Respiratory System and Diffusion

Apuntes

Respiratory System and Diffusion Diffusion of Gases and Liquids Definition: Diffusion is the intermingling or spreading out of particles from a region of high concentration to a region of low concentration until they are evenly distributed. It happens because particles are constantly moving and colliding. It does not require energy (passive process). Examples: Perfume scent spreading through a room. Oxygen diffusing from the lungs into the blood. Carbon dioxide diffusing from blood into the lungs. Composition of Air Air is a mixture of gases: Nitrogen (N₂) → ~78% Oxygen (O₂) → ~21% Carbon dioxide (CO₂) → ~0.04% Other gases → Argon, water vapor, etc. Gases Dissolving in Water Gases like oxygen and carbon dioxide can dissolve in water. Example: Oxygen dissolves in pond water for fish to breathe. In the human body, gases dissolve in the moist lining of the alveoli before diffusing into or out of the blood. Structure and Function of the Human Respiratory System Main parts: Nose/Nasal Cavity – filters, warms, and moistens air. Trachea (Windpipe) – carries air to lungs; lined with mucus and cilia. Bronchi – two main air passages into lungs. Bronchioles – smaller br...