Arterial Blood Pressure

Question 1

What is blood pressure?

Answer 1

Force exerted by the blood against the walls of the blood vessels

Question 2

What is arterial pressure?

Answer 2

Pressure exerted by blood on the arterial walls

Question 3

What is venous pressure?

Answer 3

Pressure exerted by blood in the veins

Question 4

Blood flows from _ to _ pressure

Answer 4

high to low

Question 5

Average of capillary blood pressure

Answer 5

25 mmHg

Question 6

Pulmonary pressure

Pressure in pulmonary circulation

Answer 6

8-20 mmHg

Question 7

What is systolic pressure?

Answer 7

Pressure generated during ventricular contraction

Question 8

Relation between SBP and cardiac output

Answer 8

Directly proportional

Question 9

What is diastolic pressure?

Answer 9

Pressure during cardiac relaxation

Question 10

Relation between DBP and total peripheral resistance?

Answer 10

Directly proportional

Question 11

What is the average range of blood pressure

Answer 11

Lower normal: 90/60 mmHg
Average: 120/80 mmHg
Upper normal: 140/90 mmHg

Question 12

Hypertension

Answer 12

More than 140/90 mmHg

Must be for two or more days for a hypertension diagnosis

Question 13

Hypotension

Answer 13

Less than 90/60 mmHg

Question 14

How is pulse pressure calculated?

Answer 14

Systolic BP - Diastolic BP

Question 15

What tool is used in measuring BP?

Answer 15

Sphygmomanometer

Question 16

What is Mean Arterial Pressure and how is it calculated?

Answer 16

Average of arterial pressures for one cardiac cycle
MAP = Diastolic +1/3 pulse pressure

Question 17

Normal range of MAP?

Answer 17

70 to 100 mmHg

Question 18

What are the functions of arterial blood pressure?

Answer 18

Maintains tissue perfusion
Produces capillary hydrostatic pressure which determines the filtration pressure affecting tissue fluid formation
Diastolic blood pressure:
Maintain blood flow during diastole
Essential for normal coronary blood flow
Prevent blood stasis in the arteries

Question 19

What physiological factors influence ABP?

Answer 19

Age: BP increases with age
Sex: Higher in males
Body build: Higher in obese people
Diurnal variation: Lowest during sleep due to decreased sympathetic tone and highest after waking up
Exercise and emotions: Increase arterial blood pressure
Temperature: Low temperature = vasoconstriction and increase ABP
Respiratory movement
Gravity

Question 20

How does age affect arterial blood pressure?

Answer 20

Birth: 70/50 mmHg
At 20: 120/80 mmHg
At 60: 140/90 mmHg

Question 21

How does respiratory movement affect arterial blood pressure?

Answer 21

ABP shows rhythmic fluctuations during respiration called Trabue-Hering waves
ABP increases during late inspiration
ABP decreases during late expiration

Question 22

What factors maintain ABP?

Answer 22

Cardiac output
Total peripheral resistance
Elasticity of the aorta (compliance)
Blood volume

Question 23

How can arterial blood pressure be calculated?

Answer 23

Cardiac output x Resistance

Question 24

How can cardiac output be calculated?

Answer 24

Stroke volume x Heart rate

Question 25

Why is TPR important for ABP?

Answer 25

Helps maintain DBP

Question 26

Where is TPR produced?

Answer 26

Arteriole

Question 27

What factors determine the TPR?

Answer 27

Diameter of the vessel (Inversely proportionate to TPR) Blood viscosity (directedly proportionate). The length of the vessel (directedly proportionate).

Question 28

How does atherosclerosis affect compliance?

Answer 28

Makes arterial walls rigid ## Footnote `

Question 29

Average volume of blood?

Answer 29

4.7-5.5L

Question 30

How do changes in blood volume affect ABP?

Answer 30

Increase blood volume → increase systemic filling pressure (Psf) → increase ABP Low blood volume as in haemorrhage → low blood pressure (hypotension) ## Footnote Systemic filling pressure (Psf) is the pressure in the systemic circulation when the blood flow is zero It is = 7 mmHg