Question

“Some tissues of Heart, Kidney and Gastro Intestinal tract produce Hormones”.
Substantiate the statement by naming the hormones produced by them.

Answer 1

Answer:

CONTROL BY ANTI NATRIURETIC FACTOR (ANF) - DEFINITION

A peptide called Atrial Natriuretic Factor (ANF), opposes the regulation by RAAS.

The walls of the atria of the heart release ANF in response to an increase in blood volume and pressure.

ANF inhibits the release of renin from the JGA, and thereby inhibits NaCl reabsorption by the collecting duct and reduces aldosterone release from adrenal gland.

Thus ADH, RAAS and ANF provide an elaborate system of checks and balance that regulate the kidney functioning, to control body osmolarity, salt concentrations, blood pressure and blood volume.

HORMONES OF THE STOMACH - DEFINITION

The 'G' cells of the stomach secrete the hormone called gastrin.

The stimuli for gastrin production include; ingestion of meal, distention (swelling/enlargement) of stomach and products of protein digestion.

It has 2 main functions; stimulation of gastric acid secretion and stimulation of growth of the gastric mucosa.

HORMONES OF THE SMALL INTESTINE - DEFINITION

The small intestine secretes 4 hormones; cholecystokinin, secretin, gastric inhibitory peptide (GIP) and Motilin.

While Cholecystokinin and secretin are secreted by all the three parts of the small intestine (duodenum, jejunum and ileum), GIP and motilin is secreted by only duodenum and jejunum.

Cholecystokinin is produced by the 'I' cells, 'S' cells produce secretin, GIP is formed by the 'K' cells and the 'M' cells secrete motilin

These hormones are secreted as a result of various stimuli like protein, fat, carbohydrate and acid in the intestine.

Cholecystokinin

Stimulates pancreatic enzyme and bicarbonate secretion

Stimulates contraction of the gallbladder

Also stimulates the growth of the exocrine pancreas

It inhibits gastric emptying (entry of food into intestine by emptying stomach)

Secretin

It stimulates pepsin secretion from stomach and bicarbonate secretion from both pancreas and gallbladder

Also promotes the growth of exocrine pancreas.

It inhibits gastric acid secretion.

GIP

Stimulates release of insulin from pancreas

Inhibits gastric acid secretion

Motilin

It is involved in the motility of the gastrointestinal tract.

HORMONES OF THE KIDNEYS - DEFINITION

The kidneys secrete 3 different types of hormones; erythropoietin, renin and calcitriol (1,25- dihydroxycholecalciferol).

Erythropoietin and renin are peptide hormones secreted by the juxtaglomerular cells of the kidney

Calcitriol is a steroid hormone synthesized by the cells of the proximal tubules of the nephrons.

Erythropoietin

Its production is stimulated by hypoxia (insufficient oxygen supply to the tissues)

It stimulates the formation of RBC from the haematopoietic stem cells in the bone marrow.

Renin

Decreased blood pressure, low sodium levels are the stimuli for the production of renin from the kidney.

The renin secreted has enzymatic activity and is an important part of renin-angiotensin-aldosterone system (RAAS).

The RAAS plays an important role in regulating the cardiac output and arterial pressure.

The main function of renin in the RAAS system is the conversion of angiotensinogen to angiotensin I (proteolytic activity).

Calcitriol (1,25- dihydroxycholecalciferol)

It is the active form of vitamin D.

It stimulates the formation of calcium-binding protein thereby increasing the intestinal absorption of calcium.

Thus, it plays an important role in the mineralization of the bone (bone formation)

GASTROINTESTINAL HORMONE - DEFINITION

Certain cells of the mucosa of the stomach and intestine secrete important hormones.

Stomach

Gastrin

Intestine

Secretin

Cholecystokinin-pancreozymin

Gastric inhibitory peptide GIP

Duocrinin

Enterocrinin

Vasoactive intestinal peptide

Villikinin

Somatostatin

Pancreatic polypeptide

HORMONES RELEASED BY KIDNEY - DEFINITION

The kidneys secrete three hormones:

Renin

Erythropoietin

Calcitriol

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Answer 2

Answer:

CONTROL BY ANTI NATRIURETIC FACTOR (ANF) - DEFINITION

1. A peptide called Atrial Natriuretic Factor (ANF), opposes the regulation by RAAS.
2. The walls of the atria of the heart release ANF in response to an increase in blood volume and pressure.
3. ANF inhibits the release of renin from the JGA, and thereby inhibits NaCl reabsorption by the collecting duct and reduces aldosterone release from adrenal gland.
4. Thus ADH, RAAS and ANF provide an elaborate system of checks and balance that regulate the kidney functioning, to control body osmolarity, salt concentrations, blood pressure and blood volume.

HORMONES OF THE STOMACH - DEFINITION

1. The 'G' cells of the stomach secrete the hormone called gastrin.
2. The stimuli for gastrin production include; ingestion of meal, distention (swelling/enlargement) of stomach and products of protein digestion.
3. It has 2 main functions; stimulation of gastric acid secretion and stimulation of growth of the gastric mucosa.

HORMONES OF THE SMALL INTESTINE - DEFINITION

1. The small intestine secretes 4 hormones; cholecystokinin, secretin, gastric inhibitory peptide (GIP) and Motilin.
2. While Cholecystokinin and secretin are secreted by all the three parts of the small intestine (duodenum, jejunum and ileum), GIP and motilin is secreted by only duodenum and jejunum.
3. Cholecystokinin is produced by the 'I' cells, 'S' cells produce secretin, GIP is formed by the 'K' cells and the 'M' cells secrete motilin
4. These hormones are secreted as a result of various stimuli like protein, fat, carbohydrate and acid in the intestine.
5. Cholecystokinin
6. Stimulates pancreatic enzyme and bicarbonate secretion
7. Stimulates contraction of the gallbladder
8. Also stimulates the growth of the exocrine pancreas
9. It inhibits gastric emptying (entry of food into intestine by emptying stomach)
10. Secretin
11. It stimulates pepsin secretion from stomach and bicarbonate secretion from both pancreas and gallbladder
12. Also promotes the growth of exocrine pancreas.
13. It inhibits gastric acid secretion.
14. GIP
15. Stimulates release of insulin from pancreas
16. Inhibits gastric acid secretion
17. Motilin
18. It is involved in the motility of the gastrointestinal tract.

HORMONES OF THE KIDNEYS - DEFINITION

1. The kidneys secrete 3 different types of hormones; erythropoietin, renin and calcitriol (1,25- dihydroxycholecalciferol).
2. Erythropoietin and renin are peptide hormones secreted by the juxtaglomerular cells of the kidney
3. Calcitriol is a steroid hormone synthesized by the cells of the proximal tubules of the nephrons.
4. Erythropoietin
5. Its production is stimulated by hypoxia (insufficient oxygen supply to the tissues)
6. It stimulates the formation of RBC from the haematopoietic stem cells in the bone marrow.
7. Renin
8. Decreased blood pressure, low sodium levels are the stimuli for the production of renin from the kidney.
9. The renin secreted has enzymatic activity and is an important part of renin-angiotensin-aldosterone system (RAAS).
10. The RAAS plays an important role in regulating the cardiac output and arterial pressure.
11. The main function of renin in the RAAS system is the conversion of angiotensinogen to angiotensin I (proteolytic activity).
12. Calcitriol (1,25- dihydroxycholecalciferol)
13. It is the active form of vitamin D.
14. It stimulates the formation of calcium-binding protein thereby increasing the intestinal absorption of calcium.
15. Thus, it plays an important role in the mineralization of the bone (bone formation)
16. GASTROINTESTINAL HORMONE - DEFINITION
17. Certain cells of the mucosa of the stomach and intestine secrete important hormones.
18. Stomach
19. Gastrin
20. Intestine
21. Secretin
22. Cholecystokinin-pancreozymin
23. Gastric inhibitory peptide GIP
24. Duocrinin
25. Enterocrinin
26. Vasoactive intestinal peptide
27. Villikinin
28. Somatostatin
29. Pancreatic polypeptide

HORMONES RELEASED BY KIDNEY - DEFINITION

The kidneys secrete three hormones:

1. Renin
2. Erythropoietin
3. Calcitriol