Water Balance

What are the four main ways water loss occurs in the body?

Water loss occurs through sweating (evaporation), respiration (breathing), urine (excretion), and faeces (excretion).

What stimulates the negative feedback regulation of water balance when dehydration occurs?

Water loss increases solute concentration in blood (dehydration), raising osmolarity.

What role do osmoreceptors play in water balance regulation?

Osmoreceptors in the hypothalamus detect increased osmolarity

What does the hypothalamus signal the pituitary gland to release in response to dehydration?

The hypothalamus signals the pituitary gland to release antidiuretic hormone (ADH).

What effect does ADH have on the kidneys?

ADH triggers the kidneys to reabsorb more water from urine back into the bloodstream.

What happens to ADH production when water balance is restored?

ADH production reduces, stopping the feedback loop.

How does excess water in extracellular fluid affect ADH secretion?

Excess water dilutes solutes, leading to reduced ADH secretion.

What occurs to the sensation of thirst when excess water is detected in the body?

Thirst is switched off, preventing overhydration.