Urinary system

Question 1

Bowman’s capsule 3 layers?

Answer 1

Visceral layer = podocytes –> near capillaries
Capsular (urinary) space –> receives fluid filtered
Parietal layer = endothelial cells, simple squamous

Question 2

Filtration through which 3 parts?

Answer 2

Fenestrations of endothelium –> block blood cells and platelets
Thick GBM –> restricts large proteins, organic anions
Filtration slit diaphragms –> restricts small proteins, organic anions

Question 3

Proximal convoluted tubule

Answer 3

simple cuboidal epithelium
brush border in lumen
hydroxylate vitamin D
fibroblastic interstitial cells near proximal tubules produce EPO

Question 4

Loop of Henle

Answer 4

thin limb = simple squamous epithelium
thick limb = simple cuboidal epithelium
thin ascending limb impermeable to water

Question 5

Distal convoluted tubule

Answer 5

simple cuboidal epithelium
no brush border, fewer mitochondria
aldosterone acts here –> regulates Na reabsorption

Question 6

Juxtaglomerular apparatus (JGA)

Answer 6

regulate glomerular blood flow and keep GFR constant

smooth muscle cells in adjacent arterioles contains juxtaglomerular granular cells with renin

Question 7

Collecting ducts

Answer 7

simple cuboidal epithelium

Water reabsorbed if needed by body

Question 8

Principal cells : location and what do they do?

Answer 8

In collecting ducts

Reabsorb Na and secrete K

Question 9

Intercalated cells: location and what do different types do ?

Answer 9

In collecting ducts
Type A = secrete H+ and reabsorb HCO3 & K = acidosis
Type B = secrete HCO3 & K and reabsorb H = alkalosis

Question 10

Ureters unique stratified ureothelium / transitional epithelium 3 layers?

Answer 10

Single layer small basal cells resting on thin basement membrane
intermediate region with cuboidal / low columnar cells
superficial layer of large bullous or elliptical umbrella cells –> protect against cytotoxic effect hypertonic urine

Question 11

Which part urinary passages not covered externally by adventitial layer? covered by what then?

Answer 11

Upper part bladder, covered by serous peritoneum

Question 12

Male urethra (longer), 3 segments?

Answer 12

Prostatic urethra –> through prostate gland, lined by urothelium
Membranous urethra –> through external sphincter, lined by (pseudo)stratified columnar epithelium
Spongy urethra –> longest, enclosed with erectile tissue, lined by (pseudo)stratified columnar epithelium

Question 13

Female urethra lining?

Answer 13

initially urothelium, later non-keratinized stratified squamous epithelium

Question 14

How do the macula densa regulate GFR in elevated arterial pressure?

Answer 14

Elevated pressure –> GFR up –> higher concentrations NaCl detected by macula densa (cause not reabsorbed well due to high GFR) –> release vasoconstrictors –> afferent arteriole constricted –> GFR down

Question 15

How does the RAAS system regulate GFR in decreased arterial pressure?

Answer 15

Decreased pressure –> sensed by baroreceptors afferent arteriole –> release renin –> AngII is vasoconstrictor + stimulates release aldosterone

Question 16

What is the effect of aldosterone on tubules?

Answer 16

promotes Na & water reabsorption in distal tubule and connecting tubules –> raises blood volume, therefore BP

Question 17

What is the effect of ADH (vasopressin) on tubules?

Answer 17

Activated when body is dehydrated –> collecting ducts more permeable to water.