intercambio de gases

Respiratory System Functionality

Overview of the Respiratory System

• The primary function of the respiratory system is to obtain oxygen from the air and expel carbon dioxide produced by cellular metabolism.

• Air travels through the nasal passages, where it is warmed and humidified before moving through the pharynx, larynx, trachea, and bronchi to reach the lungs.

Gas Exchange in Alveoli

• Gas exchange occurs in the alveoli via passive diffusion, equalizing gas concentrations across the capillary membrane. Oxygen-poor air rich in carbon dioxide is expelled during exhalation.

• The diaphragm and intercostal muscles facilitate air intake and expulsion.

Partial Pressures of Gases

• Clean air entering the lungs carries oxygen to alveoli; its partial pressure is measured at 104 mmHg. This indicates how much oxygen is present in a given volume of air or fluid.

• Carbon dioxide concentration in alveoli reaches 40 mmHg due to its continuous removal during exhalation; arterial blood has a P O2 of 40 mmHg and P CO2 of 45 mmHg upon reaching pulmonary capillaries.

Diffusion Dynamics

• Oxygen diffuses from alveoli into blood while carbon dioxide moves from blood into alveoli due to differences in partial pressures until equilibrium is reached (P O2 = 104 mmHg; P CO2 = 40 mmHg).

• Once equilibrium occurs at venous ends of pulmonary capillaries, there’s no net movement of gases between blood and alveoli. Blood then transports oxygen (O2) and carbon dioxide (CO2) back to tissues for further metabolic processes.

Tissue Gas Exchange

• In tissue capillaries, arterial blood's P O2 drops to around 95 mmHg as oxygen diffuses into tissues while CO2 diffuses into blood due to partial pressure differences.