Urinary System

Question 1

What are the two main functions of the kidneys?

Answer 1

1. Maintain electrolyte homeostasis

2. Maintain water homeostasis (BP)

Question 2

Name three endocrine functions of the kidney.

Answer 2

1. Make EPO
2. Renin
3. Vitamin D (1,25-hydroxycholecalciferol)

Question 3

Where does blood enter the kidneys?

Answer 3

At the hilum

Question 4

Name the arterial arrangement of the kidneys, starting at the renal artery.

Answer 4

Renal artery –> segmental artery –> interlobar artery –> arcuate artery –> interlobular artery –> glomerulus

Question 5

Which artery types are found at the cortex-medullary boundary?

Answer 5

Arcuate arteries.

Question 6

What do the efferent arterioles that leave the glomeruli become?

Answer 6

Either peritubular capillaries (if in the cortex) or medullary vasa recta.

Question 7

What is a renal corpuscle?

Answer 7

Glomerulus + Bowman’s capsule

Question 8

What is a nephron?

Answer 8

Renal corpuscle (glomerulus + Bowman’s capsule) + convoluted tubules.

Question 9

What is a uriniferous tubule?

Answer 9

Nephron + collecting duct.

Question 10

Can renal corpuscles be found in the renal medulla?

Answer 10

Nope

Question 11

What cells arise from the inner layer (viscera) of Bowman’s capsule?

Answer 11

Podocytes.

Question 12

What are the spaces called between the podocyte processes?

Answer 12

Filtration slits.

Question 13

What makes up the filtration barrier?

Answer 13

Filtration slits + glomerular basement membrane

Question 14

What cells synthesize the glomerular basement membrane?

Answer 14

Podocytes and endothelial cells.

Question 15

How large can a molecule be and pass through the glomerular filtration barrier?

Answer 15

Up to 70 kDa

Question 16

What is the composition of the glomerular basement membrane?

Answer 16

Type IV collagen, laminin, proteoglycans

Question 17

What are mesangial cells? Where are they found?

Answer 17

Supporting cells found in the endothelial basal lamina of the glomerulus that perform physical support, repair, phagocytosis, and BP monitoring.

Question 18

What happens to the filtrate in the PCT?

Answer 18

Resorption of sugars, AAs, salts.

Question 19

What is found on the apical surface of PCT cells?

Answer 19

Enzyme-rich brush border (microvilli)

Question 20

What is found on the basal surface of PCT cells?

Answer 20

Mitochondria-rich basal infoldings to pump ions into the interstitium.

Question 21

What cell type is found in the DCT? Do they have apical specializations? Do they have a lot of mitochondria?

Answer 21

Low cuboidal with diminished brush border. Fewer mt than PCT cells so they are clearer.

Question 22

Which portion of the nephron is sensitive to aldosterone?

Answer 22

The DCT. It causes increased Na+ resorption to increase BP.

Question 23

What happens in the descending loop of Henle?

Answer 23

Water leaks out of the loop and into the interstitium.

Question 24

What happens in the ascending loop of Henle?

Answer 24

Na+ is pumped into interstitium. Impermeable to water.

Question 25

What are medullary rays?

Answer 25

Clumps of collecting ducts in the center of renal lobules.

Question 26

Are collecting duct cells permeable to water?

Answer 26

Only in the presence of ADH.

Question 27

What two cell types are found in the CD and what do they do?

Answer 27

1. Intercalated cells. Subtypes: alpha can excrete H+ and beta can excrete HCO3- to maintain pH.
2. Light cells respond to ADH to permit H2O movement down the conc. gradient.

-Each type has a cilium for mechanosensitivity.

Question 28

What are ducts of Bellini aka papillary ducts?

Answer 28

When collecting ducts join = papillary ducts

Question 29

What cells make up the juxtaglomerular apparatus and what do they do?

Answer 29

1. Juxtaglomerular cells monitor BP and can release renin.

2. Macula densa cells monitor blood chemistry.

Question 30

What structures form the juxtaglomerular apparatus?

Answer 30

Where the renal corpuscle, DCT, and afferent arteriole all come into close contact in the cortex.

Question 31

What type of cells are JG cells?

Answer 31

Smooth muscle.

Question 32

Describe the renin/angiotensin pathway.

Answer 32

Low BP –> renin –> cleaves angiotensinogen –> angiotensin I –> angiotensin I cleavage by ACE from the lungs or endothelial cells –> angiotensin II (vasoconstrictor) –> aldosterone release from adrenal –> DCT increases sodium resorption

Question 33

How do macula densa cells participate in renin release?

Answer 33

They sense low sodium in the DCT and tell JG cells to make renin.

Question 34

What are calyces?

Answer 34

Where the urine is dumped from the papillary ducts of the renal pyramids.

Question 35

What type of epithelium is found in the calyces, ureter, and urinary bladder?

Answer 35

Transitional epithelium

Question 36

Describe the muscle layers of the ureter.

Answer 36

2, sometimes 3 layers.

Inner is LONGITUDINAL
Outer is CIRCULAR

3rd (outermost) layer when present: LONGITUDINAL

Question 37

Describe the bladder wall.

Answer 37

Transitional epithelium, mucosal wall with unorganized layers of smooth muscle, no distinct muscularis mucosae.

Question 38

What type of epithelium is in the tubules? Collecting duct?

Answer 38

Simple cuboidal in tubules.

Simple columnar in collecting duct.

Question 39

Do peritubular capillary cells make EPO?

Answer 39

Yes