Chapter 29: The Respiratory System Flashcards
Where gas exchanges take place between air and blood
Alveoli
Type 1 Pneumocytes
gas exchange from alveoli in to the blood
Type 2 Pneumocytes
produces surfactant
major factor in lung compliance
Alveolar Macrophages
Type 3 Phagocytic Pneumocytes
responsible for the removal of offending substances
Roles of Surfactant (3)
1) prevents alveolar collapse on expiration
2) keeps alveoli dry
3) opsonizes pathogens
Lung Compliance
how easily lungs can be inflated and recoil
______ occurs when the lungs have lost their elasticity (unable to recoil) causing the thorax to become distended.
Increased compliance
emphysema
______ occurs when lungs are stiff and unable to stretch fully
Decreased Compliance
pneumothorax, pulmonary edema, atelectasis
Ventilation
the act of breathing
movement of gases into and out of the lungs
Perfusion
provides blood to the gas exchange portion of the lungs
Diffusion
movement of gases across the alveolar-capillary membrane
In the act of ventilation, _____ is active and ______ is passive
inspiration
expiration
Ventilation is affected by gravity and _____ portions of the lungs are better ventilated depending on position
sitting/standing = apex supine = posterior portions lateral = dependent lung
Body position affects perfusion
lung tissues most dependent have better perfusion
sitting/standing = base
supine = more uniform btwn apex and base - more blood flow posteriorly
Normal Ventilation-Perfusion Ratio
air and blood must be direct to the same place at the same time
rate of vent may be slightly less than perfusion (V/Q ratio = 4:5)
Adequate ventilation with impaired perfusion is ______
Dead Space
high V/Q ratio
Dead air space results from ______
impairment of blood flow to a portion of the lung
PE, cardiogenic shock
Anatomic Dead Space
contained in conducting airways (trachea, bronchi, bronchioles, terminal bronchioles)
Alveolar Dead Space
contained in the respiratory portion of the lung
Physiologic Dead Space
includes anatomic dead space + alveolar dead space
Adequate perfusion with inadequate ventilation is _______
Shunting
low V/Q ratio
Physiologic shunts are due to _______
airway obstruction due to:
atelectasis, tumor, mucus plug
Anatomic Shunt
congenital heart defect
blood moves from the venous to arterial side of the circulation without moving through the lungs
First Aggregate Neurons
concerned primarily with INSPIRATION
control the activity of the phrenic nerves that innervate the diaphragm
Second Aggregate Neurons
concerned with BOTH inspiration and expiration
controls the motor neurons of the intercostal and abdominal muscles
Central Chemoreceptors
highly sensitive to PaCO2 and hydrogen ion concentration (increase ventilation with a rise in H+ concentration)
Peripheral Chemoreceptors
monitors PaO2 (hypoxic drive to breath) exerts little control over ventilation until the PaO2 has dropped below 60 mmHg
Lung stretch receptors respond to______
pressure changes in the walls of airways
adjust the respiratory rate and tidal volume
Lung irritant receptors are stimulated by irritants and leads to __________
airway constriction and pattern of rapid, shallow breathing
also ensures uniform lung expansion (sighing, yawning)
Lung juxtacapillary receptors (J receptors) sense ________
lung congestion
responsible for rapid shallow breathing that occurs with pulmonary edema, PE, and PNA
Neural control of the airways is under the control of the ________ nervous system
Autonomic NS (PSNS and SNS)
Parasympathetic Innervation (Cholinergic)
responds to acetylcholine
main receptor = muscarinic
causes bronchoconstriction and
increased secretion of mucous glands and goblet cells
Sympathetic Innervation (Adrenergic)
responds to norepi and epinephrine
main receptors = beta-2 adrenergic
causes relaxation of the airways, blood vessel constriction, bronchodilation, and inhibition of glandular secretions
You would use __________ to induce bronchodilation
Beta-2 agonists (Albuterol)
