hormonal control of digestion esophagus to the intestine (feeding to digestion)

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.