Ch 29 Structure and Function of Respiratory System

Comprehensive practice flashcards covering vocabulary terms from Chapter 29: Structure and Function of Respiratory System.

Respiratory System

The organ system responsible for ventilation, gas exchange, and regulating acid-base balance in the body.

Conducting Airways

The portion of airway structures consisting of the nasal passages, mouth and pharynx, larynx, trachea, bronchi, and bronchioles that conduct air into the lungs.

Respiratory Tissues

The structures involved in gas exchange, including the alveolar bundle and the respiratory membrane.

Mucociliary Blanket

A protective mechanism in the conducting airways that traps foreign particles and carries them away from the lungs using mucus and ciliated cells.

Type I Alveolar Cells

Flat squamous epithelial cells that form the thin structure of the alveolar wall through which gas exchange occurs.

Type II Alveolar Cells

Specialized alveolar cells that produce surfactant to reduce surface tension within the alveoli.

Surfactant

A substance produced by Type II alveolar cells that lowers surface tension inside the alveoli to prevent collapse.

Pulmonary Circulation

Blood circulation arising from the pulmonary artery that provides for the gas exchange function of the lungs.

Bronchial Circulation

Blood circulation arising from the thoracic aorta that supplies the lungs and other lung structures with oxygen, distributes blood to the conducting airways, and warms and humidifies incoming air.

Ventilation

The movement of gases into and out of the lungs (from the atmosphere to the lungs).

Inspiration

The phase of ventilation during which air is drawn into the lungs.

Expiration

The phase of ventilation during which air moves out of the lungs.

Atmospheric Pressure

The pressure exerted by the atmosphere on the body, also referred to as barometric pressure.

Partial Pressure

The pressure exerted by an individual gas in a mixture of gases, such as $P_{O_2}$ or $P_{CO_2}$.

Intrapulmonary Pressure

The gas pressure within the alveoli of the lungs.

Respiratory Pressure

The pressure within the respiratory passages and lungs relative to atmospheric pressure.

Lung Volumes

The amount of air exchange occurring during breathing, categorized into tidal volume, inspiratory reserve volume, and expiratory reserve volume.

Tidal Volume

The volume of air inspired or expired with each normal, resting breath.

Inspiratory Reserve Volume

The maximum amount of additional air that can be inhaled after a normal tidal inspiration.

Expiratory Reserve Volume

The maximum amount of additional air that can be forcibly exhaled after a normal tidal expiration.

Minute Volume

The total volume of air inhaled and exhaled by the lungs per minute.

Perfusion

The flow of blood through the pulmonary vessels and capillaries in the lungs.

Diffusion (Gas Exchange)

The transfer of gases across the respiratory membrane between alveoli and capillaries.

Hemoglobin-bound Oxygen Transport

The primary form of oxygen transport in which $98\%$ to $99\%$ of oxygen is carried in chemical combination with hemoglobin.

Physical Solution (Dissolved Oxygen)

The minor form of oxygen transport in which oxygen gas is directly dissolved in blood plasma.

Normal Arterial $PO_2$

The partial pressure of oxygen in arterial blood, normally maintained above $80\,\text{mm\,Hg}$ (typically $80\text{--}100\,\text{mm\,Hg}$).

Oxyhemoglobin

The oxygen-bound form of hemoglobin, reflecting the binding affinity of hemoglobin for oxygen.

Arterial Blood pH Range

The normal measure of acidity or base balance in arterial blood, defined as $7.35\text{--}7.45$.

Arterial $PCO_2$ Range

The normal partial pressure of carbon dioxide in arterial blood, starting at $35\,\text{mm\,Hg}$ (typically $35\text{--}45\,\text{mm\,Hg}$).

Arterial $HCO_3^-$ Range

The normal concentration of bicarbonate in arterial blood, defined as $22\text{--}26\,\text{mEq/L}$.

Arterial Blood Gas Sampling

The practice of using arterial blood rather than venous blood to accurately evaluate systemic blood gas concentrations and acid-base status.

Oxygen-Hemoglobin Dissociation Curve

A curve plotting percent hemoglobin saturation against partial pressure of oxygen ($PO_2$), depicting hemoglobin's binding affinity for oxygen.

Steep Region of ODC

The steep portion of the oxygen-hemoglobin dissociation curve where small decreases in $PO_2$ cause large amounts of oxygen to unload from hemoglobin to tissues.

Plateau Region of ODC

The upper flat portion of the oxygen-hemoglobin dissociation curve where hemoglobin remains highly saturated despite substantial fluctuations in $PO_2$.

Shift to Right (ODC)

A shift in the dissociation curve indicating decreased hemoglobin affinity for oxygen, promoting oxygen unloading at tissue sites.

Shift to Left (ODC)

A shift in the dissociation curve indicating increased hemoglobin affinity for oxygen, causing oxygen to bind more tightly.

Normal $P_{50}$

The partial pressure of oxygen at which hemoglobin is $50\%$ saturated.

Hemoglobin Buffer System

The chemical action of hemoglobin binding hydrogen ions and carbon dioxide to maintain blood pH balance.

Respiratory Center

The brainstem regulatory region in the pons and medulla that controls involuntary ventilation.

Pacemaker Center

The neural component within the respiratory center that generates the automatic basic rhythm of breathing.

Pneumotaxic Center

A center in the upper pons that regulates respiratory rate and depth by limiting inspiration duration.

Apneustic Center

A center in the lower pons that stimulates prolonged inspiration.

Phrenic Nerve

The motor nerve supplying motor control to the diaphragm to drive inspiration.

Automatic Regulation of Ventilation

Involuntary neural regulation of breathing driven by feedback from chemoreceptors and lung receptors.

Chemoreceptors

Sensory receptors that monitor blood levels of oxygen and carbon dioxide to adjust ventilation based on metabolic needs.

Lung Receptors

Sensory receptors in the respiratory tract that monitor breathing patterns and lung function.

Voluntary Regulation of Ventilation

Conscious breathing control initiated by the motor and premotor cortex that integrates respiration with voluntary actions like speaking, blowing, and singing.

Motor and Premotor Cortex

Brain regions responsible for initiating voluntary actions that temporarily suspend automatic breathing.

Cough Reflex

A primary defense mechanism that clears foreign particles and excess mucus from the respiratory passages.

Impaired Cough Reflex

A deficit in the cough response that heightens the risk of airway obstruction and pulmonary infection.

Dyspnea

A subjective clinical sensation described as difficulty breathing.

Frontal Sinus

An air cavity lined with mucous membrane situated in the frontal bone above the orbits.

Sphenoidal Sinus

An air space located within the sphenoid bone behind the upper nasal cavity.

Nasopharynx

The upper part of the pharynx connecting the nasal cavity above the soft palate.

Oropharynx

The middle portion of the pharynx lying behind the oral cavity.

Laryngeal Pharynx

The lowermost region of the pharynx located superior to the larynx and esophagus.

Epiglottis

A cartilaginous structure that folds over the laryngeal inlet during swallowing to block food and liquid from entering the trachea.

Larynx

The voice box organ containing vocal cords, located between the pharynx and trachea.

Trachea

The cartilaginous tube connecting the larynx to the bronchi, acting as a principal windpipe.

Terminal Bronchiole

The final segment of non-respiratory conducting airways prior to entering the respiratory zone.

Alveolar Duct

Small passages connecting respiratory bronchioles to clusters of alveoli.

Mediastinum

The central compartment of the thoracic cavity located between the left and right pleural sacs.

Parietal Pleura

The outer serous membrane attached to the inner surface of the thoracic wall.

Visceral Pleura

The inner serous membrane directly lining the outer surface of the lungs.

Pleural Space

The fluid-filled potential space enclosed between the visceral and parietal pleurae.