Pulmonary Lecture 4 Flashcards Preview

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Flashcards in Pulmonary Lecture 4 Deck (23)
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1
Q

How does gravity affect Regional Variations in ventilation

A

The top alveolus will have the weight of the lung pulling it open

The bottom alveolus will be squeezed by the wieght of the lung

VBot/VTop = 2.5

The bottom will have more airflow - Volume doesnt matter but change in volume. Because the bottom alveolus is smaller, there is a greater volume change

2
Q

In this picture will the bottom or top alveolus have more compliance

A

The bottom alveolus has higher compliance

3
Q

What are the two characteristics of Oxygen in Blood

A
  1. Oxygen is poorly soluble
  2. Oxygen binding sites on hemoglobin are mostly saturated
4
Q

How does exercise effect diffusion of Oxygen?

A

It slows diffusion because blood is flowing more quickly and there is less time for Oxygen to diffuse

5
Q

How does interstitial disease effect diffusion of Oxygen?

A

It causes a thickening in the diameter thus causing diffusion to dramatically slow

6
Q

How is Carbon Dioxide effected by interstital disease or exercise?

A

Carbon Dioxide is generally never effected by a diffusion problem because it has a much higher solubility. Sometimes it is slow, but not nny much

7
Q

Define Perfusion

A

Blood Flow in the lung

8
Q

Define Minute Perfusion

A

Blood flow in the lung in one minute
Normal = 5L

This also equal Cardiac Output as they are so close together

9
Q

How does Oxygen tension effect Perfusion

A

Hypoxic Pulmonary Vasoconstriction

It causes areas where oxygen levels are low to constrict.

Mechanism to help divert blood to a part of the lung to have higher gas exchange - adaptive mechanism

10
Q

How does Capillary Recruitment effect Perfusion?

A

Have a lung where blood vessels are relatively constricted. When exercising, it causes the blood vessels to dilate recruiting capillaries to allow for a higher gas exchange

11
Q

How does Gravity Affect Perfusion?

A

Introduces Regional Variations

Gravity generates regional variation of blood flow at different parts of the lung. If the person is standing upright the blood will pool at base of lung because of gravity. Causes blood pressure below to increase and dilate them.

12
Q

What is V/Q Mismatch

A

The ratio of the amount of ventilation that is flowing in and out of the alveolus to the amount of blood flow

V/Q

13
Q

If you occlusion of a bronchiole how is V/Q mismatch effected

A

It will lower

14
Q

If you have occlusion of an artery how wil V/Q mismatch be affected

A

It will be higher

15
Q

If there is a region of low V/Q in the lung, how will the lung compensate?

A

Other regions V/Q will become higher. This is to maintain normal CO2 Levels

16
Q

In an area that has a high V/Q to increase ventilation why will the total oxygen in the blood plateau?

A

Due to the oxyhemoglobin dissociation. Total blood volume of oxygen can only go so high due to saturation

17
Q

In a situation of V/Q Mismatch where one blood vessel has a higher V/Q and one has a lower how is oxygen affected?

A

The total oxygen will be lower due to saturation

18
Q

How does V/Q Mismatch affect arterial levels of CO2?

A

It does not have an effect.

19
Q

How does Gravity effect V/Q mismatch

A

The mechanism will favor a higher level of ventilation and perfusion at the bottom vs. the top

20
Q

How does gravity effect the pressure of the pressure in alveoli compared to the pressure in arterioles

A

It causes the pressure in arterioles to be 5-10 Torr lower

21
Q

What does complete occlusion of an arteriole lead to?

A

Dead space - as the alveoli is no part of the lung that does not engage in gas exchange

22
Q

What does complete occlusion of the bronchiole lead to?

A

Shunt: A volume of blood that does not engage in gas exchange

Causes: Lung/heart disease

23
Q

How does a shunt limit Oxygen in the blood

A

If one vessel has a V/Q of 0, no oxygen exchange in occuring. Due to oxygen hemoglobin saturation, other parts arterioles cannot make up for this decrease