endocrine system

• Hormones are chemicals that are released by endocrine glands  travel in the blood and bind to target organs causing an effect.
• Endocrine glands – Glands without ducts that secrete hormones directly into the blood

  • H Hypothalamus
  • T Thyroid gland
  • P Pancreas
  • P Pituitary gland
  • P Parathyroid gland
  • A Adrenal gland
  • T Testes
  • O Ovaries
• The Adrenal gland is important for stress responses

  • adrenal cortex - aldosterone (a mineralocorticoid), cortisol (a glucocorticoid), and androgens and estrogen (sex hormones). 
  • adrenal medulla - epinephrine (adrenaline) and norepinephrine (noradrenaline)
• There are two main types of hormones

  • Sterols (lipids that can pass through cell membranes)
  • Peptides (charged so can’t pass through cell membranes)
• Lipid soluble hormones can pass into cells and impact genes directly 

  
• Put the steps in order (lipid soluble hormones) -

  • This complex passes through the pored into the nuclear membrane 3
  • The hormone receptor complex acts as a transcription factor 4
  • This means it binds to DNA and regulates it’s expression 5
  • This DNA is then translated and this causes a change in the cell 6
  • The hormone then binds to a receptor forming a receptor hormone complex 2
  • Hormones enter the cells through the cell membrane 1
• Peptide hormones can’t pass through the membrane and so use secondary messengers
• Put the steps in order (peptide hormones) -

  • bound proteins are triggered. 2
  • A hormone binds to a receptor on the cell membrane. 1
  • This secondary messenger then triggers a response in the cell 4
  • A series of reaction involving membrane This ends with a reaction forming a secondary messenger (this is usually adenylate cyclase that turns ATP into cAMP) 3