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Anatomy & Physiology

The Human Respiratory System - Overview

Study of the Respiratory System is an essential part of many general anatomy and physiology courses, such as for clinical assistants, training in non-drug therapies (such as Massage, Aromatherapy, Acupuncture, Shiatsu, and others), and first-level academic courses such as "A"-Level Human Biology.

This page is an overview of the structure and functions of the respiratory system. For a list of links to related pages see the box in the top-left of this page.

About Respiration

Respiration consists of:

1. Breathing (inspiration and expiration),
2. Gaseous Exchange (exchange of gases between the lungs/blood and blood/tissues and vice-versa).

It is controlled by the Autonomic Nervous System (ANS), more specifically by the Medulla Oblongata.

Basic Structure of the Respiratory System

Here is the simplest possible statement of the structure of the respiratory system as a flow-chart indicating the route by which oxygen flows into the body via the airways and travels to the surfaces at which gaseous exchange with tissues occurs:

Upper Respiratory Tract :

NARES

NASO PHARYNX

EPIGLOTTIS

TRACHEA

LARYNX

Lower Respiratory Tract : (Click to view this section as a diagram instead)

TRACHEA

(BIFICATES INTO 2 BRONCHI)

BRONCHIOLES

UPPERLOWER

ALVEOLAR DUCTSALVEOLAR DUCTS

ALVEOLAR SACSALVEOLAR SACS

Although the above is a good starting point from which to memorise the structures one might need to identify in an exam, further detail will be needed when asked to "describe by means of a diagram", or similar. All but the simplest texts illustrate the upper- and lower- respiratory tracts seperately.
See pages about diagram of upper respiratory tract and diagram of the lower respiratory tract.

Memorable Facts about the Human Respiratory System

• There are two lungs in the body, the total surface area of both of these combined being equivalent to that of about 2 tennis courts (per normal adult).
• All of the blood in the body circulates through the lungs each time it passes around the body.
• If laid end-to-end the capilliaries of the lungs would stretch for approx. 44 miles (70 km).

This is the end of this page but information about other aspects of the Respiratory System, such as Pulmonary Circulation are included on other pages of this website.