Microanatomy Of The Kidneys

Question 1

What is the name of the functional units if the urinary system?

Answer 1

Nephrons

Question 2

The renal corpuscle is the first part of the nephron. What does it consist of?

Answer 2

A tubular capsule wrapped around a tight network of capillaries called the glomerulus

Question 3

Other than the renal corpuscle, what is the other part of the nephron?

Answer 3

The renal tubule

Question 4

The renal tubule consists of three segments, which are…?

Answer 4

Proximal convoluted tubule
Loop of Henle
Distal convoluted tubule

Question 5

What are the two types of nephron and what are the features of each?

Answer 5

Cortical nephrons are shorter and their entire structure exists within the cortex of the kidney
Juxtaglomerular nephrons are longer with loops of Henle descending into the renal medulla

Question 6

Which type of nephron is more prevalent?

Answer 6

Cortical nephrons

Question 7

What is the other name for the glomerular capsule?

Answer 7

Bowmans capsule

Question 8

What are the names of the vessels through which blood enters and leaves the glomerulus?

Answer 8

Afferent arterioles enter the glomerulus

Efferent arterioles leave the glomerulus

Question 9

What kind of cells make up the visceral layer of the glomerular capsule?

Answer 9

Podocytes

Question 10

Podocytes have thousands of processes that interdigitate to form filtration slits. What are these called?

Answer 10

Pedicles

Question 11

What is the structure, location and function of the juxtaglomerular cells of the kidney?

Answer 11

These are large, spindle shaped, modified smooth muscle cells that sit on top of the afferent arterioles in the kidney and secrete renin

Question 12

What is the structure, location and function of the extraglomerular mesangial cells of the kidney?

Answer 12

They are modified stellate smooth muscle cells located in the cleft between the afferent and efferent arterioles. Their function is to contract which helps to regulate the glomerular filtration rate

Question 13

What is the structure, location and function of the macula densa of the kidneys?

Answer 13

It is a region of densely packed, cuboidal to columnar epithelial cells in the early distal convoluted tubule that is also connected to the afferent arterioles. These cells are osmoreceptors and can trigger vasoconstriction and renin secretion

Question 14

What kind of epithelium exists in the tubules of the kidneys?

Answer 14

Simple cuboidal or low columnar epithelial cells

Question 15

The cells of the PVT and the renal tubule have a brush border of microvilli. T/F?

Answer 15

True - this is to aid reabsorption

Question 16

Which limb of the loop of Henle is impermeable to water?

Answer 16

The ascending loop

Question 17

Where do the collecting ducts of the nephron drain to?

Answer 17

The papillary duct of the renal pyramids

Question 18

In which parts of the renal tubule are aquaporin-1 molecules found?

Answer 18

PCT
Descending loop of Henle
Early DCT

Question 19

In which parts of the renal tubule are aquaporin-2 molecules present?

Answer 19

Late DCT

Collecting ducts

Question 20

The glomerular endothelium is fenestrated. T/F?

Answer 20

True

Question 21

Describe the myogenic response which helps maintain GFR?

Answer 21

The afferent arteriole automatically constricts in response to stretch. So when there is increased arterial pressure this helps to limit blood flow to the glomerulus and maintain GFR.
The afferent arterial will also relax when it is unstretched so as to increase blood flow and increase GFR

Question 22

The cells of the macula densa secrete adenosine and ATP in response to increased GFR. What affect does this have?

Answer 22

Constriction of the afferent arteriole to reduce GFR

Question 23

When GFR is low, the cells of the macula densa release what substance to cause afferent arteriolar dilation?

Answer 23

Nitric oxide