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A Handbook of Biology

3

Exophthalmic goiter (Grave's disease) : It is a form

of hyperthyroidism (NEET 2020). Symptoms are

enlargement of thyroid gland, protruded eyeballs,

increased BMR & weight loss.

4

Myxedema or Gull’s disease: Due to deficiency of

thyroxine in adults. Face and hands become swollen

due to deposition of fat.

5. PÅRÅTHÝRØÏD GLÅÑDS



4 parathyroid glands are present on back side of the thyroid gland, one

pair each in the two lobes of thyroid gland. They secrete Parathyroid

hormone (PTH) —a peptide hormone.

FÜÑÇTÏØÑS ØF

PÅRÅTHÝRØÏD HØRMØÑË

4

3

2

1

Increases Ca²⁺ level in blood (hypercalcemic

hormone).

Stimulates

the

bone

resorption

(demineralization). (NEET 2018)

Stimulates the reabsorption of Ca²⁺ by the renal

tubules and increases Ca²⁺ absorption from the

digested food

Along with TCT, it helps in calcium balance in

the body.

Hyposecretion of PTH results in hypocalcemia. This causes failure of skeletal muscles

to relax known as hypocalcemic tetany.

6. THÝMÜS GLÅÑD



It is located on dorsal side of the heart and aorta. It secretes thymosins

(peptide hormones).