Cardiovascular physiology: BP

Question 1

What causes coronary artery disease?

Answer 1

Atherosclerosis is the underlying cause of CAD. It is an inflammatory disease that hardens the arteries through plaque formation.

Question 2

Describe the process of atherosclerosis

Answer 2

1) fat deposits on the walls of arteries forming a fatty streak
2)A stable fibrous plaque forms
3) The vulnerable phase occurs when macrophages weaken collagen

Question 3

Describe the fatty streak phase of atherosclerosis

Answer 3

LDL-cholesterol is trapped between the endothelium and connective tissue of an artery and becomes oxidised. Macrophages ingesting cholesterol and become foam cells. Smooth muscle cells are attracted by the macrophages and begin to take in cholesterol.

Question 4

describe the stable fibrous plaque phase of atherosclerosis

Answer 4

a fat core builds under the epithelium and fibrous (collagen) scar tissue forms around the lipid core. The smooth muscles in the artery also divide and thicken the artery further.
calcification is deposited in the plaque

Question 5

Describe the vulnerable plaque phase of atherosclerosis

Answer 5

Macrophages can release enzyme that weaken the collagen that holds the fat core in place. If the plaque bursts and collagen is exposed to the bloodstream, then platelets will initiate a blood clot.

Question 6

which lifestyle factors can increase the risk of cardiovascular diseases

Answer 6

-smoking
-excessive alcohol
-unhealthy diet
-unhealthy weight
-physical inactivity
-stress

Question 7

What is pulse pressure

Answer 7

systolic-diastolic

Question 8

how is MAP calculated

Answer 8

diastolic + 1/3(systolic - diastolic)

Question 9

What does blood pressure produced by

Answer 9

the driving force of the heart pumping.

Question 10

how to arteries maintain the driving pressure of the heart?

Answer 10

when ventricular contraction occurs and blood is forced into the arteries, the volume forces the arteries to stretch and compress which helps maintain the driving pressure.

Question 11

How does sphygmomanometry measure BP

Answer 11

the pressure is first increased until the flow is blocked. The pressure is then slowly released until Korotkoff sounds can be heard. This pressure when the sounds are first heard is the systolic pressure. The sounds are heard because a bolus of blood is forced through by the higher systolic pressure. Then pressure is lowered until no sounds can be heard and this point is the diastolic pressure. the lack of korotkoff sounds indicates that systolic pressure is sufficient to allow the blood to flow at all times.

Question 12

How can an accurate BP measurement be taken?

Answer 12

-correct cuff size
-device or trained tester
-multiple measurements taken during a period of time
–> this can help mitigate effect of white coat hypertension (stress of seeing a healthcare professional)

Question 13

what are the critical BP values?

Answer 13

normal: <120/<80
elevated: 120-129/<80
hypertension stage 1: 130-139/80-89
hypertension stage 2: >140/>90

Memory: add ten for systolic and add ten for diastolic in hypertension

Question 14

How does an increase in blood pressure affect risk of developing cardiovascular diseases?

Answer 14

the risk doubles for every 20/10 mmHg increase in BP

Question 15

What is essential or primary hypertension?

Answer 15

it is heretical hypertension and is also the most common form of hypertension
-the increase in BP is a result of an increase in resistance and not CO

Question 16

How should high BP be treated before diagnosis?

Answer 16

3 months of lifestyle modification before meds

Question 17

which lifestyle modifications are the most impactful for hypertensive individuals?

Answer 17

healthy diet, aerobic exercise

Question 18

What drugs should be used to treat hypertension and what are their mechanisms?

Answer 18

Calcium channel blockers(fast)
-decreased Ca2+ entry into cardiac and smooth muscle reduces the contractile force of heart and veins. Reduces CO and resistance
Diuretics (slow)
-reduce blood vol
Beta-blockers(fast)
-suppress sympathetic stimulation
ACE Inhibitors(slow) and Angiotensin Receptor Blockers(fast)
-decrease angiotensin vasoconstriction.

Question 19

How can hypertension change the functioning of baroreceptors?

Answer 19

the constant exposure to high BP will eventually cause the baroreceptors to become used to high BP. This causes less reflex control of BP and can prevent or limit the body’s natural response to high BP.

Question 20

Explain what MAP= Q x R means

Answer 20

this means that arterial pressure is the result of flow and resistance. can be used to predict result of leftover variable if one is changed.

Question 21

if blood pressure is increasing what will happen to vagus nerve activity?

Answer 21

It will increase. it carries parasympathetic messages.

Question 22

Where are alpha 1 receptors found?

Answer 22

majority of sympathetic target tissues

Question 23

where are beta1 receptors found?

Answer 23

heart, kidney

Question 24

where are beta2 receptors found

Answer 24

certain blood vessels and organ smooth muscle.

Question 25

What type of NT do adrenergic receptors detect?

Answer 25

catecholamines

Question 26

What type of control do catecholamines have?

Answer 26

tonic

Question 27

What is the primary catecholamine used in parasympathetic refexes

Answer 27

acetylcholine

Question 28

What NT do preganglionic neurons always use

Answer 28

acetylcholine

Question 29

how can a single NT have two different outcomes at the same time?

Answer 29

different receptors

Question 30

what does the orthostatic challenge test for and what can it reveal about a person

Answer 30

test the speed of sympathetic response to a drop in BP, it can indicate systemic fatigue (baroreceptor reflex)

Question 31

Where are the baroreceptors of the body?

Answer 31

carotid arteries and aortic arch

Question 32

What is the difference between afferent and efferent

Answer 32

afferent: sensory

efferent: motor

Question 33

Parasympathetic BP control can only go where?

Answer 33

SA node

Question 34

where can sympathetic BP control go?

Answer 34

SA node, ventricular myocardium, arteriolar Smooth muscle

Question 35

what is the response to increase BP

Answer 35

less sympathetic, more parasympathetic

HR decreased, force of beat decreased, CO decreased, Vasodilation

Question 36

Baroreceptor reflexes are what type of feedback

Answer 36

negative feedback

Question 37

what is the relationship between baroreceptor afferent and efferent sympathetic signal?

Answer 37

inverse

Question 38

How does a higher level of NO affect BP

Answer 38

decrease

Question 39

Why must MAP drop before reaching the capillaries?

Answer 39

capillaries are thin and vulnerable higher pressures.