---
title: "Zona Reticularis | Anatomy and Physiology I"
description: "Zona reticularis is the adrenal cortex’s inner layer that makes weak androgens like DHEA, helping explain adrenal hormone production in Anatomy and Physiology I."
canonical: "https://fiveable.me/anatomy-physiology/key-terms/zona-reticularis"
type: "key-term"
subject: "Anatomy and Physiology I"
unit: "Unit 17"
---

# Zona Reticularis | Anatomy and Physiology I

## Definition

The zona reticularis is the innermost layer of the adrenal cortex. In Anatomy and Physiology I, it is the part of the adrenal gland that produces weak androgens like DHEA and DHEA-S.

## What It Is

The zona reticularis is the innermost layer of the adrenal cortex, sitting just outside the adrenal medulla. In Anatomy and Physiology I, you learn it as one of the three cortical zones, each with a different hormone job. The zona glomerulosa makes aldosterone, the zona fasciculata makes cortisol, and the zona reticularis makes adrenal androgens.

Its main output is weak androgen hormones, especially dehydroepiandrosterone, or DHEA, and DHEA-S. These hormones are called weak because they are not as biologically active as testosterone or estrogen on their own. In peripheral tissues, they can be converted into stronger sex hormones, which is why the zona reticularis still matters even though it does not directly make the main sex hormones.

This layer is part of the endocrine system’s bigger stress and homeostasis picture. The adrenal cortex is influenced by the hypothalamic-pituitary-adrenal axis, which starts in the hypothalamus, signals the anterior pituitary, and then affects the adrenal cortex. The zona reticularis is not the same as the medulla, which makes catecholamines like epinephrine. That distinction matters because both parts sit in the adrenal gland, but they respond to different signals and make very different hormones.

A useful way to think about the zona reticularis is as a steroid-producing zone with a specific product line. If you see a question about adrenal cortex layers, focus on whether the prompt is asking about salt balance, glucose metabolism, or sex hormone precursors. The zona reticularis is the one tied to androgen precursors, not aldosterone or cortisol.

In a class diagram or lab image, you would identify it as the thin inner band of cortex closest to the medulla. If the question asks what happens when it is active, the answer is increased adrenal androgen secretion, which can support normal development of secondary sex characteristics and provide precursor hormones for other tissues.

## Why It Matters

The zona reticularis matters because it completes the adrenal cortex’s three-part hormone pattern. Once you know the cortex is divided into zones, you can match structure to function instead of memorizing the gland as one lump. That makes it much easier to answer questions about adrenal anatomy, hormone source, and endocrine control.

It also helps you separate adrenal cortex hormones from adrenal medulla hormones. That distinction shows up a lot in A&P because the gland has two regions with very different jobs. If you can identify the zona reticularis, you can also explain why a patient with an adrenal disorder might have changes in androgen levels without the issue being about epinephrine.

This term also connects to broader endocrine reasoning. The adrenal cortex is regulated through the HPA axis, and the zona reticularis sits inside that system even though its products are not the same as cortisol or aldosterone. When you trace hormone pathways in diagrams, the zona reticularis gives you another checkpoint for deciding which hormone is coming from which layer.

## Connections

### [Adrenal Cortex](/anatomy-physiology/key-terms/adrenal-cortex)

The zona reticularis is one of the three zones inside the adrenal cortex, so you cannot place it correctly without knowing the cortex as a whole. The cortex is the steroid hormone region of the adrenal gland, and each layer has a different output. If you know the adrenal cortex first, the zona reticularis becomes the inner androgen-producing layer instead of a random label.

### [Adrenal Medulla](/anatomy-physiology/key-terms/adrenal-medulla)

The adrenal medulla sits just inside the zona reticularis, but it does a completely different job. The medulla makes catecholamines like epinephrine and norepinephrine, while the zona reticularis makes androgen precursors. Students often mix them up because they are in the same gland, so comparing them helps you sort cortex hormones from medulla hormones.

### [Hypothalamic-Pituitary-Adrenal Axis](/anatomy-physiology/key-terms/hypothalamic-pituitary-adrenal-axis)

The HPA axis is the control pathway that helps regulate adrenal hormone release, including activity in the adrenal cortex. When the hypothalamus and pituitary signal the adrenal gland, the cortex responds by changing steroid production. The zona reticularis fits into that larger feedback system, even though its main products are weak androgens instead of cortisol.

### [cortisol](/anatomy-physiology/key-terms/cortisol)

Cortisol is made in a different adrenal cortical layer, the zona fasciculata, but it is useful to compare it with zona reticularis hormones. Cortisol is a glucocorticoid tied to metabolism and stress responses, while zona reticularis hormones are androgen precursors. If you can tell those apart, you can answer most adrenal cortex questions faster.

## On the AP Exam

A quiz question may ask you to identify which adrenal cortex layer produces DHEA or to label the innermost cortical zone on a gland diagram. You might also get a compare-and-contrast item that asks which layer makes cortisol versus weak androgens. In a written response, you could trace the path from the HPA axis to the adrenal cortex and explain how the zona reticularis fits into steroid hormone production. On lab practicals, the move is usually visual identification, then matching the structure to its hormone output.

## zona reticularis vs Adrenal Medulla

These are easy to mix up because they are both part of the adrenal gland, but they are not the same region. The zona reticularis is the inner layer of the adrenal cortex and makes weak androgens, while the adrenal medulla makes catecholamines like epinephrine. If a question mentions DHEA, think cortex; if it mentions fight-or-flight hormones, think medulla.

## Key Takeaways

- The zona reticularis is the innermost layer of the adrenal cortex, located right next to the adrenal medulla.
- Its main products are weak androgens such as DHEA and DHEA-S, not aldosterone or cortisol.
- These hormones can be converted in peripheral tissues into stronger sex hormones like testosterone.
- The zona reticularis is part of the adrenal cortex, so it belongs to the steroid hormone side of the adrenal gland.
- If you can match each adrenal layer to its hormone output, adrenal anatomy becomes much easier to study.

## FAQs

### What is zona reticularis in Anatomy and Physiology I?

The zona reticularis is the inner layer of the adrenal cortex. In Anatomy and Physiology I, it is the part of the adrenal gland that produces weak androgen hormones like DHEA and DHEA-S. It is one of the three cortical zones you need to know when studying adrenal anatomy.

### What hormones does the zona reticularis produce?

It produces weak androgens, mainly DHEA and DHEA-S. These are not the body’s main sex hormones, but they can be converted into stronger hormones in other tissues. That is why this layer still matters in hormone regulation.

### How is the zona reticularis different from the adrenal medulla?

The zona reticularis is part of the adrenal cortex and makes steroid hormones, especially androgen precursors. The adrenal medulla is the inner adrenal region and makes catecholamines like epinephrine and norepinephrine. So even though they are in the same gland, they have different structures, signals, and products.

### Where is the zona reticularis located?

It is the deepest layer of the adrenal cortex, sitting just outside the adrenal medulla. On a gland diagram, it appears as the innermost cortical band. If you are labeling the adrenal gland, it is the layer between the zona fasciculata and the medulla.

## Related Study Guides

- [17.6 The Adrenal Glands ](/anatomy-physiology/unit-17/6-adrenal-glands/study-guide/o7QQ9urw5EOcLtdx)

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