Structure and Function of the Heart

Question 1

What are the layers of the heart?

Answer 1

Fibrous pericardium
Serous pericardium (parietal layer)
Pericardial cavity
Serious pericardium (visceral layer, epicardium)
Myocardium
Endocardium (inner)

Question 2

What is pericarditis?

Answer 2

Accumulation of fluid effusion in pericardium- restricts ventricular filling during diastole

Question 3

How does an action potential transfer from one cardiomyocyte to another?

Answer 3

Cardiomyocytes joined by intercelated discs with gap junctions

Question 4

What is the equation of cardiac output?

Answer 4

Heart rate x stroke volume

Question 5

Equation for stroke volume?

Answer 5

End diastolic pressure (EDP) - end systolic pressure (ESP)

Question 6

What is isovolumetric contraction?

Answer 6

Pressure within ventricle has not yet opened up valves in order for blood to exit ventricles, but atrioventricular valve closed- no change in volume within ventricle but active contraction so pressure increases

Question 7

What is isovolumetric relaxation?

Answer 7

Both valves closed
Active relaxation phase
No change in volume
No filling of ventricle 
Decreasing pressure

Question 8

What is another word for EDV?

Answer 8

Preload

Question 9

If end diastolic volume increases what does this do to stroke volume?

Answer 9

Increases stroke volume

Question 10

What increases stroke volume?

Answer 10

Decreased lattice spacing (between actin and myosin filament)- decrease distance between myofilaments- increase probability of interaction between contractile components= increase net power=stroke volume increase= increase cardiac output

Question 11

Afterload meaning

Answer 11

the amount of resistance the heart must overcome to open the aortic valve and push the blood volume out into the systemic circulation.

Question 12

A chronic increase in afterload leads to what?

Answer 12

Overall impact is stroke volume decreases

Question 13

How to increase heart rate by sympathetic nervous system?

Answer 13

NA or A bind to B1 adrenoreceptor active adrenylyl cyclase, cAMP produced lead to increase contractility
Also leads to Ca increase from L-type calcium channels

Question 14

Ejection fracture equation

What is Ejection Fracture

Answer 14

Stroke volume/ End diastolic volume

Proportion of blood pumped out with each beat
Proportion of LVEDV that is ejected

Question 15

What does ejection fracture show?

Answer 15

Measures ability of ventricles to contract