Pituitary Gland - PDF by examville

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                            PITUITARY GLAND


ANTERIOR PITUITARY


GROWTH HORMONE

       ALSO CALLED SOMATOTROPHIC HORMONE
       Synthesized by acidophil cells of anterior pituitary.
       Secreted episodically with diurnal variation, peak occurs at night time after
       sleep.

  Regulatory mechanisms

  GH releasing hormone and GH inhibitory hormone.

       Factors increasing GH secretion

  1.   Hypoglycemia
  2.   Exercise
  3.   Glucagon
  4.   Protein meals
  5.   Stress

       Factors decreasing GH secretion

  1.   GH
  2.   Glucose
  3.   Cortisol
  4.   Free fatty acids


ACTIONS

  1. Stimulates skeletal growth through somatedins.

  2. Before epiphyseal closure, GH stimulates increase in linear skeletal growth.
  3. After epiphyseal closure GH accelerates bone thickening through periosteal
      growth.

   4. Protein metabolism
                  Anabolic hormone
                  Positive nitrogen balance
                  Excretion of amino acids

   5. Increase reabsorption of Ca+, Na+, and K+ from kidneys.

   6. Carbohydrate metabolism
                 Diabetogenic -- causes hyperglycemia

   7. fat metabolism
                 Catabolic effect -- increases free fatty acids.
                 Ketogenic -- increases ketone bodies formation by hepatic
   oxidation of fatty acids.

   8. GH increases growth of thymus

   APPLIED
       Gigantism
         Overproduction of GH before epiphyseal closure

   Characteristic features
         Tall body
         Giant hands and feet
         Gynaecomastia (bilateral)


         Acromegaly
          Overproduction of GH after epiphyseal closure

         Characteristic features:
     Prognathism – widening of mandible
     Prominent brow --- enlargement of frontal, ethmoid, maxillary and mastoid
     sinuses.
     Facies -- thickening of the skin and coarse facial features
     Kyphosis
     Hypertrophy of body organs such as liver, heart, spleen.
DWARFISM
Def
								
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