Histology

Question 1

What are the two types of nephron and what is the difference?

Answer 1

Cortical nephrons
Juxtamedullary nephrons

Cortical nephrons have their glomeruli in the outer cortex. They have shorter loops of Henle, which dip only into the outer medulla. Juxtamedullary nephrons’ loops of Henle dip deeper into the inner medulla and papilla, and are vital in the concentration of urine.

Question 2

Define a glomerulus

Answer 2

A ball of capillaries surrounded by the Bowman’s capsule

Question 3

What forms the striped appearance in the medulla?

Answer 3

In the cortex, the collecting ducts, along with the straight segments of the proximal and distal tubules are gathered together in parallel bundles running perpendicular to the surface of the kidney and called medullary rays. These are visible to the naked eye as stripes in the cortex that point toward the medulla

Question 4

The kidney is covered by a _____________

Answer 4

fibrous capsule which is continuous with the connective tissue that lines the renal sinus

Question 5

Describe the difference between the cortex and the medulla?

Answer 5

The cortex is the outer layer and the glomeruli lie here for filtration
The medulla is the inner layer and contains the renal tubules for water control

Question 6

What is the basic functional unit of the kidney?

Answer 6

Nephron

Question 7

What is each nephron composed of?

Answer 7

Renal corpuscle and 3 renal tubules (proximal convoluted tubule, loop of henle and distal convoluted tubule)

Question 8

Function of the renal corpuscle?

Answer 8

Production and collection of Glomerular filtrate

Question 9

What is the renal corpuscle formed from?

Answer 9

Tuft of capillaries (glomerulus) and a cup of simple squamous epithelium at blind end of the nephron which capillaries invaginate into (Bowman’s capsule)

Question 10

The glomerulus is supplied by an __1___ and drained by an ___2____

Answer 10

1) afferent arteriole (A for arriving)

2) efferent arteriole (E for exiting)

Question 11

Describe the cell layers that separate the blood from glomerular filtrate?

Answer 11

capillary endothelium surround the capillary and on top of the glomerular capillaries lie specialised epithelium called podocytes. Between these two layers is a thicker than normal basal lamina made up of GAGs. Scattered mesangial cells produce a connective tissue core called the mesangium. These cells have several functions including support and removal of debris.

Question 12

What happens in the proximal convoluted tubule?

Answer 12

70% of sodium is reabsorbed by active transport and 70% of water by diffusion. Almost all glucose and amino acids are reabsorbed by co-transport.

Question 13

Describe the cells in the proximal convoluted tubule?

Answer 13

Lined by simple cuboidal epithelial cells with an extensive brush border than increases SA. Cells are larger than in the distal tubule.

Question 14

Function of the Loop of Henle?

Answer 14

Creation of hyper osmotic environment in the medulla therefore concentrating urine

Question 15

In most nephrons what does the loop of henle consist of?

Answer 15

Thick descending limb > thin descending limb > hairpin turn > thin ascending limb > thick ascending limb

Question 16

Thick limbs in the loop of henle are lined by ___1____

Thin limbs in the loop of henle are lined by ____2____

Answer 16

1) simple cuboidal epithelium

2) simple squamous epithelium

Question 17

What helps create the hyperosmotic environment of the loop of henle?

Answer 17

Permeability to water and ions and active transport of ions varies in different parts having a net effect

Question 18

Explain how the blood supply of the medulla is achieve without destroying the osmotic gradient?

Answer 18

There are loops of thin walled blood vessels that dip down into the medulla from above and climb back up to the cortex - these loops are called vasa recta.

Question 19

What is the function of the distal convoluted tubule?

Answer 19

acid base and water balance (absorption of sodium and water and excretion of H+ and K+ ions) > controlled by aldosterone secreted from the adrenal cortex

Question 20

Describe cells in the distal convoluted tubule?

Answer 20

These cells are smaller than the proximal convoluted tubules and have a more obvious luminal margin because they have only sparse apical microvilli

Question 21

What happens in the collecting duct?

Answer 21

ADH can increase permeability to water increasing urine concentration when low body water.

Question 22

Describe the lining of the ureter?

Answer 22

Lined by transitional epithelium AKA urothelium which is stratified and found in 3-6 layers (cells vary in shape depending on layer). The cells at the luminal surface are called umbrella cells as a are domed. These cells are backed by a lamina propria which is covered by an inner longitudinal layer of smooth muscle and an outer circular layer surrounded by an adventitia/ serosa

Question 23

What type of cells line the ureter and bladder and proximal urethra?

Answer 23

Transitional epithelium/ urothelium

Question 24

The bladder has __________

Answer 24

3 smooth muscle layers that make up the detrusor muscle and internal urethral sphincter

Question 25

In females the urethra is initially lined by ___1__ which transitions to ___2___ near its termination

Answer 25

1) transitional epithelium | 2) stratified squamous epithelium

Question 26

In males the prostatic urethra is lined by ___1____ the membranous urethra is lined by ___2_____ and the penile urethra is lined by ____3_____ which near the tip of the penis becomes ____4________

Answer 26

1) transitional epithelium 2) stratified columnar 3) stratified columnar 4) stratified squamous