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21.16:

Hormones of the Adrenal Glands

JoVE Core
Anatomy and Physiology
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JoVE Core Anatomy and Physiology
Hormones of the Adrenal Glands

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The adrenal hormones are crucial for the body's electrolyte balance and stress response. The adrenal cortex produces over two dozen types of corticosteroid hormones. The zona glomerulosa produces mineralocorticoids, such as aldosterone, that affect the electrolyte composition of body fluids. The zona fasciculata produces steroid hormones such as cortisol and corticosterone. They are collectively known as glucocorticoids because they affect glucose metabolism. In the liver, glucocorticoids speed up glucose synthesis, and in muscle and adipose tissue, they promote glycogen formation. The zona fasciculata also produces smaller amounts of androgens. Adrenal androgens stimulate the development of pubic hair in adolescents. In adult women, they promote muscle mass and blood cell formation and support the sex drive. The adrenal medulla contains two types of chromaffin cells that secrete catecholamines in response to stress. One type produces epinephrine and the other norepinephrine. These are continuously packaged in vesicles and released at low levels by exocytosis. These hormones promote strength and endurance in skeletal muscles and break down stored fat and glycogen in the adipose tissue and liver.

21.16:

Hormones of the Adrenal Glands

Adrenal hormones play a pivotal role in maintaining the body's electrolyte balance and orchestrating responses to stress, showcasing the intricate functions of the adrenal cortex and medulla.

The adrenal cortex, a powerhouse of hormone synthesis, generates over two dozen corticosteroid hormones. The zona glomerulosa produces mineralocorticoids, exemplified by aldosterone, influencing the electrolyte composition of body fluids. The synthesis of glucocorticoids such as cortisol and corticosterone occurs in the zona fasciculata. Aptly named for their impact on glucose metabolism, glucocorticoids accelerate glucose synthesis in the liver and promote glycogen formation in muscle and adipose tissue.

Additionally, the zona fasciculata produces small amounts of androgens, contributing to the development of pubic hair in adolescents and supporting muscle mass, blood cell formation, and the sex drive in adult women.

The adrenal medulla, on the other hand, houses chromaffin cells that secrete catecholamines in response to stress. Epinephrine and norepinephrine, continuously stored in vesicles and released at low levels through exocytosis, are crucial in promoting strength and endurance in skeletal muscles. Simultaneously, these hormones facilitate the breakdown of stored fat and glycogen in adipose tissue and the liver, providing the necessary energy for the body's heightened demands during stressful situations. The adrenal hormones finely tune the body's responses to ensure adaptability and survival.