Dental Physiology _ level 4 _ Classified by similarity in structure and function and paracrine secretions for regulation of digestive tract

1. Hormonal Regulation of Digestive Tract and Paracrine secretions for Regulation of Digestive Tract
BY: Olla BaEissa
 Secretin family : secretin, glucagon, VIP, GIP
HORMONE STIMULUS ORIGIN TARGET EFFECT
Secretin
Arrival of chyme in
duodenum
Duodenum
Pancreas  Stimulates the alkaline secretion
Stomach  Inhibits gastric secretion and motility
Liver  Increases rate of bile secretion
Gastric
inhibitory
peptide
(GIP)
Arrival of chyme
containing large
amount of fats and
glucose
Duodenum &
jejunum
Stomach  Inhibits gastric secretion and motility
Pancreas  Stimulates insulin secretion

2.  Gastrin family : gastrin, CCK
HORMONE STIMULUS ORIGIN TARGET EFFECT
Gastrin
- Vagus nerve,
parasympathetic
stimulation.
- Arrival of food in the
stomach.
- Arrival of chyme
containing large
amount of undigested
proteins
Stomach
Duodenum
Stomach
 Stimulates the production of acid
and enzymes
 stimulates the motility
Stomach
 Stimulates the production of acid
and enzymes
 stimulates the motility
Cholecysto
-kinin
(CCK)
Arrival of chyme
containing lipids and
partially digested
proteins
Duodenum
Pancreas  Stimulates the production of
pancreatic enzymes
Gallbladder Stimulates the contraction of GB
Duodenum Relaxation of sphincter of Oddi
Stomach  Inhibits gastric acid and motility

3. Paracrine secretions for Regulation of Digestive Tract
HORMONE STIMULUS ORIGIN TARGET EFFECT
Somatostatin Acid in the lumen
D cells in the
gastrointestinal
mucosa
Stomach
 Inhibits gastric acid secretion and
motility,
 Inhibits the secretion of: gastrin, VIP,
secretin
Small
intestine
 Inhibits the secretion of gastrin
Pancreas
 Inhibits pancreatic secretion,
 Inhibits the secretion of secretin
Gall
bladder
 Inhibits Gall bladder contraction

4. Pancreatic juice – digesting enzymes
Active enzyme Inactive enzyme
(the production form)
Activator Substrate Catalytic function
Pancreatic amylase
Starch
(polysaccharide)
α limit dextrins &
maltotriose (disaccharide) &
maltose (monosaccharide)
Pancreatic lipase Triglycerides Monoglycerides & fatty acids
Colipase Procolipase Fat droplets
Assist pancreatic lipase to act
on Triglycerides
Trypsin Trypsinogen
Entero-peptidase
Or Entro-kinase
Proteins and
polypeptides
Chymotrypsin Chymotrpsinogen Trypsin
Proteins and
polypeptides
Carboxypeptidase A Procarboxy-
Peptidase A
Trypsin Proteins and
polypeptides
Carboxypeptidase B Procarboxy-
Peptidase B
Trypsin
Proteins and
polypeptides
Elastase Proelastase Trypsin
Elastin & some
other proteins