Chapter 2 - Gas Exchange

Question 1

Whole blood consists of

Answer 1

Plasma 55%
Leukocytes 1%
Platelets 45%

Question 2

Normal blood pH

Answer 2

7.4

Question 3

Tolerances for
Arterial blood
Muscle

Answer 3

6. 9-7.5

6. 63-7.10

Question 4

Hemoglobin

Answer 4

Carries 1.39ml oxygen per gram
15g per 100ml blood
20.8 oxygen per 100ml blood
Ave person has 5L blood, 7% bodyweight

Question 5

Partial pressure

Answer 5

Calculated by total pressure of gas mix x % concentration of gas

Question 6

Why is relationship between partial pressure of oxygen and oxygen saturation sigmoidal?

Answer 6

As oxygen binds to hemoglobin it facilitates further binding
At 60mmHg curve flattens, 90% hemoglobin is saturated
Between 60-100 mmHg increases to 98%

Decrease in core temp shifts curve left
High pH shifts curve left

Question 7

How does heart work?

Answer 7

SA node generates impulse that spreads across atrium to AV node
Spreads into Purkinje system which surrounds ventricles
Stimulates ventricular contraction
0.08 m/s across atria
SA to AV to Purkinje to ventricular contraction is 0.2 secs
Deoxygenated blood returns to R atrium by superior/inferior vena cava and delivered to R ventricle
Deoxygenated blood sent to lungs by pulmonary artery
Blood returns to L atrium and delivered to L ventricle
Delivered to body via aorta

Question 8

How does ECG work?

Answer 8

P-wave - depolarization - SA-AV
QRS complex - ventricular depolarization - AV-Purkinje
T-wave - repolarization of ventricles
Atrial repolarization occurs during QRS complex, not seen

Question 9

Total peripheral resistance

Answer 9

Resistance of entire systemic circulation
Arteries are high pressure:
100 mmHg in aorta
60 mmHg in arterioles
Veins low pressure:

Question 10

BP

Answer 10

Diastole - relax

Systole - contraction

Question 11

Rate-pressure product

Answer 11

SBP x HR

Question 12

Diastolic blood pressure

Answer 12

Pressure exerted against arterial walls when no blood is being ejected from ventricles

Question 13

Mean arterial pressure

Answer 13

Mean blood pressure throughout cardiac cycle

MAP = DBP + (.333 x (SBP - DBP))

Question 14

Cardiac output

Answer 14

Amount of blood pumped in 1 minute
Q = SV x HR
SV is stroke volume
SV = EDV - ESV
EDV is end-diastolic volume
Q = (EDV - ESV) x HR

Question 15

Frank-Starling principle

Answer 15

The more the L ventricle is stretched, the more forceful the contraction, the more blood leaving the ventricle

Question 16

Respiratory structure

Answer 16

Trachea
To Bronchi
To Brionchioles
To alveoli
23 generations

Question 17

Muscles of inspiration

Answer 17

Scalenes
SCOM
Pecs major and minor

Expiration is passive
Intercostals and diaphragm relax

Question 18

Partial pressure of inspired oxygen

Answer 18

159 mmHg
Reduced to 100 mmHg as reaches alveoli due to humidifying

In blood oxygen is 40 mmHg
CO2 46 mmHg

Question 19

Oxygen uptake

VO2

Answer 19

Amount of oxygen used by tissues
Fick equation:
VO2 = Q x a-vO2
= (HR x SV) x a-vO2
= (HR) x EDV - ESV) x a-vO2

a - v02 = arterial oxygen content - venous oxygen content in mL of 02 per 100 ml blood

Tells us how much oxygen extracted from transported blood

Divide by bodyweight for relativity to bodyweight