Anatomy
This structure is the common passageway for both air and food, located behind the oral and nasal cavities.
The pharynx
Air enters the body here, where it is warmed up before traveling deeper.
The nasal cavity and mouth
Tiny air sacs at the end of each bronchiole where gas exchange occurs.
Alveoli
This sheet of muscle contracts downward during inhalation.
The diaphragm
This lung volume represents a normal resting breath, approximately 500 mL.
Tidal Volume (TV)
This airway structure houses the vocal cords and is composed of muscles, cartilage, and elastic tissue.
The larynx
These tiny tubes branch from the bronchi and carry air toward the alveoli.
Bronchioles
Oxygen diffuses from the alveoli into this surrounding structure.
Capillaries (blood)
These muscles lift the ribs and sternum during normal inspiration.
External intercostals
This is the maximum amount of air the lungs can hold in total (~5,800 mL).
Total Lung Capacity (TLC)
The trachea splits into two of these structures, one entering each lung.
Primary bronchi (bronchus)
The inner walls of the trachea are lined with this type of membrane that traps particles.
Ciliated mucous membrane (with goblet cells)
Alveolar walls are this many cells thick to minimize diffusion distance.
One cell thick
Normal expiration is described as this type of process - no muscles required.
Passive
This nonrespiratory movement clears the lower airways.
Coughing
The right lung has this many lobes
3
These hair-like structures sweep mucus toward the pharynx to be swallowed.
Cilia
This substance coats alveoli to prevent them from collapsing.
Surfactant
These receptors in the medulla monitor CO₂ and H⁺ levels to control breathing rate.
Central chemoreceptors
This lung volume cannot be measured by a spirometer because it never leaves the lungs.
Residual Volume (RV)
This double-layered serous membrane surrounds the lungs.
The pleura (pleural membrane)
These are the upper vocal folds - they do NOT produce sound.
False vocal cords
A deficiency of oxygen reaching body tissues is called this.
Hypoxia
These body structures contain peripheral chemoreceptors that detect low blood oxygen.
Carotid and aortic bodies
Over 98% of oxygen is transported in this form inside red blood cells.
Bound to hemoglobin (as oxyhemoglobin)