Week 9: Histology of the Urinary System

Question 1

Functions of the Kidney

Answer 1

homeostasis - maintain the stability of the exttracellular fluid vol, electrolyte comp, osmolarity

Question 2

How wide is diameter of renal corpusle?

Answer 2

200um

Question 3

What is function of mesangial cells

Answer 3

Contractile - can affect blood flow.

Phagocytic - to clear away cell debrus

Question 4

What is longer PCT or DCT?

Answer 4

PCT

Question 5

Differences between PCT and DCT

Answer 5

PCT have longer, more microvilli = fuzzy

Question 6

Features of filtration apparatus

Answer 6

1. glomerular capillaries ( fenestrated endothelium (90nm daimater). 2. Glomerular basement membrane (350mn) = much thicker than normal. 3. Visceral layer of Bowman’s Capsule = podocyte cells - extend cytoplasmic processes around caps = pedicels
2. Slit diaphragm - extends between pedicels

Question 7

What is normally excluded from ultrafiltrate?

Answer 7

MOlecules in plasma + > 4nm diameter, >0kDa mass, -ve charged

Question 8

Juxtaglomerular apparatus

Answer 8

1, Macula dense cells. 2. Juxtaglomerular cells. 3. Extraglomerular mesangial cells. = endocrine function, BP cotrol

Question 9

What is relesaed from where in juztaglomerular apparatus

Answer 9

renin from juxtaglomerular cells

Question 10

What does macula densa cells sense? Release?

Answer 10

Low [Na+] in distal tubule - prostaglandins = paracrine effect on juxtaglomerular cells

Question 11

What are juxtaglomerular cells - where

Answer 11

Modified SM cells in afferent arteriole walls, . Spherical nuceli, cytoplasmic granules contain RENIN