frequency of constipation
o Prevention: high fiber diet, daily walking |
|
|
Term
| dry mouth / eerostomia: causes |
|
Definition
• Lack functional salivary glands
• Infection of buccal mucosa
• Dental caries
• Dehydration
• antidepressants
• sjogern syndrome |
|
|
Term
| sjogern syndrome: cause, symptoms |
|
Definition
o Autoimmune disorder destroying exocrine glands
o Have dry mouth and dry eyes (xerophtalmia) and RA |
|
|
Term
| define digestion, what does it |
|
Definition
• Chemical breakdown of ingested food so it is absorbable
• Enzymes are secreted in salivary, gastric, and pancreatic juices |
|
|
Term
| define absorption: what are th two tyoes, explain them |
|
Definition
• Movement of nutrients, water, and electrolytes from lumen of intestine to blood
• Cellular: Substance crosses apical (luminal) membrane and is exits on basal into blood via transporters
• Paracellular: Substances move across tight junctions in intestinal epithelial cells and lateral intracellular spaces into blood |
|
|
Term
| what features of the mucosa allow for increased absorption |
|
Definition
o Longitudinal folds have villi for lots of absorption SA
o Villi are covered in epithelial cells (enterocytes) and mucous secreting cells (goblet cells) with microvilli on the surface (brush border)
o Villi are longest in duodenum
o Cells have high turnover rate. Very susceptible to irradiation and chemotherapy
o Plica circularis of kerckring: longitudinal folds in small intestines with villi (short in ileum) |
|
|
Term
where are most of the peyers patches at
where are brunner's glands at |
|
Definition
|
|
Term
| what modifies mucosal epithelium turn over, how does it turn over |
|
Definition
o has rapid turnover via apoptosis but it is modified by nutrients, especially fat
o come from stem cells at the case of crypt and migrate along crypt villus axis to intestinal lumen |
|
|
Term
| how are monosaccharudes digested, what are they |
|
Definition
Absorbed by intestinal epithelial cells
All ingested carbs must be turned into monosaccharides
Glucose, galactose, fructose |
|
|
Term
| what begins starch digestion, explain where this happens |
|
Definition
Salivary amalyase (a-amalyase)
• Begins digestion in mouth
• Inactivated by low pH of gastric contents |
|
|
Term
| how does the stomach contribute to carb digestion |
|
Definition
| pancreatic amalyase digests 1,4-glycocidic bonds making disaccharides (a-dextrinase, maltase, sucrose) |
|
|
Term
| some food is digested as a disaccharide and skips the steps in the stomach and mouth. what are these disaccharides, when and how are they broken down |
|
Definition
trehalase, lactase, and surcarse digest trehalose into 2 glucose, lactose into glucose and galactose, and surose into glucose and fructose.
the enzymes are brush border enzymes of the small intestines |
|
|
Term
| explain the absorption in the small intestines |
|
Definition
luminal side
• glucose and galactose. Na dependent co-transport (SLGT1) into cell against gradient. Energy comes from Na/K pump on apical side
•Fructose: Facilitated diffusion via GLUT5 transporter into cell. Cannot be absorbed against a gradient
Blood side
• Na/K ATPase: putting Na into blood
• Glucose, galactose, fructose: GLUT 2 transporters secondary active transport |
|
|
Term
| what is the main cause of disorders with carb absorption, what is a common example and its treatment |
|
Definition
o Mostly because carb was not broken down
o Large carbs in lumen hold in water causing diarrhea
o Lactose intolerance / hypolactasia: Lactase deficiency on brush border. Treatment: lactase supplement |
|
|
Term
| in what form do proteins need to be to be absorbed, what digests them in general |
|
Definition
AA, dipeptides, and tripeptides
proteases |
|
|
Term
| explain the cascade process of enzymes that digest proteins in the stomach and their conditions needed |
|
Definition
• pepsinogen is secreted by chief cells of stomach and activated to pepsin
• optimum pH 1-3, denatured at 5
• terminated in duodenum via bicarbonate
• not essential for protein digestion (pancreatic brush border enzymes can digest alone) |
|
|
Term
| explain the cascade of brush border endoepetidase enzymes that digest proteins in the small intestines |
|
Definition
trypsin:trypsinogen is turned into trypsin via enterokinase (a brush border enzyme). trypsin can activate more trypsinogen (autocatalyzation) or activate the other enzymes
chymotrypsin: trypsin turns chymptrypsinogen into chymotrypsin
elastase: trypsin turns proelastase into elastase |
|
|
Term
| explain the cascade of brush border enteropetidase enzymes that digest proteins in the small intestines |
|
Definition
Hydrolyze one AA at a time from C-terminal
carboxypeptidaseA: trypsin turns procarboxypeptidase A into carboxypeptidase
carboxypeptidase B: trypsin turns procarboxypeptidase B into carboxypeptidase |
|
|
Term
| why dont the enzymes of the brush border for proteins just keep digesting the body from the inside out |
|
Definition
| o after digesting proteins, the enzymes digest themselves and each other |
|
|
Term
| explain how L amino acids are absorbed |
|
Definition
Absorbed just like monosaccharides
Luminal side: 4 Na/AA co-transporters (neutral, acidic, basic, imino) on apical side energized by Na gradient via Na/K ATPase on basal side
Basal side: 4 transporters put them into blood via facilitated diffusion |
|
|
Term
| explain how tripeptides are absorbed |
|
Definition
Apical side: Separate H dependent co-transporters into IF. Gradient made by Na/H exchanger on apical side
Basal side: Most are hydrolyzed into AA by cytosolic peptidases and do facilitated diffusion to get out. The rest are absorbed unchanged |
|
|
Term
| what are some common protein digestion disorders. what are some common causes |
|
Definition
o Without gastric H+ secretion (no pepsin) protein digestion and absorption is normal showing pancreatic brush border enzymes can do it alone
o Deficiency of pancreatic enzymes or transporters
o Chronic pancreatitis and cystic fibrosis |
|
|
Term
| cystinuria: cause, effect |
|
Definition
Autosomal recessive
Transporter for dibasic AA cysteine, lysing, arginine, and ornithine missing in SI and kidney
Can’t absorb AA in intestines and excrete AA in urine
Makes stones in the kidney, ureters, and bladder |
|
|
Term
| what types of lipids are ingested, what are the differences in how they are absorbed |
|
Definition
• Triglycerides, cholesterol ester, phospholipids (all esterified)
• Monoclycerides, cholesterol, lysolecithin, and glycerol (water soluble) can be absorbed (de-esterified) |
|
|
Term
| how are lipids digested in the stomach, what hormones take part |
|
Definition
Churning: initiates breaking them into drops emulsifying, keep droplets apart
Lingual and gastric lipases: Hydrolyze 10% of TG to glycerol and FA
CCK: Slows gastric emptying so pancreatic enzymes have time to continue lipid digestion (more important) |
|
|
Term
| where is the area of most lipid digestion |
|
Definition
|
|
Term
| what is the function of bile salts, what other substance is usually with bile salts |
|
Definition
|
|
Term
| what are the pancreatic enzymes: are they active or inactive when secreted. what do they do |
|
Definition
• Pancreatic lipase: Secreted active. Hydrolyzes TG into monoglyceride and 2 FA. Inactivated by bile salts because they move enzyme from lipid-water interface, colipase solves this
• Cholesterol hydrolase: Secreted active. Hydrolyzes cholesterol ester to cholesterol and FA. Hydrolyzes ester linkages of TG making glycerol
• Phospholipase A2: Secreted as a proenzyme and activated by trypsin. Hydrolyzes phospholipids to lysolecithin and FA |
|
|
Term
| what are the pancreatic proteins: active or inactive when secreted, function |
|
Definition
| • Colipase: Secreted inactive as procolipase, activated by trypsin. Displaces bile salts from lipid-water interface. Binds to pancreatic lipase |
|
|
Term
| explaiin how lipids are absorbed |
|
Definition
o Lipids are solubized in micelles, except glycerol
o Micelles diffuse to brush border on intestinal epithelial cells (mostly mid jejunum) and release lipid
o Lipid moves down gradient
o Lipids are re-esterified inside cell SER
o Lipids are put in chylomicrons: TG and cholesterol in core. Phospholipid and apoproteins (made in epithelial cell) on outside. APO-B helps in re-absorption
o Golgi packages chylomicrons into secretory vesicles
o Exocytosis of vesicles to lacteals and to thoracic duct then blood |
|
|
Term
|
Definition
|
|
Term
| exocrine pancreas insufficiency: diseases, cause, effect |
|
Definition
Chronic pancreatitis, cystic fibrosis
Not enough pancreatic enzymes
Cannot absorb fat due to undigested TG |
|
|
Term
| duodenal acidity: issue, diseases |
|
Definition
Neutralizing doesn’t work
Pancreatic enzymes inactivated
Zollinger-Ellison syndrome
, pancreatitis |
|
|
Term
| zolliner ellison syndrome: cause, effect |
|
Definition
• Tumor causes lots of gastrin secretion
• Elevated H secretion by parietal cells |
|
|
Term
|
Definition
| • Impaired bicarbonate secretion |
|
|
Term
| deficiency of bile salts: cause, effect |
|
Definition
| ileal resection, cannot form micelles |
|
|
Term
| ileal resection: what is it, what does it break, how does this cause bad things |
|
Definition
• Removal of ileum
• Interrupts enterohepatic circulation of bile salts and they are excreted in feces
• New bile salts cannot keep up
• Bile acids are toxic to colonic mucosa and stimulate secretion of large volumes |
|
|
Term
| what does bacterial overbrowth do to lipid digestion |
|
Definition
Reduces effectiveness of bile salts by de-conjugating them (remove glycine and taurine converting them to bile acids)
Now lipid soluble they diffuse across epithelial cells before micelle formation and lipid absorption
Decreased pH deionizes too |
|
|
Term
| tropical spruse: what does it cause to happen |
|
Definition
| • Reduction in intestinal cells reduces SA allowing less lipid absorption |
|
|
Term
| abetalipoproteinemia: cause, effect |
|
Definition
• No APO B made
• Cannot absorb chylomicrons into lymph and thus lipids into the body |
|
|
Term
| what are the functions of vitamins in the body |
|
Definition
| • Co-enzymes or co-factors for metabolic reactions |
|
|
Term
| what are the fat soluble vitamins, how are they absorbed |
|
Definition
o ADEK
o Processed same as lipids |
|
|
Term
| what are the water soluble vitamins, how are they absorbed |
|
Definition
o B1, 2, 6, 12, C, biotin, folic acid, nicotinic acid, pantothenic acid
o Usually absorbed via Na dependent co-transporter in SI |
|
|
Term
| how is B12 released from food, how is it treanported |
|
Definition
B12 is released from food via pepsin . when free it binds to R proteins in salivary juices first
In duodenum proteases degrade R proteins and transfer B12 to intrinsic factor secreted by parietal cells
Intrinsic factor protects them from degradation |
|
|
Term
| gastrectomy: risks, treatment |
|
Definition
Loss of source of intrinsic factor
Cannot absorb B12
Pernicious anemia
Treatment: B12 supplement |
|
|
Term
| how is vitamin d activated |
|
Definition
• Activating vitamin D: Dietary vitamin D3 (cholecalciferol) > liver > 25-hydroxycholecalciferol > circulation PCT > 1,25-dihydroxycholecalciferol (via 1a-hydroxylase) (active form). Actions on intestine, kidney and bone.
• Calvindin D-28K: vitamin D-dependent Ca-binding protein . in intestinal epithelial cells |
|
|
Term
| what diseases are associated with vitamin D deficiency |
|
Definition
o decreased Ca
o rickets which can lead to osteomalacia |
|
|
Term
|
Definition
• absorbed on apical side as Fe or heme iron (Hb, myoglobin)
• heme iron is digested by lysosomal enzymes and released as Fe
• Fe binds to apoferritin and is transported to basolateral membrane
• Transferrin (B-globulin) binds Fe in blood and stores it in liver
• Transported to marrow for Hb synthesis |
|
|
Term
| hepcidin: where is it made, what does it do, what risks are associated with it |
|
Definition
o Fe homeostasis
o Peptide made in liver
o Regulate by inhibiting Fe transport across gut mucosa to prevent excess Fe absorption
o Inhibits transport of Fe out of macrophages where it is stored
o During inflammation it is too high and Fe can drop leading to anemia |
|
|
Term
| how much fluid is in the lumen, where did it come from |
|
Definition
• 9L of fluid in lumen
o 2L from diet
o 7L from secretions
o 100-200 mL not absorbed |
|
|
Term
| what type of fluid transport occurs in the small and large intestines, why is it different |
|
Definition
• Permeability of tight junctions determines fluid and electrolyte route (paracellular or cellular)
o Small intestine has leaky tight junctions
o Large intestines junctions are tight and don’t permit paracellular |
|
|
Term
what is the osmolality of intestinal fluid to plasma.
what is the fluid absorbed called |
|
Definition
|
|
Term
| jejunum: net absorption, luminal and blood pumps |
|
Definition
Net absorption NaHCO3
CO2 + H2O > H2CO3 > H+ + HCO3- via carbonic anhydrase
Luminal: Na / sugar or AA co transporter Na into cell. Na/H antiporter Na into cell
Blood: Na/K ATPase Na into blood. Monosaccharide or AA transporter into blood. Bicarbonate transporter into blood |
|
|
Term
| ileum: net absorption, luminal and blood pumps |
|
Definition
Net absorption NaCl
CO2 + H2O > H2CO3 > H+ + HCO3- via carbonic anhydrase
Luminal: Na / sugar or AA co-transporter into cell. Na/H antiporter Na into cell. Bicarbonate/Cl antiporter Cl into cell
Blood: Na/K ATPase Na into blood. Sugar or AA transporter into blood. Cl transporter into blood |
|
|
Term
| colon absorption pumps on lumen and blood side, how are they regulated |
|
Definition
Luminal
• Na channel into cell
o Increased synthesis via aldosterone
• K channel out of cell
o Aldosterone in effect increases K secretion
Blood
• Na/K ATPase Na into blood
• K channel into blood |
|
|
Term
| secretion in the colon occurs in what cells? what are their luminal and blood side channels and pumps |
|
Definition
Crypt cells
Luminal
• Cl channel into lumen
o Usually closed
o Opening: ACh, VIP
o Adenylyl cyclase > cAMP > opens Cl channel
Blood
• Na/K ATPase Na into blood
• Na/K/2Cl co-transporter into cell
• Water and Na go into lumen via junction
o Works more when Cl channel is open |
|
|
Term
| what are the risks of diarrhea, what processes occur, how does it affect the body |
|
Definition
High flow of intestinal fluid increases K secretion causes hypokalemia
Max loss is 9L of fluid a day
Decreased ECF, vascular volume, arterial pressure
Baroreceptors turn RAAS on but are futile
Loss of bicarbonate can cause hyperchloremic metabolic acidosis |
|
|
Term
|
Definition
• Decreased absorptive surface area, osmotic diarrhea, secretory diarrhea
• Cholera
• Ileal resection
• Zollinger Ellison syndrome |
|
|
Term
| what is the process of a cholea infection, explaiin how it leads to diarrhea |
|
Definition
1. Enters crypt cells
2. A subunit of toxin goes to basal membrane
3. Causes ADP ribosylation of a subunit of GTPase
4. GTP cannot convert back to GDP
4. Permanent action of adenylyl cyclase
5. Apical Cl channels open
6. Cl secretion pulls Na and water
7. Absorption cannot keep up
8. Severe poo |
|
|
Term
| what are the causes of decreased surface area for absorption in the colon |
|
Definition
Infection
Inflammation: caused by mucosal destruction with outflow of fluid and blood (like ulcerative colitis) |
|
|
Term
| what causes osmotic diarrhea, give an examile of a disease |
|
Definition
Presence of non-absorbable solutes in lumen causes water retention
Example: lactase deficiency, carbs not broken down |
|
|
Term
| explain why bacterial overgrowth causes diarrhea, which kind |
|
Definition
secretory diarrhea
Bacterial overgrowth (cholera, E. coli): enterotoxins affect toxin receptors to increase cAMP in cell, turning on Cl channels and inhibiting NaCl reabsorption |
|
|
Term
| explain the mechanism in secretory diarrhea |
|
Definition
Excessive secretion by crypt cells
Intestinal fluid secretion is isotonic with plasma even during fasting
Increased Cl secretion and decreased Na reabsorption |
|
|
Term
| what is exudative diarrhea, what can cause it |
|
Definition
Blood and pus in stool
Causes: E. coli, inflammatory bowel diseases, Chron’s Disease, ulcerative colitis |
|
|
Term
| what is chrons disease, how is it diagnosed |
|
Definition
o Chronic inflammatory bowel disease (IBD) where intestines are inflamed
o More frequent abdominal pain that perianal disease |
|
|
Term
| what is ulcerative colitis, how is it diagnosed |
|
Definition
o Chronic inflammatory bowel disease (IBD) where intestines are inflamed
o GI bleeding |
|
|
Term
| liver: location, fissures, surfaces, anatomical landmarks |
|
Definition
o RUQ and epigastric under ribs
o Diaphragmatic and visceral surfaces
o Fissure on visceral surface
o Porta hepatis: major vessels and nerves enter and leave
o Ligamentum teres: remnant of umbilical vein in fetus (attaches to navel) |
|
|
Term
| liver: cellular units, vessels, cells |
|
Definition
o Lobule: Hegaconal sheets of hepatocytes. Corners have portal triads (portal arteriole, portal venule, bile duct)
o Sinusoids: Large capillaries between hepatocytes that connect hepatic venis to IVC. Capillaries are in a portal system
o Kpuffer cells: Macrophages on the walls of sinusoids. Recycle blood, breakdown microbes
o Hepatocytes |
|
|
Term
| in the hepatocyte, explain what each organell is doing |
|
Definition
Many organelles
RER: manufactures blood proteins
SER: makes bile salts, detoxifies blood borne toxins
Peroxisomes: detoxify poisons (alcohol)
Golgi: modify, package, and transfer macromolecules
Mitochondria: make energy needed for functions of liver
Glycosomes: store sugar and regulate blood glucose |
|
|
Term
| where do the hepatocytes secrete bile into |
|
Definition
|
|
Term
|
Definition
o Receives 75% venous portal blood which went to intestines, stomach, pancreas and spleen first
o 25% of blood comes from hepatic artery |
|
|
Term
|
Definition
o Synthesis and secretion of bile acids
o Bilirubin production and excretion
o Detoxicy poisons and drugs
o Make blood proteins
o Excrete waste products
o Pick up glucose from the blood
o Store glucose as glycogen
o Process fats and AA
o Store some vitamins |
|
|
Term
| bile: what is it made of, how in general is it made |
|
Definition
o Bile acids are made from cholesterol in hepatocytes and transported and stored in gallbladder
o Bile acids are recirculated from ileum back to liver via enterohepatic circulation |
|
|
Term
| explain the process of RBC degredation, what happens to the biproducts |
|
Definition
o Reticuloendothelial system processes RBC
o Degraded Hb makes biliverdin (green) which is converted to bilirubin (yellow)
o Bilirubin is bound to albumin and carried to liver
o Hepatocytes take it up and conjugate with glucotonic acid via UDP glucronyl transferase
o Conjugated bilirubin is secreted into bile
o Bacterial enzymes de-conjugate into urobilinogen
o Some is absorbed back into enterohepatic circulation
o Some is converted to urobilin and stercobilin and excreted |
|
|
Term
| what are the functions of liver in carb metabolism |
|
Definition
Gluconeogenesis
Stores glucose and glycogen
Releases glucose into blood when needed |
|
|
Term
| what are the functions of the liver in protein metabolism |
|
Definition
Liver makes non-essential AA
Makes plasma proteins (albumin, clotting factors) |
|
|
Term
| what are the functions of the liber in lipid metabolism |
|
Definition
FA oxidation
Makes lipoproteins, cholesterol, and phospholipids
Converts cholesterol into bile acids |
|
|
Term
| explain liver detoxification |
|
Definition
First pass metabolism: liver sees toxins absorbed from GI before the rest of the body
Bacteria are phagocytosized via kupffer cells
Enzymes modify endogenous and exogenous toxins to make them water soluble
Phase I reactions: catalyzed by cytochrome P-450
Phase II reactions: conjugate substance with glucuronide, sulfate, AA, or glutathione |
|
|
Term
|
Definition
| UDP glucuronyl transferase is made slow after birth so it can’t conjugate bilirubin fast enough |
|
|
Term
|
Definition
May cause edema due to loss of plasma protein oncotic pressure
Hypoalbuminemia
Unable to convert ammonia from protein metabolism into urea so less will be in urine |
|
|
Term
| gall stones: cause, symptoms |
|
Definition
Bile salts crystalize to form them
Intermittent pain, obstruction, infection, fever, vomiting |
|
|
Term
| hypoalbuinemia: cause, symptom |
|
Definition
Caused by liver failure
Edema due to loss of plasma protein |
|
|
