Aldosterone Controlling sodium levels Aldosterone Aldosterone is a

Aldosterone Controlling sodium levels

Aldosterone • Aldosterone is a hormone. • It is secreted by the adrenal glands

Aldosterone is secreted by the cortex of the adrenal glands.

What is the role of aldosterone? • The primary role of aldosterone is the maintenance of a constant level of sodium ions (Na+) in the plasma of the blood. • When aldosterone is secreted into the blood the kidneys actively reabsorb sodium ions from the filtrate.

What is the role of aldosterone? • As sodium ions are reabsorbed water follows by osmosis into the blood.

• Aldosterone also increases the excretion of potassium ions (K+). • The release of aldosterone is stimulated by a fall in the volume of the blood.

Hyperaldosteronism • This occurs when the adrenal glands secrete excessive amounts of aldosterone – Conn syndrome

Hypoaldosteronism • This occurs when the adrenal glands don’t secrete enough aldosterone – Addison’s disease

Sodium and the body – research task • What are the short and long-term effects of sodium chloride (salt) deficiency on a person’s health? • When might a person be at risk of losing too much salt from their body? • Why is too much salt in our diet dangerous to our health? • Which health problems might too much salt cause us?

A person visits a hot country…. . They start to feel ill because their blood pressure is low. The low blood pressure was caused by sodium chloride deficiency. Give two symptoms they might experience due to low blood pressure. • Headache dizziness nausea • Poor balance blurred vision fatigue • Confusion rapid, shallow breathing

Describe how the adrenal cortex responds to low blood pressure… • Releases aldosterone • Which causes the reabsorption of sodium ions (in the distal convoluted tubules) • More water is reabsorbed by the kidney and so blood pressure rises.