Physiology-Thyroid and Parathyroid Mind Map

This is a mind map about physiology - thyroid and parathyroid glands, with a detailed introduction and comprehensive description. I hope it will be helpful to those who are interested!

Edited at 2023-12-02 16:35:26

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Physiology-Thyroid and Parathyroid Mind Map

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Outline

Thyroid and parathyroid glands

thyroid

Thyroid epithelial cells synthesize and secrete

Thyroxine (T4): the largest amount of secretion

Triiodothyronine (T3): most active

Trans-triiodothyronine (rT3): no biological activity

Thyroid hormones are synthesized by iodination of thyroglobulin

The acini are functional units for synthesis, secretion, and storage. The glial component in the acini is thyroglobulin, which is the reserve of thyroid hormones. T3 is synthesized from iodinated tyrosine residues.

1. Thyroid acinar polyiodine: active transport

2. Activation of iodine, iodide ions are oxidized into iodine elements through hydrogen oxide in an acidic environment

3. Activated iodine attacks the tyrosine residues of thyroglobulin to generate monoiodine and diiodotyrosine (MIT, DIT)

4.MIT, DIT double coupling to form T3 and T4

5. T3 and T4 are still on thyroglobulin molecules and stored in the follicular cavity

6. The secretion of thyroxine is controlled by thyroid stimulating hormone: TSH action - acinar cells engulf colloid - lysosomal hydrolysis - thyroglobulin releases T3 and T4 - enters capillaries

7. Thyroid hormones are transported by binding to plasma proteins

Physiological effects

1. Promote the growth and development of the body

During the embryonic period, T3 and T4 induce the synthesis of nerve growth factors and promote the formation of synapses.

Stimulates cartilage ossification, promotes long bone growth, and has a synergistic effect with GH in childhood

2. Increase the body’s heat production, related to the sodium-potassium pump

3. Effect on substance metabolism

Protein metabolism: physiological state promotes protein synthesis in muscles, liver and kidneys; excessive secretion leads to increased decomposition, increased urinary nitrogen, and osteoporosis.

Glucose metabolism: Enhance the glycemic effects of epinephrine, glucagon, cortisol, and growth hormone

Lipid metabolism: The effect on lipolysis is greater than the effect on synthesis, promoting lipolysis and fatty acid oxidation

Adjustment of function

1. The hypothalamus-pituitary-thyroid feedback axis is the basic pathway, with long feedback, short feedback, and negative feedback regulation

2. Blood iodine level directly affects the synthesis of thyroid hormone

lesions

Goiter (less iodine consumption, leading to compensatory hyperplasia of thyroid tissue), hyperthyroidism (elevated basal metabolism, unable to tolerate high temperatures)

Myxedema (hypothyroidism in adults), cretinism (significant inhibition of growth, poor sexual development)

Parathyroid gland, thyroid C cells, VD3

parathyroid hormone

Increase calcium and decrease phosphorus

1. For bones: stimulate osteolysis and increase blood calcium levels 2. For the kidneys: Enhance the reabsorption of calcium ions by the renal tubules and inhibit the reabsorption of phosphorus. 3. For the small intestine: Promote the reabsorption of calcium by the intestinal mucosa by promoting the synthesis of VD3

VD3

Increase calcium and phosphorus

It requires activation to be biologically active and is hydroxylated twice in the liver and kidneys.

Promote the reabsorption of calcium by the small intestinal mucosa, mobilize bone calcium, promote osteoclast activity, and enhance the reabsorption of renal tubular calcium by PTH

Rickets in children, osteoporosis in adults

Calcitonin secreted by thyroid C cells

Calcium reduction and phosphorus reduction

Inhibit osteoclasts and enhance calcium deposition by osteoblasts

Inhibits renal reabsorption of many salts