The document summarizes the hormonal control of digestion from the esophagus to the small intestine. Key hormones discussed include gastrin which stimulates acid production in the stomach, secretin which raises intestinal pH and stimulates pancreatic secretions, and cholecystokinin which stimulates gallbladder contraction and pancreatic enzyme secretion. The pancreas produces insulin, glucagon, and somatostatin which regulate blood sugar levels. Hormones in the small intestine include secretin, cholecystokinin, and gastric inhibitory peptide which affect gastric emptying and stimulate pancreatic and gallbladder functions.

1. DR. HARI SINGH GOUR CENTRAL UNIVERSITY SAGAR (M.P)
2018-2019
ENDOCRINOLOGY
Hormonal control of digestion-from Oesophagus to intestine
(feed to digestion)
SUBMITTED BY :- NAGENDRA SAHU (MSc 1 sem / DEPARTMENT OF ZOOLOGY)
SUBMITTED TO:- DR. RASHMI SHRIVASTAVA (DEPARTMENT OF ZOOLOGY)

2. Hormonal control of digestion -from oesophagus to intestine (feed to digestion)

3. contents
 Hormonal control of digestion in digestive parts:-
 Digestive organs:- Accessory digestive organs:-
• Oral cavity 1.Salivary gland
• Phrynx 2.Liver/gall bladder
• Oesophagus 3.Pancrease
• Stomach
• Intestine

4. Oral cavity
 Boundaries are:
• lips (anteriorly)
• cheeks (laterally)
• palate (superiorly)
 Important in:
• Ingest food
• Saliva ph-7 (moisten and soften food)
• Tongue mixes food with saliva and rolls food
into bolus before swallowing
• mastication (chewing): mechanical digestion
• secretion of saliva for digestion
(amylase; digests starch)

5. Tongue and Teeth
Tongue
• (upper part of tongue covered
with papillae taste receptor)
• filiform papillae
• fungiform papillae
• circumvallate papillae
Teeth
• mechanical breakdown
• – Incisors
• – Canines
• – Molars
• Primary or deciduous teeth 20
• Secondary or permanent teeth 32

6. Salivary gland
 major salivary glands :-
• parotid glands - produce a serous, watery
secretion.
• submaxillary (mandibular) glands –
produce a serous and mucous secretion.
• Sublingual glands - secrete a saliva
mucous in character.
• Mixture of mucus and serous fluids Helps
to form a food bolus
• Contains salivary amylase to begin starch
digestion

7. pharynx
 Pharynx
• It is the passageway from the nose and mouth to the oesophagus and respiratory
tract
Nasopharynx
Oropharynx
Laryngopharynx
Serves as a passageway for air and food
• Food is propelled to the oesophagus by two
muscle layers:-
Longitudinal inner layer
Circular outer layer
• Food movement is by alternating contractions of the muscle layers (peristalsis)

8. oesophagus
• The oesophagus is a( 25 cm) passageway from the pharynx to stomach
Contains two sphincters: upper and lower:-
 Upper sphincter is skeletal (voluntary),
 lower sphincter is smooth muscle (involuntary)
• The oesophagus is posterior to the larynx and
trachea in the neck region and upper thorax.
• It travels on the right side of the descending aorta,
passes through the diaphragm, and connects with the
stomach.

9. Stomach
• Located on the left side of the abdominal cavity Food enters at the cardio
oesophageal sphincter.
• Site where food is churned into Chyme
Protein digestion begins.
• The stomach stores food, and mixes and
mechanically and chemically digests it
• The stomach also secretes digestive juices
pepsin: digests protein
• hydrochloric acid (acidic pH, required for
pepsin activity, and to kill ingested bacteria)
• Mucus: protects the stomach wall.

10. Histology and endocrine of stomach
 Cell types:
• Chief cells: produce pepsinogen (inactive
precursor to pepsin)
• Parietal cells: produce HCL(Hydrochloric acid)
“Endocrine” cells:
• G cells: gastrin
• D cells: somatostatin (paracrine)
• Enterochromaffin-like cells: histamine
(paracrine)

11.  Gastric hormones:-
 GASTRIN:-
 Secretion:- By enteroendocrine (G) cells in gastric pits of the mucosa.
 Stimulus-: Stomach distention and acid pH of chyme causes Gastrin.
 Action:-
1. increases HCL production in stomach
2. contract lower esophageal sphincter
3. relaxes pyloric sphincter
Somatostatin:
 Secretion:- By enteroendocrine (D) cells in gastric pits of the mucosa in the pylorus.
 Stimulus:- continuously released, overridden by Gastrin and nerves
 Action:-
• Inhibition of Gastrin production

12. liver and gallbladder
• Largest gland
• Located on the right side under
the diaphragm
• Consists of four lobes
(left and right, caudate , and quadrate)
• Connected to the gall bladder via
the common hepatic duct
• Detoxifies drugs and alcohol
• Degrades hormones
• Produce cholesterol, blood proteins .

13.  Bile:-
• Produced by cells in the liver
Composition:-
• Bile salts
• Bile pigment (mostly bilirubin
from the breakdown of haemoglobin)
• Cholesterol
• Phospholipids
• Electrolytes
 Gall Bladder:-
• Sac found in hollow fossa of liver
• Stores bile from the liver
by way of the cystic duct
• Gallstones can cause blockages

14. Pancreas
• The pancreas is an digestive accessory organ
• It secrete chemicals to aid in digestion.
• Secretin will stimulate the pancreas.
• release a solution containing bicarbonate ion
• into the small intestine.
• raise the pH from 2.5 to 9.0.
• inactivates pepsin.

15. Endocrinology of pancreas
• The acinar portion of pancreas has exocrine function .
• Endocrine portion consists of islets of Langerhans.
 Insulin:-
• hetero dimeric polypeptide .
• Glucose level more than 70mg/dl stimulates insulin synthesis , primarily by
enhancing protein translation & processing .
• Produced by beta cells.
• The major organs involved in insulin metabolism are liver , kidney & the
placenta .

16.  Glucagon:-
• synthesized as precursor molecule.
• Glucagon is inactivated by liver
enzyme removes 1st 2 amino acids.
• Produced by alpha cells.
 Somatostatin:-
• Produced by delta cells.
• It inhibit secretion of insulin and
glucagon.

17. endocrinology of Small intestine
• The body’s major digestive organ.
• Site of nutrient absorption into the blood.
 Subdivisions of the Small Intestine
 Duodenum (25cm)
• Attached to the stomach
Jejunum (2.5m)
• Attaches anteriorly to the duodenum
 Ileum (3.5m)
• Extends from jejunum to large intestine

18.  SECRETIN:-
 Secretion:- By Enteroendocrine (S) cells in the Crypts of Lieberkuhn of small intestine.
 Stimulus:- Acid chyme in small intestine causes secretion of Secretin:
 Actions:-
– stimulate secretion of pancreatic juice and bile that is rich in bicarbonate ions.
– inhibit production of HCl in stomach
– enhance effects of Cholecystokinin (CCK)
– Increases rate of bile secretion by hepatocytes
 CHOLECYSTOKININ (CCK):-
 Secretion:- Enteroendocrine (CCK) cells in the small intestine mucosa Crypts of Lieberkuhn
 Stimulus:- Chayme rich in amino acids, triglycerides and fatty acids enter the small intestine.
 Actions:-
– increases secretion of pancreatic juice rich in digestive enzymes
– contracts the gallbladder
– Inhibits gastric secretion .

19. Gastric Inhibitory Peptide (GIP):-
 Secretion:- Enteroendocrine cells in the small intestine mucosa Crypts of Lieberkuhn
 Stimulus:- Chayme rich in triglycerides, fatty acids, and glucose enter the small
intestine.
 Actions:-
– Stimulates release of insulin by beta cells
– Inhibits gastric secretion and motility
– Stimulates lipogenesis by adipose tissue

20. •REFRENCE:-
1. CLASS NOTES.
2. MEDICAL PHYSIOLOGY. Viz GUYTON AND HALL.
3. WIKIPEIDA.
4. YOUTUBE.