Histology

Question 1

What are the 3 main functions of the kindeys ?

Answer 1

1. Maintain water and electrolyte homeostasis
2. Excrete toxic metabolic waste products
3. Act as an endocrine gland, producing renin and erythropoietin.

Question 2

Describe the flow of urine in the kidneys

Answer 2

From nephron ==> renal papillae ==> minor calyx’s ==> major calyx’s ==> renal pelvis ==> through pelvoureteric junction into the ureter

Question 3

What is the basic functional unit of the kindeys ?

Answer 3

The nephron

Question 4

What is the 2 main parts the kidney is composed of ?

Answer 4

Renal corpuscle and renal tubules

Question 5

What is the renal corpuscle comprised of ?

Answer 5

Formed from a tuft of capillaries called the glomerulus and the cup of simple squamous epithelium at the blind end of the nephron which the capillaries invaginate into (called Bowman’s capsule).

Question 6

Describe the key histological features of the renal corpuscle with specific reference to capillary endothelium, podocytes and mesangial cells

Answer 6

Two cell layers separate the blood from the glomerular filtrate:

• Capillary endothelium and podocytes

Scattered mesangial cells produce a connective tissue core - these cells have a number of functions including support and removal of debris

Question 7

Describe the blood supply to the golmerulus

Answer 7

Supplied by an afferent arteriole and drained by an efferent arteriole.

Question 8

Where in the kidney is the loop of henle located ?

Answer 8

The medulla

Question 9

What blood vessels dip into the medulla of the kidney along with the loop of henle ?

Answer 9

Vasa recta

Question 10

What is the thin part of the loop of henle linned by?

Answer 10

Simple squamous lining in which the nuclei typically protrude into the lumen

Question 11

What is the lining of the thick ascending part of the loop of henle ?

Answer 11

Lined by simple cuboidal epithelial cells

Question 12

What is the lining of the distal convoluted tubule ?

Answer 12

Lined by simple cuboidal epithelium

Question 13

Do the collecting ducts reside in both the cortex and medulla of the kindeys ?

Answer 13

Yes

Question 14

In the cortex of the kindey how is the collecting duct arranged ?

Answer 14

Gathered together in parallel bundles running perpendicular to the surface of the kidney and called medullary rays.

Question 15

What is the lining of the collecting ducts ?

Answer 15

Lined by simple columnar epithelium

Question 16

What is the juxtaglomerular apparatus ?

Answer 16

Formed at the site where the distal convoluted tubule passes adjacent to the vascular pole of the SAME renal corpuscle that forms part of its very own nephron

Question 17

What are the 3 components which make up the juxtaglomerular apparatus ?

Answer 17

1. The macula densa.
2. The juxtaglomerular cells.
3. The extraglomerular mesangial cells

Question 18

What is the function of the 3 components of the juxtaglomerular apparatus ?

Answer 18

1. Macula densa: Function in sensing ion composition in the DCT.
2. Juxtaglomerular cells: These cells contain/secrete renin.
3. Extraglomerular mesangial cells (lacis cells): Function is unknown.

Question 19

What is meant by the conducting parts of the urinary tract ?

Answer 19

From renal papillae to urethra

Question 20

What are almost all of the conducting parts of the urinary tract lined by ?

Answer 20

Transitional epithelium (uroepithelium)

Question 21

What is the main difference in the urethras in men and women and how is this important ?

Answer 21

• Main difference is that men have a much longer urethra - 20cm compared to womens 3-5cm
• This means women are more predisposed to UTI’s