D2

Question 1

Key stomach cell types in gastric glands

Answer 1

Mucous cell: secret mucus and bicarbonate
exocrine cell: Parietal cell : secret HCL
Enterochomaffine ( ECL) cell : secrete histamine
chief cell: secrete pepsinogen :
all into stomach lumen

Enteroendocrine cell:
G cell: gastrin
D cell: somatostatin into blood stream

Question 2

HCL role

Answer 2

activate pepsinogen ( was inactive form )
pepsin break down protein into peptide
Activate lingual lipase
inactivate salivary amylase
partially denature protein : break bonds
kill some pathogens

Question 3

Parietal cell

Answer 3

pumps H+ out to lumen
K+ into cell
against pressure graident pirmary active tranport ( use ATP )

Cl into cell from blood stream
bicarbonate into blood stream

Question 4

secondary messenger role

Answer 4

Gastrin, histamine, acetycholine : increase secondary messenger - increase pumps - more acid in stomach

somatostatin : decrease messenger - decrease in pump - less acid in stomach

Question 5

Gastric phase

Answer 5

Food arrive in stomach, receptro detect change in distention, acidity, amino acid peptide
detect change in volume and composition

Neural : parasympathetic + enteric
increase HCL
Increase gastric moility : greater gastric emptying

Hormonal: Gastrin secretion
increase HCL
increase gastric motility
relaxes pyloric sphincter
increase in lower esophageal contraction : no reflux

too much HCL - inhibit gastrin secretion and relase of somatostatin secretion - decrease of HCL Secretion

Question 6

Intestinal phase

Answer 6

food arrives in duodenum
recepter can alter gastric emptying
decreased gastric motility
increased contraction of pyloric sphincter
secretin + cck decrease gastric emptyuing

Question 7

Dumping symdrome

Answer 7

overloading of duodenum :
nausea, sweating , vomiting

Question 8

Bile composition

Answer 8

Bicarbonate : neutralize acidic chyme
cholesterol,
bile pigment
phospholipid,
organic waste
bile salts

Question 9

Enterohepatic circulation

Answer 9

Bile salt enter duodenum aid fat digestion
ileum , reabsorbed back to blood stream

Question 10

Pancreatic secretion - Bicarbonate

Answer 10

pancreatic duct cell
H+ into blood stream
Bicarbonate into pancreatic duct lumen

Question 11

Protein enzymes

Answer 11

secreted inactive then activated in duodenum with brush border enzymes _ trypsin
trypsin first activated by enterokinase 9 brush border enzyme)
it activates chymotrypsiongen
Carboxypeptidase

Pancreatice lipase + amylase activate rightaway

Question 12

Mechanical digestion of small intestine

Answer 12

1. segmentation : area of contraction/relaxation
   brings in contact with absorptive surfaces
   backward/forward motion
   garasympathetic + gastrin : increase (relax = digest more)
   sympathetic decrease (not relax, digest less)
2. migrating myoelectric complex ( MMC) last stage:
   after absorption :
   begin in antrum and moves down entire length of small intensine
   Peristaltic wave: circular muscle constrict, longitudinal muscle contract
   short distance