Lab 1 prep

Question 1

Dalton’s Law

Answer 1

• the pressure of a mixed gas is equal to the sum of the individual gas pressures

PP of indv gas = (% concentration) x (total gas pressure)

ex.
PPO2 = O2 fraction x total pressure

Question 2

atmospheric or barometric pressure at sea level

Answer 2

~760mmHg

Question 3

fraction of oxygen in air at sea level

Answer 3

20.93%

Question 4

partial pressure of oxygen (PO2)

- dry

Answer 4

~160mmHg)

0.2093 x 760mmHg

Question 5

partial pressure of oxygen (PO2)

• in the lungs
• why?

Answer 5

~150mmHg

(0. 2093 x (760mmHg - 47mmHg))
- PP of water vapour in lungs at 37’C = 47mmHg

** use this value for room air in the lungs for diffusion

Question 6

partial pressure of CO2 in room air

Answer 6

0.2 mmHg

Question 7

partial pressures and “CO2” exchange in pulmonary tissue
capillaries
- rest

Answer 7

in alveoli
PCO2 = 40mmHg

in tissues
PCO2 = 46mmHg

Question 8

partial pressures and “CO2” exchange in pulmonary tissue
capillaries
- exercise

Answer 8

in alveoli
PCO2 = 40mmHg

in tissue
PCO2 = 85mmHg

Question 9

partial pressures and “O2” exchange in pulmonary tissue
capillaries
- rest

Answer 9

alveoli
PO2 = 100-105mmHg

tissue
PO2 = 40mmHg

Question 10

partial pressures and “O2” exchange in pulmonary tissue
capillaries
- exercise

Answer 10

alveoli
PO2 = 100-105mmHg

tissue
PO2 = 15mmHg

Question 11

how PO2 can be decreased

Answer 11

1) reduced barometric pressure

2) decreased concentration in the air

Question 12

affect of altitude

Answer 12

lower barometric pressure, same concentration in the air

ex. 3000m above sea level
- air remains at 21% oxygen
- barometric pressure = 517mmHg

Question 13

avg tidal volume at rest

- what is it

Answer 13

Vt ~ 500mL

- amount of air breathed in and out with each breathe

Question 14

avg inspiratory reserve volume

Answer 14

~3L

Question 15

avg expiratory reserve volume

Answer 15

~1L

Question 16

avg dead space volume

• what is it
• effect of increasing tidal volume

Answer 16

~150mL

• volume inspired air available for gas exchange
• doesn’t significantly change with tidal volume
• % dead space volume decreases

Question 17

avg total lung capacity

Answer 17

~6L

Question 18

avg vital capacity

- what is it

Answer 18

~5L

- maximum volume forcefully inhaled and exhaled

Question 19

avg residual volume

Answer 19

~1.2L

- minimum air that always remains in the lungs

Question 20

how to measure ventilation (air volume)

Answer 20

flow meter

• inspired air (Vi) “or” expired air (Ve)
• L/min

Question 21

how to estimate VO2?

- 3 measurements

Answer 21

VO2 = Ve (FiO2 - FeO2)

gas analyzer 
- average FiO2 (fraction of inspired 
- average FeO2 (fraction of expired)
flow meter
- volume of air in 1 min

Question 22

how to calibrate an O2 gas analyzer

Answer 22

use known oxygen concentration of room

- sea level 20.93%

Question 23

estimate expired CO2 with O2 gas analyzer

Answer 23

% O2 change = % CO2 change

- inspired CO2 very low (~0.04% - insignificant)

Question 24

VO2 at rest

Answer 24

0.393 L/min

VO2 = (0.2093 - 0.17) x 10 L/min

Question 25

average Ve

Answer 25

10 L/min

Question 26

average # of breathes per min

Answer 26

12-16

Question 27

measuring HR

Answer 27

hand grip device - senses pressure of pulse heart rate monitor - measures chest movements

Question 28

ECG/EKG lead II set up

Answer 28

negative - right clavicle positive - lower left side ground - left clavicle *heart depolarization negative to positive on an angle down from right to left

Question 29

P wave

Answer 29

depolarization of atria

Question 30

Q wave

Answer 30

depolarization of interventricular septum

Question 31

R wave

Answer 31

depolarization of left ventricle

Question 32

S wave

Answer 32

depolarization of basal regions of the heart

Question 33

T wave

Answer 33

repolarization of ventricles

Question 34

order of depol and repol

Answer 34

opposite direction - ventricles last to depol, first to repol - repol continues to atria

Question 35

why is R-wave so big and sharp

Answer 35

- ventricles much larger, more cells | - all cell of ventricle depol in sync (same time)

Question 36

why is T-wave positive (positive repol?)

Answer 36

repol wave in heart travels opposite direction

Question 37

SA and AV nodes

Answer 37

``` SA - sets pace AV - slows conduction of current (depol) - coordinated contraction ```

Question 38

unique feature of cardiac muscle cells

Answer 38

self depolarizing - SA node fastest - AV node slower - purkinjie fibers slowest

Question 39

Calculating mean arterial pressure

Answer 39

``` mean arteriole pressure = blood flow (Q) x total peripheral resistance (TPR) ```

Question 40

average HR at rest

Answer 40

75bpm

Question 41

length of systole and diastole

Answer 41

``` rest - 1/3 systole - 2/3 diastole exercise - 1/2 systole and diastole ```

Question 42

when taking BP, name of the sound to listen for

Answer 42

Korotkoff sounds

Question 43

two ways to take BP

Answer 43

indirect - BP cuff and stethoscope - listen for korotkoff sounds direct - insert a catheter

Question 44

work (W) calculation

Answer 44

Work = Force x Distance = Mass x RPM

Question 45

Work units

Answer 45

Joules (Newtons x meters)

Question 46

power calculation and units

Answer 46

= work / time - J/s - Watts (W)

Question 47

equipment used in first lab | - ventilation, frequency, volume, body temp

Answer 47

vernier equipment

Question 48

changes with exercise

Answer 48

Increase - co2 - temp - BP (systole + mean arteriole pressure) - increase HR - increase Vt and f *diastole minor increase or decrease