Aldosterone is secreted by:

Options

A. Zona glomerulosa - outer layer of adrenal cortex.
B. Zona fasciculata - middle layer of adrenal cortex
C. Zona reticularis - inner layer of adrenal cortex
D. Adrenal Medulla

Answer

**Step-by-Step Solution:**

1. **Identify the Hormone and Its Function**: Aldosterone is a hormone that plays a crucial role in regulating blood pressure and electrolyte balance by promoting sodium retention and potassium excretion in the kidneys.

2. **Locate the Source of Aldosterone**: Aldosterone is secreted by the adrenal glands, which are located on top of each kidney.

3. **Understand the Structure of the Adrenal Gland**: The adrenal gland is divided into two main parts: the adrenal cortex and the adrenal medulla.

4. **Examine the Adrenal Cortex**: The adrenal cortex is further divided into three zones:
- **Zona Glomerulosa**: The outermost layer that primarily secretes mineralocorticoids, including aldosterone.
- **Zona Fasciculata**: The middle layer that secretes glucocorticoids, such as cortisol.
- **Zona Reticularis**: The innermost layer that secretes androgens.

5. **Determine the Correct Answer**: Since aldosterone is a mineralocorticoid secreted by the outermost layer of the adrenal cortex (zona glomerulosa), the correct answer to the question is **zona glomerulosa**.

**Final Answer**: Aldosterone is secreted by the **zona glomerulosa**.

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