Disorders of the Circulatory System (week7)

Question 1

which side is the venous side of the heart

Answer 1

right side

Question 2

what type of blood is flowing on the venous side of the body and is it going toward or away from the heart?

Answer 2

deoxygenated blood flowing back in

Question 3

What side of the heart is the arterial side and does blood flow toward or away in this side?

Answer 3

left side and away from.
arterial = away

Question 4

what is the blood flow of the heart starting from the right artium

Answer 4

right artrium ->
tricuspid valve ->
right ventricle ->
pulmonic valve ->
pulmonary arterioles ->
pulmonary capillaries [gas exchange with alveoli occurs here] ->
pulmonary venules ->
pulmonary veins ->
left atrium ->
mitral (bicuspid) valve ->
left ventricle ->
aortic valve ->
aorta (part of this freshly oxygenated blood goes into coronary arteries, which branch off the aorta just beyond the aortic valve &
feed heart. part goes up to brain tissue via carotids rest goes to tissue beds of remainder of body) ->
arterioles of tissues ->
capillaries [gas exchange with tissue occurs here] ->
venules ->
veins ->
inferior vena cava (from body) or superior vena cava (from head) ->
right atrium

Question 5

what is CO?

Answer 5

CO is the average amount of blood the LV ejects (and is therefore in circulation) per minute; normal = 4-6L/min

Question 6

what is the formula for CO?

Answer 6

HR X SV

Question 7

What are the 3 factors of SV

Answer 7

a) contractility of the cardiac muscles (pump action)

b) preload (venous return to the heart)

c) afterload (arterial resistance to cardiac blood flow)

Question 8

What are the electrical properties of the heart

Answer 8

HR and rhythm

Question 9

what is heart rate

Answer 9

the rate of impulses generated by the SA node & traveling throughout the heart is called heart rate;

normal is 60-100 impulses/ minute, but since each impulse generates a contraction or “beat” of the heart, we say “beats/minute.”

Question 10

what is systole

Answer 10

a) this is the part of heart cycle in which RV & LV are contracting & ejecting blood from their chambers into the pulmonary artery
and the aorta, respectively.

b) it occurs between the “lub” (closure of AV valves) and the “dub” (closure of pulmonic & aortic valves)

c) begins with electrical signal generated by SA node -> spreads throughout atria to AV node to ventricles; as each cardiac muscle cell receives an electrical signal, it depolarizes and contracts

d) this results in ventricular contraction & simultaneous ejection of blood from right ventricle into pulmonary vasculature & left ventricle into systemic vasculature.

Question 11

What is stroke volume

Answer 11

the amount of blood ejected PER CONTRACTION– ie, during every systole– is called stroke volume (SV) & the average amount is ~70ml/beat. (sort of a “constant”
number)

Question 12

What is diastole?

Answer 12

(the part of heart cycle in which RV & LV are
receiving blood from RA & LA = filling with blood)

Question 13

what is preload?

Answer 13

volume

what comes to the ventricles before contraction

Question 14

what does contractility of the cardiac muscles refer to?

Answer 14

pump action

the property of contractility includes how well the cardiomyocytes respond to electrical signals (PQRST) and contract —ie, how efficiently the cardiac cells are working together to eject blood, how “toned” the heart muscle is

Question 15

what is afterload?

Answer 15

resistance to normal forward flow

any form of resistance to ejection of blood from a heart chamber; ie, resistance to forward flow of blood.
1) a certain amount of afterload, or resistance, is normal; normal afterload exists when the receiving arteries have:
a) normal vasomotor tone, that is, the arterial walls have a muscle tone which is flexible, compliant, not too constricted, not too dilated—“just right”