Endocrine System: Thyroid and Parathyroid Hormones

These flashcards cover key concepts about the thyroid and parathyroid hormones, as well as related endocrine functions discussed in the lecture.

Thyroid Hormone Synthesis

Requires iodine and tyrosine in the diet.

Forms of Thyroid Hormone

T3 (triiodothyronine) and T4 (thyroxine).

Function of Thyroid Hormone

Regulates basal metabolic rate and energy usage.

Relationship between Thyroid Hormone and TSH

An increase in thyroid hormone levels causes an increase in TSH (Thyroid Stimulating Hormone) secretion.

Action of Calcitonin

Decreases blood calcium levels by increasing osteoblast activity.

Parathyroid Hormone (PTH) Effect

Raises blood calcium levels by acting on bones and kidneys.

Stimulus for PTH Release

Low blood calcium levels.

Vitamin D Activation

Requires modification in both the liver and kidneys.

Function of Vitamin D

Increases calcium absorption in the intestines.

Adrenal Gland Layers

Three zones: zona glomerulosa, zona fasciculata, zona reticularis.

Hormone Secreted by Zona Glomerulosa

Aldosterone, which regulates sodium reabsorption in kidneys.

Hormone Secreted by Zona Fasciculata

Cortisol, which stimulates gluconeogenesis and has anti-inflammatory effects.

Cushing's Syndrome

Excess cortisol secretion, often iatrogenic (caused by medical treatment).

Addison's Disease

Insufficient production of cortisol, leading to glucocorticoid deficiency.

Effects of Growth Hormone

Regulates growth and development; excess leads to acromegaly.

Function of Adrenal Androgens

Stimulate masculinity traits and body hair growth at puberty.