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93 terms

Physiology - Respiratory System

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Respiration
The process of gas exchange within the body; includes internal respiration and external respiration
Internal Respiration
Cellular respiration that occurs in the mitochondria
External Respiration
The exchange of oxygen and carbon dioxide between the atmosphere and the tissues of the body; involves both the respiratory and cardiovascular systems
Pulmonary Ventilation
The movement of air into and out of the lungs by bulk flow
Upper Airways
Air passages in the head and neck; include the nasal cavity, oral cavity, and pharynx
Pharynx
A passageway leading from the mouth to the esophagus or larynx that serves as a common passageway for food and air
Respiratory Tract
Air passages leading from pharynx to lungs
Conducting Zone
The upper part of the respiratory tract; conducts air from the larynx to the lungs; no gas exchange occurs
Respiratory Zone
The lower part of the respiratory tract; the site of gas exchange within the lungs
Larynx
The initial passageway of the respiratory tract, which contains the vocal cords
Glottis
Opening to the larynx
Epiglottis
A flap of tissue over the glottis that prevents food or water from entering the larynx when swallowing
Trachea
Cartilaginous tube of the respiratory tract, located between the larynx and the bronchi
Bronchi
Branched tubes of the respiratory tract, located between the trachea and bronchioles of the lungs
Secondary Bronchi
Branches off the bronchi leading to the lungs
Bronchioles
Small tubules leading from the bronchi to the alveoli; less than 1 mm in diameter
Goblet Cells
Epithelial cells in the respiratory tract and GI tract that secrete mucus
Cillia
Hairlike processes found on certain epithelial cells in the respiratory tract and oviduct
Respiratory Bronchioles
Small tubules of the respiratory tract located between terminal bronchioles and alveolar ducts
Alveoli
Terminal sacs of the respiratory tract, where most gas exchange occurs; usually grouped in clusters
Alveolar Sacs
Clusters of alveoli at the end of an alveolar duct
Type I Alveolar Cells
Epithelial cells lining alveoli
Respiratory Membrane
The structure across which gas exchange occurs in the lungs; a barrier between blood and air consisting of capillary endothelial cells and their basement membranes and alveolar peithelial cells and their basement membranes
Chest Wall
Structures that protect the lungs and form an airtight compartment around them; includes the rib cage, sternum, thoracic vertebrae, muscles, and connective tissue
Internal Intercostals
Muscles of expiration that are located between the ribs
External Intercostals
Inspiratory muscles of the chest wall
Diaphragm
Primary inspiratory muscle for respiration; the muscular partition that separates the abdominal and thoracic cavities
Pleura
The membrane that lines the chest wall and lung, forming a pleural sac around each lung
Pleural Sac
membrane surrounding each lung
Intrapleural Space
A fluid-filled compartment located between the lungs and chest wall; is bounded by the visceral and parietal pleura
Atmospheric Pressure
Pressure of outside air; at sea level, 760 mm Hg or 1 atmosphere
Intra-alveolar Pressure
The pressure exerted by the air within the alveoli
Intrapleural Pressure
The pressure of the fluid inside the pleural space
Transpulmonary Pressure
The difference between the intrapleural pressure and the intra-aveoolar pressure, which represents the distending pressure acting on the lungs
Boyle's Law
Law showing the inverse relationship between pressure and volume
Pulmonary Surfactant
Detergent-like substance secreted by type II alveolar cells; decreases the surface tension in the lungs
Type II Alveolar Cells
Cells that line alveoli and secrete surfactant
Spirometer
Device for measuring lung volumes
Lung Volumes
Measures of the amount of air that enters or leaves the lungs under certain conditions
Tidal Volume (Vt)
The volume of air that moves into and out of the lungs during a normal, unforced breath
Inspiratory Reserve Volume (IRV)
The maximum volume of air that can be inspired from the end of a normal inspiration
Expiratory Reserve Volume (ERV)
The maximum volume of air that can be expired from the end of a normal expiration
Residual Volume (RV)
The volume of air remaining in the lungs after a maximum expiration
Inspiratory Capacity (IC)
The maximum volume of air that can be inspired at the end of a resting expiration; it is the sum of tidal volume and inspiratory reserve volume (IC = Vt + IRV)
Vital Capacity (VC)
The maximum volume of air that can be expired following a maximum inspiration; it is the sum of the tidal volume, inspiratory reserve volume, and expiratory reserve volume (VC = Vt + IRV + ERV)
Total Lung Capacity (TLC)
The volume of air in the lungs at the end of maximum inspiration; it is the sum of the tidal volume, inspiratory reserve volume, expiratory reserve volume, and residual volume (TLC = Vt + IRV + ERV + RV)
Functional Residual Capacity (FRC)
The volume of air remaining in the lungs at the end of a tidal expiration; it is equal to the expiratory reserve volume and the residual volume (FRC = ERV + RV)
Forced Vital Capacity (FVC)
The maximum amount of air a person can forcefully expire following a maximum inspiration
Forced Expiratory Volume (FEV)
A measure of the percentage of the forced vital capacity that can be exhaled within a certain time frame
Minute Ventilation
The total amount of air that flows into or out of the respiratory system in a minute
Respiration Rate
Frequency of breaths
Alveolar Ventilation
A measure of the volume of fresh air reaching the alveoli each minute, which is minute ventilation corrected for dead space volume; also called minute alveolar ventilation
Anatomical Dead Space
Conducting zone of the respiratory tract; air in this region does not participate in gas exchange
Respiratory Quotient
The ratio of carbon dioxide produced by the body to tthen consumed
Partial Pressure
The proportion of the pressure of an entire gas mixture that is due to the presence of an individual gas
Mixed Venous Blood
Blood in the pulmonary artery that includes a mixture of blood returning from all the systemic veins to the right atrium
Hyperpnea
An increase in ventilation to meet an increase in the metabolic demands of the body
Hypoventilation
A condition in which ventilation is insufficient to meet the metabolic demands of the body
Hyperventilation
A condition in which ventilation exceeds the metabolic demands of the body
Bohr Effect
Effect of hydrogen ions on the ability of hemoglobin to bind oxygen
Carbaminohemoglobin
Hemoglobin with carbon dioxide bound to it
Carbamino Effect
Decrease in the affinity of hemoglobin for oxygen when carbon dioxide binds to hemoglobin
Carbonic Anhydrase
Enzyme that catalyzes the reversible reaction converting carbon dioxide and water to carbonic acid
Chloride Shift
The movement of chloride ions into erythrocytes in exchange for movement of bicarbonate into plasma
Haldane Effect
Effect of oxygen on the binding of carbon dioxide to hemoglobin
Phrenic Nerve
Nerver that innervates the diaphragm
Intercostal Nerves
Spinal nerves that innervate the intercostal muscles of respiration
Inspiratory Neurons
CNS neurons that have an increased firing rate during inspiration
Expiratory Neurons
Neurons in the central nervous system that increase their firing rate during expiration
Ventral Respiratory Group (VRG)
Respiratory control center in the medulla; contains inspiratory and expiratory neurons
Dorsal Respiratory Group (DRG)
Respiratory control center located on the dorsal side of the medulla; contains primarily inspiratory neurons
Pontine Respiratory Group (PRG)
Respiratory center of the pons containing both inspiratory and expiratory neurons
Central Pattern Generator (CPG)
In the respiratory system, network of neurons responsible for establishing the breathing rhythm
Chemoreceptors
Receptors that monitor the concentration of certain chemicals in various locations in the body
Peripheral Chemoreceptors
Chemoreceptors located in the carotid arteries that respond to changes in arterial Po2, Pco2, and pH and are involved in regulating ventilation
Central Chemoreceptors
Chemoreceptors located in the medulla oblongata that respond directly to changes in hydrogen ion concentration in the cerebrospinal fluid and indirectly to arterial Pco2; function in regulating ventilation
Acidosis
Condition in which arterial blood pH is 7.35 or lower
Alkalosis
Condition in which arterial blood pH is 7.45 or higher
Respiratory Acidosis
Decrease in blood pH caused by increases in plasma carbon dioxide levels
Respiratory Alkalosis
Increase in blood pH caused by decreases in plasma carbon dioxide levels
Ventilation
Respiratory process by which gases are moved into and out of the lungs
Compliance
A measure of the ability of blood vessels or other hollow structures to stretch as the pressure inside them rises
Surface Tension
The result of an inward pull among the molecules of a liquid that brings the molecules on the surface closer together
Eupnea
Easy or normal breathing
Dyspnea
Difficulty breathing
Apnea
Temporary cessation of breathing
Buffer
A compound that prevents sharp, sudden changes in pH
Metabolic Acidosis
Decrease in blood pH in response to changes other than carbon dioxide levels
Metabolic Alkalosis
Increase in blood pH in response to changes other than carbon dioxide levels
Hypocapnia
Decreased level of carbon dioxide in the bloodstream
Hypercapnia
Increased amount of carbon dioxide in the blood
Hypoxia
A dangerous condition in which the body tissues and cells do not have enough oxygen
Cyanosis
Bluish discoloration of the skin caused by a lack of adequate oxygen