Respiration During Exercise Part 1 W7 Flashcards
What is the primary purpose of the respiratory system?
To maintain arterial blood-gas homeostasis
What 4 step process allows the respiratory system to maintain arterial blood-gas homeostasis?
1) Pulmonary ventilation
2) Alveolar gas exchange
3) Gas Transport
4) Systemic gas exchange
What is the epiglottis?
Separates upper and lower respiratory tracts
What is pleura?
Membranes enclosing the lungs
What is greater, intrapleural pressure or atmospheric pressure?
Atmospheric as intrapleural pressure is always lower to allow the lungs to stay inflated and prevent alveoli from collapsing
How many airway generations are there?
23
What is the main bronchi?
Z1 extending to the terminal bronchioles (Z16)
Where does gas exchange occur?
In the respiratory zone (Z17-23)
Where does pulmonary gas exchange occur?
Across the pulmonary capillary
What are alveolar cells called?
Pneumocytes
What are Type I cells (alveolar) like?
Cover 95% of the internal surface of the alveolus and are critical for gas exchange
What are Type II cells (alveolar) like?
They release surfactant
What is a surfactant?
A molecule that lowers the surface tension
What is the volume of gas passing though a sheet dependent on? (4)
1) Surface Area
2) Thickness
3) Diffusion Coefficient
4) Pressure Gradient (Alveolar to Arterial)
What are the 5 layers that are involves the diffusion path from alveolar gas to the erythrocyte?
1) Surfactant
2) Alveolar epithelium
3) Interstitium
4) Capillary endothelium
5) Plasma
What is the mechanics of breathing?
They are concerned with the movement of air into and out of the lungs by changes in pressure, flow and volume
How does inspiration happen?
The thoracic cavity increases as respiratory muscles contract
What is the vertical change of the thoracic cavity during inspiration?
Diaphragm contracts: vertical dimension of the thoracic cavity increase
What is the lateral change of the thoracic cavity during inspiration?
Rib are elevated and thoracic cavity widens
What is the anterior-posterior change of the thoracic cavity during inspiration?
Inferior portion of the sternum moves anteriorly and thoracic cavity expands
What is bilateral phrenic nerve stimulation?
A non-volitational measure of diaphragmatic fatigue
What is Ohm’s law?
Current= voltage/resistance
In Ohm’s law, what is airflow dependent upon?
Pressure gradient and airway resistance
What is Poiseuille’s Law?
Dependent upon length and radius of a tube
What is the major determinant of airway resistance?
Radius (raised to the fourth power)
What is the dead space>
The volume of air not participating in gas exchange
What is pulmonary volume (on a graph)?
1 segment
What is pulmonary capacity (on a graph)?
2 or more segments
What is resistance to airflow mainly determined by?
Airway diameter
What is forced vital capacity (FVC)?
The maximum volume air that can be forcefully expired after a maximum inspiration
How is COPD characterised?
Increased airway resistance
Reduced FEV1/FVC
