Pulmonary System (Test 2)

Question 1

What is the vital capacity?

Answer 1

The maximum volume that can be inspired after a maximal expiration

VC=ERC+TV+IRV

~4700mL

Question 2

In which form most of the CO2 in arterial blood is carried?

Answer 2

As bicarbonate in plasma

CO2 + H2O H2CO3 HCO3- + H+

Question 3

What is the normal arterial oxygen carrying capacity?

Answer 3

(amount of hemoglobin in 100 mL of blood)*(amount of oxygen 1 g of hemoglobin can store)

(X g Hb in 100 mL blood)*(1.34 mL O2/g Hb)

Question 4

If PAO2 is 100 mmHg, hemoglobin concentration is 12 g/100 ml, and Saturation O2 is 97%, what is the concentration of oxygen bound to hemoglobin?

Answer 4

12.0 g Hb/100 ml blood × 1.34 ml O2/g Hb × .97 = 15.6 ml O2/100 ml blood

Question 5

A student has climbed to an altitude where the barometric pressure PB is 523 torr. She has hyperventilated in response to the hypoxia so her PAO2 = 70 torr and R = .83. What is her PACO2? Water vapor pressure in the airways is 47 mm Hg.

Answer 5

25 torr. Use the Alveolar air equation: PAO2 = PIO2 - (PACO2/R) where PIO2 = .21 (PB-47). Rearrange: PACO2 = R (PIO2 - PAO2).

Question 6

What happens to the oxygen binding on hemoglobin when blood temperature increases?

Answer 6

Less oxygen chemically bound to hemoglobin at the same PO2

Question 7

When the respiratory muscles are relaxed in a normal person with open airways, what is the volume of the lungs?

Answer 7

Functional Residual Capacity (FRC)

Question 8

Does muscle directly control lung movement?

Answer 8

No muscle directly attaches to the lungs. Lungs are wrapped by two layers of pleura membranes, the pressure in the space between the pleura membranes is always negative than alveolar pressure.

Question 9

During normal quiet inspiration, what change will the intrapleural pressure be?

Answer 9

more negative

Question 10

How are inspired gases mixed in the alveolar space?

Answer 10

Simple diffusion

Question 11

A subject with a dead-space of 150 ml breathed 10 breaths per minute with a tidal volume of 500 ml. What is his alveolar ventilation VA?

Answer 11

3.5 liters/minute

Question 12

In general, what is the relationship between body weight and conducting dead-space?

Answer 12

1 ml per pound

Question 13

What are the effects of acidity, DPG or temperature on the oxyhemoglobin dissociation curve?

Answer 13

Increasing the acidity, DPG or temperature of the blood will shift the curve to the right.

Question 14

As mixed venous blood enters and travels through capillaries in well- ventilated areas of the lung, what happens to the blood pH?

Answer 14

The pH increases

Question 15

What is the effect of increase in arterial CO2 on ventilation?

Answer 15

It will stimulate both the peripheral and central chemoreceptors thus increase ventilation

Question 16

What do you expect on the CO2 response curve with acclimation to altitude?

Answer 16

Shift to the left (that is, increase the respiratory response to a given arterial PCO2)

Question 17

What is the effect of hydrogen ion concentration on peripheral chemoreceptor activity?

Answer 17

The activity increases linearly with hydrogen ion concentration in the range of 40-45 mEq/L

Question 18

Do terminal bronchioles belong to the respiratory zone?

Answer 18

No. The respiratory zone consist of Respiratory bronchioles Alveolar ducts Alveolar sacs.

Question 19

What type of flow is the movement of air into the airways?

Answer 19

bulk flow

Question 20

How does the radius influence the airway resistance?

Answer 20

Poiseuille’s law states that airway resistance inversely proportional in the order of 4 to airway radius.

Question 21

What are the alveolar pressures in the absence of surfactant two alveoli of different size sharing an alveolar duct?

Answer 21

Have different alveolar pressure (Psmall>Plarge).

Question 22

What is value of the ratio of FEV1/FVC as % - the proportion of total volume of air that can be expired in the first second of expiration (% of predicted value) in a normal individual?

Answer 22

80%

Question 23

According to Fick’s first law, how do gases diffuse from alveoli to the cells are related to the membrane thickness?

Answer 23

Flow is inversely proportional to membrane thickness.

Question 24

How Does COPD Differ from Asthma?

Answer 24

The lung inflammation in asthma can be triggered by contact with substances that trigger allergies. However, in contrast to asthma, COPD the inflammation is not triggered by allergies and does not respond well to anti-inflammatory medication. In fact, the lungs of patients with COPD have evidence of permanent damage with destruction and plugging of the airways.

Question 25

What change in the concentration of diphosphoglycerate (DPG) will shift the oxygen saturation curve to the left?

Answer 25

decrease

Question 26

Which is effect of CO on the oxygen saturation curve?

Answer 26

Shift the curve to the left

Question 27

In which form the majority of O2 is transported in the blood?

Answer 27

bound to hemoglobin

Question 28

What is the critical enzyme used in CO2 transportation?

Answer 28

Carbonic anhydrase. It catalyzes CO2 + H2O H2CO3 in the lung and peripheral tissues.

Question 29

What do Boyle’s law, Henry’s law, Dalton’s law and law of Laplace refer to?

Answer 29

Boyle’s law: P1V1 = P2V2

Henry’s Law: partial pressure is the same on both sides of the liquid-air border

Dalton’s law: in the air, total pressure is the sum of partial pressures.

Law of Laplace: smaller diameter produce higher pressure due to surface tension.

Question 30

What change in lung compliance under different medical conditions?

Answer 30

Increase in Emphysema, decrease in fibrosis, no change or decrease in asthma

Question 31

What is tidal volume?

Answer 31

The lung volume change during a normal (without forcing) inspiration and expiration cycle.

Question 32

In what forms CO2 is present in the blood?

Answer 32

CO2 is carried in the blood in three forms:
10% : CO2 dissolved in the plasma
30% : HbCO2
60% : HCO3-

Question 33

What is the major form of O2 in the blood?

Answer 33

98.5% of O2 binds to hemoglobin, 1.5% dissolved.

Question 34

What is the effect of PO2 on oxygen saturation of hemoglobin?

Answer 34

O2 binding to hemoglobin increased with PO2 when it is less 80 mmHg, when PO2 is above 80 mmHg, no significant increase in O2 binding will occur.

Question 35

What is the function of carbonic anhydrase in the alveolar capillaries and in the muscle capillaries (or other peripheral tissue), respectively?

Answer 35

In lungs, carbonic anhydrase converts H2CO3 to CO2 and H2O; in peripheral tissue, carbonic anhydrase converts CO2 and H2O to H2CO3.

Question 36

What is and how do you calculate alveolar ventilation? (Va)

Answer 36

Amount of air entering alveoli per minute

Va=(Vt-Vd)*f 
where:
Vt=tidal volume
Vd=dead space (1 mL per pound)
f=breaths/min

Question 37

functions of conducting zone (5)

Answer 37

1. Transmission-low resistance pathway
2. Defends against microbes, toxins and foreign matter.
3. Air Treatment - filtration
4. warming
5. humidifying

Question 38

functions of respiratory zone

Answer 38

1. Provides O2
2. Eliminates CO2
3. Regulates blood pH
4. Forms speech sound
5. Defends against microbes
6. Traps and dissolves blood clots

Question 39

Alveolar P_O2 calculation

Answer 39

pO2 ≈ F_O2 (Patm – P_H2O) – pCO2/RQ

F_O2=fraction of air that is O2=0.21
RQ=respiratory quotient=.8