Respiratory System Overview

Functions and Anatomy of the Respiratory SystemPage 1

The respiratory system supplies the body with oxygen and eliminates carbon dioxide through a series of organs including the nose, pharynx, larynx, trachea, bronchi, and lungs. The nasal cavity warms, humidifies, and purifies inhaled air, while the pharynx serves as a shared passage for food and air. The larynx acts as a voice box and airway protector via the epiglottis.

Lungs and Gas Exchange StructuresPage 2

The lungs house the bronchi, bronchioles, and alveoli. The respiratory zone, specifically the alveoli, is the exclusive site of gas exchange. Alveolar walls, capillaries, and basement membranes form the respiratory membrane, which facilitates gas movement. Surfactant, produced by cuboidal cells, ensures alveolar function.

Mechanics of Breathing and Respiratory VolumesPage 3

Breathing (pulmonary ventilation) relies on pressure changes where volume expansion leads to inspiration and recoil leads to expiration. Lung capacity includes tidal volume (normal breathing), inspiratory/expiratory reserve volumes, and residual volume, which keeps alveoli inflated. External and internal respiration describe the exchange of gases between blood, lungs, and tissues.

Control of RespirationPage 4

Respiratory rhythm is regulated by the medulla and pons. While neural control sets the pace, chemical factors—primarily carbon dioxide levels and blood pH—are the most significant influencers of breathing rate. Physical, emotional, and voluntary factors can also temporarily modify respiratory patterns.