Paper 2 - Excretion Flashcards
1
Q
How does the kidney carry out its role of excretion?
A
- Glucose, water, mineral ions and urea diffuse across partially permeable membrane into Bowman’s capsule as the Glomerular Filtrate
- All of glucose is reabsorbed back into blood at proximal convoluted tubule
- Water, urea and mineral ions travel through ureter to bladder and are excreted out of urethra
2
Q
How does the kidney carry out its role of osmoregulation?
A
- Water concentration in blood in controlled by ADH
- If low water concentration in blood is detected, ADH makes collecting duct more permeable to water
- So water diffuses into blood via osmosis
3
Q
Define excretion
A
The removal of metabolic waste
4
Q
Describe the role of ADH in regulating the water content in blood
A
- If low water concentration in blood is detected, hypothalamus signals to posterior pituitary gland to secret ADH into blood
- ADH increases the permeability of the collecting duct to water
- So water diffuses into blood via osmosis
5
Q
Why does selective reabsorption of glucose occur at the proximal convoluted tubule?
A
- All glucose is reabsorbed into blood via active transport
- Glucose is needed for aerobic respiration to produce energy for cells
6
Q
Describe ultrafiltration
A
- Blood enters through renal arteriole
- The arteriole supplying blood to the glomerulus is wider that the arteriole that takes it away to there is a high blood pressure
- This blood pressure forces water, urea, glucose and mineral ions to diffuse into Bowman’s Capsule
7
Q
Describe the structure of the nephron
A
Renal artery
↓
Glomerulus
↓
Bowman’s capsule
↓
Proximal convoluted tubule
↓
Loop of Henlé
↓
Distal convoluted tubule
↓
Collecting duct
8
Q
Describe the structure of the urinary system
A
Kidneys
↓
Ureter
↓
Bladder
↓
Urethra
9
Q
What does urine contain?
A
- Urea
- Water
- Mineral ions
10
Q
What is the composition of the Glomerular filtrate?
A
- Urea
- Mineral ions
- Water
- Glucose
