Breath

Breath

Breath is the process of moving air into and out of the lungs to facilitate gas exchange with the internal environment, primarily by bringing in oxygen and flushing out carbon dioxide. This process is essential for maintaining the homeostasis of the body and is a critical component of the respiratory system.

Physiology of Breathing

Breathing involves two main processes: inhalation and exhalation.

Inhalation

Inhalation, or inspiration, is the process of drawing air into the lungs. This occurs when the diaphragm, a dome-shaped muscle located at the base of the lungs, contracts and moves downward. This movement increases the volume of the thoracic cavity, reducing the pressure inside the lungs relative to the outside atmosphere, causing air to flow in.

Exhalation

Exhalation, or expiration, is the process of expelling air from the lungs. It is typically a passive process that occurs when the diaphragm relaxes and moves upward, decreasing the volume of the thoracic cavity and increasing the pressure inside the lungs, forcing air out.

Control of Breathing

Breathing is controlled by the respiratory center in the medulla oblongata and the pons of the brainstem. These centers regulate the rate and depth of breathing based on the body's needs, which are influenced by factors such as carbon dioxide levels, oxygen levels, and pH of the blood.

Chemoreceptors

Chemoreceptors located in the carotid bodies and aortic bodies detect changes in blood pH, carbon dioxide, and oxygen levels, sending signals to the respiratory center to adjust breathing accordingly.

Disorders of Breathing

Breathing can be affected by various disorders, which can be classified into obstructive and restrictive types.

Obstructive Disorders

Obstructive disorders, such as asthma and chronic obstructive pulmonary disease (COPD), are characterized by difficulty in exhaling air from the lungs due to narrowed airways.

Restrictive Disorders

Restrictive disorders, such as pulmonary fibrosis, involve difficulty in fully expanding the lungs due to stiffness in the lung tissue or chest wall.

Clinical Significance

Breathing is a vital sign and is often assessed in clinical settings to determine a patient's respiratory status. Abnormal breathing patterns, such as tachypnea, bradypnea, or dyspnea, can indicate underlying health issues that require medical attention.

See Also

• Respiratory system
• Gas exchange
• Ventilation (physiology)