---
title: "Sebaceous Gland | Anatomy and Physiology I"
description: "Sebaceous gland is an oil gland in the skin that releases sebum to protect and lubricate the surface in Anatomy and Physiology I."
canonical: "https://fiveable.me/anatomy-physiology/key-terms/sebaceous-gland"
type: "key-term"
subject: "Anatomy and Physiology I"
unit: "Unit 5"
---

# Sebaceous Gland | Anatomy and Physiology I

## Definition

A sebaceous gland is a skin oil gland that produces sebum. In Anatomy and Physiology I, it is an accessory structure of the integumentary system, usually attached to hair follicles.

## What It Is

A sebaceous gland is a small exocrine gland in the skin that makes sebum, the oily material that coats and protects the skin surface. In Anatomy and Physiology I, you usually learn it as one of the accessory structures of the integumentary system, along with hair, nails, and sweat glands.

Most sebaceous glands empty into a hair follicle, which is why they are closely tied to the pilosebaceous unit. That connection matters because sebum does not usually just sit in a gland. It moves through a duct and reaches the follicle and skin surface, where it mixes with sweat and helps form the thin protective film on the body.

Sebum is not the same as sweat. Sweat is mostly watery and is released by sweat glands for cooling and minor waste removal. Sebum is oily, so its job is more about lubrication, limiting water loss, and helping keep skin and hair from drying out. It also contributes to the slightly acidic surface environment of the skin, which makes life harder for some microbes.

Sebaceous glands are widespread, but they are missing from the palms of the hands and soles of the feet. They are especially abundant on the face, scalp, chest, and back, which is why those areas often feel oilier. If a class image shows a hair follicle with a side pouch or cluster of cells opening into it, that is often the sebaceous gland.

Hormones matter here too. Androgens can increase sebaceous gland activity, which is one reason oiliness often rises during puberty. When the gland produces too much sebum or when the follicle opening gets clogged, the result can be comedones and acne. So this structure is not just a label on a diagram, it connects skin anatomy, hormones, and common skin conditions.

## Why It Matters

Sebaceous glands matter because they connect skin structure to skin function in a very direct way. When you study the integumentary system, you are not just memorizing parts on a diagram. You are tracing how the skin stays intact, moist, and protected while still interacting with the outside world.

This term helps explain why some body regions look and behave differently from others. The face and scalp are rich in sebaceous glands, so they tend to produce more oil than the palms or soles, which lack these glands entirely. That difference shows up in everyday observations, from oily skin to the way certain rashes or breakouts cluster in sebaceous-rich areas.

Sebaceous glands also give you a clear example of how hormones affect anatomy and physiology. The same gland can be relatively quiet in one stage of life and much more active during puberty or other hormone shifts. That makes it useful for connecting endocrine changes to visible skin changes, especially in acne-related questions.

In lab images, diagrams, or tissue models, being able to identify a sebaceous gland helps you separate it from sweat glands and understand the full pilosebaceous unit. That kind of identification skill comes up a lot in A&P when you have to match structure with function, or explain why a certain skin condition develops where it does.

## Connections

### Sebum

Sebum is the oily secretion made by sebaceous glands. If you know the gland but not the product, you miss the function. Sebum coats the skin and hair, reduces water loss, and helps create the protective surface layer that keeps skin from drying out too fast.

### Pilosebaceous Unit

The pilosebaceous unit is the hair follicle plus the sebaceous gland that opens into it. This connection explains why sebum is usually delivered through the follicle instead of directly onto the skin. It also helps you understand how clogged follicles can lead to comedones and acne.

### Comedo

A comedo forms when a hair follicle opening gets blocked by oil and dead skin cells. Sebaceous gland activity can feed into this process by adding more sebum to the blockage. In acne, comedones are one of the first visible signs that the follicle is not draining normally.

### [Eccrine Sweat Gland](/anatomy-physiology/key-terms/eccrine-sweat-gland)

Eccrine sweat glands are different from sebaceous glands because they make watery sweat for cooling, not oily sebum for lubrication. Comparing the two is a common way to test whether you can tell the difference between skin glands by structure and function. Their outputs, ducts, and roles are not the same.

## On the AP Exam

A diagram question may point to a gland next to a hair follicle and ask you to identify it as a sebaceous gland, not a sweat gland. A short-answer prompt may ask how the skin’s protective barrier is maintained, and you would explain that sebum helps prevent water loss and keeps the surface lubricated. In a case study on acne, you might trace how increased androgen levels raise sebum production, which can contribute to clogged follicles and comedones. On practical quizzes, expect to match the gland with its oily secretion and its usual location in the pilosebaceous unit.

## sebaceous gland vs Eccrine Sweat Gland

These are both skin glands, but they do different jobs. Sebaceous glands release oily sebum into hair follicles, while eccrine sweat glands release watery sweat onto the skin surface for cooling. If the question mentions lubrication, oiliness, or hair follicles, think sebaceous gland. If it mentions cooling or sweating, think eccrine.

## Key Takeaways

- A sebaceous gland is an oil gland in the skin that produces sebum, not sweat.
- Most sebaceous glands open into hair follicles, so they are closely tied to the pilosebaceous unit.
- Sebum helps reduce water loss, lubricate the skin and hair, and support the skin’s protective barrier.
- Sebaceous glands are common on the face, scalp, chest, and back, but they are absent from the palms and soles.
- Increased androgen activity can raise sebum production, which is one reason these glands are connected to acne.

## FAQs

### What is a sebaceous gland in Anatomy and Physiology I?

A sebaceous gland is a skin gland that makes sebum, an oily secretion. In Anatomy and Physiology I, it is part of the integumentary system’s accessory structures and is usually associated with a hair follicle.

### Where are sebaceous glands found?

Sebaceous glands are found throughout most of the skin, but not on the palms of the hands or soles of the feet. They are especially numerous on the face, scalp, chest, and back, which is why those areas often seem oilier.

### How is a sebaceous gland different from a sweat gland?

Sebaceous glands produce oily sebum, while sweat glands produce watery sweat. Sebaceous glands usually empty into hair follicles, but eccrine sweat glands open onto the skin surface. That difference is often the easiest way to tell them apart on diagrams.

### Why do sebaceous glands matter for acne?

When sebaceous glands make too much sebum, the oil can mix with dead skin cells and clog a follicle opening. That blockage can form a comedo, which may become part of the acne process. Hormonal changes, especially during puberty, can make this more likely.

## Related Study Guides

- [5.2 Accessory Structures of the Skin ](/anatomy-physiology/unit-5/2-accessory-structures-skin/study-guide/nr9xrmrHZhGOqQyN)

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