Genitourinary

Question 1

5 functions of the kidney?

Answer 1

Excretion if metabolic products
Excretion of foreign substances
Homeostasis
Regulate BP
Secrete hormones

Question 2

What is the function of the detrusor muscle?

Answer 2

Contracts → bladder pressure rises → urination

Question 3

What is the function of the trigone?

Answer 3

Sends signals to the brain when stretched to indicate need for urination

Question 4

Function and control of internal and external sphincters?

Answer 4

Both prevent urination
Int - involuntary
Ext - voluntary

Question 5

Function of bulbourethral gland?

Answer 5

Only in males

Produces thick lubricant which is added to semen to aid sperm survival

Question 6

Which parts of the nephron are rich in mitochondria? (4)

Answer 6

PCT
DCT
Thick ascending LoH
Intercalated cells of CD

Question 7

Nephron parts low in mitochondria?

Answer 7

Thin ascending and descending LoH

Principal cells of CD

Question 8

What are the two types of nephron?

Answer 8

Superficial (cortex and outer medulla)
Juxtamedullary (cortex, outer and inner medulla)

More superficial

Question 9

What are the constituents of the juxtaglomerular apparatus?

Answer 9

Macula densa - distal convoluted tubule
Extraglomerular mesangial cells
Juxtaglomerular cells - afferent arteriole

Question 10

Function of the JGA?

Answer 10

GFR regulation via tubulo-glomerular feedback mechanism

Renin secretion for Bp

Question 11

Which cells secrete renin?

Answer 11

Juxtaglomerular cells

Question 12

How does fluid move from the glomerulus into bowmans capsule?

Answer 12

Passive

Hydrostatic pressure of heart

Question 13

Describe how the structure of capillary endothelium supports transport?

Answer 13

It’s fennestrated so it’s highly permeable to fluid and solutes but impermeable to cells and proteins

Question 14

Describe structure of glomerular basement membrane

Answer 14

Epithelial Podocytes

Slit diaphragm between podocytes thin and porous to allow through small molecules and water

Question 15

What are the differences between hydrostatic and oncotic pressure?

Answer 15

HP - pressure exerted by fluid, solute and fluid are pushed out

OP - pressure exerted by solute, fluid molecules drawn in a cross semipermeable membrane

Question 16

Net ultrafiltration pressure equation?

Answer 16

HP in glomerular capillaries - HP in BC - OP in GC

Question 17

What is the glomerular filtration rate?

Answer 17

Amount of fluid filtered from glomeruli into bowmans capsules per unit time

Question 18

GFR equation?

Answer 18

Ultrafiltration pressure x Kf (ultrafiltration coefficient)

Question 19

Normal GFR ranges?

Answer 19

M - 90-140

F - 80 - 125

Question 20

What can a fall in GFR show?

Answer 20

Renal disease

Increase in waste products in plasma

Question 21

What are the 2 ways GFR is regulated?

Answer 21

Myogenic mechanism

Tubulo-glomerular feedback mechanism

Question 22

Explain the myogenic mechanism

Answer 22

Arterial pressure increases 
Afferent arteriole stretches
Arteriole contracts so vessel resistance rises
Reduced blood flow
GFR maintained

Question 23

Explain the tubule-glomerular feedback mechanism

Answer 23

Increase GFR
Increased NaCl in LoH
Change detected by macula densa
Increased ATP and adenosine discharged
Afferent arteriole contracts
GFR decreases to stabilise 

Vice verse for decrease

Question 24

What is renal clearance?

Answer 24

Volume of plasma that is completely cleared of a substance per unit time
Only concerned with excretory role of kidneys
Rate of removal of a substance from the blood via excretion in the urine

Question 25

Renal clearance equation?

Answer 25

C= (u x v) / p U : concentration of substance in urine V : rate of urine production P : concentration in plasma

Question 26

How can GFR be measured practically?

Answer 26

By measuring the renal clearance for a substance that is freely filtered and not reabsorbed nor secreted in the nephron Amount filtered = amount excreted

Question 27

What is the ideal molecule for GFR measurement and why is it not used?

Answer 27

Inulin Not toxic, measurable in urine and plasma But not found in mammals so needs to be transfused

Question 28

What molecule is commonly used to measure GFR and why?

Answer 28

Creatinine - waste product from creatine muscle metabolism Amount released is fairly constant Freely filtered and not reabsorbed

Question 29

What can indicate renal foliage relating to creatniine?

Answer 29

Low creatinine clearance | High plasma creatinine

Question 30

What is one problem with creatinine and how is it resolved?

Answer 30

A small amount is secreted into nephron but this is taken into account in GFR calculations

Question 31

What is renal plasma flow?

Answer 31

Volume of plasma that reaches kidneys per unit time

Question 32

When does renal clearance equal renal plasma flow?

Answer 32

When total amount of a molecule entering the kidney is excreted

Question 33

What molecule is used in measured rpf and why?

Answer 33

``` Para aminohiupparte (PAH) All is removed from plasma via filtration and secretion ```

Question 34

What is the filtration fraction?

Answer 34

The ratio of the amount plasma that is filtered and the amount that arrives at afferent arteriole =GFR/RPF

Question 35

What is the normal range for filtration fraction?

Answer 35

0.15 - 0.20

Question 36

What substances are 100% reabskrbed in PCT?

Answer 36

Glucose | Amino acids

Question 37

What other substances are reabsorbed in PCT?

Answer 37

``` Na+ Cl- HCO3- Water Urea ```

Question 38

What substances are secrete into pct?

Answer 38

``` Drugs Ammonia Bile salts Prostaglandins Vitamins ```

Question 39

What are the 3 transporters involved in sodium and bicarbonate reabsorption?

Answer 39

Na+ H+ antiporter Na+K+ATPase pump Na+HcO3- symporter

Question 40

How are carbonate ions formed in pct cells?

Answer 40

CO2 diffuses into cell | Combines with water in presence carbonic anhydrase to form Hc and HCO3-

Question 41

What are the 3 transporters in glucose reabsorption in the pct?

Answer 41

SGLT2 - Na+ glucose symporter Na+K+ATPase pump GLUT2 glucose transporter

Question 42

What substances are reabsorbed in LoH?

Answer 42

Water Na+ Cl-

Question 43

Outline the reabsorption in LoH

Answer 43

Thin descending limb - water moves out, impermeable to ions Bottom = hyperosmolar fluid Thin ascending limb - impermeable to water, ions passively move out Thick ascending limb - ions are actively pumped out Top = hypo-osmolar fluid

Question 44

What substance move through the paracellular pathway in thick AL?

Answer 44

Ca2+ Na+ K+ Mg2+

Question 45

What 3 transporters are in the thick ascending limb?

Answer 45

Na+K+Cl- symporter Na+K+ATPase pump K+Cl- symporter

Question 46

What substances are reabsorbed in the early DCT?

Answer 46

Na+ Cl- Ca2+

Question 47

What transporters are in the early DCT?

Answer 47

Na+ Cl- : Na+Cl- symporter , ATPase pump, K+Cl- symporter Ca2+ : ATPase pump, Na+Ca2+ antiporter, Ca2+ATPase pump

Question 48

What are the 2 types of cells in the distal DCT and CD? + functions

Answer 48

Principal - Na+ , water reabsorption, K+ secretion | Intercalated cell - maintain acid-base balance

Question 49

How is Na+ reabsorption regulated?

Answer 49

Aldosterone increases apical Na+ channels and basolateral ATPase pumps

Question 50

How is water reabsorption regulated?

Answer 50

ADH increases apical aquaporins

Question 51

Outline reabsorption and secretion in distal DCT and CD

Answer 51

Sodium moves in through apical sodium channels It is exchanged with potassium via basolateral ATP pump Potassium is secreted into tubular fluid via potassium channels Water is reabsorbed by aquaporins on apical and basolateral membranes

Question 52

What are the 2 types of intercalated cells and their functions?

Answer 52

a - HCO3- reabsorption, H+ sercretion | B - H+ reabsorption, HCO3- secretion

Question 53

What are the 2 transporters found on intercalated cells

Answer 53

H+ATPase pump | Cl-HCO3- antiporter