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REFLEXES:

STIMULUS:

Gastroenteric reflex

Gastric stretching (after eating)

Gastroileal reflex

Gastric stretching (after eating)

Enterogastric reflex

Duodenal stretching

Defecation reflex

Rectal wall stretching

HORMONE:

Gastrin

EFFECT:

stimulates motility increases secretion along small intestine triggers ileocecal valve to relax increases passage of materials from small to large int. inhibits myenteric plexus slows down peristalsis by constricting pyloric sphincter  triggers peristaltic contractions to force feces out of colon to rectum  stimulates mass movement in large intestine  internal anal sphincter relaxes & external anal sphincter contacts & can be voluntarily relaxes= defecation

EFFECT ON TARGET:

G cells (in pyloric glands of pylorus of stomach)

partially digested proteins in stomach

parietal & chief cells (of gastric glands)

 stimulates cell secretions (pepsinogen & HCl)  increases motility & gastric wall contractions

Duct cells (of pancreas)

CCK

Duodenum

Lipids and proteins in duodenum

Acinar cells (of pancreas)

Triglycerides & FA in duodenum

Stomach

Proteins in duodenum

Stomach

Chyme in duodenum

Intestinal capillaries

Duodenum

[gastric inhibitory peptide]

VIP

[vasoactive intestinal peptide]

Uses both gastroenteric & gastroileal reflexes

TARGET:

Chyme in duodenum [pH lower than 4.5]

Intestinal Gastrin

Can be enhanced by gastrin

STIMULUS FOR SECRETION:

Duodenum

GIP

Can be enhanced by gastrin

SECRETED BY/ SOURCE:

Secretin

[cholecystokinin]

INFO:

Duodenum Duodenum

 triggers pancreatic cells to secrete water & ion buffer solution  increases pH of chyme  inhibits parietal & chief cells  stimulates liver to produce bile  produce & secrete pancreatic enzymes  stimulates bile secretion  relaxes hepato-pancreatic sphincter  stimulates contractions in gallbladder wall  inhibits gastric juice secretion  inhibits gastric juice secretion  inhibits gastric motility  increases gastric juice secretion [activates more pepsinogen for better protein digestion in stomach]  vasodilates/ relaxes intestinal capillaries to increase nutrient absorption  inhibits gastric juice secretion


CARBOHYDRASES

PROTEASES

ENZYME:

SECRETED BY/ SOURCE:

TARGET/ DIGESTS FROM:

PRODUCTS/ DIGESTS DOWN TO:

SALIVARY AMYLASE

parotid salivary glands

Complex carbs/ starches

Disaccharides & trisaccharides

PANCREATIC ALPHA- AMYLASE

pancreas

Complex carbs/ starches

Disaccharides & trisaccharides

MALTASE/ SUCRASE/ LACTASE

Brush border of small intestine

Maltose, sucrose, lactose

Monosaccharides

PEPSIN RENNIN

LIPASES

NUCLEASES

chief cells in stomach chief cells in stomach

INFO:

proteolysis

Secreted as pepsinogen; activated by HCl acid

curdles milk proteins

Only in newborns

DIPEPTIDASES/ PEPTIDASES

Brush border of small intestine

Dipeptides, tripeptides

Amino acids

ENTEROPEPTIDASE [AKA ENTEROKINASE]

Brush border of small intestine

Trypsinogen

Trypsin

TRYPSIN

Pancreas

proteolysis

ELASTASE

Pancreas

proteolysis

CARBOXYPEPTIDASE

Pancreas

proteolysis

CHYMOTRYPSIN

Pancreas

proteolysis

LINGUAL LIPASE

lingual glands in tongue

triglycerides

Fatty acids

PANCREATIC LIPASE

pancreas

triglycerides

Fatty acids

GASTRIC LIPASE

chief cells in stomach

milk fats

Fatty acids

Pancreas

Nucleic acids [RNA or DNA]

Nitrogenous bases

Secreted as trypsinogen; activ by enteropeptidase [aka enterokinase] Secreted as proelastase; activ by trypsin Secreted as procarboxypeptidase; activ by trypsin Secreted as chymotrypsinogen; activ by trypsin starts lipid digestion Needs bile salts



hormones enzymes reflexes rev