Tag: zoology

In humans, the Kidney is the excretory organ. Nephron or uriniferous tubule is the structural and functional unit of the kidney. On an average, 25-30 gm of urea is excreted out per day through urine. Hence uriniferous tubules are mainly concerned with removal of urea from the blood.

The nephrons along with collecting ducts are called as uriniferous tubule. The nephron is the structural and functional unit of the kidney. The body of the nephron is divided into  Bowman's capsule, PCT, Henle's loop and DCT. Hence glomerulus does not belong to the uriniferous tubule. Glomerulus are the tuft of capillaries present in the Bowman's capsule.

Renin is produced in the kidney by the juxtaglomerular cells of renal cortex. It participates in the renin–angiotensin–aldosterone system which maintains the blood pressure and fluid balance in the body. It breaks the angiotensinogen secreted from the liver into a peptide angiotensin I. Angiotensin I is further cleaved into angiotensin II. Angiotensin II acts on the adrenal glands and releases aldosterone which acts on the collecting tubules to absorb more sodium ions which in turn increases the absorption of water and increases the blood volume.  It also acts on the CNS to increase water intake by stimulating thirst. So the correct answer is 'Renin'.

The nephron is the structural and functional unit of the kidney. It is also called as uriniferous tubule. The active absorption of Na+ ion followed by the absorption of Cl created high osmotic pressure in the uriniferous tubule.

Juxta-glomerular cells are specialized smooth muscle cells of the afferent arteriole, which supplies blood to the glomerulus. When the kidney receives the low volume of blood (low glomerular blood flow)the juxtaglomerular cells are stimulated to release renin.