Block 4.5 -- Gas Exchange and Respiratory Rate

Question 1

Exchange of gases between the atmosphere and blood – Brings in what and eliminates what?

Answer 1

Brings in O2 and eliminates CO2

Question 2

Homeostatic regulation of body pH via selective retention vs excretion of what?

Answer 2

CO2

Question 3

Ventilation (breathing) is the mechanical process that moves air into and out of the what?

Answer 3

Lungs

Question 4

What between blood and lungs and between blood and tissues?

Answer 4

Gas exchange

Question 5

Is ventilation and gas exchange in the lungs external or internal respiration?

Answer 5

External respiration

Question 6

Is oxygen utilization and gas exchange in tissues external or internal respiration?

Answer 6

Internal respiration

Question 7

Oxygen utilization by tissues to make ATP is what process?

Answer 7

Cellular respiration

Question 8

Gas exchange in the lungs occurs via what?

Answer 8

Diffusion

Question 9

O2 concentration is higher in the blood or lungs, so where does it diffuse to?

Answer 9

Higher in the lungs, so it diffuses into blood

Question 10

CO2 concentration is higher in the blood and lungs, so where does it diffuse to?

Answer 10

Higher in the blood, so it diffuses into lungs and out of blood

Question 11

What is the partial pressure of carbon dioxide and oxygen in the alveoli and arterial blood?

Answer 11

PO2 = 100 mmHg
PCO2 = 40 mmHg

Question 12

What is the partial pressure of carbon dioxide and oxygen in the tissues and venous blood?

Answer 12

PO2 = Less than 40 mmHg
PCO2 = More than 46 mmHg

Question 13

Aerobic metabolism consumes what and produces what?

Answer 13

Consumes O2 and produces CO2

Question 14

In bulk flow, it flows from regions of higher or lower pressure to higher or lower pressure?

Answer 14

Higher to lower pressure

Question 15

Muscle contraction creates what (Lung volume changes)?

Answer 15

Pressure gradients

Question 16

Breathing is an active process which requires muscle contraction to create changes in what?

Answer 16

Pressure

Question 17

When the muscles of the thoracic cage and diaphragm contract, does the thoracic cavity and lungs expand or diminish?

Answer 17

Thoracic cavity and lungs expand

Question 18

What are three important physical properties of the lungs?

Answer 18

Compliance, elasticity, and surface tension

Question 19

Alveoli and blood capillaries quickly reach equilibrium for what two things?

Answer 19

CO2 and O2

Question 20

The amount of a gas that can dissolve in liquid depends on what three things?

Answer 20

Temperature of the fluid, partial pressure, and solubility in the liquid (constant)

Question 21

What is the major determining factor for the amount of a gas that can dissolve in a liquid?

Answer 21

Partial pressure

Question 22

What is the constant factor for blood in the amount of a gas that can dissolve in a liquid?

Answer 22

Temperature

Question 23

What is the major determining factor for the amount of a gas that can dissolve in a liquid in all places?

Answer 23

Solubility of the liquid

Question 24

Inspired air has an abnormally low what content?

Answer 24

Oxygen

Question 25

What is a major factor influencing atmospheric oxygen?

Answer 25

Altitude

Question 26

As altitude increases, atmosphere pressure increases or decreases?

Answer 26

Decreases

Question 27

What is the atmospheric pressure at sea level?

Answer 27

760 mmHg

Question 28

Alveolar ventilation is what?

Answer 28

Inadequate

Question 29

Decreased lung what due to fibrotic, restrictive pulmonary diseases, and lack of surfuctant?

Answer 29

Decreased lung compliance

Question 30

Increased airway what due to narrowing/obstruction by mucus or bronchoconstriction?

Answer 30

Increased airway resistance

Question 31

CNS depression slows breathing rate and decreases depth of breathing. What two things can cause this?

Answer 31

Alcohol poisoning and drug overdose

Question 32

Increased CO2 triggers increases what?

Answer 32

Respiratory response

Question 33

Respiratory response is limited by what availability?

Answer 33

Bicarbonate HCO3-

Question 34

The respiratory response is limited by a decrease in sensitivity as pH gets closer to what?

Answer 34

7.4

Question 35

Skeletal muscles, unlike cardiac muscles, are not spontaneously activated so they must get stimulated by what?

Answer 35

Neurons

Question 36

Rhythmic pattern of contraction and relaxation of breathing muscles arises from a neural network from cerebral cortex (what breathing) and respiratory control centers of pons and medulla oblongata (what breathing)?

Answer 36

Voluntary breathing and involuntary breathing

Question 37

Motor neurons innervate diaphragm/other breathing muscles, which is regulated by descending neurons from the brainstem (which two things)

Answer 37

Pons and medulla

Question 38

By law of mass action, when plasma H+ increases, decreasing pH, what also increases?

Answer 38

Plasma partial pressure of CO2

Question 39

By law of mass action, when plasma partial pressure of CO2 decreases, what decreases, causing what to increase?

Answer 39

Plasma H+ decreases, increasing pH

Question 40

Does an increase in the rate and depth of breathing increase or decrease plasma partial pressure of CO2?

Answer 40

Decreases

Question 41

Levels of what are the major regulator of respiratory rate?

Answer 41

CO2

Question 42

Which part of the brainstem regulates intrinsic rhythmicity, which is influenced by other factors?

Answer 42

Medulla

Question 43

Is involuntary breathing or voluntary breathing intrinsic to medulla?

Answer 43

Involuntary breathing

Question 44

Is involuntary breathing or voluntary breathing input from cerebral cortex?

Answer 44

Voluntary breathing

Question 45

Automatic control of breathing is influenced by feedback from what? These monitor pH (plasma of CO2) of blood and interstitial fluids in the brain. Sensitivity is modulated by what?

Answer 45

Chemoreceptors, plasma of O2

Question 46

Central chemoreceptors in medulla respond to plasma CO2 to increase H+ if plasma CO2 is what?

Answer 46

Increase in plasma CO2 increases H+

Question 47

Peripheral chemoreceptors in carotid arteries and aortic arch respond to what three things?

Answer 47

Plasma CO2, pH, and O2

Question 48

Increase in plasma CO2 increases H+ in interstitial fluid, sensed by chemoreceptors in the medulla and increases what? This is not directly due to changes in plasma what (H+ cannot cross the blood-brain barrier)

Answer 48

Ventilation and plasma pH

Question 49

Do peripheral or central chemoreceptors take longer?

Answer 49

Central chemoreceptors

Question 50

Which chemoreceptors are responsible for 70-80% of increased ventilation?

Answer 50

Central chemoreceptors

Question 52

Blood PO2 on Ventilation -- Indirectly affects ventilation by affecting chemoreceptor sensitivity to what?

Answer 52

Partial pressure of CO2

Question 53

Blood PO2 on Ventilation -- Low blood O2 makes carotid bodies much more sensitive to what?

Answer 53

CO2

Question 54

Blood PO2 on Ventilation -- Hypoxic Drive: Carotid bodies respond directly to low oxygen dissolved in plasma, which is below what mmHg?

Answer 54

70 mmHg

Question 55

Major control by peripheral chemoreceptors is achieved by monitoring what two things?

Answer 55

CO2 and O2