The innermost layer of the adrenal cortex is the:

The correct option is Zona reticularis.

Explanation

The adrenal glands are paired endocrine glands situated superior to the kidneys. Structurally and functionally, the gland is divided into two distinct regions: the outer adrenal cortex and the inner adrenal medulla. The adrenal cortex is further differentiated into three distinct histological zones.

Zonal Arrangement of the Adrenal Cortex (from Outer to Inner):

• Zona Glomerulosa: This is the outermost layer of the adrenal cortex, located immediately beneath the connective tissue capsule. It is responsible for secreting mineralocorticoids (e.g., aldosterone).
• Zona Fasciculata: This is the middle and widest layer of the cortex. It primarily secretes glucocorticoids (e.g., cortisol).
• Zona Reticularis: This is the innermost layer of the adrenal cortex, adjacent to the adrenal medulla. It is responsible for producing weak androgens (sex hormones).

Note on Medulla: The Medulla is the central core of the adrenal gland, not a layer of the cortex. It secretes catecholamines (epinephrine and norepinephrine).

Key Takeaway: The layers of the adrenal cortex, from the capsule inwards, follow the sequence: Glomerulosa → Fasciculata → Reticularis (Mnemonic: GFR).