Respiratory System Overview

Respiratory System

The respiratory system is a crucial part of human physiology, responsible for supplying oxygen to the body's cells while removing carbon dioxide waste products. It consists of several organs working together to facilitate this process. These organs include the nose, nasal cavities, trachea, bronchioles, lungs, pleurae, diaphragm, and intercostal muscles.

Nose and Nasal Cavities

Your journey towards breathing starts with your nose, which acts as the first line of defense against dust particles, tiny organisms like bacteria, and larger pollutants. This protection occurs because the air you breathe in passes through your nasal cavity where these particles get trapped by mucus produced by special glands located within the nasal lining.

Trachea, Bronchioles, Lungs, Pleurae

Once past the nose, the air travels down the throat into your trachea, also known as your windpipe. The trachea splits into two branches called bronchi, one leading to each lung. Within the lungs themselves, these bronchi divide further into smaller branches called bronchioles, which terminate in tiny air sacs called alveoli.

Alveoli are where the actual exchange of oxygen and carbon dioxide occurs. Oxygen from the alveoli enters tiny blood vessels called capillaries, and carbon dioxide from these capillaries enters the alveoli. The exchange happens across the thin walls of the alveoli, a process called diffusion.

The pleurae, a thin layer of tissue, surrounds each lung, with one layer attached to the lung and the other to the chest wall. The pleurae keep the lungs from rubbing against the chest wall and provide a lubricated space for the lungs to move during breathing.

Diaphragm and Intercostal Muscles

The diaphragm, a large dome-shaped muscle, is responsible for most of the work during breathing. It contracts and pulls downward, enlarging the chest cavity and drawing air into the lungs. When the diaphragm relaxes, it moves upwards, reducing the chest cavity and forcing air out of the lungs.

In addition to the diaphragm, the intercostal muscles between the ribs help with the mechanics of breathing. These muscles contract and expand the rib cage, contributing to the expansion and contraction of the chest cavity.

Control of Breathing

The process of breathing is controlled by the respiratory center in the brainstem, which receives information about oxygen levels in the blood. When oxygen levels fall, the respiratory center sends signals to the diaphragm and intercostal muscles to increase the rate and depth of breathing. Conversely, when oxygen levels rise, the respiratory center slows down the rate and depth of breathing.

Smoking and Lung Health

Smoking, especially long-term, affects lung health negatively. It causes chronic inflammation and damage to the airways, increasing the risk of developing chronic obstructive pulmonary disease (COPD). However, avoiding smoking can help improve lung function and reduce the risk of respiratory diseases.