Hormones of Heart, Kidney and Gastrointestinal Tract - Practice Questions & MCQ

• Kidneys secrete three hormones:
  • Renin
  • Erythropoietin
  • Calcitriol 

Renin:    

• Released by the cells of the juxtaglomerular complex when the rate of ultrafiltration falls.
• Renin acts upon the angiotensinogen and converts it to angiotensin I.
• Angiotensin I is converted to angiotensin II by the enzyme ACE.
• It increases the blood pressure and enhances the blood pressure

Erythropoietin:

• It is released when oxygen is lowered. 
• It stimulates the bone marrow to increase the production of RBCs.

Calcitriol:

• It is the active form of vitamin D.
• It promotes the absorption of calcium and phosphorus in the small intestine.
• It accelerated bone formation.
   

Placenta:

• Placenta denotes the connection between the foetus and uterine wall of the mother.
• It is a temporary endocrine gland.
• It secretes hormones like oestrogens, progesterone, human chorionic gonadotropin (HCG), chorionic thyrotropin, chorionic corticotropin and relaxin.
• HCG stimulates corpus luteum to release progesterone.
• Relaxin causes relaxation of the ligaments of the pubic symphysis.

Heart:

• Cardiocytes release peptide hormone called atrial natriuretic factor (ANF).
• ANF inhibits the release of renin from the juxtaglomerular cells of kidneys.
• It lowers the blood pressure.

Gastrointestinal Tract:

• The cells of the mucosa in the stomach and intestine release some important hormones as follows:
  • Gastrin: It is secreted by gastric cells of the stomach. It stimulates gastric glands to secrete and release the gastric juice. It also stimulates gastric motility.
  • Enterogastrone or Gastric Inhibitory Peptide: It is se­creted by the duodenal epithelium. It inhibits gastric secretion and motility. It slows gastric contrac­tion.
  • Secretin: It is secreted by the epithelium of the duodenum. It releases bicarbon­ates in the pancreatic juice. It increases the secretion of bile.
  • Cholecystokinin: This hormone is secreted by the epithelium of the entire small intestine. It stimulates the gallbladder to release bile and pancreas to secrete and release digestive enzymes in the pancreatic juice.