Animal Coordination, Control and Homeostasis

The endocrine system uses hormones — chemical messengers produced by glands, carried in the blood, acting on target organs.

Key glands: pituitary (master gland), thyroid (produces thyroxine to control metabolism), adrenal (adrenaline), pancreas (insulin/glucagon), ovaries (oestrogen/progesterone), testes (testosterone).

Nervous vs hormonal: nervous is fast, short-lasting, electrical, precise. Hormonal is slower, longer-lasting, chemical, widespread.

Adrenaline is released in 'fight or flight' situations: increases heart rate, blood flow to muscles, and glucose release.