Endocrine 1

• Endocrine Organs


  • Anterior Pituitary
  • Posterior Pituitary
  • Thyroid
  • Thymus
  • Pineal Gland
  • Parathyroid
  • Testes
  • Ovaries
  • Pancreas
• Anterior Pituitary (Adenohypophysis)


  M.y. F.L.A.T. P.i.G.
• Releasing/Inhibiting Hormones


  Produced by the Hypothalamus
• Posterior Pituitary (Neurohypophysis)


  Stores ADH & Oxytocin
• ADH


  Water Retention
• Oxytocin


  Uterine Contractions
• Pineal Gland


  Melatonin - ZZZ'S
• Parathyroid


  Increase Calcium in Blood
• Thyroid Hormones (T3/T4)


  Produced by Follicle Cells
• Calcitonin


  • Produced by C or Parafollicular Cells
  • Decrease Calcium in Blood
  • Increase Metabolism (Chemical Reactions)
• Parathyroid Hormone


  Increase Calcium in Blood
• Thymosin


  Stimulates T cell production
• Sertoli Cells


  Inhibin inhibits FSH
• Testes


  • Leydig Cells
  • Testosterone - Masculine Traits
• Duodenum


  Secretin - Stimulates Duodenum, Stomach & Pancreas
• Glucagon


  Increase Glucose in Blood
• Insulin


  Decrease Glucose in Blood
• Antagonists (opposite) ex. Glucagon & Insulin
• Endocrine


  Slow, hormones through interstitial fluid
• Nervous


  Fast, neurotransmitters through synapses
• How hormones communicate


  • Direct cell to cell through gap junctions
  • Paracrine - cell to cell in same tissue with the chemical moving through interstitial space
  • Autocrine - cell releases chemical which acts on the cell that released it
  • Endocrine through the blood (the highway of the body); sends it far away
• Hormones are mainly controlled by negative feedback
• Target Cells/Tissues


  Receptors on the surface, chemicals bind to these receptors and causes changes inside the cell with the receptor
• Classes of hormones


  • Amino Acid
  • Peptide (majority are peptide hormones)
  • Lipid
  • Steroid (from cholesterol) (needs taxi/carrier)
• Amino Acid hormones


  • Thyroid Hormones (needs taxi/carrier)
  • Catecholamines - Epi, Norepi., Dopamine
  • Serotonin
  • Melatonin
• Peptide hormones


  • FSH/LH/ADH/TSH/Prolactin/(i)/GH
  • ADH/Oxytocin
  • Insulin
• Lipid hormones


  • Eicosanoids - Prostaglandins = Pain, Leukotrienes = Inflammation
• Steroid hormones


  • Male & Female Reproductive
  • Kidney and Adrenal
• Down regulation


  Too much hormone in the blood causes cells to reduce/decrease the number of receptors
• Up-regulation


  Too little of a hormone in the blood causes an increase in the number of receptors
• How do hormones interact with the cell


  • Some cells have receptors on the surface of the cell, uses a second messenger system
  • Some cells have receptors in the cytoplasm
• Second Messenger System


  G protein links first messenger to second messenger
• Examples of second messengers

  • cAMP
  • Ca*
• second messenger system

  Can either increase or decrease metabolic rate
• G protein


  An enzyme complex coupled to a membrane receptor that serves as a link between the first and second messenger
• Effects on cAMP Level

  Many G proteins, once activated, exert their effects by changing the concentration of cyclic AMP, which acts as the second messenger within the cell
• Increased production of cAMP


  1. Activates enzymes

  2. Opens ion channels
• Decreased cAMP levels


  Reduced enzyme activity
• First Messenger Examples


  • Epinephrine and norepinephrine
  • Calcitonin
  • Parathyroid hormone
  • ADH, ACTH, FSH, LH, TSH
• Activation of the adenylate cyclase enzyme converts ATP → cAMP