Korteks Adrenal 1 : Dasar Korteks Adrenal

Summary

This video explains the structure and function of the adrenal glands, which are located above the kidneys. It describes the two layers of the adrenal glands: the cortex and the medulla. The cortex is divided into three zones—glomerulosa, fasciculata, and reticularis—each producing different steroid hormones like aldosterone, cortisol, and dehydroepiandrosterone (DHEA). These hormones are lipophilic and are transported in the blood by specific plasma proteins. The video delves into the role of each hormone and their respective effects on the body.

Takeaways

• 😀 The adrenal glands are located near the kidneys and are often referred to as suprarenal glands.
• 😀 The adrenal glands consist of two layers: the outer cortex and the inner medulla.
• 😀 The adrenal cortex has three zones: the outer zona glomerulosa, the middle zona fasciculata, and the inner zona reticularis.
• 😀 The adrenal cortex produces steroid hormones, which are all derived from cholesterol, a precursor molecule.
• 😀 In the zona glomerulosa, pregnenolone is converted into mineralocorticoids, mainly aldosterone.
• 😀 In the zona fasciculata, pregnenolone is converted into glucocorticoids, primarily cortisol.
• 😀 In the zona reticularis, pregnenolone is converted into sex hormones, mainly dihydroepiandrosterone (DHEA).
• 😀 All adrenal steroid hormones are lipophilic (fat-soluble), and they require carrier proteins for transport in the bloodstream.
• 😀 Cortisol is carried by corticosteroid-binding globulin (CBG), also known as transportin.
• 😀 Aldosterone and DHEA are transported by albumin in the blood.
• 😀 Each adrenal hormone has specific roles in regulating functions such as electrolyte balance (aldosterone), stress response (cortisol), and sexual functions (DHEA).

Q & A

What is the primary function of the adrenal glands?

The adrenal glands produce essential hormones that regulate functions like metabolism, stress response, and immune function. These hormones include mineralocorticoids, glucocorticoids, and sex hormones.

Why are the adrenal glands called 'suprarenal glands'?

The adrenal glands are also known as 'suprarenal glands' because they are located just above (supra) the kidneys (renal).

What are the two main layers of the adrenal gland?

The two main layers of the adrenal gland are the adrenal cortex (outer layer) and the adrenal medulla (inner layer).

What are the three zones of the adrenal cortex, and what do they produce?

The three zones of the adrenal cortex are the zona glomerulosa, zona fasciculata, and zona reticularis. The zona glomerulosa produces mineralocorticoids (e.g., aldosterone), the zona fasciculata produces glucocorticoids (e.g., cortisol), and the zona reticularis produces sex hormones (e.g., dehydroepiandrosterone, DHEA).

How is cholesterol involved in hormone production in the adrenal cortex?

Cholesterol serves as the precursor molecule for all steroid hormones produced in the adrenal cortex. It is converted into pregnenolone, which is then further modified into active hormones by enzymes specific to each zone.

What are the functions of aldosterone, cortisol, and DHEA?

Aldosterone helps regulate sodium and potassium levels in the body, cortisol is involved in stress response, metabolism, and immune regulation, and DHEA is a precursor to sex hormones and influences the development of secondary sexual characteristics.

Why are hormones produced by the adrenal cortex considered lipophilic?

The hormones produced by the adrenal cortex, such as cortisol, aldosterone, and DHEA, are lipophilic (fat-soluble) because they are derived from cholesterol, a lipid-based molecule.

How are lipophilic hormones transported in the bloodstream?

Lipophilic hormones are transported in the bloodstream bound to plasma proteins. For example, cortisol binds to corticosteroid-binding globulin (CBG), while aldosterone and DHEA bind to albumin.

What enzyme activity is specific to each zone of the adrenal cortex?

Each zone of the adrenal cortex has enzymes that are specialized in converting pregnenolone into specific hormones. For instance, the zona glomerulosa has enzymes that convert pregnenolone into aldosterone, the zona fasciculata converts it into cortisol, and the zona reticularis produces sex hormones like DHEA.

What is the relationship between the adrenal glands and the kidneys?

The adrenal glands are located just above the kidneys and are closely involved in regulating functions that affect kidney function, such as fluid balance, blood pressure, and electrolyte levels, particularly through the action of aldosterone.