Structure and Function of the Human Respiratory System

Nasal Cavity

Warms and humidifies the inspired air.

Pharynx

Tube that delivers air from mouth to nose to the trachea.

Larynx

Voice box; protects the lower respiratory tract from aspirating food.

Trachea

Windpipe; connects larynx to bronchi; passage of air.

Bronchus

Tube that connects into each lung.

Bronchiole

Small branches of the bronchial tubes that lead to alveoli.

Alveoli

Air sacs; the site of gas exchange.

Lungs

Main organ that removes oxygen from the air and passes it into the bloodstream.

Diaphragm

Muscle that helps the lungs to pull air in and push air out.

Breathing

Physical act of inhaling and exhaling air.

Respiration

More complex process occurring at the cellular level.

External Respiration

Exchange of oxygen and carbon dioxide between the air and blood within the lungs.

Internal Respiration

Exchange of oxygen and carbon dioxide between the blood and blood cells.

Cellular Respiration

Use of oxygen to break down sugar in food, producing energy (ATP) and releasing carbon as a waste product.

Path of Air

Sequence of air movement from mouth/nose to alveoli.

Inhale

Ribs move outward and diaphragm moves downward, creating more space in the chest area.

Exhale

Ribs move inward and diaphragm moves upward, creating less space in the chest area.

Gas Exchange

Process where oxygen enters the blood and carbon dioxide is removed in the alveoli.

Common Colds

Caused by rhinovirus; symptoms include sneezing and runny nose.

Influenza

Caused by viral infection; symptoms include chills, fever, and fatigue.

Pneumonia

Inflammation of alveoli; symptoms include fever and difficulty in breathing.

Tuberculosis

Caused by bacterial infection; symptoms include severe cough and weight loss.

Asthma

Chronic condition with extra mucus in airways; symptoms include breathing difficulty and wheezing.

Bronchitis

Inflammation of bronchial tubes; symptoms include cough with mucus and chest soreness.

Emphysema

Damage to alveoli leading to lack of oxygen supply; symptoms include shortness of breath and chronic coughing.

Chronic Obstructive Pulmonary Disease (COPD)

Group of lung diseases associated with smoking; symptoms include long-term airflow obstruction.

Lung Cancer

Caused by carcinogen exposure; symptoms include bloody coughs and weight loss.