Take a Breath: RT Edition Flashcards

A set of vocabulary flashcards covering the anatomy, physiology, and physics of the respiratory system as presented in the RT Edition lecture.

Resting minute ventilation ($V_E$)

The volume of air moved per minute at rest, calculated as tidal volume multiplied by respiratory rate, averaging approximately $6\,L/min$ for an adult.

Tidal volume ($V_T$)

The volume of air moved in a single breath, averaging approximately $500\,mL$ in an average adult.

Conducting zone

The structures from the nose through the terminal bronchioles (1–8) that warm, filter, and humidify air but do not participate in gas exchange.

Respiratory zone

The site of gas exchange, consisting of respiratory bronchioles, alveolar ducts, and alveoli.

Mucociliary escalator

A defense mechanism consisting of ciliated pseudostratified columnar epithelium and a mucus layer that traps and sweeps particles out of the airway.

Pharynx

A shared passage for air and food, divided into the nasopharynx, oropharynx, and laryngopharynx.

Epiglottis

A structure in the larynx that closes over the airway during swallowing to prevent aspiration.

Trachea

The windpipe, held open by $16\text{--}20$ C-shaped cartilage rings and ending at the carina.

Right mainstem bronchus

A shorter, wider, and more vertical airway compared to the left, making it the classic path for aspirated objects or misplaced ET tubes.

Bronchioles

Progressively smaller airway branches that lack cartilage and rely on smooth muscle tone; they are the primary target of bronchodilators.

Visceral pleura

The slippery membrane located directly on the surface of the lung.

Parietal pleura

The membrane lining the inner chest wall.

Type I Pneumocytes

Thin, flat cells making up about $95\%$ of the alveolar surface area, specialized for fast gas diffusion.

Type II Pneumocytes

Cuboidal cells that produce surfactant and can regenerate Type I cells after lung injury.

Surfactant

A substance that lowers surface tension in the alveoli to prevent collapse, following Laplace's Law.

Phrenic nerve

The nerve arising from roots $C3$, $C4$, and $C5$ that drives the diaphragm.

Diaphragm

The primary muscle of inspiration, responsible for $75\text{--}80\%$ of the work of quiet breathing; it contracts and flattens to drop intrathoracic pressure.

Anatomic dead space

The volume of air in the conducting zone (approximately $150\,mL$ or $1\,mL$ per pound of ideal body weight) that does not reach the alveoli for gas exchange.

Fick's Law

The principle stating that gas diffusion is favored by increased surface area, a thinner membrane, and a larger pressure gradient.

Boyle's Law

A physics principle stating that at a constant temperature, pressure and volume are inversely related ($P_1V_1 = P_2V_2$).

Intrapulmonary pressure

The pressure inside the alveoli, which drops to $-1\,cmH_2O$ during inspiration and rises to $+1\,cmH_2O$ during expiration.

Intrapleural pressure

The pressure in the space between the pleura, which is always negative relative to atmospheric pressure (about $-5\,cmH_2O$ at rest) to keep the lungs inflated.

Medulla Oblongata

The part of the brainstem containing the dorsal and ventral respiratory groups that act as the pacemaker for ventilation.

Pons

Contains the pneumotaxic and apneustic centers that fine-tune the breathing rhythm and smooth the transition between inhalation and exhalation.

Central chemoreceptors

Receptors in the medulla that monitor CSF pH reflecting $CO_2$ levels; they provide the primary drive to breathe.

Peripheral chemoreceptors

Receptors in the carotid and aortic bodies that primarily sense low arterial $O_2$ and pH.

Aerobic Metabolism

The efficient process of converting glucose into ATP (about $36\,ATP$ per glucose molecule) using $O_2$ in the mitochondria.

Hypoxia timeline

The period of approximately $4\text{--}6\,minutes$ after which irreversible brain injury can begin due to oxygen deprivation.