URINARY SYSTEM

Question 1

What are the primary functions of the urinary system?

Answer 1

• Excretion and elimination of wastes from the body
• Fluid and solute balance (osmoregulation)
• pH balance

Question 2

What are the secondary functions of the urinary functions?

Answer 2

• Endocrine function: vitamin D, renin, EPO

- Metabolic function: glucose homeostasis

Question 3

What are the major components of the urinary system?

Answer 3

• Kidney: produces urine
• Ureter: transports urine from kidney to bladder
• Bladder: temporarily stores urine
• Urethra: transports urine to exterior

Question 4

Where are the kidneys located?

Answer 4

• They are paired, located between T12 and L3, right is lower than left
• retroperitoneal

Question 5

What is the nephron and what are the components?

Answer 5

• The functional unit of the kidney
• renal corpuscle: glomerulus and glomerular capsule
• renal tube: Proximal convoluted tubule (PCT), nephron loop
• Dsital convoluted tubule (DCT)
• Collecting ducts

Question 6

What are the components of the nephron’s blood supply

Answer 6

1. Afferent arterioles - blood to the glomerulus
2. Glomerular capillaries
3. Efferent arteriole - blood from the glomerulus
4. Peritubular capillaries - blood around the renal tubule (specifically the nephron loop)

Question 7

What are the 3 stages of urine formation in the nephron?

Answer 7

1. Filtration
2. Reabsorption
3. Secretion

Question 8

List, in order, the process of urine formation in the kidney

Answer 8

1. Renal tubule
2. Collecting duct
3. Papillary duct
4. Minor calyx
5. Major calyx
6. Renal pelvis
7. Ureter
8. Bladder
9. Urethra

Question 9

How is urine moved through the body?

Answer 9

By peristalsis

Question 10

How much blood does the glomerular filtrate daily?

Answer 10

180L

Question 11

Excretion =

Answer 11

Filtration - Reabsorption + secretion

Question 12

What are Starling’s forces?

Answer 12

Fluid movement due to filtration across the glomerular capillary wall, depends on balance between pressures

• Hydrostatic pressure
• Oncotic (osmotic) pressure

Question 13

What is the glomerular filtration rate and what is it affected by?

Answer 13

GFR = volume of filtrate produced per minute (90-125mL/min)

Affected by: large renal blood flow, high fluid permeability of the filtration barrier, large filtration area and highly positive filtration pressure

Question 14

Define tubular reabsorption and secretion

Answer 14

Reabsorption = movement from nephron into blood
Secretion = movement from blood into the nephron 

Both are selective (diffusion, osmosis, channel or carrier mediated transport)