Urinary and Digestive System Flashcards
What is the descending limb of loop of henle not permeable to?
Ions. Only permeable to water
What is ascending limb of loop of henle permeable to?
Ions. Not permeable to water
When is the collecting duct permeable to H2O?
When ADH is present
What is the function of the vasa recta?
maintains high sodium concentration in medulla of kidney by continually returning water to the blood stream
What kind of receptors are JG cells?
baroreceptors
What enzyme do JG cells secrete?
Renin
What is the function of Renin?
Activate Angiontensinogen to Angiotensin I
What converts Angiotensin I to Angiotensin II?
ACE
Why would a JG cell secrete Renin?
To increase blood pressure
What does Angiotensin II cause release of?
ADH
What receptors do macula densa have?
Chemoreceptors
When filtrate osmolarity is low, what do macula densa tell JG cells?
To secrete Renin and dilate afferent arterioles
What hormone in the urinary system increases vasoconstriction to increase blood pressure?
Angiotensin II
When plasma pH is to high, what is in the urine?
bicarbonate
When plasma pH is low, what is in the urine?
Protons
Function of pancreatic lipase
turn triglyceride into fatty acids and monoglycerides
what turns polysaccharides into disaccharides in the mouth?
Ptyalin
What turns polysaccharides into disaccharides in the small intestine?
Pancreatic amylase
What turns disaccharides into monosaccharides in the intestine?
brush border disaccharidases
what turns polypeptides into dipeptides and tripeptides in the stomach?
Gastric acid, Pepsin
What turns polypeptides into dipeptides and tripeptides in the duodenum?
Pancreatic Proteases
What turns dipeptides and tripeptides into single amino acids in intestine?
brush border peptidases
In peristalsis what prevents bolus from flowing backwards?
circular muscles
In peristalsis what pushes bolus forward?
longitudinal muscles
What are the two network of neurons in the enteric nervous system?
Myenreric plexus and submuscosal plexus
What is the function of the myenteric plexus?
Gut motility. Coordination of circular and longitudinal muscles
What is function of submucosal plexus?
Regulates enzyme secretion, gut blood flow, and ion-water balance in lumen
What do gastric glands secrete?
Gastric acid and Pepsinogen
What do goblet cells secrete?
mucous
What is difference between endocrine and exocrine secretion?
Endocrine don’t have ducts and enter blood stream they are hormones. Exocrine secrete into ducts these are enzymes.
What cells in the pancreas are exocrine?
Pancreatic acinar cells
What cells in pancreas are endocrine?
Islets of Langerhaans. They are supplied with capillaries
What does parietal cells secrete?
HCl in stomach
What is the function of HCl in the stomach?
Destroy microorganisms, acid-catalyzed hydrolysis of dietary proteins, convert pepsinogen to pepsin
What cells secrete pepsinogen?
Chief cells
What does pepsin do?
Proteolysis
What is chyme?
Food mixed with gastric secretions
What is function of pyloric sphincter?
prevents passage of food from stomach to duodenum
What hormone regulates the passage of food from stomach to the duodenum?
CCK
What do G cell secrete?
Gastrin
What does gastrin stimulate?
acid and pepsin secretion. Gastric motility
What stimulates G cells to release gastrin?
food in stomach and parasympathetic nervous system
What does histamine do in digestive system?
Binds to parietal cells to stimulate acid release
When is histamine secreted?
In response to stomach stretching and gastrin
Where does absorption begin?
duodenum
What is function of the intestinal villus in small intestine?
capillaries absorb nutrients, lacteals transport dietary fats, contains Peyer patches which monitor GI for infection
What is function of bile?
Vehicle for disposal of waste and essential for digestion of fats
What duodenal enzyme activates trypsinogen?
enterokinase
What duodenal enzymes hydrolyze smallest carbohydrates and proteins?
brush border enzymes
What are the duodenal hormones?
CCK, Secretin, enterogastrone
When is CCK secreted?
When there is fat in the duodenum
What does CCK do?
causes pancrease to secrete more enzymes, bile release from gall bladder, and decrease gastric motility. Prevent stomach emptying
When is secretin secreted?
When there is acid in duodenum
What does secretin do?
Makes pancrease release bicarbonate to neutralize HCl
Duodenal pH must be what for max enzyme function?
Neutral
What does enterogastrone do?
decrease stomach emptying
What is function for colonic bacteria?
immunity and supply vitamin K
