Respiratory - Ventilation

Question 1

Define:

Ventilation

Answer 1

How gas gets from the atmosphere to the alveoli

Question 2

Define

Boyle’s law

Answer 2

The pressure and volume of a gas are inversely related
Increase V decrease P

Question 3

How does Boyle’s Law apply to us?

Answer 3

When the diaphragm contracts, the volume of the thoracic cavity increases and intrapleural pressure decreases

Question 4

Define

Henry’s Law: The amount of a gas that dissolves into a fluid is related to…

Answer 4

The solubility of the gas into the fluid
The temperature of the fluid and
The partial pressure of the gas

Increase Temp decrease solute solubility

Question 5

How does Henry’s Law apply to us?

Answer 5

The chemical properties of O2 and CO2 will dictate how much of each gas is present in the blood

Question 6

Define

Dalton’s Law

Answer 6

The total pressure of a gas mixture is equal to the sum of the pressures that each gas exerts independently

Add up partial pressures of all gases for total pressurue

PO2 = PB x FO2

Question 7

What effect does increasing altidue have on fractional concentration of oxygen?

Answer 7

Increase altidue -> fractional concentration of oxygen remains unchanged

PO2 decreases

Question 8

What occurs at the beginning of inspiration?

Answer 8

Ambient air brought into airways warmed and humidified
By larynx -> saturated w/water vapor
PP of other gasses diluted
PO2 in a humidified mixture: 150 mmHg

Question 9

What affect does water vapor have on O2 in ventiliation?

Answer 9

% of O2 remains unchanged
PO2 is decreased

Question 10

Define

Total Ventilation (VE)

Equation

Answer 10

Amount of air moved per minute
VE = VT x f

Total lVentilation = Tidal Volume x Respiratory Rate

Question 11

What affect does anatomical dead space have on depth of breathing, VT and f?

Answer 11

VT and f increase
depth of breathing

Question 12

What happens to the portion of inspired air that gets to site of gas exchange?

Answer 12

It remains in conducting airways
Useless for gas exchange
large effect on VE efficiency

500 mL air moved in and out -> 350 mL exchanged between atm and alveoli

Question 13

Define

Anatomical dead space

Answer 13

Structure with no gas exchange
In conducting airways

Question 14

What needs to be considered to determine alveolar ventilaton?

Answer 14

Dead Space

Question 15

Alveolar dead space

Answer 15

In alveoli with poor circulation n
Insignificant in healthy lung - usully O
Lethal in diseased lung

Question 16

Physiological Dead space

Answer 16

Anatomical + alveolar dead space
Usually the same as anatomical because alveolar is usually 0

Question 17

Define

Alveolar Ventilation (VA)

Answer 17

VA = (TV - anatomic dead space) x resiratory rate
VA = (VT = VD) x f

more important than VE

Question 18

How does “old” air enter the alveoli?

Answer 18

At end of expiration, “old” air from previous breath is in dead space
Next inspiration “old air pushed back into alveoli

Question 19

Alevolar ventilation is best increased by…

Answer 19

increasing tidal volume

Question 20

What two variables of Alveolar Ventilation can be altered?

Answer 20

TV and f

Question 21

What is the relationship between Alveolar Ventilation and PaCO2

PaCO2 = partial pressue of CO2

Answer 21

They are inversely related
Increase ventilation decrease CO2

changing VA is the mechanism for regulating PaCO2

Question 22

If you hyperventilate, PaCO2..

Answer 22

decreases

panic attack -> blow off alot of CO2

Question 23

If you hypoventilate, PaCO2…

Answer 23

goes up

Question 24

How do you determine if VA is adequate?

Answer 24

By looking at PaCO2
If PaCO2 is high, VA is not adequate for level of CO2

Not enough or too much ventilation

Question 25

Eucapnia | VA

Answer 25

Normal

Question 26

Hypercapnia | VA

Answer 26

Hypoventilation | decreased ventilation

Question 27

Hypocapnia | VA

Answer 27

Hyperventilation | Increase ventilation

Question 28

How do we measure the amount of O2 reaching the alveoli?

Answer 28

The Alveolar Gas Equation measures the partial pressure of O2 in the alveolus | assumes R is 0.8

Question 29

Why is the Alveolar Gas Equation so important?

Answer 29

Allows us to calculate A-a gradient and determine the source of hypoxemia PO2 in alveolus - PO2 in arterial blood

Question 30

# Define Respiratory Quotient

Answer 30

Ratio of CO2 produced by VCO2 (by body) to O2 taken up (VO2) Depends on the rate of metabolism and substrate burned

Question 31

What causes the difference between PAO2 to PaO2? | In healthy individual, PAO2 very close to PaO2

Answer 31

A-a gradient due to regional differences in Va/Q Anatomic shunt (blood bypasses alveoli) Bronchial veins drain into pulmonary veins

Question 32

# T or F Alveolar ventilation is best increased by increasing respiratory rate

Answer 32

False | TV

Question 33

# T or F A gas diffuses down its partial pressure gradient

Answer 33

True

Question 34

# T or F Hypercapnia refers to excess CO2 in the arterial blood that is caused by hypoventilation

Answer 34

True

Question 35

# T or F The volume of air that remains in the conducting airways, and thus not available for gas exchange, is known as alveolar dead space

Answer 35

False | Anatomic dead space

Question 36

The pressure extered by the weight of the air in the atmosphere on objects on the earth's surface

Answer 36

Atmospheric pressure

Question 37

How much effort is required to stretch or distend the lungs

Answer 37

Compliance

Question 38

The pressure and volume of a gas are inversely related

Answer 38

Boyle's Law