Dr. Poole's Test

Question 1

What is the principle function of the lung?

Answer 1

1. gas exchange (principle function)
2. acid base regulation
3. filter toxins

Question 2

By what process do O2 and CO2 move between the air and blood within the lung?

Answer 2

diffusion (from higher to lower pressure)

Question 3

Ficks law

Answer 3

Vgas= A/T x D (Pa- Pblood)

increased surface area
decreased thickness
CO2 is more diffusible
Change in pressure is more in favor of oxygen

Question 4

What are the two zones of the lung and in which one does the most gas reside?

Answer 4

1. conduction zone (airways that do not help with gas exchange) (150 ml)
2. respiratory zone (alveoli) (2-5 L)

Respiratory zone takes up most of the volume of the lung (2-5 L)

Question 5

How may airway bifurcations are found in the human lung?

Answer 5

23 bifurcations

First 16 in conducting zone
last 7 in the respiratory zone

Question 6

Draw a graph depicting the relationship between airway generation and total airway cross sectional area

Answer 6

pg 5 lecture 1 and 2

Question 7

What are the 3 cell types found in the alveoli an what are their functions?

Answer 7

1. Type 1 (egg shaped) (90% of alveolar wall)
2. Type 2 ( secretes surfactant lowering surface tension)
   (these contribute to the high compliance and distensibility of the lung)
3. macrophages (engulf tiny particles too small to be filtered out upstream)

Question 8

type 1 alveolar cells

Answer 8

egg shaped and make up 90% of the alveolar wall

Question 9

type 2 alveolar cells

Answer 9

• secrete surfactant lowering the surface tension

- contributes to the high compliance and distensibility of the lung

Question 10

macrophages

Answer 10

engulf tiny particles too small to be filtered out upstream

Question 11

What are the two main forms of connective tissue found in the lungs?

Answer 11

collagen and elastin

Question 12

ventilation at rest

Answer 12

7,500 ml/min or 7.5 L/min

Question 13

tidal volume

Answer 13

500 ml or .5 L

Question 14

respiratory frequency

Answer 14

15 breaths/min

Question 15

alveolar gas volume

Answer 15

3,000 ml 3L

Question 16

dead space volume

Answer 16

150 ml or .15 L

Question 17

pulmonary capillary blood volume

Answer 17

70 ml

Question 18

pulmonary blood flow

Answer 18

5000 ml/min

Question 19

alveolar ventilation

Answer 19

5250 ml/min

Question 20

functional residual capacity

Answer 20

volume of gas in the lung at expiratory level

Question 21

total lung capacity

Answer 21

volume of gas in the lungs at the end of max inspiration

how much you can breathe in

Question 22

residual volume

Answer 22

volume of gas in the lungs at the end of maximal expiration

left over air/gas

Question 23

vital capacity

Answer 23

maximal volume that can be expired after maximal inspiration
(greatest volume of air that can be exhaled)

Question 24

Explain why it is more efficient to breathe more deeply (increase tidal volume) than increase breathing frequency.

Answer 24

deeper breathing is more efficient

rapid shallow breathing wastes too much air in the dead space

Question 25

Where in the lung does most of the inspired air go and why?

Answer 25

ventilation is much higher at the base of the lung due to gravity - it is reduced when the subject lies down and reduced the vertical height of the lung

Question 26

what is the only respiratory muscle active at rest?

Answer 26

diaphragm

Question 27

Define lung compliance

Answer 27

pressure vs volume (we want a big change in volume but not a big change in pressure) we don't breath at higher lung volumes because the lung is stiff up there

Question 28

What happens to the respiratory system when some knucklehead sticks a knife into the pleural space?

Answer 28

pneumothorax - pierced chest wall and intrapleural space - the lung is trying to collapse while the chest wall is trying to spring outward

Question 29

what relationship determines the shape of expiratory flow V(volume) and how is this affected by emphysema and fibrosis?

Answer 29

emphysema- high lung compliance, low recoil (baggy lung) (intrapleural pressure is less negative) fibrosis- low compliance, high recoil (intrapleural pressure is more negative)

Question 30

emphysema

Answer 30

low recoil decreased alveolar pressure increased Resistance

Question 31

fibrosis

Answer 31

lungs so stiff that TLC cannot be achieved increased alveolar pressure no change or slight decrease in resistance

Question 32

Why are peak flows so low in emphysema?

Answer 32

the lung is baggy and has low recoil - alveolar pressure is decreased - low recoil - increased resistacne

Question 33

Why is the pressure of O2 (PO2) in the alveolar space ~ 100 mmHg?

Answer 33

use the alveolar gas equation

Question 34

alveolar gas equation

Answer 34

PAO2 = PIO2- (PCO2/R)

Question 35

inspired air equation

Answer 35

PIO2 = (21/100) x (barometric pressure - 47)

Question 36

At a pressure of 100 mmHg, how much O2 can be carried in the arterial blood?

Answer 36

use Hb equation?

Question 37

Hb equation

Answer 37

02 ml/100 ml = ([Hb] x 1.34 x .97) + (PO2 x .003)

Question 38

What are the values for arterial and venous po2 and pCO2?

Answer 38

Arterial PaO2= 100 mmHg Venous PvO2= 40 mmHg Arterial PaCO2 = 40 mmHg Venous PvCO2 = 46 mmHg

Question 39

Draw a graph depicting the change in PO2 of red blood cell as it traverses the pulmonary capillary

Answer 39

pg 14 Lecture 5

Question 40

Why is the alveolar PO2 (PAO2) 100 mmHg whereas that in dry inspired air is 159 mmHg?

Answer 40

use PIO2 = (21/100) x (barometric pressure - 47) plug that into PAO2= PIO2 - (PCO2/R) takes into account the water vapor

Question 41

in what region of the brain are the inspiratory and expiratory neurons located?

Answer 41

pons and medulla

Question 42

medulla

Answer 42

pattern generator produces stimulus has CN X and IX respiratory rythmicity

Question 43

CN X

Answer 43

``` vagus nerve (from lungs) has pulmonary stretch receptors ```

Question 44

CN IX

Answer 44

glossopharyngeal nerve (from the carotid bodies)

Question 45

pons

Answer 45

fine tunes and modulates the stimulus | off switch that terminates respiration

Question 46

what is the main regulated variable?

Answer 46

PCO2= 40 mmHg

Question 47

what stimulates the central chemoreceptors?

Answer 47

transduced through cerebrospinal fluid (ECF) | -increased ventilation in response to: increased PCO2

Question 48

what stimulates carotid bodies (peripheral chemoreceptors)?

Answer 48

increased ventilation in response to : decreased PaO2 decreased pH increased PaCO2

Question 49

true or false: central chemoreceptors are behind the blood brain barrier so H+ of HCO3- doesn't affect them

Answer 49

True. H+ and HCO3- does not affect the central chemoreceptors. ONLY PCO2 affects the central chemoreceptors

Question 50

What is the mechanism by which a systemic lactic acidosis causes hyperventilation?

Answer 50

drives pH down and hits the peripheral chemoreceptors or carotid bodies due to decreased pH (more acidic)

Question 51

hyperventilation

Answer 51

lowering of arteriole carbon dioxide

Question 52

Why is pulmonary artery pressure much lower than systemic arterial pressure?

Answer 52

the pulmonary arteriole walls are very very thin because they do not have to push blood out to the body if the pulmonary arteriol pressure was high the blood gas barrier would have to be thicker causing a problem for blood oxygenation and CO2 removal

Question 53

explain why pulmonary vascular resistance increases at higher lung volume, high pulmonary artery pressures?

Answer 53

at high high lung volumes the capillaries are being stretched increasing resistance?

Question 54

give reasons you don't want to breathe at higher lung volumes

Answer 54

- high vascular resistance making the right side of the heart work harder - takes more work

Question 55

what are the 2 processes by which pulmonary vascular resistance decreases during exercise?

Answer 55

recruitment and distension

Question 56

Fick equation: calculate VO2 if cardiac output is 30,000 ml/min and O2 content falls from 20ml/100ml in arterial blood to 3 ml/100ml in venous blood?

Answer 56

use VO2= Q (CaO2 - CvO2/100) 3,000 ml x (20ml-3ml/100) = 5.1 L

Question 57

Ficks equation

Answer 57

VO2 = Q ( CaO2 - CvO2/100)

Question 58

How does pulmonary blood flow change as we move down the lung?

Answer 58

the lung is more perfused at the base of the lung - blood flow is greatest at base - ventilation is greatest at base

Question 59

How does the ventilation to perfusion ratio change as we move up the lung?

Answer 59

ventilation to perfusion ratio increases as you go up the lung - you blow off more CO2 allowing for more room at the apex for O2

Question 60

Draw an O2 dissociation curve and label the points

Answer 60

pg 24 Lecture 9 and 10

Question 61

calculate arterial O2 content at Hb 15 10 and 5

Answer 61

use the Hb equation O2 ml/100ml = (Hb x 1.34 x .97) + (PO2 x .003)

Question 62

Hb equation

Answer 62

O2 ml/100ml = (Hb x 1.34 x .97) + PO2 x .003)

Question 63

how much does arterial O2 content increase when a person breathes 100% O2?

Answer 63

slightly increases | arterial blood is 97% saturated at rest so if a person breathes 100% its only increases that 3%

Question 64

what three properties of exercising muscle helps shift the O2 dissociation curve to the right? How does this affect O2?

Answer 64

1. increase in temp 2. increase in PCO2 3. decrease in pH O2 comes off much easier O2 binds less tight

Question 65

in what three forms is CO2 carried in the blood? Which is the most important for carrying Co2 from the muscles to the lungs?

Answer 65

1. Bicarbonate (60%) 2. proteins / carbomino compounds (30%) (Hb) 3. dissolved (10%)

Question 66

What are the solubility of O2 and CO2?

Answer 66

O2 = .003 (change in pressure is more in favor of O2) CO2= .067 CO2 has a greater solubility and dissolves easier across the membrane