Leblanc cardiac mechanic slides

Question 1

When you have shortening of muscle fibers what does it cause?

Answer 1

ejection

Question 2

Does heart contract in a linear fashion?

Answer 2

no

Question 3

In normal heart, changes in tensions and length are transformed into changes in (blank)

Answer 3

pressure and volume

Question 4

Contraction of the heart increase (blank). What is this law called

Answer 4

wall stress

Laplace’s law

Question 5

The greater the wall thickness, the less the (blank)

Answer 5

wall stress

Question 6

What is teh equation for leplaces law?

Answer 6

wall stress= (pressure X radius)/ wall thickness

Question 7

Is there an optimal length of sarcomere, Why?

Answer 7

Yes, it is aound 2 mm, because you want to create the most tension, (think slingshot, you want to pull back hard enough to get the rock to go but not too hard or you will break it)

Question 8

Are the resting and active tension length curves in cardiac and skeletal muscle the same?

Answer 8

NOOOOO because the resting tension in heart muscles steadily increases

Question 9

What is the equation for active tension?

Answer 9

total-passive

Question 10

As you increase tension, your (blank) will increase

Answer 10

force

Question 11

When you have active tension what ion is present?

So in passive tension this is not there.

Answer 11

calcium

Question 12

What is preload?

Answer 12

it is the pressure volume relationship at the point of complete ventricular filling

Question 13

How do you find stroke volume?

Answer 13

isovolumetric point of systole MINUS isovolumetric point of diastole. OR end disastolic volume-end systolic volume

Question 14

How do you find ejection fraction?

Answer 14

stroke volume/ end diastolic volume

Question 15

How do you find pulse pressure?

Answer 15

Peak of systole minus end of isovolumetric systole point

Question 16

What is contractiltiy?

Answer 16

the change in ventricular pressure during isovolumetric contraction of heart

Question 17

The greater the load the velocity (blanks) exponentially.

Answer 17

velocity declines

Question 18

Th greater the force the (blank) the velocity

Answer 18

the slower

Question 19

What is the pressure volume loop?

Answer 19

it is a magically graph the explains all the phases of the heart. Filling, isovolumetric contraction, period of ejection and isovolumetric relaxation.

Question 20

What is end-systolic pressure?

Answer 20

the point at the very end of systole before isolvolumetric relaxation

Question 21

What is starlings law of the heart?

Answer 21

If you increase end diastolic volume you will increase contraction of the heart. (i.e more blood in the more contraction you need to pump blood out)

Question 22

Venous return is your (blank) load

Answer 22

preload

Question 23

Preload is the end-diastolic volume (EDV) at thebeginningof (blank)

Answer 23

systole

Question 24

The End diastolic volume or preload is directly related to the degree of (blank) of the myocardial sarcomeres

Answer 24

stretch

Question 25

The product of stroke volume and heart rate determines the (blank)—the primary function of the heart.

Answer 25

cardiac output

Question 26

If you increase your preload what will happen?

Answer 26

you will increase your pressure (force of contraction), stroke volume, ejection fraction. end systolic volume stays the same

Question 27

IF you decrease your preload what will happen?

Answer 27

you will decrease your pressure (force of contraction), stroke volume and ejection fraction. End systolic volume stays the same

Question 28

What happens if you increase afterload?

Answer 28

increase end systolic volume, stroke volume decreases, ejection fraction decreases

Question 29

What happens if you decrease afterload?

Answer 29

increase stroke volume,decrease end systolic volume, increase ejection fraction

Question 30

what is the influence of cardiac contractility on pressure volume loops IF increased->?

Answer 30

stroke volume increases, EF increases, end systolic pressure decreases. (steeper endsystolic pressure volume curve)

Question 31

what is the influence of cardiac contractility (ANS intervention) on pressure volume loops IF decreased->?

Answer 31

End systolic pressure will increase, stroke volume decrease, EF decreases (flatter endsystolic pressure volume curve)

Question 32

What 3 things control contraction?

Answer 32

preload, afterload, and contractility

Question 33

An increase or decrease in preload will respectively increase or decrease (blank)

Answer 33

stroke volume and peak developed pressure

Question 34

An increase in afterload will increase (blank) and decrease stroke volume; a decrease in afterload will slightly decrease peak developed pressure and slightly increase (blank)

Answer 34

peak pressure | increase stroke volume

Question 35

An increase in cardiac contractility will increase (blank) ; a decrease in contractility will have the opposite effect

Answer 35

peak pressure and stroke volume

Question 36

What is the equation for stroke work?

Answer 36

pressure X stroke volume

Question 37

What has more stroke work, the left or right ventricle?

Answer 37

left

Question 38

If you increase stroke volume what do you increase?

Answer 38

EF, and Pulse pressure