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# Human Respiratory System ## Diagram of the Human Respiratory System - **Nasal Cavity** - **Oral Cavity** - **Pharynx** - **Larynx** - **Trachea** - **Bronchus** - **Alveoli** - **Bronchioles** - **Diaphragm** - **Lungs** - **Heart** ## Gaseous exchange in lungs The exchange of gases - carbon d...

# Human Respiratory System ## Diagram of the Human Respiratory System - **Nasal Cavity** - **Oral Cavity** - **Pharynx** - **Larynx** - **Trachea** - **Bronchus** - **Alveoli** - **Bronchioles** - **Diaphragm** - **Lungs** - **Heart** ## Gaseous exchange in lungs The exchange of gases - carbon dioxide and oxygen occurs in the alveoli or air sacs in the lungs. When the air rich in oxygen enters the lungs and reaches the alveoli, oxygen moves from the inhaled air to the alveoli and combines with the pigments called haemoglobin of the blood. Blood carries oxygen to all parts of the body. Carbon dioxide, which is the result of cell respiration, diffuses from the alveoli and through the nose. ## Cellular respiration Blood travels from the heart and pumps blood throughout the body through arteries. This blood eventually travels to the smaller arteries and finally to capillaries. Oxygenated blood away from the alveoli goes to all other tissues and organs and carries glucose (food) which is used by the cells to form a form that the cell can use. Carbon dioxide, which is the result of cell respiration, is now absorbed by the capillaries and sent back to the heart. This cycle is completed as the blood is then expelled through the path of oxygen entering the body during respiration.