Human Anatomy & Physiology: The Respiratory System

Vocabulary practice flashcards covering respiratory tract anatomy, histology, surfactant function, the four steps of respiration, and pulmonary ventilation mechanics.

Function of the Respiratory System

To obtain $O_2$ for the body's cells and eliminate $CO_2$ produced by the cells.

Cellular Respiration

The chemical process through which body tissues generate $ATP$, represented by the equation $C_6H_{12}O_6 + O_2 \rightarrow CO_2 + H_2O + ATP + \text{heat}$.

Upper Respiratory System

The division of the respiratory tract comprising the mouth, nose, and pharynx; functions to warm, filter, and humidify incoming air.

Pseudostratified Ciliated Columnar Epithelium

The epithelial tissue lining the respiratory tract equipped with cilia ("little hair") that push debris-laden mucus away from the lungs (out via nose blowing or swallowed in the back of the throat).

Goblet Cells

Mucus-producing cells found within pseudostratified ciliated columnar epithelium that produce sticky mucus to trap debris.

Lower Respiratory System

The division of the respiratory tract responsible for carrying air to and from the lungs, subdivided into the conducting portion and the respiratory portion.

Conducting Portion

The portion of the lower respiratory system responsible for moving air in and out; includes the larynx, trachea, and bronchial tree.

Larynx

An airway structure composed of nine pieces of cartilage whose function is to protect and keep the airway open.

Trachea

The central conducting tube that descends towards the lungs.

Bronchial Tree

The branching passages of the conducting portion, consisting of bronchi (where the trachea splits and branches) and bronchioles (smaller bronchi).

Respiratory Portion

The functional portion of the lower respiratory system consisting of the alveoli, where gas exchange occurs.

Alveolar Macrophages

Immune cells residing in the alveoli that act as "back up protection" by engulfing and destroying foreign matter.

Simple Squamous Epithelium (Alveoli)

The extremely thin tissue layer lining the alveoli that is $70\times$ thinner than a piece of paper, facilitating efficient gas diffusion.

Alveolar Surface Tension

The inward pulling force created when moisture ($H_2O$) inside the alveoli forms hydrogen bonds with other $H_2O$ molecules, making collapsed alveoli difficult to reopen.

Surfactant

A substance produced in the lungs that prevents hydrogen bonds from forming between water molecules when alveoli collapse during exhalation, making them easier to open upon inhalation.

Respiratory Distress in Premature Infants

A condition in infants born before surfactant production begins (at approximately $7\text{ months}$), forcing them to exert excessive effort to break alveolar hydrogen bonds during each breath, resulting in exhaustion without support.

Pulmonary Ventilation

The first step of respiration, consisting of inhalation and exhalation to move air between the atmosphere and alveoli.

External Respiration

The second step of respiration involving gas exchange between the alveoli and pulmonary capillaries ($O_2$ moves from alveoli to capillaries; $CO_2$ moves from capillaries to alveoli).

Gas Transport

The third step of respiration, transporting $O_2$ from the lungs to tissues (to make ATP) and $CO_2$ from tissues to the lungs via the bloodstream.

Internal Respiration

The fourth step of respiration involving gas exchange between systemic capillaries and tissues ($O_2$ moves from systemic capillaries to tissues; $CO_2$ moves from tissues to systemic capillaries).

Boyle's Law

The physical law stating that increasing volume decreases pressure ($\text{increase volume} = \downarrow\text{pressure}$) and decreasing volume increases pressure ($\text{decrease volume} = \uparrow\text{pressure}$).

Atmospheric Pressure

The baseline environmental pressure, which is always $1\text{ atmosphere}$ ($760\,mmHg$).

Inhalation (Mechanics)

The mechanical process where expansion of the thoracic cavity volume lowers intrapulmonary pressure to $759\,mmHg$, causing air to move from the higher atmospheric pressure ($760\,mmHg$) into the lungs.

Exhalation (Mechanics)

The mechanical process where reduction of the thoracic cavity volume increases intrapulmonary pressure to $761\,mmHg$, forcing air out of the lungs into the lower atmospheric pressure ($760\,mmHg$).