---
title: "Schwann Cell | Anatomy and Physiology I"
description: "Schwann cells are PNS glial cells that myelinate axons, speed nerve impulses, and support peripheral nerve repair in Anatomy and Physiology I."
canonical: "https://fiveable.me/anatomy-physiology/key-terms/schwann-cell"
type: "key-term"
subject: "Anatomy and Physiology I"
unit: "Unit 4"
---

# Schwann Cell | Anatomy and Physiology I

## Definition

Schwann cells are the glial cells of the peripheral nervous system that wrap axons, form myelin, and help damaged peripheral nerves regrow in Anatomy and Physiology I.

## What It Is

Schwann cells are the support cells of the peripheral nervous system, the network of nerves outside the brain and spinal cord. In Anatomy and Physiology I, you usually meet them when you study how nerves carry signals quickly and how injured peripheral nerves can recover.

Their best-known job is making the myelin sheath around many peripheral axons. Myelin is a fatty layer that wraps the axon like insulation around a wire. That insulation keeps the electrical signal from leaking out and lets impulses travel much faster between the cell body and the target tissue, whether that target is a muscle, gland, or sensory receptor.

A single Schwann cell does not coat the whole length of a long nerve fiber. Instead, one Schwann cell wraps one segment of one axon, then the next Schwann cell picks up the next segment. The small gaps between these myelinated segments are called nodes of Ranvier, and those gaps are what make saltatory conduction possible, meaning the impulse seems to jump from node to node instead of moving slowly down every inch of membrane.

Schwann cells do more than make myelin. They also surround unmyelinated axons, giving them support, and they help maintain the local environment around peripheral neurons. That support matters because neurons are highly active cells with a lot of metabolic demand, and they depend on surrounding tissue for stability and recovery after stress or injury.

Another big difference from many other nervous system support cells is that Schwann cells help repair peripheral nerves after damage. If a peripheral axon is cut or crushed, Schwann cells can guide regrowth by forming a pathway for the regenerating axon and releasing signals that support survival and repair. This is one reason peripheral nerves generally have better recovery potential than nerves in the central nervous system.

If Schwann cells are damaged or their myelin is disrupted, nerve signaling slows down or becomes disorganized. That is why disorders affecting Schwann cells can cause weakness, numbness, or poor muscle control. In A&P, that makes Schwann cells a good example of how structure and function are tightly connected in nervous tissue.

## Why It Matters

Schwann cells matter because they explain why peripheral nerves can send signals quickly enough for movement, sensation, and reflexes to work the way they do. Without myelin, an action potential travels more slowly and less efficiently, which changes how the nervous system communicates with muscles and sensory receptors.

They also connect directly to the course theme of structure matching function. When you see a myelinated peripheral nerve fiber, you are not just identifying a cell type. You are seeing a system built for speed, insulation, and repeat signaling. That idea shows up again when you compare myelinated versus unmyelinated axons, or when you track what happens to nerve function after injury.

Schwann cells are also a useful comparison point for pathology. If a case mentions numbness, tingling, weakness, or slowed conduction in peripheral nerves, the myelin sheath and the Schwann cells that make it are often part of the explanation. In class discussions, lab images, or case-based questions, they help you connect symptoms to the tissue that is failing.

They matter for regeneration too. A lot of nervous tissue is not easy to replace, but peripheral nerves have some repair capacity, and Schwann cells are a major reason why. That makes them a good bridge between normal anatomy, injury response, and disease.

## Connections

### [Myelin Sheath](/anatomy-physiology/key-terms/myelin-sheath)

Schwann cells are the cells that make myelin in the peripheral nervous system. The myelin sheath is the insulating layer that lets impulses move faster and more efficiently along an axon. If you are asked to identify what speeds conduction in a peripheral nerve, the Schwann cell and the myelin sheath go together.

### Axon

The axon is the nerve fiber Schwann cells wrap and support. Schwann cells do not replace the axon’s job of carrying the electrical signal, but they change how well that signal moves. A question about nerve conduction often needs both parts of the relationship, the axon as the signal pathway and the Schwann cell as the support cell.

### Glial Cell

Schwann cells are one type of glial cell, which means they are not the main signal-conducting cells of the nervous system. In Anatomy and Physiology I, this helps you separate neurons from the support cells that protect, feed, insulate, and maintain them. Schwann cells are the peripheral nervous system version of that support.

### [Multiple Sclerosis](/anatomy-physiology/key-terms/multiple-sclerosis)

Multiple sclerosis is often brought up when students are learning about myelin, but it affects the central nervous system, not the peripheral nervous system. That distinction matters because Schwann cells make myelin in the PNS, while oligodendrocytes do that job in the CNS. The comparison helps you keep the two systems straight.

## On the AP Exam

A quiz item or lab image question may show a myelinated nerve fiber and ask you to name the cell that forms the peripheral myelin sheath. You might also have to trace what happens when a Schwann cell is damaged, such as slower impulse conduction, poor coordination, or weaker nerve recovery after injury.

In diagrams, look for the segmented wrapping around a peripheral axon and the gaps between segments. If the prompt asks why a signal travels faster in a peripheral nerve, the answer usually points to myelin made by Schwann cells and saltatory conduction at the nodes of Ranvier. In a case study, tie symptoms like numbness or weakness to disrupted peripheral nerve signaling rather than to the brain or spinal cord.

## Schwann cell vs Astrocyte

Schwann cells and astrocytes are both glial cells, but they work in different parts of the nervous system. Schwann cells are in the peripheral nervous system and make myelin around peripheral axons, while astrocytes are in the central nervous system and support neurons, regulate the environment, and help maintain the blood-brain barrier. If a question is about peripheral nerve insulation, choose Schwann cell.

## Key Takeaways

- Schwann cells are the glial cells of the peripheral nervous system, not the neurons that carry the signal.
- Their main job is to make the myelin sheath around many peripheral axons, which speeds up impulse conduction.
- One Schwann cell myelinates one segment of one axon, which is why peripheral nerves are built in repeated sections.
- They also support unmyelinated axons and help damaged peripheral nerves regenerate after injury.
- If a peripheral nerve is not working normally, Schwann cell damage or myelin loss is one of the first ideas to check.

## FAQs

### What is a Schwann cell in Anatomy and Physiology I?

A Schwann cell is a glial cell in the peripheral nervous system that surrounds axons and forms myelin. In A&P I, you usually learn it as the support cell that helps peripheral nerves conduct impulses faster and recover after injury.

### Do Schwann cells make myelin?

Yes. Schwann cells make the myelin sheath in the peripheral nervous system. That myelin acts like insulation, which increases the speed and efficiency of nerve impulse transmission.

### How are Schwann cells different from astrocytes?

Schwann cells are in the peripheral nervous system and myelinate peripheral axons. Astrocytes are in the central nervous system and help support neurons, regulate the chemical environment, and maintain the blood-brain barrier. They are both glial cells, but they do different jobs in different places.

### Why are Schwann cells important after nerve injury?

Peripheral nerves can regenerate better than central nervous system nerves partly because Schwann cells guide regrowth. They help create a pathway for the axon and release signals that support repair, which is why peripheral nerve injury does not always mean permanent loss.

## Related Study Guides

- [4.5 Nervous Tissue Mediates Perception and Response ](/anatomy-physiology/unit-4/5-nervous-tissue-mediates-perception-response/study-guide/A7HZZQ374HYLsRQk)
- [12.3 The Function of Nervous Tissue ](/anatomy-physiology/unit-12/3-function-nervous-tissue/study-guide/OFl7ya3xNrivK3BS)

## About This Document

Canonical Fiveable pages are available as Markdown at the same path plus `.md`.

- [llms.txt](https://fiveable.me/llms.txt): index of Fiveable's sections and URL patterns
- [llms-full.txt](https://fiveable.me/llms-full.txt): complete subject and unit listing
- [MCP server](https://fiveable.me/mcp): call Fiveable as tools instead of fetching pages (`https://fiveable.me/api/mcp`)
- [MCP server for AP teachers](https://fiveable.me/mcp/teachers): a teacher's classes, assignments and AP-rubric grading (`https://fiveable.me/api/mcp/teacher`)

## Structured Data

```json
{"@context":"https://schema.org","@graph":[{"@type":"LearningResource","@id":"https://fiveable.me/anatomy-physiology/key-terms/schwann-cell#resource","name":"Schwann Cell | Anatomy and Physiology I","url":"https://fiveable.me/anatomy-physiology/key-terms/schwann-cell","learningResourceType":"Concept explainer","educationalLevel":"AP® / High School","about":{"@id":"https://fiveable.me/anatomy-physiology/key-terms/schwann-cell#term"},"audience":{"@type":"EducationalAudience","educationalRole":"student"},"dateModified":"2026-07-03T02:20:41.765Z","isPartOf":{"@type":"Collection","name":"Anatomy and Physiology I Key Terms","url":"https://fiveable.me/anatomy-physiology/key-terms"},"publisher":{"@type":"Organization","name":"Fiveable","url":"https://fiveable.me"}},{"@type":"DefinedTerm","@id":"https://fiveable.me/anatomy-physiology/key-terms/schwann-cell#term","name":"Schwann cell","description":"Schwann cells are the glial cells of the peripheral nervous system that wrap axons, form myelin, and help damaged peripheral nerves regrow in Anatomy and Physiology I.","url":"https://fiveable.me/anatomy-physiology/key-terms/schwann-cell","inDefinedTermSet":{"@type":"DefinedTermSet","name":"Anatomy and Physiology I Key Terms","url":"https://fiveable.me/anatomy-physiology/key-terms"}},{"@type":"FAQPage","mainEntity":[{"@type":"Question","name":"What is a Schwann cell in Anatomy and Physiology I?","acceptedAnswer":{"@type":"Answer","text":"A Schwann cell is a glial cell in the peripheral nervous system that surrounds axons and forms myelin. In A&P I, you usually learn it as the support cell that helps peripheral nerves conduct impulses faster and recover after injury."}},{"@type":"Question","name":"Do Schwann cells make myelin?","acceptedAnswer":{"@type":"Answer","text":"Yes. Schwann cells make the myelin sheath in the peripheral nervous system. That myelin acts like insulation, which increases the speed and efficiency of nerve impulse transmission."}},{"@type":"Question","name":"How are Schwann cells different from astrocytes?","acceptedAnswer":{"@type":"Answer","text":"Schwann cells are in the peripheral nervous system and myelinate peripheral axons. Astrocytes are in the central nervous system and help support neurons, regulate the chemical environment, and maintain the blood-brain barrier. They are both glial cells, but they do different jobs in different places."}},{"@type":"Question","name":"Why are Schwann cells important after nerve injury?","acceptedAnswer":{"@type":"Answer","text":"Peripheral nerves can regenerate better than central nervous system nerves partly because Schwann cells guide regrowth. They help create a pathway for the axon and release signals that support repair, which is why peripheral nerve injury does not always mean permanent loss."}}]},{"@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Anatomy and Physiology I","item":"https://fiveable.me/anatomy-physiology"},{"@type":"ListItem","position":2,"name":"Key Terms","item":"https://fiveable.me/anatomy-physiology/key-terms"},{"@type":"ListItem","position":3,"name":"Unit 4","item":"https://fiveable.me/anatomy-physiology/unit-4"},{"@type":"ListItem","position":4,"name":"Schwann cell"}]}]}
```