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Exam 2- GI and CV
N/A
280
Physiology
Graduate
09/29/2012

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Term
4 tissue layers of the GI tract
Definition
inner most- mucosa; submucosa; muscularis externa; serosa
Term
mucosa components
Definition
mucus, endocrine, epithelial, exocrine, stem cells, tight junctions, exocrine glands, lamina propria layer (arterioles, venules, capillaries, lymphatic vessels- lacteals), muscular mucosa, villi, microvilli
Term
submucosa components
Definition
blood and lymph vessels, submucosa nerve plexus
Term
muscularis externa components
Definition
inner circular sm musc; outer longitudinal sm musc; myenteric nerve plexus (primarily responsible for reg of motility)
Term
GI functions
Definition
digestion, motility, secretion, absorption, excretion
Term
Short loops
Definition
all in the ENS; mechano/chemosensors send info to ENS neuron which affects the sec cell, sm musc, endocrine cells, and other neurons
Term
long loops
Definition

PS and SNS innervation of the short loop; sensory neurons send info to CNS 

CNS to PSNS or SNS affect the sec cells, ENS neurons, endocrine cells, sm musc 

Term
where is meal in the cephalic, gastric and intestinal phase?
Definition
mouth, stomach, and smint respectively
Term
mastication functions
Definition
mix food with saliva and lubricates food to be able to swallow; break up food into smaller pieces, mix starches with amylase
Term
what happens in the oropharyngeal phase?
Definition
tongue move bolus to oropharynx--> stim pressure R-->initiate swallowing reflex- inhib of respiration, close air passageways, contraction of pharyngeal musc to move bolus to esophagus, relax of UES (to open) into esophagus 
Term
esophageal phase
Definition

primary peristalsis initiated by swallowing; ring of sm musc constricts above bolus propogates distally to move bolus to stomach- LES at end closed at rest relaxes to open allow bolus to stomach

secondary peristalsis- intiatied by distension- proceeds like primary; moves mat left behind to stomach 

Term
receptive relaxation
Definition
food in stomach--> stretch R in lining--> signal to CNS --> signal to PSNS via the vago-vagal reflex --> fundus relax and expands to receive meal (NT is NO)
Term
how does food move through the stomach once it enters the stomach
Definition
at rest- slow wave depol 3 times/min; when have vago-vagal reflex cause spike potentials which cause AP in sm musc so now contracts 3 times/min moving food from top to bottom (peristalsis)
Term
peristalsis in the stomach is due to what solute conductance increasing?
Definition
calcium
Term
how does food get out of the stomach to the smint?
Definition
the peristalsis from the stomach moves small mat out through the pyloric sphincter; lg part cant get through
Term
how does large particles leave the stomach to the smint?
Definition
peristalsis moves lg part to bottom of stomach cant get through the pyloric sphincter; contractions will smash the antrum into the food into the closed pyloric breaking into smaller pieces and then shooting through backwards to be even smaller; when small enough move through sphincter
Term
how is the contraction of the stomach regulated?
Definition
distension of the distal stomach (due to vago-vagal reflex); spikes due to PSNS activity; short cholinergic reflexes in ENS; gastrin
Term
how is the gastric emptying regulated?
Definition
size of material; liquid quick elim from stomach; make up of the material- carbs fast, protein middle, fats slow; high osmolarity and low pH slow the emptying
Term
vomiting events
Definition
reverse peristalsis in smint moves int content to stomach, pyloric sphincter and antrum contract prevent movement back to int; retching- inspire against closed glottis, LES relaxes, constriction of ab musc, contents into esophagus (secondary peristalsis to move back to stomach); vomiting- all plus forceful ab contraction, stretch neck, elevate hyoid bone, relax UES, evac gastric contents
Term
vomiting stimulants
Definition
GI tract irritation, noxious substances, toxins, pain, dizziness, motion sickness, chem stim of R in chemoR tigger zone in brain, distressing emotional visual and olfactory stim, reflex controlled by vomiting center in medulla
Term
smint motility
Definition
peristalsis- infrequent, short distance, dies out; major- segmentation- circ sm musc contracts alternate contractions to move material back and forth; higher freq at proximal end than distal so slow moves down the smint
Term
what are the functions of smint motility
Definition
mix chyme with exocrine sec to dig, reduce part sz further, circulate chyme along int wall for absorption, propel through int
Term
regulation of contractions in smint
Definition
distension of intestine (myogenic reflex) if stretch wants to contract; intestine-intestinal reflex- doesnt move food, if over distend GI tract will shut down motility
Term
gastroileal reflex
Definition
eat meal mat into stom need to have room for mat into smint, gastrin rel from stomach through G cells will stim movement down the ileum to move mat into the colon
Term
what hormone stimulates movement of mat through the smint to the colon
Definition
gastrin
Term
large intesting motility
Definition
segmentation contraction, distension is major stimulus
Term
mass movement
Definition
propulsive ring of contraction elongates distally move contents toward rectum (toothpaste squeezing); 3-4 times a day
Term
gastrocolic reflex
Definition
ingestion of meal and distension of stom stim colonic mass movement through neural reflexes or hormonal mech
Term
migrating motility complex 
Definition
occurs during fasting, house cleaning, all sphincters open, contraction in stomach, duodenum, jejunum, ileum; happens every 90 minutes; motilin stimulates
Term
what hormone stimulates MMC?
Definition
motilin
Term
defecation events
Definition
triggered by distension of rectum- intial relaxation of internal anal sphincter and transient contraction of external; awareness of need; voluntary contraction of ab muscles (valsalva maneuver) and relax of external anal sphincter; involuntary contraction of distal colong and relaxation of internal anal sphincter
Term
deglutition
Definition
swallowing
Term
what increases the tone of the LES
Definition
intra abdominal pressure
Term

what decreases the tone of the LES


 

Definition
ethanol, chocolate, peppermint, progesterone
Term
LES tone decreasing can cause what?
Definition
heartburn
Term
functions of stomach
Definition
store ingested material, convert ingested material into chyme, control the rel of chyme into the smint
Term
proximal stomach
Definition
fundus, upper body
Term
thin layers of sm musc are found where in the stomach
Definition
proximal stomach
Term
thick layers of sm musc are found where in the stomach
Definition
distal stomach
Term
what is the distal stomach
Definition
lower body and antrum
Term
food into stomach stimulates what?
Definition
stretch R in the lining of the stomach
Term
what does the vago-vagal reflex cause?
Definition
causes receptive relaxation to expand the fundus for receiving a meal
Term
what ANS branch causes receptive relaxation?
Definition
PSNS
Term
what is the NT for receptive relaxatioN?
Definition
NO
Term
what does the vago-vagal reflex doe to the slow wave potentials?
Definition
puts spikes on them causing AP and therefore contraction
Term
contraction in the stomach is due to what?
Definition
distension stimulating the stretch R which tell CNS via vago-vagal reflex (sends PSNS activity down) PSNS puts spikes on the slow wave potentials causing AP and contraction
Term
what are some things that slow down the gastric emptying?
Definition
fats, high osmolarity and low pH
Term
how can the duodenum regulate gastric emptying?
Definition
signals to stomach neuronally and hormonally to regulate emptying; GLP1 rel from duod to inhibit
Term
GLP-1
Definition
glucagon like peptide; rel from the duod to inhibit gastric emptying and GI motility; control amt of food coming to the smint
Term
what will stimulate the release of CCK
Definition
fats and aa
Term
how does CCK slow gastric emptying?
Definition
inhibits proximal contractions
Term
vomiting, emesis
Definition
inspire against closed glottis, LES relaxes, contraction of ab muscles, contents into esophagus, stretch neck, elevate hyoid bone, relax UES
Term
myogenic reflex
Definition
stretch causes the desire to contract
Term
saliva functions
Definition
protection, lubrication, neutralization of acid, cleansing
Term
how does saliva protect?
Definition
antibacterial activity- lysozyme and lactoferrin punch holes in the wall of bacteria
Term
how does saliva neutralize acid?
Definition
bicarbonate in the saliva, (reflex from stomach)
Term
how does saliva lubricate?
Definition
mucus
Term
how does saliva cleanse?
Definition
water
Term
how does saliva digest?
Definition
salivary amylase begins digestion of carbs
Term
why does digestion of starches by salivary amylase stop when it gets to the stomach?
Definition
the acidity kills the enzyme
Term
salivon
Definition
fxnl unit of salivary gland
Term
salivon components
Definition
acinar cells and duct cells
Term
acinar cells secrete what?
Definition
secrete amylase lysozyme, mucus, and other inorganic comp Na, Cl, K, HCO3, and water into the saliva; same concentration as in plasma; movement things from ECF into the cells in the glands 
Term
what do the duct cells do in the salivon?
Definition
once components travel from the acinar cells to the ducts the duct changes the composition of the salia by sec more bicarb and more K; and reabsorbing some Na and Cl
Term
final product of saliva?
Definition
higher conc of K and bicarb and lower conc of Na and Cl
Term
what are the controls of salivation?
Definition
stimulated by thought of food, smell, mech stim, taste (acid); neural mechanism- most impt ctrl is PSNS, SNS small transient stim; both stim sec of salivary gl
Term
gastric glands, oxyntic glands
Definition
in stomach; HCl, mucus and pepsinogen are mjor secretions
Term
surface epithelials cells int he stomach secrete what? and why?
Definition
mucus and bicarb for protection of the stomach
Term
mucus neck cells are found where?
Definition
in the neck of the duct
Term
mucus neck cells sec what?
Definition
mucus
Term
what do parietal cells secrete?
Definition
HCl and intrinsic factor
Term
what do chief cells secrete?
Definition
pepsinogen
Term
what is pepsinogen impt for?
Definition
converted to pepsin for digestion of pr
Term
what cells sec the hormone gastrin?
Definition
G cells
Term
where are the ECL cells located?
Definition
in the lamina propria
Term
what do the ECL cells secrete?
Definition
histamine
Term
where are the D cells
Definition
in the lamina propria
Term
what do D cells sec?
Definition
stomatostatin
Term
what is somatostatin?
Definition
a hormone 
Term
what cells interact to control rel of HCl and pepsinogen?
Definition

surface epithelial cells, mucus neck cells, parietal cells, chief cells, G cells, D cells, ECL cells

 

Term
what does HCl do in the stomach?
Definition
kills bacteria, activates pepsinogen, denatures protein
Term
what activates pepsinogen?
Definition
HCl and pepsin
Term
how do parietal cells secrete HCl?
Definition
uses H/K ATPase to bring K in and H out into the lumen
Term
where does the H come from that is secreted by Parietal cell?
Definition
H comes from the dissoc of water to H and OH
Term
what happens to the OH that is formed from the disocc of water after the H is sec out of the parietal cell?
Definition
OH combines with another H in the cell
Term
where does the H come from the OH binds to in the parietal cell?
Definition
the enz carbonic anyhdrase takes H2O and CO2 and converts it to H2CO3 which dissoc to bicarb and H
Term
how do we move bicarb out of the parietal cell?
Definition
Cl/Bicarb counter transporter moves Cl into the cell and bicarb out
Term
how is bicarb transported out of the cell?
Definition
by secondary AT with the Cl/bicarb counter transporter
Term
after bicarb is transpoted out of the cell how does the resulting Cl in the cell get moved back out?
Definition
Cl goes with K back out of the cell
Term
where do the bicarb and the H go after leaving the parietal cell?
Definition
bicarb goes to teh blood and H goes to the lumen of the stomach
Term
what are the direct stimulants of HCl secretion?
Definition
stim of parietal cells by vagus nerve (ACh activate M R); hormone gastrin binds to parietal cells to cause secretion of HCl; histamine binds to parietal cells to cause secretion of HCl
Term
how can HCl be indirectly stimulated for secretion?
Definition
vagus can stimulate ECL cell to release histamine which can then go to stimulate the parietal cell to sec HCl; vagus can stim G cell to rel gastrin which can go stim parietal cells to cause sec
Term
what are cephalic phase stimuli?
Definition
taste smell chewing swallowing
Term
what does the vagus stimulate in the cephalic phase?
Definition
myenteric plexus
Term
vagus stimulation of the myenteric plexus can stim parietal cells to directly cause what secretion?
Definition
HCl
Term
cholinergic neurons can stimulate ECL to rel what? and subsequently secrete what?
Definition
secrete histamine and therefore secrete HCl through stimulation of the parietal cells by histamine stimulation
Term
short reflexes of the gastric phase are due to what?
Definition
distension of the stomach
Term
how can ENS cause secretion of HCl?
Definition
stim neurons to ECL, parietal cells, G cells; ECL sec histamine which go stim parietal to sec HCL; parietal cell stim causes sec of HCl; G cells sec gastrin which can then go stim the ECL and parietal cells--> rel of histamine (which then also goes to parietal cells to stim HCl) and rel of HCl
Term
peptides, Ca, coffee can stimulate what cells? 
Definition
stimulate G cells to secrete gastrin rel
Term
how is HCl secretion inhibited in the gastric phase?
Definition
D cells rel somatostatin hormone (stimulated for rel by acid); if there is excess acid want to inhibit the secretion of HCl; so acid stim D cells to rel somatostatin; somatostatin inhibits gastrin rel from G cells (which then doesnt stim ECL or parietal cells for HCl sec); also inhibits ECL cells from sec histamine- less histamine stim par cells for HCl sec
Term
excess vomiting causes loss of blank and build up of blank
Definition
HCl in vomit, bicarb
Term
excess vomiting can cause you to become what?
Definition
alkalotic
Term
excess vomiting shuts down the negative feedback system of ?
Definition
somatostatin
Term
what are HCl secretion inhibitors of the intestinal phase?
Definition
acid, hyperosmotic solutions, FA
Term
how do acid hyperosmotic solutions and FA inhib HCl secretion the intestinal phase?
Definition
these hit the duod and stim neurons ENS in the int that go back to the stomach to inhibit acid secretion; they also stimulate cells in duod that rel hormone enterogastrone- goes into circulation and inhibits acid release and titrate amt of acid coming out of stom into duod (gives smint time to process components; we would damage smint and inactivate enz that we are using to digest the food there if had acid in the smint
Term
what is the purpose in inhibiting acid secretion during the intestinal phase?
Definition
if we have acid coming into the smint then the smint will be damaged and the enz we are using to dig our food will be inactivated
Term
what cells secrete IF?
Definition
parietal cells
Term
what is IF required for?
Definition
absorption of B12
Term
how is IF rel stimulated?
Definition
same mechanisms as HCl
Term
achlorhydric (Cant sec HCl bc damage to parietal cells) causes what?
Definition
pernicious anemia, bc need IF to absorb B12; causes somthing with RBC formation
Term
where is pepsinogen made?
Definition
by rough ER
Term
pepsinogen is packaged into zymogen granules at?
Definition
the rough ER
Term
what is the stimulus of rel of pepsinogen from the zymogen granules into the lumen?
Definition
PSNS
Term
how is pepsinogen activated?
Definition
acid in the stomach and other activated pepsin
Term
what does pepsin digest?
Definition
protein
Term
what are the stim for mucus secretion?
Definition
mechanical and cholinergic
Term
gastric mucosal barrier
Definition
bicarb and mucus and tight junctions- prevents pepsin from getting to epith cells and eating them up
Term
exocrine portion of pancreas
Definition
ducts, acinar cells sec enz impt for dig of pr carbs and fats; 
Term
what do duct cells in the exocrine duct of panc sec?
Definition
electrolytes
Term
what do acinar duct cells of exocine panc sec?
Definition
enzymes
Term
what do duct cells of exocrine panc secrete?
Definition
bicarb and water
Term
feed forward system of exocrine panc acinar cells
Definition
chewing, reflexes from vagus imput to acinar cause sec of enz to prep for food coming down
Term
acid stimulated the S cells in the exocrine duct of panc to sec what?
Definition
hormone secretin
Term
secretin goes in ciruclation and goes to duct cells in exocrine panc to 
Definition
cause sec of bicarb and water
Term
secretin causes the sec of bicarb and water from the duct cells of exocrine panc gl in the smint because
Definition
if the bicarb wasnt there it would be an acid environment (from stomach acid) and then would inhibit the enz you sec for digestion
Term
what cells in duodenum to fats and aa stimulate?
Definition
I cells- to release CCK
Term
CCK stimulates what?
Definition
acinar cells to rel panc enz for digestion
Term
bile salts are made from 
Definition
cholesterol 
Term
micelles are made from
Definition
outer ring is bile salts and phosphatidinyl choline
Term
bile salts are synth by 
Definition
the liver
Term
water is reabsorbed to concentrate the micelles in the... 
Definition
gall bladder
Term
fat into the duod will stim the I cells to rel CCK which causes
Definition
stimulates sec of panc enz, and relax the sphincter of oddi and contraction of the gall bladder so that micelles will go into the smint where they can aid in the dig of fats
Term
how much bile salts are reabsorbed at the ileum?
Definition
95%
Term
FA, steroids, and ethanol can transport across the PM via
Definition
diffusion
Term
how do we absorb solutes?
Definition
sodium solute co transporters; solute from lumen into epith (NA in too) use fac diff for solute to blood and Na pump for Na to blood
Term
most nutrients are absorbed where?
Definition
smint (D>J>I, simply bc less to be absorbed)
Term
brush border
Definition
luminal side, bc of microbilli; 
Term
carbs pr fats are absorbed very well where in the smint?
Definition
entire smint
Term
where is iron absorbed?
Definition
only in the duodenum
Term
where are bile salts absorbed?
Definition
ileum
Term
where is vita B12 absorbed?
Definition
ileum
Term
digestion and absorption of carbs
Definition
mouth- salivary amylase starts breaking down starch, stops when hits stom; in smint- panc sec panc amylases- breakdown to disacc, oligosacc, trisacc, only monosacc absorbed; enterocytes(epith cells of GI tract) have oligosaccaridases- break down to monosacc; gluc and galac are hexoses, fructose is pentose; gluc/galac use Na/gluc dependent co transporter, out by fac diff; fructose uses fac diff on both membranes
Term
digestion and absorption of pr
Definition
activate pepsinogen to pepsin via acid; pepsin starts the pr dig; in smint- not HCl to activate enz- so trypsinogen sec by panc goes interacts with enteropeptidases on brush border to trypsin- act trypsinogen and other proteolytic enz; pepsin and panc proteases break down into oligopeo, aa, and dipep- dipep and aa taken up, oligopep further interact with brush border proteases; Na/aa cotransporter, then fac diff; dipep/ H cotransport, dipep broken down in epith, aa out by fac diff
Term
digestion and absorption of fat
Definition
antral systole- slamming turns to sm fat droplets to duod; stim sec of bile and micelles, bile salt comp coat droplets keep emulsified, digested by panc lipase with help of colipase- into tryglycerides to FA and MG; rel from droplet but not soluble so react to form micelle diffuse into epith cells via simple reesterified to triglycerides- protein coat to make chylomicron- makes water soluble leaves cell via exocytosis to lacteals- eventually to bl; 
Term
absorption of vitamins
Definition
fat soluble ADEK follow lipid absorption- in micelles then incorp into chylomicrons req bile salts; water soluble vitas B1, B2, B6, B12, C, folic acid, niacin, pantothenic acid use simple diff, fac diff, secondary AT, and endocytosis; 
Term
B12 absorption
Definition
needs IF, bind to IF in stomach- complex then travel to smint to Ileum; there is a R for the complex on the luminal mem, takes into cell and complex dissoc; transcobalmin pr binds to B12 in cell- new complex goes across basolateral side into bl; goes to tissues needed esp for formation of RBC
Term
major electrolytes
Definition
Na, Cl, K, H and bicarb
Term
Na Absorption
Definition
Na/ solute cotransporters used to absorb solutes, nut; Na into epith along grad Na/H counter trasnporter; Na in H out, Na channels down grad into epith cell; allow reabsorb into epith cell; to get out basolateral side use Na/K ATPase Na out to bl, K into cell
Term
Cl absorption
Definition
as Na is reabsorbed across epith layer- sets up elec grad cause Cl to diffuse across cells through Cl channel and through tight junctions
Term
K absorption
Definition
K in lumen come to equilibrium with basolateral side as water absorbed, inc conc of K in lumen (less water) it will then go down electrochem grad to go across cell into basolateral side PASSIVE
Term
H/Bicarb absorption
Definition
H from stomach, bicarb from panc; these will combine to make H2CO3 and then dissoc to water and CO2, CO2 diffuses across to plasma dn water will diffuse across with its gradient
Term
Ca absorption
Definition
2 mech: whole length of smint can go down its grad across the cells bt the cells in the tight junctions- ec grad from lumen to bl; paracellular pwy, passive;;;; 2nd- occurs in duodenum- active pwy; Ca absorbed through Ca channels on luminal side of epith cells; Ca bound to pr calbindin in the epith cell then diffuse across cell on basolateral side by Ca/ATPase and other is Na/Ca countertransporter out of cell of basolateral side (Vita D3 reg the mech by inc the amt of Ca channels on luminal side of epith cell- inc amt of calbindin- inc number of Ca/ATPase enhance ability of cell to absorb Ca from Gi tract by more channels, calbindin, and CaATPase
Term
Iron absorption
Definition
hard to absorb; Iron/H cotrasnporter across luminal side; pr mobilferrin binds iron in cell goes to basolateral side; out with fac diff; bl iron is bound to transferrin; if dont need iron in bl then apoferritin pr bind to iron and be stored in cell as ferritin
Term
osmotic diarrhea 
Definition
normally solutes transported acoss epith, water goes with solutes to keep isotonic but absorb unsoluble solutes then no longer have water reabsorbed to blood
Term
osmotic diarrhea causes
Definition
ingestion of solutes that are inherently difficult to absorb (Mg salts, sorbitol, polyethylene glycol (Miralax)); primary malabsorptions (loss of solute transporter, uncommon); secondary malabsorptions- lactose intolerance, if cant breakdown lactose then cant reabsorb water
Term
osmotic diarrhea volume and treatments
Definition
large volume >1 L/day, stops when you stop ingesting food
Term
secretory diarrhea
Definition
solutes transported from the basolateral and going to lumen, retain water in the lumen of the GI tract
Term
secretory diarrhea causes
Definition
bacterial infection of the GI tract (cholera)- produce enterotoxins that stim intestinal and colonic secretion; fat malabsorption- in the colon, bact metab fats to prod substances that are secretogogues to coloncytes
Term
secretory diarrhea volume and treatment
Definition
large volume >1L/day, those caused by bacteria persist even after fasting
Term
exudative diarrhea
Definition
damage to epith lining of int, bact infection, trauma; rel of pr, wbc, rbc into smint bring water with them, mucus
Term
exudative diarrhea causes
Definition
dysentery- bact inf, shigella, amoebic dysentery causes damage to Gi tract, blood and mucus in the stools; inflammatory bowel disease- caused by some bact inf; ulcerative colitis; chrohn's disease; 
Term
exudative diarrhea volume
Definition
freq passage > 6 times a day of sm vol stool 1 L/day
Term
other causes of diarrhea
Definition
increased motility (impt factor in irregular bowel fxn seen in irritable bowel syndrome, cant have time to absorb water); excess use of laxatives
Term
consequences of diarrhea
Definition
dehydration, losing K and Na, hyponatremia and hypokalemia, metabolic acidosis- loss of bicarb not reabsorbing it, panc is sec bicarb to neutralize acid normally would reabsob bicarb form water and CO2, not occuring; death
Term
constipation
Definition
infreq or difficult evac of the feces; causes blockage of rectum, dilated or atrophic colon, elevated levels of progesterone, lack of dietary fiber, emotional disturbances, medication
Term
ulcers
Definition
breakdown in mucosa of stomach or duod, may lead to GI bleeding, obstruction, penetration and perforation of GI(bact into cavity major inf); causes- helicobactor pylori, NSAIDS, zollinger-ellison syndrome; treatment- combo  of drugs to prevent acid rel (antihistmaines or proton pump inhib) and antibiotics
Term
zollinger- ellison syndrome
Definition
gastrin secreting tumors in the panc duod or both; gastrin stim rel of histamine from ECL and stim sec of HCl from parietal; therapies- antihistamines, H2 antagonists, proton pump inhibitors
Term
gas
Definition
swallow 50-500 ml/day of hair, major source is neutralization of acid by bicarb- form water and CO2, L of CO2/day reabsorb and exhaled, major source of gas is bact fermentation in the colon; any nut not dig bact will dig and create various gases; beans hard to digest deliver lots of nut to bact; borborygmus due to gas going back and forth across sphincters; passage of gas out of GI is due to diff in the P of gases in the lg int and that of atmostphere; flatus 500-1500 ml/day
Term
the hydrostatic P of the bl is increased by the pumping action of the
Definition
left and right ventricles
Term
driving force for bl flow to the peripheral vascular beds and lungs
Definition
due to the pressure increase by the pumping action of the RV and LV
Term
blood flow
Definition
measured in units of volume per unit time L/min
Term
pressure grad 
Definition
usually measured in mmHg
Term
resistance to bl flow occurs
Definition
because fo the shear forces that exist bt the bl and the vessel wall and bc of bl viscosity
Term
resistance to blood flow is black to the 4th power radius of the BV
Definition
inversely proportional
Term
As the radius of BV dec by a factor of 2 the resistance blank by a factor of blank
Definition
increases, 16
Term
Flow =
Definition
change in pressure/resistance
Term
bl flow is directly proportional to blank and inversly proportional to blank
Definition
pressure gradient, vascular resistance
Term
mitral valve
Definition
2 cusps; bt LA and LV; passive opening when BP in LA is higher than in the LV; close passively; papillary muscles hold them in
Term
tricuspid valve
Definition
3 cusps, in bt RA and RV; opens passively closes passively held by papillary muscles
Term
cardiac valves present blank resistance to blood flow
Definition
little
Term
blank pressure differences across the cardiac valves are sufficient ot produce blank bl flows
Definition
small, large
Term
gap junctions
Definition
adj to intercalated disks, low resistance pwy permits cell to cell conduction of AP
Term
conductin system
Definition
comprised of cardiac musc cells that have become spec for conduction of AP rather than contractile force
Term
SNS innervation of the heart
Definition
NE primary NT, assoc with mainly beta-adrenergic R
Term
PSNS innervation of the heart
Definition
ACh primary NT and assoc R are M
Term
SA node
Definition
prod cardiac AP, establish HR
Term
AV node
Definition
located at base of RA near tricuspid valve; slow conduction through the heart; allows for complete contraction of atria before ventricular contraction; only electrical connection bt the atria and the ventricles
Term
Cardiac AP
Definition
Phase 4: RMP -90 mV; prolonged plateau phase resulting in total AP duration of 300-400 ms; Phase 0: Rapid depol- VG Na open (K perm dec); Phase 1: initial repolarization; Phase 2: plateau- K channels closed, VG Ca L open enter cell; Phase 3: Final repolarization-Ca channels close and K open 
Term
pacemaker activity
Definition
cell sof SA node; no stable RMP; slow depolarization until threshold then AP initiated, no plateau phase; intrinsic activity to heart; slow depol- beginning Na funny opens bc of previous repol, and then at end Ca T open and close causes threshold reach; at threshold VG Ca L opens briefly carries positive in causing depol; Repol- L Ca close and K perm returns to normal
Term
ECG
Definition
recording elec act of heart from external electrodes; P- depol of atria, QRS- ventricular depol; T- ventricular repol; detect abnormalities in electrical events; doesnt detect abnormal mech activity unless causes a disturbance in electrical activity
Term
ECC in heart
Definition
AP to T tubules; Ca from plateau phase of CardiacAP causes rel of Ca from SR; inc in cytosolic Ca conc that initiates contraction is result of Ca being rel from SR and Ca entering the cell from the outside; removal of Ca- AT to SR by Ca ATPase, and one also on PM; and Ca/Na exchanger; amount of Ca in cytosol determines strength of contraction
Term
refractory period inthe heart
Definition
lasts almost as long as mechanical contraction, due to long plateau phase of Cardiac AP; impossible to produce tetanic contractions
Term
diastole
Definition
ventricles relaxing and filling
Term
systole
Definition
ventricles contract and eject blood
Term
rapid filling phase
Definition
early in diastole P grad is rel large results in fast filling
Term
slow filling phase
Definition
as diastole progresses P grad diminishes and vent filling slower
Term
atrial contraction phase
Definition
as result of elec activity LA contracts and pushes additional sm amt of bl into vent
Term
EDV
Definition
end diastolic volume- total vol of bl contained int he bl at the end of atrial contraction
Term
rapid ejection phase
Definition
vent P exceed aortic P and aortic valve will open, permitting bl to flow from the vent to the aorta
Term
slow ejection phase
Definition
bl flow out of the vent slowly diminsh 
Term
ESV
Definition
end systolic volume; amt of bl contained in the vent at the end of the ejection phase
Term
SV
Definition
stroke volume; difference between EDV and ESV; EDV-ESV
Term
EF
Definition
ejection fraction; amt of blood ejected during a contration expressed as percentage of total amt of bl contained in the ventricle at the end of diastole; normal is about 60%; EF = SV/EDV
Term
aortic pressures
Definition
during diastole dec from 120 mmHg to 80 mmHg; result of bl leaving aorta; at valve opening bl ejected to the aorta rapid inc in aortic P
Term
right heart pressures
Definition
the peak pulmonary artery P around 24 mmHg, diastolic pulmonary P is about 8 mmHg as compared to 120 and 70 for aorta
Term
first heart sound
Definition
result of closing of the mitral and tricuspid valves at the beginning of systole
Term
second heart sound
Definition
result of closing of the aortic and pulmonic valves at the end of systole
Term
third heart sound
Definition
turbulence assoc with transition from the rapid filling phase to the slow filling phase; mid diastole; commonly heard when ventricle is dilated and atrial P is high
Term
fourth heart sound
Definition
due to movement of bl assoc with atrial systole; late in diastole; common heard in hearts which the ventricle is very stiff like hypertrophied heart
Term
heart murmurs
Definition
caused by blood flowing through abnormally small opening or in narrowed BV
Term
CO
Definition
cardiac output, vol of bl pumped by each vent per min; avg 5 L/min; found by SV * HR
Term
PSNS Control of HR
Definition
normally PSNS> SNS so HR approx 70 bpm rather than intrinsic 100 for SA node; increasing PSNS dec the number of Na funny and Ca T channels open--> longer time to threshold, fewer AP, lower HR; also hyperpolarizes cell- contrib to inc amt of time it takes to reach threshold;;; SNS activity increase--> inc number of Na funny and Ca T open reach threshold faster, inc HR
Term
Effect on AV by SNS
Definition
increase SNS activity, inc the velocity of conduction of AP through the AV node
Term
effect on AV by PSNS
Definition
inc PSNS activity, dec velocity of conduction of AP through AV node
Term
Control of SV
Definition

ventricles dont empty with each beat so alter SV by alter force of contraction- alter EDV or alter SNS or both;

 

Term
Altering EDV and effect on SV
Definition
filled more, greater contraction; as SV inc EDV inc; frank starrling mech; rel to length tension prop of tissue; effect of this mech is that CO of the LV and RV are equal
Term
effect of SNS on SV
Definition
SNS to myocardium and SA; inc activity, inc cardiac contractility (strength of contraction at any given EDV); change sin contractility independent of changes in EDV; inc SNS shift ventricular fxn curve up and left; SV is greater at any given EDV; inc SNS causes contraction and relaxation of vent to occur more rapidly thus compensating for effects of inc HR on vent filling
Term
EF provides a blank measure of contractility
Definition
indirect
Term
SNS and Cardiac contractility
Definition
open more PM Ca L during plateau, inc amt of Ca from SR; stim of Ca reabsorption to SR; alter binding of Ca to troponing; Inc cardiac contractility are result of inc in amt of free Ca during contraction and inc in rate of removal of Ca from cytosol during relaxation
Term
Afterload
Definition
magnitude of aortic P or pulmonary artery P against which the vent must eject its load of bl
Term
inc in after cause
Definition
stroke volume to decrease
Term
serve as conduits to move bl from LV to more distant parts of periphery
Definition
aorta and large systemic arteries
Term
aorta and large systemic arteries provide blank resistance
Definition
low 
Term
SP
Definition
systolic pressure; max P achieved during systole in the aorta
Term
DP
Definition
diastolic pressure; min P in the aorta before ejection begins
Term
PP
Definition
pulse pressure; diff bt the SP and DP
Term
MAP
Definition
mean arterial P; = DP + 1/3 PP; 
Term
magnitude of PP determined by 
Definition
amt of bl ejected by ventricle per beat (SV) and rate of ejection of blood from the ventr and the compliance of the arterial system
Term
compliance
Definition
how easily an elastic str can be stretched; =change in volume/ change in P; larger more easy
Term
arterioles
Definition
determine the relative bl flows to the various organs for a given MAP and play a major role in determining the MAP
Term
Ohm's law
Definition
Flow = pressure grad/ resistance
Term
arterioles are major site of blank to bl flow
Definition
resistance
Term
if MAP is constant, as arteriolar resistance increases to a vascular bed the amoutn of blood that will flow into that bed
Definition
decreases
Term
active hyperemia
Definition
increased bl flow as result of inc metab activity; result of production or loss of certain materials in the immed vicinity or within the vascular bed; low O2--> inc the amt of bl flow bc need bl to bring O2
Term
flow autoregulation
Definition
maintenance of bl flow in the face of changes in MAP; same mech as active hyperemia
Term
SNS NE cause blank by activating alpha R
Definition
vasoconstriction
Term
dec SNS discharge relaxes the sm musc and produces
Definition
vasodilation
Term
NO is a vaso....
Definition
dilator
Term
NO impt in control of blood flow in the blank and blank
Definition
GI and penis where they mediate erection
Term
in coronary and skeletal vascular sm musc beta 2 R predom and epinephrine binding causes
Definition
vasodilation
Term
epinephrine binding to alpha R in vascular beds causes
Definition
vasoconstriction
Term
angiotensin II
Definition
vasoconstrictor
Term
vaso pressin
Definition
vasoconstrictor
Term
atrial natiuretic peptide
Definition
vasodilator
Term
NO
Definition
continuously rel from endothel cells and induces vasodilation
Term
PGI2
Definition
prostacyclin; vasodilation
Term
ET-1
Definition
endothelin-1; paracrine vasoconstrictor
Term
endothel cells in cap are not attached tightly to one another but separated by 
Definition
intercellular clefts
Term
precap sphincters
Definition
control bl flow from the metarterioles into the cap and contract or relax in response to local metabolites
Term
Blood flow velocity
Definition
in cap much less than in arterioles; V=F/A; V = blood flow velocity; F= blood flow and A total cross sectional area at that level of the circulatory system
Term
bulk flow distributes of redistributes
Definition
the ECF
Term
net filtration P eqn
Definition
(Pc-Pif) - (PIp-PIif); in systemic cap beds there is net movement of fluid out of cap at arterial end and net into the cap at the venous end; positive out of cap, favor filtration; negative in favor absorption; in pulmonary cap mag different so net reabsorption happens along entire length 
Term
exchange of materials in the venules
Definition
occurs but only a small amount
Term
driving force for bl flow from the veing back to the heart
Definition
P grad bt the peripheral veins and RA (5-10 mmHg); resistance is low
Term
veins also serve a storage fxn in that total vol of the peripheral veins can be altered by SNS acting on sm musc in walls of vessels to cause
Definition
vasoconstriction
Term
skeletal muscle pump
Definition
as veins compressed bt contracting skel musc, bl forced toward heart but cant move in opp direction bc of the valves
Term
respiratory pump
Definition
diaphragm down, inc intraab P and peripheral venous P; intrathoracic P dec so dec P in large veins in thorax; inc the P grad and thus inc the amt of bl flowing back to heart
Term
VR and CO
Definition
must be identical except for very brief periods of time
Term
lymphatic cap
Definition
large water filled channels that are perm to all ISF components including pr
Term
fat absorbed from the GI system enters the CV system by way of the 
Definition
lymphatic system
Term
sm musc in the walls of the lymph vessels exhibit blank which propels the lymph toward the heart
Definition
rhythmical contraction
Term
lymph vessels have valves that establish
Definition
unidirectional flow
Term
sm musc in the lymph system is 
Definition
activated by stretch and will begin rhythmic contraction when the lymph vessels become distended
Term
major CV variable being regulated in the systemic circulation
Definition
MAP
Term
MAP =
Definition
CO * TPR
Term
baroreceptor reflex
Definition
(and changes in hormonal sec) provide means of controlling MAP over the time span of seconds to hrs
Term
baroR are collection of nerve ending in the 
Definition
carotid sinuses and the arch of the aorta
Term
baroR are stretch R whose rate of firing is directly proportional to the 
Definition
P present in the lg BV where they are located
Term
afferent neurons from the baroR travel to the blank control centers in the brainstem
Definition
CV
Term
medullary CV center
Definition
primary integrating center for the ctrl of BP; input comes from arterial BaroR and output goes to heart arterioles and veins
Term
short term control of BP
Definition
baroR reflex
Term
adaptation of stretch R to prolonged inc or dec in BP limits abiliy of syst to deal with 
Definition
sustained inc or dec in arterial P
Term
long term regulation of BP
Definition
accomplished mainly through regulation of Bl vol by the kidneys
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