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Human Body
101
Follicle-stimulating hormone (FSH) and luteinising hormone (LH) are both gonadotropins i.e. stimulate gonads (sex glands).
The hypothalamus receives inputs from parts of the body including the emotional centres of the brain. Whenever required it produces releasing factors which stimulates the pituitary to produce trophic hormones, which in turn stimulate the other glands to release the hormone needs for the occasion.
The other hormones are growth hormone and prolactine which stimulates the secretion of milk in the breasts. Growth hormone is still rather a mystery. Its job is to stimulate growth in the growing years but it works on many systems even after adolesecnce. At various times of life, the thyroid and sex-hormones also share a growth promoting role.
Functions of the two posterior pituitary hormones are more specific Antidiuretic hormone (ADH) is responsible for the regulation of water loss from the kidneys through braking effect.
The other hormone-oxytocine is most important during child-birth and breast-feeding. It causes the uterus to contract which will result in the expulsion of the fetus.
The posterior pituitary is not really an endocrine but a storage depot of the hormones secreted by the hypothalamus. (1) The Thyroid Gland
The thyroid gland consists of two lateral maroon.coloured masses astride the upper end of the trachea, close to the larynx. The two lobes are connected with a narrow strip of the same tissue just below the Adam's apple. Each lobe is about 5 cms. in length, 3 cms. in width and about 1 to 2 cms. thick. The normal thyroid of an adult weighs 25 to 40 gms. but its size fluctuates with age, habitation and diet. It is heavier in the female than in the male, and becomes enlarged during sex-excitement, menstruation and pregnancy. The vascular supply to this gland is by four main arteries and is exceptionally rich. Probably more blood flows through it in proportion to its size than through any
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