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Flashcards in Physiology Test II by Jill Deck (31)
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1

What is diffusion regulated by?

Concentration of gases

2

What is the atmospheric pressure for O2?

160mmHg

3

What is the atmospheric pressure for CO2?

0mmHg

4

What is the % in atmospheric air of N2, O2, and CO2?

N2= 79%
O2= 21%
CO2=0%

5

What happens to air when it is moved into alveoli?

It is humidified= water is added (more so when you have a fever)

6

True or False. Oxygen is very soluble, and so CO2.

False,
Oxygen is not very soluble, while
CO2 is extremely soluble.

7

How much more diffusable is CO2 than O2?

20x more diffusable

8

Diffusion is a function of 3 factors. What are they?

Concentration Gradients (partial pressures)
Solubility of Gases
Nature of any barriers (lung histology)

9

Lung Histology is an __________ parameter that is relatively ________.

Anatomical
Constant

10

What two factors of lung histology are important in diffusion?

Area and Distance

11

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

12

Gas solubility is a function of ________ and is or is not dynamically changeable?

Chemsitry
Is not dynamically changeable

13

Gas solubility is determined by 2 factors:

Solubility Coefficient and Molecular Weight of the gas

14

Gas partial pressures link _________ to ___________/_______.

Ventilation to Body Consumption/Production

15

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

16

What are the partial pressures of O2 and CO2 in the lungs? (alveoli)

O2- 105mmHg
CO2- 40mmHg

17

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

18

How many breaths does it take to full exchange all air?

10 breaths!
This is important to stabilize partial pressures

19

Does H2O displace partial pressures of the lungs upward or downward?

Downward.
This depends on current air humidity (atmosphere)

20

When blood is flowing away from alveoli, where is O2 being swept to?

In to tissues

21

When blood is flowing towards alveoli, where is CO2 being swept to?

Lungs

22

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

23

What is the O2 consumption rate when resting? Exercising?

Resting= 250mL/min
Exercising= 1000mL/min

24

What is alveolar pressure of oxygen directly proportional to?

Ventilation rate, or 1/O2 consumption rate

25

What is the CO2 production rate when resting? Exercising?

Resting= 200mL/min
Exercising= 800mL/min

26

What is alveolar pressure of CO2 directly proportional to?

1/ventilation rate, or CO2 production rate

27

The required balance between rate of flow and the rate of ventilation is known as what?

The ventilation-perfusion ratio (V/Q)

28

What happens when the V/Q=0?

There is no ventilation (an alveolus that is obstructed). This is when a shunt occurs.

29

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.

30

What happens when the V/Q= infinite?

There is no blood flow (an obstructed blood vessel)
= physiological dead space