Biology - B7 Animal coordination, control and homeostasis

Define adrenalin

Released from the adrenal glands in exciting or threatening situations to prepare the body for fight to flight

Name the effects adrenalin has on the body

• Increased heart rate - allows faster delivery of oxygen and glucose to muscles

• Increased blood pressure - due to increased force of heart contractions

• Increased blood to muscles - dilation of arterioles allows for a higher rate of respiration

Name the target organs for adrenalin

• Lungs

• Muscles

• Heart

Define thyroxine

• Effects metabolic rate

• Released by thyroid gland

Explain the order in which thyroxine is released

Hypothalamus —> TRH —> pituitary gland —> TSH —> thyroid gland

—> thyroxine

What happens if you have an overreactive thyroid gland

• Weight loss

• Trouble sleeping

• Heart palpitation

What happens if you have an underactive thyroid gland

• Tiredness

• Anxiety

Describe the role of oestrogen

• Secreted by the ovaries

• Repairs and thickens uterus lining

• Stimulates release of LH