Peripheral Resistance: Control of Blood Pressure

Question 1

What is the normal blood pressure range?

Answer 1

90/60 to 120/80

Question 2

What sides of the heart control the pulmonary and systemic circulations?

Answer 2

Right side: Pulmonary Circulation

Left side: Systemic Circulation

Question 3

Which set of circulation has a high blood pressure, systemic or pulmonary?

Answer 3

Systemic circulation is higher

Question 4

Which set of chambers have higher blood pressure, the atria or ventricles?

Answer 4

Ventricles

Question 5

What is the normal bpm of the heart?

Answer 5

70

Question 6

What is Diastole?

Answer 6

Diastole is the part of the cardiac cycle when the heart refills with blood following systole

Question 7

What is Systole?

Answer 7

Systole is the contraction phase of the cardiac cycle that results in the ejection of blood into an adjacent chamber or vessel

Question 8

The highest pressure is found where? In systole or diastole?

Answer 8

Systole

Question 9

The lowest pressure is found where? In systole or diastole?

Answer 9

Diastole

Question 10

What is the equation for Vascular Resistance?

Answer 10

Q = ΔP / R

Q = Flow per unit time
ΔP = Change in Pressure
R = Resistance

Question 11

Define “Resistance”

Answer 11

Impediment to blood flow along a vessel

Question 12

How do tissues control blood flow pumping through?

Answer 12

Precapillary sphincters control the microcirculation

Question 13

What controls the actions of pre-capillary sphincters in the tissues?

Answer 13

Metabolic products
Hypoxia
Increased CO2
NO

Question 14

State the two components of the sympathetic control coordinating short-term blood pressure control

Answer 14

Vasomotor centre in the medulla

Sympathetic fibres to all vessels in the body

Question 15

The sympathetic fibres mediate their affects to smooth and cardiac muscle via which receptors?

Answer 15

Alpha adrenoreceptors

Question 16

How is one way you can demonstrate that blood pressure is under sympathetic control?

Answer 16

Under anaesthesia, blood pressure will fall because anaesthesia turns off a patient’s sympathetic nervous system

Question 17

What affects does SNS stimulation have on BP?

Answer 17

1. Increased constriction, increases peripheral resistance and BP
2. Venous constriction increases venous return
3. Cardiac effects such increase in HR, inotropy / lusitropic effects

Question 18

Define Lusitropy?

Answer 18

Myocardial relaxation

Question 19

Define Inotropy?

Answer 19

Force of muscular contraction

Question 20

Where are the Arterial Baroreceptors located?

Answer 20

Internal carotid

Aortic arch

Question 21

If blood pressure falls short term, how do the Baroreceptors respond?

Answer 21

Pressure falls, causing a decrease in impulse firing rate of baroreceptor, which is transmitted to the medulla to increase sympathetic tone which will correct pressure

Question 22

Aside from baroreceptors, what other receptors are there to control BP (short term) and where are they found?

Answer 22

Low pressure receptors / Volume receptors

Located in Vena Cava, pulmonary arteries, and atria

Question 23

What is Pressure Diuresis?

Answer 23

A form of renal long term control of blood pressure, by increasing urine output

Question 24

How can you treat hypertension? 6 examples of drug classes

Answer 24

Diuretics
Beta blockers
Alpha blockers
ACE Inhibitors
Calcium antagonists
Angiotensin Receptor Blockers

Question 25

What do Beta blockers do to lower blood pressure?

Answer 25

• Reduce cardiac output
• Reduce renin release
• Sympathetic inhibition

Question 26

Give 2 examples of ACE inhibitor drugs

Answer 26

Lisinopril

Captropril

Question 27

Give 2 examples of Angiotension Receptor Blocker drugs

Answer 27

Losartan

Valsartan