Pulmonary Mod. 3 Respiratory Fxn

Question 1

What is Gas Exchange driven by at pulmonary capillaries and systemic capillaries

Answer 1

is driven by pressure gradients at both pulmonary capillaries & systemic capillaries

Question 2

Alveoli/Capillary Gradients

Answer 2

Alveoli PO2=103mmHg

Capillary PO2=40mmHg

Question 3

Carbon Dioxide PP

Answer 3

Alveoli PCO2=40mmHg

Pulmonary Capillary PC02=45mmhg

Question 4

Capillary/Tissue Gradients: Oxygen

Answer 4

can be as low as 20mmHg
Tissue Capillary PO2 of blood entering tissue=90-100mmHg

Blood leaving tissue capillaries (has delivered it’s O2) is 40mmhg

Question 5

Capillary/Tissue Gradients: Carbon Dioxide

Answer 5

Tissue PCO2=as high as 46mmHg

Tissue Capillary PCO2 of blood entering: 40mmHg

Blood leaving has increased it’s CO2 and will be 45mmHg

Question 6

Pulmonary Perfusion

Answer 6

Resting CO= 5L/min

Exercise CO= may increase up to 25L/min

Question 7

Alveoli Ventilation Distribution

Answer 7

Base: alveoli smaller w/reduced surface tension, easier to inflate. Responsible for normal tidal volume ventilation

Apex: less compliant
alveoli contain larger residual air, larger w/increased surface tension (more difficult to inflate)
inflate during extreme ventilation

Question 8

Pulmonary Perfusion Distribution

Answer 8

pulm circ. gravity dependent
BASE: increased blood flow at base of lungs
APEX: decreased blood flow at apex of lungs

Question 9

If alveolar gas pressure exceeds capillary pressure

Answer 9

perfusion slows or stops

the capillary collapses or is compressed thus blood flow stops

Question 10

Upright Lung; Zone I

Answer 10

alveolar pressure>arterial capillary pressure> venous capillary pressure

Perfusion is stopped by alveolar pressure

Question 11

Upright Lung: Zone II

Answer 11

Arterial Capillary Pressure>alveolar pressure>venous capillary pressure

perfusion is slowed down by alveolar pressure

Question 12

Upright Lung: Zone III

Answer 12

Arterial capillary pressure>venous capillary pressure>alveolar pressure

prefusion is not effected by the alveolar pressure

Question 13

Ventilation/perfusion (V/Q) Ratio

Answer 13

compares amnt of air that enters the alveoli each minute with the amount of blood that travels through pulmonary capillaries each minute

Question 14

V/Q at rest

Answer 14

4.2/5.0=0.8

4. 2=TV-dead space(150)x12(breath/min)
5. 0=resting perfusion c/o

Question 15

V/Q during moderate exercise

Answer 15

ventilation and respiration increase proportionately

V/Q remains at 0.8

Question 16

V/Q During Intense Exercise

Answer 16

V/Q increases to 5/1
ventilation increases much more than pefusion
lungs not eliminating factor in exercise

Question 17

If Blood Flow is obstructed (i.e pulmonary embolism)

Answer 17

V/Q=increase

Question 18

If Ventilation is obstructed (i.e COPD)

Answer 18

V/Q= decrease

Question 19

Oxygen Transport Across Alveolar capillary

Answer 19

pressure gradient driven

Time: rest: RBC takes .75 seconds to travel through pulmonary capillary. Only .25 seconds is needed to binds O2 to Hb

Question 20

Saturation of Oxygen in the Blood

Answer 20

at 100% sat=transports a maximum of 20mL of O2 per 100 ml of blood

Question 21

Right Shift in oxyhemoglobin dissociation curve is:

Answer 21

Decreased affinitiy for Hb and O2

acidosis (elevaged H+ levels) and hypercapnia (elevated CO2 levels)

Question 22

Left Shift in oxyhemoglobin dissociation curve is:

Answer 22

Increased affinity for the Hb and O2
alkalosis
hypocapnia (decreased CO2 levels)

Question 23

Three forms of carbon dioxide transport

Answer 23

CO2 dissolves in plasma
CO2 binds to hemoglobin
CO2 forms bicarbonate HC03

Question 24

CO2 dissolves into plasma

Answer 24

approx. 5-10% of transported CO2 in this form

continues to maintain gradient of alveoli/tissue CO2 to RBC Co2

Question 25

CO2 binds to hemoglobin

Answer 25

approx 5-30% of CO2 transported in this form

Question 26

CO2 forms bicarbonate (HCO3)

Answer 26

approx 60%-90% transported CO2 in this form

CO2 enters RBC

Question 27

CO2 Transport in Tissue-Bohr Effect

Answer 27

Elevated CO2 values will decrease Hb-02 affinitiy and encourage CO2-Hb binding
Bohr effect

Question 28

CO2 Transport In Lungs- Haldane Effect

Answer 28

Elevated O2 values will decrease Hb-CO2 affinity and encourage Hb-O2 binding
Haldane effect

Question 29

The FLAT top portion of oxyhemoglobin dissociation curve

Answer 29

Represents a buffer zone (60-100mmHg)

Question 30

The STEEP portion of the oxyhemoglobin dissociation curve

Answer 30

Progressively favors O2 to be released into system tissue, o2 disassociates from Hb.

Capillaries in hypoxic tissue will have lower pp of o2 so it’s easier for O2 to be released in hypoxic tissue