Hormones (pg. 48)

• Hormones are chemical messengers produced in glands sent in the blood. They're carried in the blood plasma to other parts of the body, but only affect particular cells (called target cells) in particular places.
• Hormones control things in organs that need constant adjustment. They travel quite slowly and tend to have relatively long-lasting effects.
• Adrenaline is produced in adrenal glands (on top of the kidneys) and readies the body for a 'fight or flight' response. It increases heart rate, blood flow to muscles and blood sugar level.
• Insulin is produced in the pancreas and helps control the blood sugar level. It stimulates the liver to turn glucose into glycogen for storage.
• Testosterone is produced in the testes and is the main male sex hormone. It promotes male secondary sexual characteristics.
• Progesterone is produced in the ovaries and supports pregnancy. It maintains the lining of the uterus.
• Oestrogen is produced in the ovaries and is the main female sex hormone. It controls the menstrual cycle and promotes female secondary sexual characteristics.
• ADH (anti-diuretic hormone) is produced in the pituitary gland in the brain and controls the water content. It increases the permeability of the kidney tubules to water.
• FSH (follicle-stimulating hormone) is produced in the pituitary gland and is a female sex hormone. It causes an egg to mature in an ovary and stimulates the ovaries to produce oestrogen.
• LH (luteinizing hormone) is produced in the pituitary gland and is a female sex hormone. It stimulates the release of an egg from an ovary.
• Nerves:

  1. Very fast message.
  2. Act for a very short time.
  3. Act on a very precise area.
• Hormones:

  1. Slower message.
  2. Act for a long time.
  3. Act in a more general way.