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Flashcards in Urinary System Deck (39)
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1
Q

What are the two main functions of the kidneys?

A
  1. Maintain electrolyte homeostasis

2. Maintain water homeostasis (BP)

2
Q

Name three endocrine functions of the kidney.

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

Where does blood enter the kidneys?

A

At the hilum

4
Q

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

A

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

5
Q

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

A

Arcuate arteries.

6
Q

What do the efferent arterioles that leave the glomeruli become?

A

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

7
Q

What is a renal corpuscle?

A

Glomerulus + Bowman’s capsule

8
Q

What is a nephron?

A

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

9
Q

What is a uriniferous tubule?

A

Nephron + collecting duct.

10
Q

Can renal corpuscles be found in the renal medulla?

A

Nope

11
Q

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

A

Podocytes.

12
Q

What are the spaces called between the podocyte processes?

A

Filtration slits.

13
Q

What makes up the filtration barrier?

A

Filtration slits + glomerular basement membrane

14
Q

What cells synthesize the glomerular basement membrane?

A

Podocytes and endothelial cells.

15
Q

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

A

Up to 70 kDa

16
Q

What is the composition of the glomerular basement membrane?

A

Type IV collagen, laminin, proteoglycans

17
Q

What are mesangial cells? Where are they found?

A

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

18
Q

What happens to the filtrate in the PCT?

A

Resorption of sugars, AAs, salts.

19
Q

What is found on the apical surface of PCT cells?

A

Enzyme-rich brush border (microvilli)

20
Q

What is found on the basal surface of PCT cells?

A

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

21
Q

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

A

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

22
Q

Which portion of the nephron is sensitive to aldosterone?

A

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

23
Q

What happens in the descending loop of Henle?

A

Water leaks out of the loop and into the interstitium.

24
Q

What happens in the ascending loop of Henle?

A

Na+ is pumped into interstitium. Impermeable to water.

25
Q

What are medullary rays?

A

Clumps of collecting ducts in the center of renal lobules.

26
Q

Are collecting duct cells permeable to water?

A

Only in the presence of ADH.

27
Q

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

A
  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.

28
Q

What are ducts of Bellini aka papillary ducts?

A

When collecting ducts join = papillary ducts

29
Q

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

A
  1. Juxtaglomerular cells monitor BP and can release renin.

2. Macula densa cells monitor blood chemistry.

30
Q

What structures form the juxtaglomerular apparatus?

A

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

31
Q

What type of cells are JG cells?

A

Smooth muscle.

32
Q

Describe the renin/angiotensin pathway.

A

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

33
Q

How do macula densa cells participate in renin release?

A

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

34
Q

What are calyces?

A

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

35
Q

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

A

Transitional epithelium

36
Q

Describe the muscle layers of the ureter.

A

2, sometimes 3 layers.

Inner is LONGITUDINAL
Outer is CIRCULAR

3rd (outermost) layer when present: LONGITUDINAL

37
Q

Describe the bladder wall.

A

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

38
Q

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

A

Simple cuboidal in tubules.

Simple columnar in collecting duct.

39
Q

Do peritubular capillary cells make EPO?

A

Yes