Respiratory

Inspiration

The process of inhaling air from the external environment into the lungs.

Expiration

The process of exhaling air from the lungs to the external environment.

External respiration

The exchange of oxygen (O2) and carbon dioxide (CO2) between the air and blood.

Internal respiration

The exchange of oxygen (O2) and carbon dioxide (CO2) between blood and tissue cells.

Cellular respiration

Energy-releasing chemical reactions that occur inside cells, serving as the last stage of respiration and providing energy for all living functions.

Nose (nasal passage)

The passageway for air from the external environment into the body, lined with ciliated cells that catch particles, covered in a mucus-secreting membrane, and well-supplied with blood vessels to warm and moisten air.

Pharynx (throat)

A shared passage for food and air, with the epiglottis closing over the opening to the trachea when swallowing to prevent food from entering the respiratory tract.

Larynx (voice box)

A structure made from cartilage containing vocal cords, which relax during breathing and contract during speaking to produce sound.

Trachea (windpipe)

A tube held open by semicircular cartilage rings, lined with ciliated cells that catch debris and secrete mucus to trap and transport debris.

Bronchi (singular: bronchus)

Airway passages lined with ciliated and mucus-producing cells that divide from the trachea, leading into the lungs and terminating in alveoli for gas exchange.

Alveoli

Cluster of tiny air sacs (around 300 million) in the lungs, with a one-cell thick and moist membrane surrounded by capillaries for gas exchange between air and blood during external respiration.

Lungs

Organs surrounded by thin pleural membranes, expanding and contracting with the chest cavity, with the right lung having 3 lobes and the left lung having 2 lobes.

Tidal volume

The amount of air moved in and out with each breath.

Inspiratory reserve volume

The amount of air that can be taken in beyond the tidal volume using forced inspiration.

Expiratory reserve volume

The amount of air that can be forced out by contracting chest and abdominal muscles beyond the tidal volume.

Vital capacity

The maximum volume of air that can be moved in and out during a single breath, calculated as the sum of tidal volume, inspiratory reserve volume, and expiratory reserve volume.

Residual Volume

The amount of air remaining in the lungs even after the deepest possible expiration, keeping the lungs inflated.

Tonsillitis

An infection of the tonsils in the pharynx, often viral, leading to breathing impairment and potential removal of tonsils, which are lymph nodes involved in immunity.

Laryngitis

Inflammation of the larynx, often due to viral infections, allergies, or voice strain, resulting in reduced larynx vibration and ability to produce sounds.

Bronchitis

Inflammation of the bronchi leading to mucus accumulation, often expelled by coughing.

Pneumonia

Inflammation of the alveoli leading to fluid accumulation, reducing gas exchange and tissue oxygen levels.

Pleurisy

Swelling and irritation of the pleura, the membranes surrounding the lungs, causing chest pain and discomfort.

Emphysema

A condition where the walls of the alveoli break down, reducing elasticity, surface area, gas exchange, and tissue oxygen levels.

Asthma

A chronic obstructive lung disease affecting bronchi and bronchioles, leading to decreased airflow.

Lung cancer

Uncontrolled and invasive growth of abnormal cells in the lungs, posing a serious health risk.