Ch. 23: A&P of Respiratory System Flashcards
How many lobes does each lung have?
Right - 3
Left - 2
Do conducting airways serve a purpose?
Yes, they are a path for air to move into respiratory airways, but do not participate in gas exchange. So they are anatomical dead space that holds approx. 150mL of air or 2mL/kg
What is the point called where the trachea divides?
The carina
What reflexes happen when the carina is stimulated?
The cough reflex and bronchoconstriction
Which bronchus is larger, therefore has a higher chance of aspirated material to be found there?
The right bronchus. The left bronchus is smaller due to the heart taking up anatomical space.
Do respiratory airways serve a purpose?
YES, this is where gas exchange occurs!
How much space do the respiratory airways hold?
Approx. 2.5-3L
BONUS Why is there never 100% arterial oxygenation?
The bronchial circulation dumps unoxygenated blood back into the vena cava and pulmonary veins, therefore even though there can be 100% oxygenated blood right after alveolar capillaries, it always mixes with unoxygenated blood before it goes back into the left atrium.
Define ventilation
The movement of air between the atmosphere and the alveoli
Define diffusion
movement of oxygen and CO2 between the pulmonary capillaries and the alveoli
Define transportation
movement of oxygen and CO2 in the blood to and from cells
What is airway pressure
the pressure in the conducting airways
intrapleural pressure
pressure in the narrow space between the visceral and parietal pleurae
intra-alveolar pressure
pressure inside the alveoli
transpulmonary pressure
pressure difference between the intra-alveolar pressure and the intrapleural pressure
intrathoracic pressure
pressure within the entire thoracic cavity.
What is compliance and how do we calculate it?
The extent to which the lungs expand. It equals:
change in lung volume (L) /
change in lung pressure (cm H2O)
A&P changes in respiratory system with aging?
A-P diameter increases Compliance is increased Anatomical dead space increases Residual volume increases Muscle strength decreases # of alveoli decreases Alveolar elasticity is decreased Chest wall motility is decreased VC decreases Blood oxygen levels decreased Anemia is common d/t decreased hgb.
Vt
Tidal volume ~500mL
IRV
Inspiratory reserve volume ~3000mL
ERV
Expiratory reserve volume ~1100mL
RV
Residual volume ~1200mL
VC
Vital Capacity ~4600mL
TLC
Total Lung capacity ~5800mL
Factors affecting alveolar-capillary gas exchange
Surface area available for diffusion. E.g. lung removal or disease processes such as emphysema or bronchitis
Thickness of the A-C membrane. E.g. conditions such as pneumonia, interstitial lung disease, and pulmonary edema
Partial pressure of alveolar gas. E.g. ascent to high altitudes where PP of O2 is reduced
Solubility and molecular weight of the gas. E.g. CO2 diffuses more rapidly than O2 d/t increased solubility.
Physiologic shunt
Low ventilation/perfusion ratio. When perfusion exceeds ventilation, blood passes by alveoli w/o gas exchange. Seen with pneumonia, atelectasis, tumor, or mucus plug
Alveolar dead space
High ventilation/perfusion ratio. When ventilation exceed perfusion. Seen with pulmonary embolus, pulmonary infarction, cardiogenic shock, and mechanical ventilation with high Vt.
Chemoreceptors involved in respiratory function
Central: sense changes in CO2 content, located near medulla and in close contact with CSF. As pH increases d/t increased CO2, the respiratory center in medulla is stimulated to increase respirations
Peripheral: sense changes in O2 content, located in the aortic arch and carotids. These exert little control over normal respirations until PaO2 is below ~60 mm Hg
