28-31. Respiratory

Question 1

What are the 2 principle physiologic functions of the lung?

Answer 1

• O2 in

- CO2 out

Question 2

Define ventilation.

Answer 2

Moving air in/out of lungs

Question 3

What is the main energetic difference between the mechanics of breathing at rest vs. during exercise?

Answer 3

• At rest = active inhalation, passive exhalation

- During exercise = active inhalation and exhalation

Question 4

What are the 3 pre-conditions of oxygen transport system?

Answer 4

• Respiratory system is predicated on diffusion gradients
• Only facilitation is pumping fluids faster
• Gears must turn in concert

Question 5

What 2 lung volumes add up to form the total lung capacity?

Answer 5

• Residual volume

- Vital capacity

Question 6

How do residual volume and vital capacity differ in regard to ventilation?

Answer 6

• Residual volume = extra air that sits in airways and lung that never leaves
• Vital capacity = max air in + max air out

Question 7

Roughly how big is the volume of a non-exchanging tubing in the lung?

Answer 7

30%

Question 8

What is the main determinant of the portion of each breath wasted on dead space ventilation?

Answer 8

Depth of breath

Question 9

What are the factors that influence the rate of a gas’ diffusion across a membrane

Answer 9

• Surface area
• Thinness of barrier
• Pressure differential

Question 10

Describe the concept of Va/Q. What is the normal Va/Q ratio in humans?

Answer 10

• Va = ventilation of alveoli
• Q - cardiac output through lung
• These 2 flows must be proportional
• In humans = 0.8

Question 11

What would happen to the balance of perfusion and ventilation in a lung where half of the alveoli had filled up w/ fluid and pus? Would the PaO2 be elevated or depressed?

Answer 11

• Less perfusion
• Half venous blood and half alveolar blood going back into the body
• PaO2 would decrease

Question 12

How does ventilation and diffusion combine to move O2 from outside the body to the tissues and CO2 from the tissues to the environment?

Answer 12

• Ventilation moves air through pulmonary system

- Diffusion brings O2 into blood and CO2 out of blood based on differential pressure gradients

Question 13

How does mitochondrial uptake of O2 drive O2 uptake?

Answer 13

Mitochondrial uptake blood more –> lung needs to uptake more O2 to reoxygenate blood

Question 14

What percentage of its working capacity does the lung use to meet the demands of rest?

Answer 14

10-20%

Question 15

Out of Ve, PaO2, PaCO2, pH. Which are regulated variables? Which are controlled?

Answer 15

• Regulated = PaO2, PaCO2, pH

- Controlled = Ve

Question 16

Define hypoxemia.

Answer 16

Low levels of arterial O2 (PaO2

Question 17

Define eupnea.

Answer 17

Ventilation appropriate to body’s needs

Question 18

Define hyperpnea.

Answer 18

Elevated ventilation usually appropriate to need (exercise)

Question 19

Define hyperventilation.

Answer 19

Ventilation beyond that needed to maintain blood gases

Question 20

Define hypocapnea.

Answer 20

Low blood CO2 from too much breathing

Question 21

Define hypercapnea.

Answer 21

Increased arterial CO2 often due to insufficient ventilation (asthma attack)

Question 22

Define eucapneic hyperpnea.

Answer 22

Ventilatory response to exercize

Question 23

What is normal PaCO2?

Answer 23

40 mmHg

Question 24

What ventilation pattern leads to hypocapnea?

Answer 24

Hyperventilation

Question 25

What is the equation for oxygen consumed?

Answer 25

VO2 = total ventilation x (ambient O2 - expired O2)

Question 26

What are 3 major ways that CO2 travels in the bloodstream from the working muscles to the lungs?

Answer 26

• Dissolved in plasma
• Bound to hemoglobin
• In the form of bicarbonate

Question 27

What percentage of a person’s resting oxygen consumption is being used by ventilatory muscles like the diaphragm and intercostals?

Answer 27

1-2% at rest

Question 28

During submaximal exercise, what percentage of VO2 is being used to power ventilation? How does this change at high intensity work?

Answer 28

• 4%

- Can get above 10% during high intensity work

Question 29

What is CLCP?

Answer 29

Critical lactate clearance point = highest workload at which lactate blood concentration can be stabilized

Question 30

How is RER defined?

Answer 30

Amount of CO2 produced / amount of O2 consumed

Question 31

What is the meaning of a resting RER of 0.7? 1.0?

Answer 31

• 0.7 = mostly fat is being metabolized

- -1.0 = only metabolizing CHO

Question 32

How can RER go beyond 1.0? Where does the extra CO2 come from?

Answer 32

-More CO2 produced than O2 consumed

Excess CO2 comes from increase in lactate and increase in buffering of blood lactate by bicarbonate

Question 33

How is it possible that an Olympic endurance athlete could take 3 months off from training and still have a higher VO2max than well-conditioned college athletes?

Answer 33

50% of VO2 max is genetic