Renal System And Micturition

Question 1

What are the functions of the renal system?

Answer 1

Fluid balance 
Creates electrolytes
Acid balance 
Regulates blood pressure  
Elimination of drugs

Question 2

List the order of blood supply through the kidneys…

Answer 2

Renal artery 
Arcuate arteries 
Afferent arteriole 
Glomerulus 
Efficient arteriole 
Peritubular capillaries
Veins 
Renal vein

Question 3

Hw do the kidneys work?

Answer 3

Filter around 180 litres of plasma per day
A filter rate of less than 60mls per min is suggestive of renal failure
The entire plasma volume is filtered 60 times day

Question 4

What is the function of nephron in urine formation?

Answer 4

Glomerular filtration
Tubular reabsorption
Tubular secretion

Question 5

What is the filtration membrane?

Answer 5

Allows free movement of water and solutes smaller than 3nm

Barred molecules include albumin and erythrocytes

Question 6

What is the glomerular filtration rate?

Answer 6

Total amount of filtration formed by the kidneys each min

Average: 125ml/min
180ml/day
1ml/min of urine

Question 7

What factors can affect Glomerular filtration rate?

Answer 7

Total surface area available
Filtration membrane permeability
Net filtration pressure
Increase in blood pressure

Question 8

How does reabsorption in the proximal convoluted tubule occur?

Answer 8

Reabsorption occurs via:

1. passive reabsorption
   - some urea
   - water
   - chloride
   - bicarbonate
2. active reabsorption
   - glucose
   - amino acids
   - vitamins

Question 9

What substances cannot be reabsorbed via the proximal convoluted tubule?

Answer 9

50 - 60% of urea
Creatinine
Uric acid

Question 10

What is the nephron loop?

Answer 10

Water leaves the descending limb via osmosis - concentration filtrate
Na+ & Cl- are then reabsorbed via the ascending loop - dilute filtrate

Question 11

What gets reabsorbed via the distal convoluted tube?

Answer 11

Sodium
Potassium
Water - anti diuretic hormone

Question 12

What is micturition?

Answer 12

Emptying of the bladder
Stretching of the bladder wall
Initiates the micturition reflex
The destructor muscle contracts and the internal urethral sphincter opens

Question 13

What is the composition of urine?

Answer 13

96% water 
4% solids 
Drugs 
Uric acid 
Nitrogenous waste 
Salts

Question 14

What are the physical characteristics of urine?

Answer 14

Volume 
Colour 
Turbidity 
Odour 
pH
Specific gravity