Genitourinary system

Question 1

What is the function of the kidneys

Answer 1

Excretion of metabolic products - urea, uric acid, creatinine

Excretion of foreign substances - dugs

Homeostasis - body fluids, electrolytes and acid-base balance

Regulates blood pressure

Secretes hormones - erythropoietin, renin

Question 2

What is the function of renal blood supply to kidneys

Answer 2

Provide oxygen and nutrients

Secretion of drugs

Reabsorption of different substances

Question 3

Function of detrusor muscle

Answer 3

Contracts to build pressure in the urinary bladder support urination

Question 4

Function of trigone

Answer 4

Stretching of this triangular region to its limit signals the brain about the need for urination

Question 5

Function of internal sphincter

Answer 5

Involuntary control to prevent urination

Question 6

Function of external sphincter

Answer 6

Voluntary control to prevent urination

Question 7

Function of bulbourethral gland

Answer 7

Produces thick lubricant which is added to watery semen to promot sperm survival

Question 8

What is the superficial to juxtamedullary nephron ratio

Answer 8

10:1

Question 9

What is the difference between superficial nephron and juxtamedullary nephron

Answer 9

Superficial goes to outer medulla

Juxtamedullary goes to inner medulla

Question 10

What is the function of juxtaglomerular apparatus

Answer 10

GFR regulation through tubulo-glomerular feedback mechanism

Renin secretion for regulating blood pressure

Question 11

What are the different renal processes

Answer 11

Glomerular filtration

Reabsoprtion

Secretion

Excretion

Question 12

What is the filtration barrier of the glomerulus

Answer 12

Highly permeable to fluids and small solutes

Impermeable to cells and proteins

Question 13

What kind of process is golmerular filtration

Answer 13

Passive process - driven through semipermeabel golmerular capillaries into Bowman’s capsule

Question 14

Hydrostatic pressure

Answer 14

Pushing

Fluid exerts this pressure

Solute and fluid molecules shoved out

Question 15

Oncotic pressure

Answer 15

Pulling

Solutes exert this pressure

Fluid molecules drawn in

Question 16

What is the net ultrafiltration pressure

Answer 16

Ultrafiltration pressure = Hydrostatic pressure (glomerular) - hydrostatic pressure (bowmans) - oncotic pressure of plasma proteins

Question 17

What is the Glomerular Filtration Rate

Answer 17

Amount of fluid filtered from glomeruli into Bowman’s capsule

Sum of filtration rate of all functioning nephrons

GFR = Pressure (ultrafiltration) x ultrafiltration coefficient (membrane permeability and surface area)

Fall in GFR can be renal disease, build up of excretory products in plasma

Question 18

What is the healthy GFR for male and femal

Answer 18

90-140 mL/min

80-125 mL/min

Question 19

What is the myogenic mechanism of regulation of GRF

Answer 19

Arterial pressure increases

Afferent arteriole stretches

Arteriole contracts

Vessel resistance rises

Blood flow reduces

GFR stays same

Question 20

What is the tubulo-glomerular feedback mechanism

Answer 20

Increase/Decrease in GFR

Increase/Decrease NaCl in Loop of Henle

Change detected by macula densa

Increased/Decreased ATP and adenosine discharged

Afferent arteriole constricts/dilates

GFR stabilizes

Question 21

What is renal clearance

Answer 21

The number of litres of plasma that are completely cleared of the substance per unit time

Only concerned with the excretory role played by the kidneys

Question 22

What is the renal clearance formula

Answer 22

C = (U X V) / P mL/min

U= concentration of substance in urine

V = rate of urine production

P = concentrstion of substance in plasma

Question 23

How can GFR be emasured by renal clearance

Answer 23

If a molecule is freely filtered and neither reabsrobed nor secreted

Question 24

What are molecules that are freely filtered

Answer 24

Inulin - plant polysaccharide, non toxic, not found in mammals so has to be transfsued

Creatinine - Waste product from creatien in muscle metabolism, creatinine released is fairly constant, small amount is secreted into nephron so not a perfect. molevule. Process for estimating creatinine in blood and urine can account for that

Question 25

What is renal plasma flow

Answer 25

Total amount of molecule entering kidney equals amount excreted, renal clearance of this molecule equals renal plasma flow

Question 26

What are examples of renal plasma flow

Answer 26

Para aminohippurate - all PAH is removed from the plasma passing through kidney through filtration and secretion

Question 27

What is the filtration fraction

Answer 27

Amount of plasma which is filtered which arrives via the afferent artriole ranges from 0.15-0.20 15% of plasma FF = GFR/RPF

Question 28

What are the different transport mechanisms of renal tubules

Answer 28

Passive Transport Active Transport Primary active Secondary active/ coupled transport (movement of one solute along electrochemical gradient provides energy for other solute to move against it) - symport Na+ Glucose symporter - antiport Na+ H+ antiporter

Question 29

Reabosportion in the early proximal convoluted tubule Sodium and Bicarbonate

Answer 29

**Sodium and Bicarbonate reabsorption** Using Na+ K+ ATPase Pump Na+ H+ antiporter Na+ HCO3- symporter Angiotensin 2 regulates Na+ reabsorption by increasing Na+ H+ antiporters

Question 30

Reabsorption in the early proximal convoluted tubule glucose reabsorption

Answer 30

**Glucose rebsorption** Na+ Glucose symporter SGLT2 Glucose transporter GLUT2

Question 31

Reabsorption in early proximal convoluted tubule substances

Answer 31

**Substances reabsorbed:** 67% Na+, 67% Cl-, 80% HCO3-, 100% Glucose, 67% water, 100% amino acids, 50% urea **Substances secreted**: drugs, ammonia, bile salts, prostaglandins, vitamins

Question 32

Reabsorption in henle's loop substances

Answer 32

25% Na, 25 Cl, 15 water

Question 33

Reabsorption in the early distal convoluted tubule

Answer 33

Na and Cl reabsoption Active Ca reabsorption Na+Ca antiporter Ca ATPase pump No water enter

Question 34

Reabsorption in distal DCT and Collecting duct Principal cell

Answer 34

Na+ reabsorption and K secretion Aldosterone regulates Na reabsorption by increase apical Na channels and basolateral NaK ATPase pumps ADH regulates water reabsorption by increasing apical aquaporins

Question 35

Reabsorption in distal DCT and Collecting duct Intercalated cell

Answer 35

Maintain acid-base balance Alpha : HCO3 reabsorption and H secretion Beta: HCO3 secretion and H reabsorption