Respiratory-38 Flashcards
T/F Because dogs, cats, and pigs don’t sweat through their skin, the respiratory system plays an important role in regulation temperature.
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What are the four major functions of respiration
Mechanics of pulmonary ventilation (movement of air into and out of lungs AKA breathing
Diffusion of O2 and CO2 btw alveoli and blood
Transport of O2 and CO2 in bood and body fluids
Regulation of ventilation
What are some accessory muscles and when are they used?
Sternoclediomastoid
Scalenus
Contract only during forceful inspiration
What are the major muscles of inspiration and when are they used?
External intercostal muscles
Diaphragm
Contract every inspiration; relaxtion and causes passive expiration
What are muscles of active respiration and when are they used?
Internal intercostal muscles
Abdominal muscles
Contract only during active respiration
1 cm H20 equals
0.75 mmHg
Relationship between lung volume and pleural pressure
Pleural pressure is the pressure of fluid in the narrow space btw the lung pleura and chest wall pleura.
As lung volume increases, pleural pressure decreases to allow lungs to expand.
What is alveolar pressure
Pressure of air inside the lung alveoli.
Has a range of +1 (expiration) 0 (no air) -1 (inspiration)
As lung volume increases, inspire (-1 ->0->+1)
As lung volume decreases, expire (+1->0->-1)
What is transpulmonary pressure
The difference between the alveolar pressure and pleural pressure.
A measure of the elastic forces that tend to collapse the lungs
What is compliance of lungs?
Extent to which lungs expand for each unit increase in transpulmonary pressure
What determines the compliance of lungs?
- ->What contributes to the majority of compliance?
- What greatly increases surface tension elastic forces of lungs?
Elastic forces of lung tissue (elastin and collagen)
Elastic forces caused by surface tension of fluids that line the inside wall of alveoli.
- ->2/3 of total elastic force of lungs
- ->Elastic forces increase if surfactant is not present in alveolar fluid.
Explain surface tension elastic force in alveoli
Inner surface of alveoli is lined with water that attempts to contract to force air out through bronchi.
Water surface is always attempting to contract (think of what holds rain drops together)
T/F Surfactant increases surface tension of water
F
Decreases
What secretes surfactant?
Type II alveolar epithelial cells
Structure of surfactant
hydrophilic portion dissolved in water. Hydrophobic portion in air. Causes 1/12 to 1/2 surface tension in water.
Formula for calculating pressure in alveoli. What can you conclude about this? How is a lung more likely to collapse.
Pressure= 2 X Surface tension/ Radius of alveoli
The smaller the alveolus, the greater the surface tension pressure.
The smaller the alveoli, the more likely lung will collapse.
What is tidal volume
Volume of air inspired or expired with each breath
What is inspiratory reserve volume?
Maximum extra volume of air that can be inspired above tidal volume
What is expiratory reserve volume
Maximum extra volume of air that can be expired by forceful expiration after the end of normal tidal volume
What is residual volume
Volume of air remaining in lungs after the most forceful expiration.`
What is inspiratory capacity
Tidal volume plus inspiratory reserve volume
What is functional residual capacity
Expiratory reserve volume plus residual volume
What is vital capacity
Inspiratory reserve volume plus tidal volume plus expiratory volume.
What is total lung capacity?
Maximum volume to which the lungs can be expanded with the greatest possible effort
