Hormones

• What are hormones?

  Chemical messengers which travel in the blood to activate target cells |
• • Released directly in the blood to regulate bodily processes
  • Carried in the blood plasma to other parts of the body but only affect particular cells in particular organs (target organs)
• Endocrine system

  • Hormones are produced in and secreted by glands called endocrine glands
  • These make up the endocrine system
  • Uses hormones to react to changes in the environment or changes inside the body
• Endocrine glands

  1. Pituitary glands

  • Produces many hormones that regulate body conditions
  • Sometimes called the master gland
• 2. Pancreas

  • Produces insulin which is used to regulate the blood glucose level
• 3. Thyroid

  • Produces thyroxine, which is involved in regulating things like the rate of metabolism, heart rate and temperature
• 4. The adrenal glands

  • Produce adrenaline, which is used to prepare the body for fight or flight response
• 5. The ovaries (female)

  • Produces oestrogen which is involved in the menstrual cycle
• 6. The testes (male)

  • Produces testosterone which controls puberty and sperm production in males
• Comparing nerves and hormones

  • Hormones are carried in the blood, so they tend to travel around the body slower compared to nervous impulses
  • Hormones tend to have relatively long-lasting effects
  • Hormones and nerves do similar jobs in the body but with a few differences
• Nerves

  • Fast action
  • Act for a short time
  • Acts on a very precise area

  Hormones

  • Slower action
  • Act for a long time
  • Acts in a more general way