Normal Respiratory Function and Assessment

A set of vocabulary flashcards covering the anatomy, physiology, life span considerations, and defense mechanisms of the respiratory system based on the lecture notes.

Alveoli

Millions of tiny, thin-walled epithelial air sacs in contact with a capillary network where gas exchange takes place.

Diaphragm

The primary muscle of breathing that separates the chest from the abdominal cavity.

Ventilation

The physical process of moving air into and out of the lungs through volume and pressure changes in the chest cavity.

Inspiration

An active process where the diaphragm and external intercostal muscles contract, enlarging thoracic volume and decreasing intrathoracic pressure.

Exhalation

A passive process where the diaphragm and intercostal muscles relax, causing the thorax to return to its smaller resting size and air to flow out.

Diffusion

The process by which molecules move from an area of greater concentration or pressure to an area of lower concentration or pressure.

$$PaO_2$$

The partial pressure of oxygen in the arteries, indicated by the lowercase "a".

Hemoglobin

Molecules on red blood cells that carry $97\%$ of oxygen to the tissues in molecular form.

Bicarbonate buffer system ($HCO_3^-$)

A transport mechanism for carbon dioxide formed when $CO_2$ combines with water, playing a major role in acid–base balance.

Respiratory centers

Specialized neurons in the brainstem that generate regular impulses transmitted to respiratory muscles for rhythmic contraction and relaxation.

Chemoreceptors

Sensors in the aortic arch, carotid arteries, and medulla sensitive to circulating levels of carbon dioxide and hydrogen ions.

Mucociliary escalator

A defense mechanism where ciliated cells provide motion to a mucous blanket to carry trapped matter upward and out of the respiratory tract.

Macrophages

Specialized scavenger white blood cells at the alveolar level that engulf bacteria and particles to decrease infection risk.

Surfactant

A substance that decreases surface tension and permits alveolar expansion, not produced in sufficient quantities until late in gestation.

Apnea

The abnormal cessation of breathing for $20$ seconds or longer.

Epinephrine

A hormone produced by the adrenal glands when stimulated by tobacco, causing increased heart rate, blood pressure, and respiratory rate.

Hypercapnia

An excess of carbon dioxide in the blood; older adults typically show a decreased response to this condition.