Human endocrine system

• Endocrine system


  Composed of glands which secrete chemical messengers called hormones directly into the bloodstream

  The blood carries the hormones to a target organ where it produces an effect

  Compared to the nervous system, the effects are slower but act longer
• Brain


  Exerts control over most endocrine glands directly or indirectly via pituitary gland
• Pituitary / Master gland


  Secrets hormones, may which act in other glands

  Located below the brain
• Thyroid gland

  Around the neck

  Secretes thyroxine - important in growth and control of metabolic rate
• Pancreas


  Secretes insulin
• Adrenal gland

  Located above kidneys

  Produce adrenaline and secretes hormones in homeostasis
• Testes


  Secrets testosterone

  Secondary sexual characteristics
• Ovaries


  Oestrogen and progesterone

  Periods and pregnancy

  Secondary sexual characteristics
• Actions of pituitary gland

  1 - secretes hormones which act indirectly on the body by controlling secretions of other endocrine gland: adrenal gland, thyroid gland, ovaries or testes

  2 - secretes hormones acting differently on parts of or while body: ADH in kidney for osmoregulation, growth hormone and oxytocin in the uterus during contractions via childbirth
• Difference between endocrine and nervous system

  Endocrine have glands which secretes hormones through blood to tissues, slower transport but longer effect

  Nervous - relies on electrical impulses, short effect but transport is fast to your nerve cells

  Both have receptors and effectors
• Summary

  In addition to communicating with the fast acting nervous system, the body can also send messages using the endocrine system. This involves glands which secrete hormones directly into the blood and all over the body. Some have specific types of action where they bind to receptor proteins on the surface of target cells, other hormones have more widespread effect. Endocrine system is important to homeostasis