---
title: "Bronchial Vein | Anatomy and Physiology I"
description: "Bronchial vein in Anatomy and Physiology I: the vessel that drains the bronchi and lung connective tissue, returning used blood to systemic circulation."
canonical: "https://fiveable.me/anatomy-physiology/key-terms/bronchial-vein"
type: "key-term"
subject: "Anatomy and Physiology I"
unit: "Unit 20"
---

# Bronchial Vein | Anatomy and Physiology I

## Definition

The bronchial vein is a small vein in Anatomy and Physiology I that drains blood from the bronchi and supporting lung tissue. It carries that blood back toward the heart, not through the gas-exchange part of the lungs.

## What It Is

The bronchial vein is the vessel that drains the bronchi and nearby connective tissue in the lungs in Anatomy and Physiology I. Its job is to carry blood away from the airway walls and support structures after those tissues have used oxygen and nutrients.

This is a good place to separate the bronchial circulation from the pulmonary circulation. The pulmonary circuit is the route that brings blood to the alveoli for gas exchange, but the bronchial vessels feed the lung tissue itself. The bronchial veins collect the blood left over from that tissue and return it to the venous side of circulation.

A useful detail is that the lungs are not “self-supplied” only by the blood flowing through the alveoli. The bronchi, pleura, and connective tissues need their own oxygenated blood supply through the bronchial arteries, and then the bronchial veins drain that blood after exchange has happened in those tissues. So even though the lungs are the organ for oxygen exchange, parts of the lung still need their own mini supply-and-drain system.

Most of the blood from the bronchial veins eventually joins larger thoracic veins and returns toward the heart. In class diagrams, you may see this described as a drainage pathway rather than a separate loop like the pulmonary circuit. That distinction matters because the bronchial veins are part of the body’s tissue drainage, not the main route for getting oxygen into the blood.

If you are tracing circulation step by step, think of the bronchial vein as the “cleanup” side of lung tissue circulation. It picks up blood from the bronchi and connective tissue after those structures have been served, then sends it back into the venous system so circulation can continue.

## Why It Matters

The bronchial vein matters because it shows that the lungs have two different circulation stories happening at once. One story is the pulmonary circuit, where blood goes to the alveoli to pick up oxygen. The other is the bronchial circulation, which feeds the lung tissue itself and then drains it back through bronchial veins.

That distinction shows up a lot in Anatomy and Physiology I when you compare oxygenated versus deoxygenated blood, or when you trace where a vessel belongs on a diagram. If you confuse bronchial veins with pulmonary veins, you can miss the bigger pattern: not every vessel connected to the lungs is doing gas exchange.

It also helps explain why the lungs can stay alive and functional as tissue. The bronchi and connective tissue need their own blood supply, just like muscles or the brain do. The bronchial vein is part of the return path after those tissues have received what they need.

When you understand this vessel, the whole circulatory pathway looks more organized. You can see which vessels are part of nourishing lung tissue, which vessels are moving blood for gas exchange, and how blood returns to the heart from the chest.

## Connections

### Bronchial Arteries

Bronchial arteries are the paired vessels that bring oxygenated blood to the bronchi and connective tissue of the lungs. The bronchial vein is the return side of that same local circulation. If you know the arteries supply the lung tissue, the veins make sense as the drainage route after those tissues have been served.

### [Pulmonary Circulation](/anatomy-physiology/key-terms/pulmonary-circulation)

Pulmonary circulation is the main loop that carries deoxygenated blood from the heart to the lungs and returns oxygenated blood to the heart. The bronchial vein is not part of the gas-exchange route through the alveoli. Instead, it drains the lung tissue itself, which is a different job from pulmonary blood flow.

### Systemic Circulation

Systemic circulation includes the blood vessels that supply and drain the tissues of the body outside the gas-exchange loop. Bronchial veins fit into that broader idea because they return blood from lung tissue back toward the venous system. This is a good reminder that the lungs have both pulmonary and systemic-style blood supply patterns.

### [Abdominal Aorta](/anatomy-physiology/key-terms/abdominal-aorta)

The abdominal aorta is another major artery that gives off branches to body tissues, just like the thoracic aorta gives rise to bronchial arteries in the chest. Comparing these helps you see a pattern in vascular anatomy: large arteries branch off to feed specific tissues, and veins then drain those tissues back toward the heart.

## On the AP Exam

A quiz question might ask you to identify which vessel drains the bronchi or to distinguish bronchial veins from pulmonary veins on a diagram. In a lab practical, you may be shown a lung or thoracic circulation model and asked to trace where blood from the bronchial tissue goes next. In written answers, use the term when explaining why the lungs have a local blood supply separate from gas exchange. If a question gives you a vessel and asks whether it belongs to pulmonary circulation or tissue drainage, the bronchial vein points to drainage of the lung structures, not the alveoli.

## bronchial vein vs Pulmonary Circulation

These get mixed up because both involve the lungs, but they do different jobs. Pulmonary circulation moves blood to the alveoli for gas exchange, while the bronchial vein drains the bronchi and supporting lung tissue. If the question is about oxygen pickup and carbon dioxide release, think pulmonary. If it is about blood leaving the lung tissue itself, think bronchial vein.

## Key Takeaways

- The bronchial vein drains blood from the bronchi and supporting connective tissue of the lungs.
- It belongs to the drainage of lung tissue, not the main gas-exchange route through the alveoli.
- The bronchial vein pairs with the bronchial arteries, which supply the same lung structures.
- This vessel helps show the difference between pulmonary circulation and the blood supply of the lung tissues themselves.
- On diagrams and practicals, it is usually tested as part of tracing where blood in the chest goes next.

## FAQs

### What is bronchial vein in Anatomy and Physiology I?

The bronchial vein is the vessel that drains blood from the bronchi and supporting tissue of the lungs. It returns that blood toward the venous system after the tissue has been supplied by bronchial arteries. It is not the main vessel for gas exchange in the alveoli.

### How is the bronchial vein different from the pulmonary vein?

A pulmonary vein carries oxygenated blood from the lungs back to the heart after gas exchange. A bronchial vein drains the lung tissue itself, especially the bronchi and connective tissue. That difference is why they show up in different parts of the circulatory pathway.

### Does the bronchial vein carry oxygenated or deoxygenated blood?

It mainly carries deoxygenated blood from the lung tissues it drains. That blood has already delivered oxygen to the bronchi and connective tissue. The vein then returns it toward the heart through the venous system.

### Why do the lungs need bronchial veins if pulmonary veins already return blood from the lungs?

Because not all lung blood is doing the same job. Pulmonary veins return blood that has picked up oxygen in the alveoli, while bronchial veins drain the tissues that make up the lung walls and airways. The lung needs both gas exchange and its own tissue circulation.

## Related Study Guides

- [20.5 Circulatory Pathways ](/anatomy-physiology/unit-20/5-circulatory-pathways/study-guide/nKkAS5lkN4RVf6Kk)

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