ENDOCRINE SYSTEM
ENDOCRINE GLANDS
Hypothalamus
- part of fore-brain, secretes neurohormones,
which effect the release of hormones from
pituitary.
- Acts as the thermostat.
PITUITARY GLAND
- smallest endocrine gland.
- Somatotrophicharmone: Its hypersecretion
leads to acromegaly in adults and gigantium
in children. Its hyposecretion leads to
dwarfness in children.
- Gonadotrophic harmone (GTH) : Stimulates
the primary sex harmones
- Lactogenic hormone: Initiates milk
production in the pregnant females.
- Thyrotrophic hormone: regulation of thyroid
secretion.
- Adrenocorticotrophic hormone (ACTH)
- Diabetogenic or Metabolic Hormone:
- Oxytocin or Pitocin: smooth muscle
contractions, helps in the secretion of milk.
- Vasopressin or ADH (Anti-Diuretic
Hormone): Hypoactivity leads to Diabetes.
THYROID GLAND
- It is the largest endocrine gland located in
the neck between the trachea and larynx.
Controls BMR (Basal Metabolic Rate) it is
1600 Kcal/day
Secretes:
- Thyroxine: Hypoactivity in children leads to
cretinism.
- A diet, poor in iodine which is insufficient
for the synthesis of thyroxin, leads to simple
goiter.
- Its hyperactivity leads to increased metabolic
activities
- Thyrocalcitonin
– controls the amount of
calcium in the body.
Hashimoto Disease:thyroid gland is destroyed. It
is known as suicide of the thyroid.
PARATHYROID GLAND
- Secretes Parathormone, which is also known
by the name of Collip’s Hormone.
- It influences calcium and phosphorus
metabolism (Ca level = 12 mg/100 ml of
blood)
- Removal of this gland leads to death due to
tetany (cramps, tremors and convulsions in
muscles)
- Hyperactivity withdraws calcium from bones
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