urinary

Question 1

functions of urinary system

Answer 1

• produce and secrete urine
• regulate plasma volume and BP
• regulate water + electrolyte balance
• excrete toxic by-products (urea)

Question 2

Nephron

Answer 2

blood -> renal corpuscle (cortex) -> proximal tubule (cortex) -> loops of henle (medulla) -> distal tubule (cortex) -> collecting duct (medulla)

Question 3

renal corpuscle

Answer 3

produces glomerular filtrate from blood -> released into bowman’s space -> flows to proximal tubule (blood leaves via efferent arteriole)

bowman’s capsule, bowman’s space inside, glomerulus (network of capillaries)

Question 4

bowman’s capsule

Answer 4

parietal layer on outside, visceral layer covering glomeruli (contains podocytes)

Question 5

podocytes

Answer 5

cells covering glomeruli, allow filtering of blood
- primary processes, secondary processes (pedicels) wrap around capillaries
- filtration slits between pedicels
- slit membrane composed of nephrin protein

Question 6

filtration barrier

Answer 6

filtrate passes through:

capillary
1. fenestrated glomerular capillary endothelium
2. basement membrane (prevent passage of large proteins)
3. podocyte processes w pedicels
(precent passage of some small molec)
bowman space

Question 7

renal corpuscle filtrate composition

Answer 7

water, glucose. AAs, ions, urea, small amount of proteins

Large molec and cells stay in blood

Question 8

vasa recta

Answer 8

Efferent arteriole from renal corpuscle forms vasa recta, surrounding all parts of the nephron
- secretes and reabsorbs solutes

Question 9

diabetes mellitus

Answer 9

loss of functional glomeruli, resulting in kidney failure
- histology: sclerosed glomeruli (amorphous, pink hyaline material)

hyperglycemia -> down-reg of nephrin -> flattening of pedicels + thickening of basement membrane (more porous to large proteins) -> proteinuria

Question 10

proximal tubule

Answer 10

in nephron, cortex, b/w corpuscle and loops of henle
- simple cuboidal
- tall microvilli increase surface area -> reabsorption
- Capillaries reabsorb 65% of ions, water, glucose, AAs from filtrate

Question 11

loops of henle

Answer 11

in nephron, medulla, b/w proximal tubule and distal tubule
1. thin descending loop
2. thin ascending loop
3. thick ascending loop

Question 12

thin descending loop

Answer 12

first loop of henle
- simple squamous
- aquaporin channels -> water permeable
- water resorption to vasa recta

Question 13

thin ascending loop

Answer 13

second loop of henle
- simple squamous
- no aquaporins -> water impermeable

Question 14

thick ascending loop

Answer 14

final loop of henle
- simple cuboidal
- reabsorption of electrolytes to vasa recta

Question 15

distal tubule

Answer 15

in nephron, cortex, b/w loops of henle and collecting duct
- simple cuboidal
- water impermeable
- Fine-tuning reabsorption of Na+ to capillaries
- macula dense pumps Na out of filtrate
- short microvilli

Question 16

histology - proximal vs distal tubule

Answer 16

Proximal: tall microvilli
distal: short microvilli, more basophilic

Question 17

juxtaglomerular complex

Answer 17

where afferent arteriole and distal tubule are in close proximity
- regulating blood pressure and salt levels

Question 18

juxtaglomerular cells

Answer 18

In tunica media of afferent arteriole
- modified smooth muscle cell
- secretes renin into blood

Question 19

macula densa

Answer 19

part of epithelium of distal tubule
- simple columnar
- detects low Na+ levels

Question 20

extraglomerular mesangial cells

Answer 20

thought to help signalling between macula densa and juxtaglomerular cells

Question 21

renin-angiotensin-aldosterone system

Answer 21

Liver prod angiotensinogen -> kidney’s renin converts it to angiotensin I -> ACE converts it to angiotensin II -> many effects

If BP and BV decr, filtrate flow slows and sodium loss occurs. Low Na is detected by macula densa, signals to JG cells to release renin

Question 22

aldosterone

Answer 22

stimulates Na+ reabsorption in thick ascending loop

Question 23

anti-diuretic hormone

Answer 23

incr water permeability of collecting ducts -> less urine -> incr BV + BP

Question 24

angiotensin II

Answer 24

increases Na+:
- incr aldosterone
- constricts efferent arteriole -> incr pressure and glomerular filtration rate -> incr Na+ in distal tubule

incr BV and BP:
- incr ADH
- vasoconstrictor

Question 25

collecting duct

Answer 25

medulla, after distal tubule, goes to minor and major calyces, then to ureter (leaving kidney)
- simple cuboidal/low columnar
- perinuclear halo (glycogen for transcr of aquaporins is stored)
- distinct cell border
- impermeable to water usually (aquaporins stored in vesicles), but becomes permeable in the presence of ADH (water->blood)

Question 26

tubulointerstitial nephritis

Answer 26

inflammatory injuries to tubules and interstitium (space surrounding functional tissue)
- from toxins or infections
- leukocyte infiltration (blue)
- interstitial fibrosis (more c. tissue)
- tubular atrophy

Question 27

ureter

Answer 27

transports urine from kidneys to bladder

Question 28

ureter - epithelium

Answer 28

transitional (urothelium)
- cytoskeleton very dynamic, facilitates cell shape change
- as lumen fills, cells flatten and slide over e/o
- umbrella cells, domed shape
- has plaques which are impermeable to urine + hinges between plaques (flexible)
- fusiform vesicles

Question 29

uroplakin

Answer 29

integral protein in umbrella cells
important for:
1. membrane permeability
2. strengthen apical surface

Question 30

fusiform vesicles

Answer 30

dips in epithelium which disappear when distended

Question 31

ureter - lamina propria

Answer 31

connective tissue, blood vessels, nerves
- provides O2 and nutrients to epithelium

Question 32

ureter - muscularis

Answer 32

helps with peristalsis

• smooth muscle
  upper ⅔: 2 layers
• inner longitudinal
• outer circular

lower ⅓: 3 layers
- inner longitudinal
- middle circular
- outer longitudinal

Question 33

ureter - adventitia

Answer 33

adipose, blood vessels, nerves
- supports ureter and connects to surrounding tissue

Question 34

bladder

Answer 34

stores and excretes urine

Question 35

bladder - epithelium

Answer 35

transitional
- umbrella cells at surface

Question 36

bladder - lamina propria

Answer 36

connective tissue, blood vessels, nerves
- supports epithelium

Question 37

bladder - muscularis

Answer 37

Named detrusor muscle
3 smooth muscle layers:
- inner longitudinal
- middle circular
- outer longitudinal

• thicker than in ureter

Question 38

bladder - adventitia

Answer 38

connective tissue, blood vessels, nerves
- lower part of bladder
- does not secrete fluid
- connects to surr tissues

Question 39

serosa

Answer 39

mesothelial cells lining top of bladder
- secrete serous fluid
- exposed to abdominal category

Question 40

urethra

Answer 40

transport urine from bladder to body exterior

epithelium: 2 female, 3 male

Question 41

urethra - lamina propria

Answer 41

fibroelastic CT
- mucous glands (lubricating)

Question 42

urethra - muscularis

Answer 42

2 smooth muscle layers
- inner longitudinal
- outer circular

Question 43

urethra - adventitia

Answer 43

CT, blood vessels, nerves

Question 44

female urethra epithelium

Answer 44

transitional -> str sq epithelium

Question 45

male urethra epithelium

Answer 45

prostatic urethra: transitional
membranous urethra: str columnar
spongy/penile urethra: str sq

Question 46

transitional cell carcinoma

Answer 46

cells of transitional epithelium (ureter, bladder, urethra)
- enlarged nuclei
- pleomorphic (variable size and shape) nuclei