wk 1 7 Physiology of Digestion and Absorption 1

Question 1

the small intestine recieves chyme from stomach, pancreatic juice and bile from gall bladder. Through which sphincter are each received from

Answer 1

Chyme - pyloric sphincter
Pancreatic - sphincter of Oddi
Bile - sphincter of Oddi

Question 2

name given for intestinal juice secreted by small instestines

Answer 2

succus entericus

Question 3

name of valve which moves the remaining residues from small to large intestine

Answer 3

ileocaecal valve

Question 4

3 components of small intestine

Answer 4

duodenum
jejunum
ileum

Question 5

what aspects of small intesting increase the surface dimension, which one is the greatest

Answer 5

circular folds of kerckring
villi
microvilli (largest)

Question 6

what are the secretions of the small intestine (7)

Answer 6

gastrin 
ghrelin 
glucagon-like insulinotropic peptide (GIP)
glucagon-like peptide-1 (GLP-1) 
cholecystokinin (CKK) 
secretin
motiilin

Question 7

cells which both the duodenum and jejunum secrete

Answer 7

CCK - from I cells
Motilin - from M cells
GIP - an incretin from K cells

Question 8

effect of incretins on pancreas

Answer 8

act upon beta cells, stimulate release of insulin

Question 9

3 areas where ghrelin is secreted from

Answer 9

Gr cells from gastric antrum (outlet proportion, no acid)
small intestine
pancreas
also elsewhere

Question 10

L cells of the gut secrete

Answer 10

GLP-1

Question 11

t/f gastrin 
cholecystokinin (CKK) 
secretin
motiilin 
glucagon-like insulinotropic peptide (GIP)
glucagon-like peptide-1 (GLP-1) 
ghrelin 
these secretions act on G-protein coupled receptors

Answer 11

true

Question 12

the mechanisms involved of secretion are:
distension/irritation, gastrin, CKK, secretin, para/sympa nerve activity
which ones increase/decrease secretion

Answer 12

all except sympa enhance

Question 13

t/f secretion of small intestine contains no digestive enzymes

Answer 13

true

Question 14

aqueous salt is part of the secretion of small intestines, what is its purpose

Answer 14

enzymatic digestion

Question 15

function of ‘chopping’

Answer 15

moves chyme back and forth in stomach

Question 16

t/f segmentation (mixing) involves the alternating contraction/relaxation of longlitudinal muscles

Answer 16

false

it is the contraction/ relaxation of circular muscle

Question 17

what is BER of GI
what initiates BER
where are these cells located in stomach, small/large intestine

Answer 17

Basal Electrical rhythm, controls contraction 
Pacemaker (interstitial cells of Cajal) 
Stomach- longitudinal 
Small- circular
Large- circular

Question 18

in the duodenum, what activates segmentaion

Answer 18

distension by entering chyme

Question 19

define distension

Answer 19

outward expansion of stomach

Question 20

segmentation in the empty ileum is triggered by gastrin from the stomach, name given for this reflex

Answer 20

gastroileal reflex

Question 21

Migrating Motor Complex (MMC) is on the activities occurring in he fasting state, explain what it does

Answer 21

clears small intestine through peristalsis

Question 22

what inhibits MMC

Answer 22

feeding and vagal activity (remeber:activity of fasting statw)

Question 23

what triggers/suppresses MMC)

Answer 23

motilin triggers

gastrin and CCK suppress

Question 24

pancreatic juice is an exocrine secretion, what does it consist of

Answer 24

digestive enzymes (acinar cells) 
aqueous NaHCO3- solution (duct cells)

Question 25

insulin and glucagon are endocrine pancreatic secretions, how are they secreted

Answer 25

via blood

Question 26

t/f acidic solutions are high in HCO3-

Answer 26

false

alkaline solutions are high in HCO3- (duct cells)

Question 27

effect of pancreatic duct cells

Answer 27

neutralises acidic chyme entering duodenum, providing optimum pH and protects mucosa

Question 28

t/f amylase and lipase enzymes do not require activation once secreted to the duodenum

Answer 28

true

amylase and lipase are both pancreatic*

Question 29

4 proteases require activation by enterokinase (mucosal cells) when entering the duodenum, what are their inactivated names

Answer 29

trypsinogen
chymotrypsinogen
procarboxypeptidase A and B

Question 30

when would enzymes stored in the zymogen granules of acinar cells be released

Answer 30

in response to elevated Ca2+

Question 31

what does the activation of trypsin autocatalyse

Answer 31

chymotrypsinogen - chymotrypsin

procarboxypeptidase AandB - carboxypeptidase AandB

Question 32

`what does amylase catalyse

Answer 32

hydrolysis of starch into sugars

Question 33

what does lipase do

Answer 33

breaks down fats into monoglycerides and 2 fatty acids

Question 34

outline the pancreatic control of acid levels

Answer 34

acid in duodenal lumen
increase in secretin release from S cells
activates pancreatic duct cells, increases secretion of aqueous NaHCO3 solution

Question 35

outline pancreatic secretions control on digestion

Answer 35

fat and protein in duodenum
incr CCK release from I cells
activates acinar
incr secretion of digestive enzymes in duodenum (lipase,amylase, procarboxypeptidase AandB, chymotrypsinogen, trypsinogen)

Question 36

what mediates the membrane digestion in the small intestines

Answer 36

enzymes situated at the brus border of epithelial cells

Question 37

define absorption

Answer 37

absorbable products of digestion are transferred across the apical (brush border) and basolateral membranes of enterocytes

Question 38

what are enterocytes

Answer 38

absorptive cells of intestinal epithelium

Question 39

name given for overall process of digestion and absorption

Answer 39

assimilation