1.2 Explain the microanatomy of the kidney.

2. Understand the maintenance of water and salt balance.

2.1 Explain the role of the kidneys in maintaining blood volume, blood pH and osmolality.

2.2 Discuss how this balance can be influenced by environmental factors.

3. Understand common diseases of the urinary system.

3.1 Analyse how common diseases affect the function of the urinary system.

3.2 Discuss the wider effects of kidney disease on the human body.

Hormone involved: Antidiuretic Hormone (ADH) (produced by the hypothalamus and released by the pituitary gland)

Process:

1. Stimulus: Blood water levels decrease (e.g., dehydration) or blood osmolarity increases.

2. Receptor: Osmoreceptors in the hypothalamus detect the change in blood osmolarity.

3. Control Centre: The hypothalamus triggers the release of ADH from the pituitary gland.

4. Effector: ADH causes the kidneys to reabsorb more water by increasing the permeability of kidney tubules (collecting ducts).

5. Response: Blood water levels increase, osmolarity returns to normal, and ADH secretion decreases (negative feedback).

Efferent - 'leading out'

Medulla - 'inner part of the organ'

Proximal - near the main 'body'

Distal - far from the main 'body'

Convoluted - intricately folded, twisted or coiled.