Upgrade to remove ads
physio final exam
Terms in this set (39)
What are the three functions of gastric acid secretion?
1) activates pepsinogen
2) breaks down connective tissue in diet
3) kills micro-organisms
What micro-organism does gastric acid not kill? Why?
-survives by making urease to form ammonia
What does H.pylori result in?
-inflammation causing peptic ulcers
-body starts to kill own cells in stomach
due to exposure of acid
How do cells produce acid?
-by the parietal cells
-lots of mitochondria, needs ATP to push against increased concentration gradient
What is the first process that produces acid?
1) H formed from CO2 +H2O using Carbonic anhydrase
What is the second process that produces acid?
2) H pumped into lumen by H/K-ATPase
-knocked out by drugs to decrease stomach acid
What is the third process that produces acid?
3) Cl- exits via channel (into the lumen)
What is the fourth process that produces acid?
4) HCO3/Cl exchanger moves HCO3 out of cell, Cl in
What are the three secretagogue?
What is acetylcholine released by?
What is the stimuli for release in acetylcholine? (2)
1) central- sight and smell of food
2) local- protein in stomach
What is gastrin released by?
G cells in gastric antrum
What is the stimulus for release in gastrin?
protein, stomach distention, Ach
What is histamine released by?
enterochromaffin- like cells (ECL)
-binds to H2 receptors on parietal cell
What is the stimulus for release in histamine?
Ach and gastrin
inhibition of acid secretion is generally released from what?
What are the three inhibitors for acid secretion?
1) secretion (stimulus and acid)
2) GIP (gastric inhibitory polypeptide)
3) CCK (fatty acids and peptides)
What is the role of tight junctions?
-make mucosa impermeable to H+
What is mucus secreted by?
surface and neck cells
What is bicarbonate secreted by?
surface epithelial cells
What are the three actions of prostaglandins?
1) acid secretion decreases
2) cytoprotective properties (protect mucosa
3) stimulate fluid secretion
What are prostaglandins inhibited by?
aspirins and NSAIDS (non steroidal anti-inflammatory drugs)
pancreatic exocrine secretion enters what?
ducts and enzymes
Enzymes are secreted from where in pancreatic secretion? release stimulated by what?
secreted from acinar cells (where enzymes are made)
stimulated by CCK
Bicarbonate secretion function?
neutralizes stomach acid
Bicarbonate secreted from? stimulated from?
- secreted from duct cells (where bicarbonate is made)
-stimulated by secretion (triggered by acid)
What is the first step of bicarbonate secretion?
H+ and HCO3- is formed by carbonic anhydrase
What is the second step of bicarbonate secretion?
H+ pumped out on basolateral side by Na+/H+ exchanger
What is the third step of bicarbonate secretion?
-HCO3/Cl exchange on luminal side
What is the fourth step of bicarbonate secretion?
-Cl secreted into lumen by Cl channel (CFTR)
What is cystic fibrosis defect?
-cystic fibrosis transmembrane regulator
What is the type of channel is Cystic fibrosis?
What does Cystic fibrosis defect cause? (2)
1) reduced fluid secretion (mucosa starts to dry up, decreases protection)
2) more mucus formation (trouble breathing)
What is the function of Villi?
What is the function of crypts?
During absorption what occurs?
-Na+ enters enterocyte by glucose, amino acids, H+
During secretion what occurs?
1) Na/K/2Cl carrier on basolateral side
2) Cl enters lumen via CFTR
3) Na+, water diffuse into lumen
What is the role of cAMP?
keeps CFTR open (opposite of cystic fibrosis effect)
What stimulates cAMP?
-Cholera toxin ( blood volume-> BP-> death)
-VIP (neurotransmitter affects smooth muscle, endocrine tumors)
THIS SET IS OFTEN IN FOLDERS WITH...
Digestion and Absorption
Endocrine principles/ The pituitary
YOU MIGHT ALSO LIKE...
Digestion part 1
First Aid - GI Hormones
Chapter 24, Eating and Excreting
OTHER SETS BY THIS CREATOR
Older Adult- Nutrition
Hormones of the Adrenal Cortex
OTHER QUIZLET SETS
COMLEX set 1
Medical Microbio Terms: Lecture 1
Developing and Developed Counries
Bio exam 2