Hormonal/Endocrine system

• The Endocrine System

  A group of specialised tissues known as glands that produce chemicals called hormones
• Hormone

  Chemical messages produced by endocrine glands and carried to another part of the body through the bloodstream where it had a specific affect
• most hormones are globular proteins
• Gland

  A gland is an organ that produces particular chemical substances for release into either the bloodstream or ducts
• Exocrine Glands


  Have ducts (tubes) that are responsible for carrying and transporting the chemical substances produced by the gland eg. Salivary or tear glands
• Endocrine Glands

  Endocrine Glands are ductless. They secrete hormones directly into the bloodstream eg. Thyroid or pituitary gland
• Pituitary Gland

  • Location

  base of the brain

  • Hormone Secreted

  1. ADH
  2. FSH
  3. LH
  4. TSH (thyroid-stimulating hormone)

  • Hormone Role

  1. ADH is responsible for osmoregulation
  2. FSH stimulates the production of the Graafian Follicle and the hormone oestrogen in the female. Stimulates sperm production in the male
  3. LH stimulates ovulation and the production of progesterone in females, in males it stimulates testosterone
  4. TSH stimulates the thyroid gland to produce thyroxine when levels are low
• Hypothalamus

  • Location

  above the pituitary gland

  • Hormone Secreted

  TRH

  • Hormone Role

  Stimulates the pituitary gland to make TSH, therefore it is involved in homeostasis
• Pineal Gland

  • Location

  middle of the brain

  • Hormone Secreted

  Melatonin

  • Hormone Role

  controls our circadian rythm, blue light decreases production
• Ovaries

  • Location

  either side of the uterus

  • Hormone Secreted

  Progesterone

  Oestrogen

  • Hormone Role

  1. Progesterone

  inhibits LH

  1. Oestrogen

  inhibits FSH, stimulates LH and causes endometrium to thicken
• Endocrine System Disorders

  • Hypothyroidism

  Thyroid Gland not producing enough thyroxine

  • Effect

  low metabolic rate

  • Symptoms

  tiredness and weight gain

  • Treatment

  take thyroxine tablets or eat more iodine