Physiology of digestion and absorption - consolidation

Question 1

what is absorbed in the ileum

Answer 1

micronutrients (eg vitamin b12)

Question 2

4 juices secreted in small intestine

Answer 2

chyme
pancreatic juice
bile
succus entericus

Question 3

another name for the brush border

Answer 3

microvilli

Question 4

7 hormones secreted by the small intesine

Answer 4

Gastrin
Ghrelin
GLP-1
GIP 
CKK
secretin 
Motilin

Question 5

other than the duodenum, where is gastrin released

Answer 5

from g cells of gastric antrum

Question 6

GIP is an incretin, what is this

Answer 6

act upon Beta cells of pancreas, stimulate release of insulin

Question 7

which other hormone is an incretin

Answer 7

GLP-1

Question 8

functions of ghrelin

Answer 8

increass appetite

Question 9

3 gut hormones associated with enhances peristalsis

Answer 9

gastrin
CKK
secretin

Question 10

3 components of secretion

Answer 10

mucus - protection/lube
aqueous salt - for enzymatic digestion
no digestive enzymes

Question 11

3 channels involved in the secretiojn

Answer 11

NA+/K+ ATPase
Na+/K+/2Cl- co-transporter
Chloride channel (CFTR)

Question 12

where are the aqeuous salts secreted from (mostly)

Answer 12

crypts of Lieberkuhn

bottom areas of villi

Question 13

sodium chloride and accompanying water are moved in what direction

Answer 13

basolateral membrane - lumen

Question 14

what drives the co-transporter

Answer 14

low intracellular conc of Na

secondary active transport

Question 15

how does chlorine enter lumen

Answer 15

difference in electrochemical gradient, incr in chloride in basolateral membrane when pumpeed in, CFTR balances

Question 16

factors of cystic fibrosis in intestine

Answer 16

cystic fibrosis - not only sticky mucus, electrolytes and enzymes decr.

Question 17

t/f K,Na,Cl, and H20 are found in lumen

Answer 17

false

K is not (or not as much)

Question 18

when does segmentation occur

Answer 18

during meal
very rigorous after meal
(little/none between)

Question 19

which hormone triggers segmentation, when does it occur, what is this reflex called

Answer 19

gastrin
when empty, anticipation of food
gastroileal reflex

Question 20

MMC characteristic

Answer 20

clears small intestine of debris,mucus and soughed epithelial cells
goes through full smll intestin

Question 21

which hormone triggers MMC

Answer 21

motilin

Question 22

which 2 hormones suppress MMC

Answer 22

gastrin

CCK

Question 23

t/f vagal activity enhances MMC

Answer 23

false

inhibited by feeding and vagal

Question 24

macroslide antibiotics mimic effect of

Answer 24

motilin
triggers MMC
may cause GI disturbances

Question 25

for pancreatic duct cells, chloride is secreted in via CFTR, yet recycled. what is it exchanged for when it enters the lumen

Answer 25

HCO3- | for neutralisatin

Question 26

3 proteases secreted by pancreas

Answer 26

trypsinogen chymotrpysinogen procarboxypeptidase A and B

Question 27

which duodenum enzyme activates pancreatic proteases

Answer 27

enterokinase

Question 28

3 phases of control of pancreatic secretion (cephalic, gastric, intestinal)

Answer 28

cephalic - mediated by vagal (due to acinar) gastric -distension evokes vagovagal reflex, parasympa stimulation of acinar and duct cells intestinal - majority of secretion, due to release of secretin/CKK

Question 29

t/f disaccharides can be absorbed

Answer 29

false only monosaccharides gluocse/galactose ect

Question 30

t/f tetrapeptides can be absorbed

Answer 30

true | usually broken down in epithelium

Question 31

differenc in links in amylose and amylopectin (starch compounds)

Answer 31

amylose - str8 chain alpha 1,4 links amylopectin - branches alpha-1,4 alpha-1,6

Question 32

when starch is digested, broken down to ogliosaccharides, what do these consist of

Answer 32

alpha limit dextrins malotriose maltose (alpha-amylase used to break down, salivary and pancreatic glands)

Question 33

enzymes associated with membrane digestion (ogliosaccharidases)

Answer 33

lactase maltase sucrase-isomaltase

Question 34

alpha limit dextrins

Answer 34

stay connected since alpha-amylase cannot break branches adjacent to alpha-1,4 links / alpha-1,6 branches

Question 35

all ogliosaccharidases can cleave alpha-1,4 linkages, what does this yield? which one works differently

Answer 35

glucose lactase - breaks down lactose to glucose and galactose

Question 36

which ogliosaccharidases can break the banching alpha-1,6 linkages of alpha limit dextrins

Answer 36

isomaltase

Question 37

glut 2 is the faciliated diffusion for

Answer 37

all monosaccharides

Question 38

which type of enzymes digest proteins first, what is also required sometimes to digest proteins

Answer 38

``` luminal enzymes (to amino) brush border enzymes (to amino) apical membrane transporters may carry them as peptides, then undergoes intracellular hydrolysis ``` or it can be carried as a peptide without intracellular hydrolysis

Question 39

outline digestion in stomach (luminal enzymes)

Answer 39

HCl begins | Pepsin cleaves proteins to peptides (favours aromatic/larger AA- endopeptidase) (nonessential)

Question 40

outline digestion in duodenum

Answer 40

5 pancreatic proteases either endo/exopeptidase | exo-at end/ C terminals

Question 41

which of the pancreatic proteases are exopeptidase

Answer 41

Procarboxypeptidase A and B

Question 42

product of pancreatic endopeptidases

Answer 42

ogliopeptides (2-6 amino acids)

Question 43

why is there so may brush border enzymes

Answer 43

to compensate for the large diversity in AA

Question 44

t/f brush border peptidases have a larger affinity for ogliopeptides

Answer 44

true

Question 45

cytoplasmic peptidases primarily hydrolyse

Answer 45

di/tripeptides

Question 46

how many sodiium dependant transporters are found at brush border, what do they do how many are sodium independent

Answer 46

5 moves neutral amino acids up a conc gradient (hartnup disease) 2 (cystinuria)

Question 47

basolateral has 5 different mechanisms, how many mediate efflux of amino acids and are Na+ independent, and how many mediate influx

Answer 47

3 2 (bidirectional)

Question 48

PepT1 transports

Answer 48

di/tri/tetrapeptides via proton gradient at brush border

Question 49

most amino acids are transported to cell by

Answer 49

sodium dependent transporters

Question 50

why is brush border acidic

Answer 50

Na+/H+ exchanger,