Hormones

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  • Created by: Liv Scott
  • Created on: 18-03-15 08:21
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  • Hormones
    • Glands
      • Exocrine- secret into ducts
      • Endocrine- secret hormones directly into blood
        • Catcholamine hormones- protein, bind to extracellular receptors
        • Steroid hormones- non-protein, pass through phospholipid bilayer
    • Adrenaline
      • Adrenal glands
        • 1 on each kidney
        • Adrenal medulla (middle) secrets catecholiamine e.g. adrenalin
        • Adrenal cortex (outer) releases steroid hormones
      • Catecholoamine hormone
      • Primary messenger, bind to receptor on cell
        • Activates extrinsic protein- adenyl cyclase
          • Coverts ATP to cAMP
            • Causes enzyme reactions e.g. more glucose produced
    • Pancreas
      • Endocrine & exocrine
        • Exo- most cells secrete enzymes into ducts
        • Endo- islets of Langerhan
          • Alpha cells- glucagon
          • Beta cells- insulin
    • Glucoregulation
      • Too low
        • Detected by alpha cells, secret glucagon
          • Goes to hepatocytes
            • Effects
              • Glycogenolysis (glycogen to glucose)
              • Gluconeongenesis (amino acids & fats to glucose)
      • Too high
        • Detected by beta cells, secrete insulin
          • Travel to target tissue- hepatocytes, muscle cells etc.
            • Binds to receptor & activates adenyl cyclase
              • Effects
                • More glucose channels
                  • More glucose into cell
                • Glycongensis (glucose to glycogen)
                • More glucose into fat
                • More respiration
      • Diabetes
        • Blood glucose conc. can't be controlled effectively
        • Type 1
          • Early onset
          • Caused by autoimmune disease, body destroys beta cells
          • Treated with insulin injections
          • Genetic link
        • Type 2
          • Drop in the no. of function insulin receptors
          • Reduces ability of liver & muscles to respond to insulin
          • Genetic link
          • Environmental risks
            • Can be controlled by diet & execrise
        • Production of insulin
          • Previously from pigs
            • Now from GM bacteria
              • Exact match, not rejected
              • More effective
              • Cheaper to manufacture
              • Produced to meet demand
              • Fewer ethical issues
              • Lower risk of infection
          • Stem cell
            • Unspecialised cells, can grow into B cells- produce insulin normally
    • Control of heart rate
      • Nervous
        • Cardiac muscle- myogenic
        • SAN is pacemaker
          • Initiates action potential, transmits down atrial wall to AVN
            • Wave down Purkyne fibres to ventricles
        • Cardiovascular centre in medulla oblongata
        • Acceletrator nerve increase HR
          • Antagonistic
            • Vagus nerve decrease HR
              • Heart rate lowers
                • High BP- measured by baroreceptor
          • Heart rate increases
            • Low pH (increased CO2)
        • Vagus nerve decrease HR
          • Heart rate lowers
            • High BP- measured by baroreceptor
      • Hormonal
        • Adrenalin released in response to stress (increases HR)

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