Mechanics of Ventilation Flashcards
Muscle activity during inspiration
Diaphragm: contracts and moves downwards
External intercostals: contract and lifts the rib cage up and out
Thoracic cavity volume changes during inspiration
volume increases as air enters and diaphragm flattens
Lung volume changes during inspiration
volume increases as the lungs expand
Pressure changes during inspiration
intrapulmonary and intrapleural pressure decreases as lung volume increases
Air movement during inspiration
air flows into the lungs
Surfactant function and importance
Function: fluid secreted by type II alveolar cells that reduces surface tension in the lungs
Importance: makes breathing easier and prevents the lung from collapsing
Brain nuclei involved in ventilation control
- ventral respiratory group
- dorsal respiratory group
- pontine respiratory group
Respiratory cycle definition
one complete inspiration and expiration
Quiet vs forced breathing
Quiet: breathing while at rest, effortless and automatic
Forced: deep, rapid breathing
Central chemoreceptors function and location
Location: medulla oblongata
Function: monitor the pH of cerebrospinal fluid
Peripheral chemoreceptors location and function
Location: carotid and aortic bodies
Function: respond to changes in O2, CO2, and pH in the blood
Hering-Breuer reflex
- reflex triggered by excessive inflation of the lungs
- stops inhalation and prevents overinflation of the lungs
What is anatomical dead space?
- portion of the respiratory system that doesn’t take part in gas exchange; conducting zone
- reduces the amount of fresh air that reaches the alveoli
Effects of disrupted thoracic cavity pressure
pneumothorax: air entering into the pleural can increase pressure in the lungs and cause them to collapse
Define eupnea
normal, quiet breathing
Define apnea
temporary cessation of breathing (skipping a breath)
Define dyspnea
shortness of breath
Define hyperpnea
increased rate and depth of breathing in response to exercise, pain, or other conditions
Define hyperventilation
increased pulmonary ventilation in excess of metabolic demand
Define hypoventilation
reduced pulmonary ventilation
Define tachypnea
rapid breathing
Define respiratory arrest
permanent cessation of breathing
Define orthopnea
dyspnea that occurs when a person is lying down
Define kussmaul respiration
deep, rapid breathing
