Respiratory System Structure and Function Flashcards

A set of 50 vocabulary flashcards reviewing the anatomical structures, physiological mechanics, volume measurements, gas exchange and transport processes, and neural control mechanisms of the human respiratory system.

Upper Respiratory System

The division of the respiratory system located above the larynx, including the nose, nasal cavity, sinuses, and pharynx.

Lower Respiratory System

The division of the respiratory system located below the larynx, including the larynx, trachea, bronchus, bronchioles, smallest bronchioles, and alveoli.

Larynx

The area of the throat containing the vocal cords, used for breathing, swallowing, and talking.

Conducting Portion

The section of the respiratory tract extending from the nasal cavity to the terminal bronchioles.

Respiratory Portion

The section of the respiratory tract consisting of respiratory bronchioles and alveoli, where gas exchange occurs.

Alveoli

Air-filled pockets within the lungs where all gas exchange takes place between air and circulating blood.

Type I Pneumocytes

Thin, delicate simple squamous epithelial cells in the alveoli where the majority of gas exchange occurs.

Type II Pneumocytes

Septal cells in the alveolar epithelium that produce surfactant to reduce surface tension and prevent alveolar collapse.

Alveolar Macrophages

Also known as dust cells, these cells patrol alveolar surfaces to clear particles and pathogens.

Surfactant

An oily secretion containing phospholipids and proteins that coats alveolar surfaces, reduces surface tension, and decreases the work of breathing.

External Respiration

The integrated process including all functions involved in exchanging oxygen ($O_2$) and carbon dioxide ($CO_2$) between the circulating blood and the environment.

Internal Respiration

The cellular process resulting from cellular respiration, involving the uptake of oxygen ($O_2$) and production of carbon dioxide ($CO_2$) within individual cells.

Pulmonary Ventilation

The physical movement of air into and out of the respiratory tract to provide alveolar ventilation.

Boyle's Law

The physical law defining the relationship between gas pressure ($P$) and volume ($V$), expressed as $P = \frac{1}{V}$.

Respiratory Cycle

A single cycle of breathing consisting of an inspiration (inhalation) followed by an expiration (exhalation).

Pleural Fluid

A fluid residing between the parietal and visceral pleurae that acts as a lubricant to reduce friction during lung movements.

Compliance

An indicator of lung expandability referring to the ease with which the lungs can expand and contract.

Elasticity

The ability of lung tissue to recoil back to its original shape after being stretched.

Atmospheric Pressure

The weight of air, equal to normal sea-level values of $1\text{ atm}$, $760\text{ mmHg}$, or $101.325\text{ kPa}$.

Tidal Volume (TV)

The volume of air moved into or out of the lungs during a single respiratory cycle under quiet, resting conditions (typically $500\text{ mL}$).

Diaphragm

The primary respiratory muscle whose contraction accounts for approximately $75\%$ of normal air movement during inhalation.

External Intercostal Muscles

Primary respiratory muscles that assist inhalation by elevating the ribs, contributing approximately $25\%$ of normal air movement.

Respiratory Minute Volume (MV)

The total volume of air moved into and out of the lungs per minute, calculated as $\text{respiratory rate} \times \text{tidal volume}$.

Inspiratory Reserve Volume (IRV)

The amount of air that can be taken in over and above the resting tidal volume during a maximal inspiration ($3300\text{ mL}$ in males, $1900\text{ mL}$ in females).

Expiratory Reserve Volume (ERV)

The amount of air forcibly expelled after completing a normal quiet respiratory cycle ($1000\text{ mL}$ in males, $700\text{ mL}$ in females).

Residual Volume (RV)

The volume of gas remaining in the lungs after a maximal exhalation ($1200\text{ mL}$ in males, $1100\text{ mL}$ in females).

Minimal Volume

The component of residual volume that remains in the lungs even if they collapse, ranging from $30\text{ mL}$ to $120\text{ mL}$.

Inspiratory Capacity (IC)

The maximum amount of air that can be drawn into the lungs after a normal tidal exhalation, calculated as $IC = IRV + TV$.

Functional Residual Capacity (FRC)

The volume of air remaining in the lungs after a normal tidal exhalation, calculated as $FRC = ERV + RV$.

Vital Capacity (VC)

The maximum amount of air that can be moved into or out of the lungs in a single respiratory cycle, calculated as $VC = IRV + TV + ERV$.

Total Lung Capacity (TLC)

The total volume of the lungs, calculated as $TLC = VC + RV$ ($6000\text{ mL}$ in males, $4200\text{ mL}$ in females).

Fibrosis

A lung condition resulting in decreased compliance, making the lungs stiffer and harder to expand.

Emphysema

A chronic lung disease characterized by increased lung compliance and decreased elasticity, leading to alveolar destruction and air trapping.

Respiratory Membrane

The thin barrier across which gas exchange occurs in the lungs, composed of alveolar epithelium, capillary endothelium, and their shared basement membrane.

Oxyhemoglobin ($HbO_2$)

The compound formed when oxygen molecules reversibly bind to iron ions within hemoglobin.

Bohr Effect

The effect where hemoglobin's oxygen binding affinity is inversely related to acidity ($pH$) and carbon dioxide concentration.

Carbonic Anhydrase

An enzyme inside red blood cells that catalyzes the conversion of carbon dioxide ($CO_2$) and water ($H_2O$) into carbonic acid ($H_2CO_3$).

Carbaminohemoglobin

The compound formed when carbon dioxide binds directly to the amino groups of globular proteins in hemoglobin ($23\%$ of $CO_2$ transport).

Chloride Shift

An exchange process that moves bicarbonate ions ($HCO_3^-$) out of red blood cells into plasma in exchange for chloride ions ($Cl^-$) without requiring ATP.

Apneustic Center

Paired nuclei in the pons that provide continuous stimulation to the dorsal respiratory group (DRG) center in the medulla oblongata.

Pneumotaxic Center

Paired nuclei in the pons that inhibit the apneustic centers, promote passive or active exhalation, and regulate respiratory rate and depth.

Dorsal Respiratory Group (DRG)

The inspiratory center in the medulla oblongata that functions during both quiet and forced breathing.

Ventral Respiratory Group (VRG)

The center in the medulla oblongata containing inspiratory and expiratory areas that function only during forced breathing.

Glossopharyngeal Nerve (N IX)

Nerve transmitting sensory signals from carotid body chemoreceptors and baroreceptors to respiratory centers in response to changes in blood $pH$ or $PO_2$.

Vagus Nerve (N X)

Nerve carrying sensory signals from aortic body chemoreceptors and lung stretch receptors to the respiratory centers.

Central Chemoreceptors

Sensory receptors on the ventrolateral surface of the medulla oblongata that monitor and respond to changes in the $PCO_2$ and $pH$ of cerebrospinal fluid.

Hypercapnia

An abnormally high level of arterial carbon dioxide partial pressure ($PCO_2$), which stimulates chemoreceptors to accelerate breathing cycles.

Hypocapnia

An abnormally low level of arterial carbon dioxide partial pressure ($PCO_2$), which inhibits chemoreceptors and decreases the respiratory rate.

Cardiac Output (CO)

The volume of blood pumped by the heart per minute, calculated as $\text{Heart Rate (HR)} \times \text{Stroke Volume (SV)}$.

Phrenic Nerve

The motor nerve arising from the spinal cord that innervates and controls the diaphragm.