Flashcards in Physiology Test II by Jill Deck (31)
What is diffusion regulated by?
Concentration of gases
What is the atmospheric pressure for O2?
What is the atmospheric pressure for CO2?
What is the % in atmospheric air of N2, O2, and CO2?
What happens to air when it is moved into alveoli?
It is humidified= water is added (more so when you have a fever)
True or False. Oxygen is very soluble, and so CO2.
Oxygen is not very soluble, while
CO2 is extremely soluble.
How much more diffusable is CO2 than O2?
20x more diffusable
Diffusion is a function of 3 factors. What are they?
Concentration Gradients (partial pressures)
Solubility of Gases
Nature of any barriers (lung histology)
Lung Histology is an __________ parameter that is relatively ________.
What two factors of lung histology are important in diffusion?
Area and Distance
What 4 basic components of the respiratory membrane of the interalveolar septum are important for diffusion?
- Type 1 pneumocytes
- Basement membrane of type 1 cell
- Basement membrane of endothelium
- Type 1 capillary cell
Gas solubility is a function of ________ and is or is not dynamically changeable?
Is not dynamically changeable
Gas solubility is determined by 2 factors:
Solubility Coefficient and Molecular Weight of the gas
Gas partial pressures link _________ to ___________/_______.
Ventilation to Body Consumption/Production
What is Henry's Law?
[Diffused gas]= partial pressure x solubility
Therefore, because solubility is set, VOLUME DISSOLVED IS DIRECTLY PROPORTIONAL TO PRESSURE, Therefore
Henry's Law- D=Pressure Differential
What are the partial pressures of O2 and CO2 in the lungs? (alveoli)
What 5 factors affect partial pressures in the lungs?
1. Mixing of new and old air (inhalation to exhalation)
2. Humidification of incoming air
3. Absorption of O2 into the blood
4. Production of CO2 from the blood
5. Ventilation which exchanges air
How many breaths does it take to full exchange all air?
This is important to stabilize partial pressures
Does H2O displace partial pressures of the lungs upward or downward?
This depends on current air humidity (atmosphere)
When blood is flowing away from alveoli, where is O2 being swept to?
In to tissues
When blood is flowing towards alveoli, where is CO2 being swept to?
Which factor is arguably the main factor of partial pressures in the lungs?
Ventilation- greatly affects partial pressure as it is the rate & depth of breathing combined
What is the O2 consumption rate when resting? Exercising?
What is alveolar pressure of oxygen directly proportional to?
Ventilation rate, or 1/O2 consumption rate
What is the CO2 production rate when resting? Exercising?
What is alveolar pressure of CO2 directly proportional to?
1/ventilation rate, or CO2 production rate
The required balance between rate of flow and the rate of ventilation is known as what?
The ventilation-perfusion ratio (V/Q)
What happens when the V/Q=0?
There is no ventilation (an alveolus that is obstructed). This is when a shunt occurs.
What is a physiological shunt?
Happens when ventilation to an alveolar area is cut-off. This de-oxygenated blood will join any oxygenated blood from normal areas.