Function Of Thyroid Gland:
Metabolic Action:
1) On carbohydrate Metabolism: Thyroid hormones raised the blood sugar level by increasing food
intake, enhances intestinal glucose absorption & hepatic glycogenolysis by enhensing the activity of
glucose-6-Phosphate. The hormone also increases hepatic gluconeogenesis by enhensing the activities of
pyruvate carbolylase & PEPCEK. 2. This hormones also increases the oxidation of Glucose in Tissues.
2) On protein Metabolism:
i.Thyroid hormones inhibit protein synthesis & large doses.
ii) In moderate doses it shows protein anabolic effect.
ii) In moderate doses it shows protein anabolic effect.
3) On Fate Metabolism: i) T3 & T4 stimulate the catabolism of fat by activating the enzyme lipase present
in the tissue. ii) Increase the oxidation of fatty acid. Iii) Consent of cholesterol of fatty is inversely
proportional with the level of thyroidactivity.
in the tissue. ii) Increase the oxidation of fatty acid. Iii) Consent of cholesterol of fatty is inversely
proportional with the level of thyroidactivity.
4)BMR & Calorigenesis: T3 & T4 increases the BMR by stimulating oxidation of food staff in the tissues
& therefore they are also called calorigenic hormones. During cold, the secretion of thyroid hormones is
increased which by stimulating calorigenesis help in thermoregulation & prevent called of body tempr.
5)Vitamin Metabolism: i) Asist in conversion of carotene to vitamin A & Vitamin A to Retinol. ii)
Increase the requirement of vitamin B6 Vitamin B12 & Vitamin c. iii) Hyperthyroidism may caused
vitamin D deficiency.
& therefore they are also called calorigenic hormones. During cold, the secretion of thyroid hormones is
increased which by stimulating calorigenesis help in thermoregulation & prevent called of body tempr.
5)Vitamin Metabolism: i) Asist in conversion of carotene to vitamin A & Vitamin A to Retinol. ii)
Increase the requirement of vitamin B6 Vitamin B12 & Vitamin c. iii) Hyperthyroidism may caused
vitamin D deficiency.
6) On Calcium & phosphorous Metabolism: Remove Ca & P form the bones leading to osteoporosis. This
action differs from that of parathyroid in causing no rise of serum, calcium & increasing calcium lost both
the feces & urine.
action differs from that of parathyroid in causing no rise of serum, calcium & increasing calcium lost both
the feces & urine.
7) Growth & Differentiation: Thyroid hormones act synergistically with the growth hormone & thus
promote nitrogen retention protein synthesis, body growth & tissue differentiation. The resorption & to
lesser degree Of bone formation. Normal development Of brain required thyroid hormone, without this
hormone there is decrease myelinogenesis & retarded axonal ramification.
promote nitrogen retention protein synthesis, body growth & tissue differentiation. The resorption & to
lesser degree Of bone formation. Normal development Of brain required thyroid hormone, without this
hormone there is decrease myelinogenesis & retarded axonal ramification.
Action on Circulatory System:
Thyroid hormone increases absorption of Vitamin B12 from the intestine which is require for synthesis of Haemoglobin & there by erythroporesis. T3 & T4 increases the activity of harm.
Action of Digestive system: T4 & T3 promote hunger apetite moment of gastro intestinal tract &
absorption of various substances from the intestine.
absorption of various substances from the intestine.
Action On Reproductive system:
1. The activity of thyroid varies mostly at different ages specially in the female. Thyroid hormones controle the normal function of gonads & development of secondary sex characters. T4 & T3 show increase activity at puberty, during menturation, pregnancy & lactation, after the menopause it tends to atrophy.
2. Less amount of this hormones secretion delays on set of puberty.
3. Increase the output & fat content of milk.
3. Increase the output & fat content of milk.