HomeMedicine & HealthAnatomy & PhysiologyWhat is Capillary?
Medicine & Health·1 min·Updated Mar 12, 2026

What is Capillary?

Capillary Blood Vessel

Quick Answer

A capillary is a tiny blood vessel that connects arteries and veins. They play a crucial role in the circulatory system by allowing the exchange of oxygen, nutrients, and waste products between blood and tissues.

Overview

Capillaries are the smallest blood vessels in the body, often just one cell thick. They form a network that reaches nearly every cell, allowing for efficient exchange of substances. Oxygen and nutrients from the blood pass through capillary walls into tissues, while waste products like carbon dioxide move from tissues into the blood. The structure of capillaries is designed to facilitate this exchange. Their thin walls and large surface area make it easy for materials to diffuse in and out. For example, after eating, glucose from digested food enters the bloodstream through capillaries in the intestines, providing energy to cells throughout the body. Understanding capillaries is important in medicine and health because they are vital for maintaining healthy tissues and organs. Any issues with capillary function can lead to serious health problems, such as poor circulation or tissue damage. This highlights their significance in both anatomy and physiology.


Frequently Asked Questions

Capillaries allow for the exchange of oxygen, nutrients, and waste products between blood and surrounding tissues. This exchange is essential for maintaining healthy cellular function and overall bodily health.
Capillaries are much smaller and have thinner walls compared to arteries and veins. While arteries carry blood away from the heart and veins return it, capillaries serve as the site for nutrient and gas exchange.
Capillaries are crucial because they facilitate the delivery of essential substances to cells and the removal of waste. Without proper capillary function, tissues can suffer from lack of oxygen and nutrients, leading to various health issues.