Term
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Definition
1.Ingestion-Intake of food
2.Digestion-Breakdown of molecules (both mechanical and chemical.
3.Absorption-uptake nutrients into blood/lymph.
4.Defecation-elimination of undigested material. |
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Term
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Definition
breaks up food particles, assists in producing spoken language.
Pharynx-swallows |
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Term
Stages of digestion
1. Mechanical Digestion |
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Definition
physical breakdown of food into smaller particles.
Teeth and churning action of stomach and intestines. |
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Term
Stages of digestion
2. Chemical digestion |
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Definition
-Series of hydrolysis reactions that break macromolecules into monomers.
-Enzymes from saliva, stomach, pancreas & intestines.
Resulting materials-
polysaccharides into monosaccharides
proteins into amino acids
fats into fatty acids |
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Term
Digestive tract (GI tract)
Accessory organs |
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Definition
30 feet long from mouth to anus.
teeth, tongue, liver, gallbladder, pancreas, salivary glands. |
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Term
Tissues of GI tract
1. Mucosa |
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Definition
Epithelium, lamina propria, Muscularis mucosae,
Keep it sliding! |
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Term
Tissues of the GI Tract
Muscularis externa |
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Definition
-inner circulr layer
-outer longitudinal layer
Keep it moving! |
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Term
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Definition
Part of the PNS-
Able to function independently of CNS.
Composed of 2 nerve networks:
1. Submucosal plexus
2. Myenteric plexus |
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Term
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Definition
1.controls glandular secretion of mucosa
2.contractions of muscularis mucosae.
keep it sliding |
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Term
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Definition
1.controls peristalsis
2.controls contractions of muscularis externa
Keeps it moving |
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Term
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Definition
| Only duodenum, pancreas, and parts of large intestine are on the back of the peritoneum. |
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Term
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Definition
| suspends GI tract and forms serosa (visceral peritoneum) of stomach and intestines. |
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Term
Lesser Omentum
Greater Omentum |
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Definition
L-attaches stomach to liver.
G-covers small intestines like an apron and stores fat. |
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Term
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Definition
mesentary of small intestines holds many blood vessels
mesocolon anchors colon to posterior body. |
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Term
| Short myenteric reflexes and long vagovagal reflexes |
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Definition
short-swallowing
long-controls contraction of the gastrointestinal muscle layers in response to distension of the tract by food. This reflex also allows for the accommodation of large amounts of food in the gastrointestinal tracts.(parasympathetic stimulation) |
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Term
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Definition
| messengers diffuse into bloodstream distant targets |
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Term
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Definition
| Messengers diffuse to nearby target cells |
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Term
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Definition
keep food between teeth for chewing.
Lips-cutaneous area vs. red area (vermilion-color) have lots of nerve endings |
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Term
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Definition
muscular food manipulator of food.
Papillae and taste buds on dorsal surface. |
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Term
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Definition
| Allow breathing and chewing at the same time. |
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Term
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Definition
20 deciduous teeth-baby teeth by 2 yrs.
32 permanent teeth-adult- 6-25 yrs.
Occlusal surfaces and cusp numbers differ. |
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Term
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Definition
| outer layer outside of bone where tooth attaches. When you have peridontal disease, the ligament gets eaten away and tooth falls out. |
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Term
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Definition
| Non cellular secretion, Hardest bone in the body. |
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Term
Cementum and dentin
&
root canal |
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Definition
living tissue.
Root canal-leads into pulp cavity->nerves and blood vessels. |
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Term
| Incisors, Canines, premolars, molars |
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Definition
1.nippers and bitters
2.canines are called eye teeth, form fangs, used to pierce to kill.
3. premolars-bicupids, transitional teeth between canines and molars.
4. Molars vary considerably between species and used as grinding teeth in humans. |
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Term
SALIVA
enzymes in saliva:Salivary amylase & Lingual Lipase |
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Definition
Moisten food and breaks down carbs and fats.
1.Salivary amylase-breaks down carbs.
2.lingual lipase breaks down fats when it hits stomach but it is made in saliva.
2.Cleanse teeth
3.Inhibit bacteria
4.Bind food together.
4.Bind food together into bolus.(lingual lipase and salivary amylase make bolus, which is food that you chew and turns into big blog you swallow. |
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Term
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Definition
contact of food with sensory receptors triggers chewing reflex.
->tounge, buccinator & orbicularis oris manipulate food.
-->masseter and temporalis elevate teeth to crush food.
-->medial and lateral pterygoids swing teeth in side to side action of molars |
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Term
| Salivary amylase & Lingual lipase |
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Definition
->SA-begins starch digestion
->LL-digests fat, activated by stomach acid. |
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Term
| Mucus, lysozyme, IgA, and electrolytes |
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Definition
aids in swallowing (mucus)
Lysozyme-enzyme that kills bacteria
IgA- inhibits bacterial growth
Electrolytes-Na, K, and Cl, HCO3 and HPO4 |
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Term
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Definition
Hypotonic solution *(fewer solutes that the ECF of body) of 99.5% water and solutes. (slightly Acidic)
Ph is 6.8-7.0 acidic |
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Term
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Definition
1-1.5L a day.
Cells filter water from blood and other substances.
Food stimulates receptors that signal salivatory nuclei in medually and pons. |
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Term
| Parasympathetic and Sympathetic stimulation |
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Definition
Para-salivary glands produce thin saliva, rich in enzymes.
Sympa-produce less abundant, thicker saliva, with more mucus.
Higher brain centers stimulate salivatory nuclei so sight, smell, and thought of food cause salivation.Just thinking about food=Salivation. |
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Term
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Definition
Straight muscular tube-skeletal muscle in upper part and smooth in lower part in order to stop from stuff coming in.
It extends from pharynx to cardiac stomach-->hiatus-->diaphram.
LES-closes orifice to reflux (prevent stuff going back up) |
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Term
| Swallowing(Deglutition) & Peristalsis |
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Definition
1.Series of muscular contractions coordinated by center in medulla and pons.
2. Can swallow upside down due to Peristalsis (one way wave of muscular contrations) |
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Term
| Buccal Phase of swallowing |
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Definition
| tongue collects food and pushes it back into oropharynx. |
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Term
| Pharyngeal-Esophageal Phase of swallowing |
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Definition
1.Soft palate rises and blocks nasopharynx.(Uvula rises back up so food doesn't go back into their nose)
2.Infrahyoid muscle lifts larynx, epiglottis folded back.
3.Pharyngeal constrictors push bolus down esophagus.
-liquid in 2 s and food in 8s.
LES relaxes. |
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Term
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Definition
Mechanically breaks up food, liquifies food and begins chemical digestion of protein and fat, resulting in soupy mixture called CHYME.
Does NOT absorb significat amount of nutrients but does absorb aspirin and some lipid soluble drugs.
Hydorchloric Acid takes food and turnes it into chyme. |
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Term
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Definition
1.Innervented by para vagus nerve and sympa fibers from celiac plexus.
Blood from stomach enters hepatic portal circulaiton and is filtered through liver before returning to the heart! |
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Term
| Stomach Wall (your stomach can expand to 1 gallon) |
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Definition
Mucosa-1.simple columnar glandular epithelium.
2.Lamin propria is filled with gastric pits.
Muscularis Externa has 3 layers;
1.Longitudinal-goes lenght of stomach
2.Circular-goes around stomach
3.Oblique-goes diagonal
All muscles smash up food. |
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Term
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Definition
Mucous cells
regenerative cells
parietal cells
cheif cells
enteroendocrine cells
g cells |
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Term
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Definition
secrete mucus-to protect wall of stomach to protect itself.
g-cells gastrin- enzyme in the stomach. |
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Term
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Definition
| Secrete HCL and Intrinsic factor. HCL is manufactured in parietal cells. Contains CAH which speeds up reactions. |
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Term
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Definition
1.Secrete pepsinogen= breaks down small peptides/proteins.
2.Chymosin and lipase in infancy |
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Term
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Definition
secrete histamine, hormones, and paracrine messengers.
Histamine- |
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Term
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Definition
Parietal cells contain CAH-> Carbonic Anhydrase.
CO2 + H2O--> H2CO3--> HCO3- + |
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Term
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Definition
Stomach is full of HCL
1.Activates pepsin and lingual lipase
2.breaks up connective tissues and plant cell walls.
3.Liquefies food to form chyme
4.converts ingested ferric ions (Fe3+) to ferrous ions (Fe2+)
5.Absorbed and used for hemoglobin synthesis.
6.Destroys ingested bacteria and pathogens.
7.Breaks down large proteins. |
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Term
Intrinsic Factor for Gastric
pernicious anemia |
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Definition
1.Essential for B12 absorption by small intestine.
2.RBC production-lack causes pernicious anemia
Pernicious anemia is a disease that occurs when your intestines cannot absorb b12. |
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Term
Gastric enzymes PEPSIN & gastrin
(Enzyme in stomach) |
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Definition
1.Pepsin-protein digestion
-secreted as pepsinogen (inactive form and is activated by HCl which converts it to pepsin (active). The two work together to break down proteins.
Gastrin- |
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Term
Gastric enzyme LIPASE & CHYMOSIN
(In stomach) |
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Definition
Lipase-digests butterfat of milk in infant.
Chymosin-Curdles fat
These only work when we are kids.
Chymosin-curdles milk by coagulation proteins. |
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Term
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Definition
1.Swallowing center signals stomach to relax.
2.food stretches stomach activation a receptive-relaxation response. Resists stretching briefly, but relaxes to hold more food.
2.Rhythm of peristalsis controlled by pacemaker cells in longitudinal muscle layer.
-contraction every 20s mixes food w/ gastric juice
-stronger contration at pyloric region, ejects 3mL
-Typical meal emptied from stomach in 4 hours |
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Term
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Definition
Caused by chemical or psy irritants.
Ementic center in medulla causes;
1.retching:
-Lower esophageal sphincter relaxes
-stomach & duodenum contract spasmodically.
2. Vomiting
-when abdominal contraction forces upper esophageal sphincter to open. |
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Term
Gastric function
1.Cephalic Phase |
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Definition
Sight, smell, taste, or thought of food.
Vagus nerve stimulates gastric secretion and motility. |
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Term
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Definition
Activated by presence of food or semidigestion protein.
-by stretch or increased pH.
Secretion stimulated by:
1.Ach-para fibers
2.Histamine-from gastric enteroendocrine cells causes gastric secretion.
3.Gastrin-from pyloric G Cells secrets intrinsic factor, HCl, and pepsin
Stimulates parietal and chief cells |
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Term
3.Intestinal Phase
COME back to this one! |
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Definition
Duodenum regulates gastric activity though hormones and nervous reflexes.
2.Enterogastric reflex-duodenum inhibits stomach. Caused by acid and semi-digested fats in duodenum. (tells the stomach to slow down bc there is duodenum still has food to process) |
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Term
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Definition
A series of muscular contraction coordinated by the center in Medualla and pons.
Monitor signals from cranial nerves 5,7,9,and 12. |
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Term
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Definition
zymogens are inactive form. they are precursor molecules that have to be activated. Anything that ends with ogen are zymogens.
when pepsiongen is activated it turns into pepsin |
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Term
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Definition
Swallowing center signal stomach to relax. (the moment you swallow the stomach starts opening sphincter, food starts coming down and LES opens to take food in)
food stretches stomach activating a receptor-relaxation response (when you eat food and it goes into your stomach it automatically causes your stomach muscle to relax then it expands and makes more room for food)
Resists then relaxes. |
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Term
| Pacemaker cells in stomach |
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Definition
control rythum of peristalsis.
Every 20sec there is a contraction that churns and mixes food w/gastric juice.
Stronger contractions at pyloric region ejects 3mL
Meal emptied in 4 hours |
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Term
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Definition
1.Excess stretch of stomach-eat too much.
2.Psychological or chemical irritants like bacteria.
Side note-bile comes back up from duodenum when there is nothing in your stomach. |
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Term
| Ementic center in medualla and Vomiting |
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Definition
1.Retching-LES relaxes
2.stomach & duodenum contracts spasmodically to force stuff out.
3.vomitting when abdominal contraction forces upper esophageal to open. |
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Term
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Definition
| Most in duodenum b/c everything dumps in duodenum. likely to get cancer. |
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Term
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Definition
| Slight, smell, taste, or though of food. Vagus nerve stimulates gastric secretion and motility. |
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Term
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Definition
Food in stomach or semi digested proteins activate gastric activity an is stimulated by:
*ACh-Parasym fibers
*Histamine-from enteroendrine cells->cause gastric secretion
*Gastrin-from pyloric g cells
->stimulates parietal and chief cells.
Parietal->intrinsic factor and HCL
Chief-->pepsin-->breaks down protein. |
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Term
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Definition
the duodenum regulates gastric activity (tells it to slow down) via hormones, and nervous reflexes.
1.at first gastric activity increases.
2.Enterogastric reflex-duodenum has food in its area and is still processing it so it tells stomach to slow down.
3.Chyme stimulates duodenal cells to release:
*Secretin
*CCK (cholecystokinin)
*GIP (Gastric inhibitory peptide) |
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Term
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Definition
-3 pounds= brain equal important.
-Contains tiny cylinders called hepatic lobules (have triads)
*4 lobes-quadrate, cuadate, R&L
*Round ligament-umbilical vein (left over after we are born) |
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Term
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Definition
*Blood filtered by hepatocytes on its way to central vein.(going back to heart)
Each corner of liver (lobule) has:
Bile ductile-collects bile from canaliculi between sheets of hepatocytes to be secreted from liver in hepatic ducts.
*Branch of hepatic artery-carries oxy blood from the heart to tissues of liver.
*branch of hepatic portal vein-nutrient rich blood coming into liver from stomach and intestines through this portal vein.
*Hepatic Vein-takes blood out of liver into vena cava and into the heart. Something about central canal also. |
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Term
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Definition
1.Metabolizes carbs, fats, and proteins.
disassembles and reassembles into food you need.
2.Bile salts emusifles-breaks down big chunks into small chunks.
3.stores glycogen
4.excretes biliruben from breakdown of heme group in RBC.Yellow
5.processes drugs, alcohol, and hormones.
6.kuffer cells-fixed macrophages to filter blood.
7.vitamin D-activated by skin and kidney and liver. |
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Term
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Definition
1.Retroperitoneal gland-posterior to stomach.
2.endocrine-secretes insulin and glucagon into the blood. I-lowers G-elevates.
3.Exocrine-Secretes 1500mL of pancreatic juice including Na bicarbonate (baking soda), H20, enzymes, zymogens.
Bicarbonate neutralizes the acid. |
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Term
| Hepatopancreatic sphincter |
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Definition
| regulates release of bile and pancreatic juice into duodenum. |
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Term
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Definition
| Made by the liver but is stored in the gallbladder. All it does is break down big chunks to small chunks. |
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Term
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Definition
-gb stores and concentrates bile, IT BACKS UP INTO THE GALLB. FROM A FILLED BILE DUCT.
-It makes it a lot more concentrated 20x more of what it was when it was in the liver. |
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Term
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Definition
bili-heme group breakdown
stero-intestinal bacteria convert bili to stero |
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Term
| Enterohepatic circulation |
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Definition
recycle of bile acids in ileum-
gallbladder dumps bile into small intestine. In ileum bile is reabsorbed and sent to the liver.
Intestines to liver. |
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Term
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Definition
*Zymogens=proteases->enzyme that breaks down proteins.
Trypsinogen
chymotrypsinogen
procarboxypeptidase
Amylase-breaks down carbs
lipase-breaks down fats
Ribonuclease & deoxyribonuclease-break down nucleaic acids.
Pancrease secretes these into the duodenum.
Pancrease breaks down everything! |
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Term
Activation of Zymogens
Trypsinogen, chymotrypsin, and carboxypeptidase (SECRETIONS) |
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Definition
You just need one enzyme to start the process.
Trypsinogen is converted to trypsin by enterokinase.
Trypsin also converts chymotrypsin and carboxypeptidase.
They all get activted in small intestine and begin digestion of food. |
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Term
Hormonal control of secretion (small intestine)
CCK |
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Definition
| CCK-released from duodenum in response to arrival of acid and fat.(chyme from stomach flows into duodenum and d releases cck)Causes contraction of gallbladder(squeeze bile in), secretion of pancreatic enzymes and relaxes of hepatopancreatic sphincter (allows secretion into duodenum) |
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Term
Hormonal control of secretion (small intestine)
SECRETIN |
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Definition
| Secretin-released from duodenum in response to acidic chyme.Stimulates all ducts to secrete more bicarbonte-Buffer that will nutrilze all acid in small intestine. |
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Term
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Definition
| Gastrin-g-cells->from stomach and duodenum weakly stimulates gallbladder contraction and pancreatic enzyme secretion. |
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Term
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Definition
Hydrolyze DNA and RNA to nucleotides
*nucleosidases and phosphates of brush border split them into phosphate ion, ribose, or deoxyribose sugar and nitrogenous bases. |
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Term
| How vitamins are absorbed |
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Definition
absorbed unchanged- A,D,E, and K with other lipids-
-B and C complex by simple diffusion
-B12 bound to intrinsic factor |
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Term
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Definition
absorbed along small intestine
Na cotransported
Cl exchanged for bicarbonate reversing stomach
iron and calcium absorbed as needed |
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Term
| Water absorption/diarrhea/constipation |
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Definition
8L absorbed by small intestine,
water follows solutes
Diarrhea-occurs when too little water is absorbed in small intestine.
Constipation-occurs when too much water is absorbed by small intestine. |
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Term
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Definition
Gas-average person produces 500mL a day.
most of it is swallowed air (no odor)
Protein produces odor |
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Term
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Definition
Consists of water and solids(bacteria,mucus,undigested fiber, fat and sloughed epithelial cells)
Haustral contractions occur every 20min
you pass about 1-3x per day
triggered by gastrocolic and duodenocolic reflexes |
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Term
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Definition
1.stretching of the rectum stimulates defecation
2.Intrinsic defecation reflex via myeneteric plexus
-causes muscularis to contract and internal sphincter to relax.
-it happens only if external anal sphincter is voluntarily relaxed.
3.Parasympathetic defecation reflex involves spinal cord
via stretching of rectum sends sensory signals to spinal cord.
-splanchnic nerves return signals intensifying peristalsis. |
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