Thyroid Gland and Hormones lec 11

Flashcards related to thyroid gland function and regulation.

Thyroid Gland

Butterfly-shaped organ at the base of the neck that produces hormones regulating bodily functions.

Thyroxine (T4)

Main hormone secreted by the thyroid, converted into T3, regulating body's metabolism.

Triiodothyronine (T3)

Active form of thyroid hormone, derived from T4, with a more immediate effect on metabolism.

Thyroid Hormone Release

Regulated by the hypothalamus and pituitary gland, maintains balance in the body.

Hypothyroidism

Underactive thyroid, leads to fatigue, weight gain, and cold intolerance.

Hyperthyroidism

Overactive thyroid, leads to weight loss, increased heart rate, and anxiety.

Goiter

Enlargement of the thyroid, often caused by iodine deficiency.

Hypothalamus

Releases TRF to stimulate the pituitary gland to release TSH.

Pituitary Gland

Secretes TSH which stimulates the thyroid gland.

Functions of T3/T4

Induces metabolism, stimulates bone growth, induces heat production, supports brain development, and supports the reproductive system.

Thyroxine (T4)

Main circulating thyroid hormone, inactive, can penetrate cell membrane.

Triiodothyronine (T3)

Main active form of thyroid hormone but cannot penetrate cell membrane.

Calcitonin

Induces preservation of calcium by decreasing osteoclasts and reabsorption from bone.

TSH

Stimulates thyroid follicular cell and Na+/I- symporter to transport iodide from blood into follicular cells.

Deiodination

Removing iodine molecules via enzyme deiodinases in the liver.

TSH and LH

Can bind to each other's receptors due to structural similarities.

T3 influence on Brain Development

Preserves neurons, induces maturation and synaptic plasticity in the brain.

Iodine Deficiency

Insufficient dietary intake or insufficient uptake, leading to thyroid gland growth.

Secondary Goiter

Due to over-secretion of TSH, FSH, LH, hCG, or ACTH linked with chronic stress.

Allohol

Inhibits hypothalamus, thus inhibiting TH release which leads to bad metabolism of alcohol.