Describe the microscopic anatomy of the proximal convoluted

Describe the microscopic anatomy of the proximal convoluted tubule, distal convoluted tubule and nephron loop.

Solution

Nephron is considered as the structural and functional unit of kidney.

Nephron eliminates wastes from the body controlling blood pressure, electrolytes level and regulates blood pH.

Renal tubule is the part of the nephron consisting of following parts they are.

proximal convoluted tubule

Loop of henle , Descending loop of henle and ascending loop of henle.

Ascending loop is further classified as Thin ascending loop and thick ascending loop.

Distal convoluted tubule.

Anatomy of proximal convoluted tubule , it is the duct like portion of the nephron which leads from bowmans capsule to the loop of henle.the luminar epithelia;l cells of this segment is covered densely with hair like projections called Microvilli.these microvilli increase the surface area .the cytoplasm of the cells is densely packed with mitochondria which gives the acidophilic appearance.These mitochondria helps in the active transport of sodium ions creating a gradient and thus helps in the water flow following sodium ions.Cuboidal epithelial cells line the lumen of the proximal tubules with extensive lateral digitations and they give the dirty apperance when viewed under microscope.Proximal convoluted tubule is seen in the renal cortex with convolutions called pars convoluta and the proximal straight cells found in the renal medulla are called pars recta.

Distal convoluted tubule:it is the portion of the nephron between loop of henle and collecting duct.It is lined with simple cuboidal cells with size smaller than proximal convoluted tubule. It is having numerous mitochondria, large lumen with basal infoldings.Macula Densa is the region where distal convoluted tubule contacts the cortical ascending limb of the loop of henle.

Nephron loop is also called Loop of henle: It consists of four parts they are descending limb of loop of henle.it has sharp bend in the renal medulla going from descending limb to the thin ascending limb.It is highly permeable to water.

Thin ascending loop of henle : it is highly permeable to ions, but impermeable to water.

Ascending limb of loop of henle:here sodium potassium and chlorides are reabsorbed.

Cortical ascending limb: It drains urine in to the distal convoluted tubule.The epithelium lining in the nephron loop is the simple squamous epithelium.