BMS10-1024 Cardiac Function 1 Flashcards Preview

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Flashcards in BMS10-1024 Cardiac Function 1 Deck (24)
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1
Q

What happens when the heart gets over stretched?

A

Contractile force is weaker as myosin and actin aren’t overlapping so SV is decreased

2
Q

Where is the dicrotic notch?

A

After the Pulmonary valve shuts

3
Q

Atrial systole account for how much ventricular filling?

A

Less than 20%

4
Q

How does the rest of the ventricle get filled?

A

Elastic recoil

5
Q

Describe the atria wave (3)

A

Atria contracts
Mitral valve shuts as ventricles contract
Blood flows back into the atria
Mitral valve opens

6
Q

How do you find the stroke volume from a ventricular volume graph?

A

Distance vertically between LVEDV and RVEDV

7
Q

P

A

Atrial depolarisation

8
Q

QRS

A

Ventricular depolarisation

9
Q

T

A

Ventricular repolarisation

10
Q

Describe the 4 sounds due to the heart

A

Ventricles contract
Pulmonary/aortic valves shut
Mitral and tricuspid valves open
Atrial contract

11
Q

When is atrial contracting heard?

A

With a raised end diastolic pressure

12
Q

What causes murmurs?

A

Turbulent blood

13
Q

2 causes of murmurs

A

Narrowing

Valve incompetence

14
Q

What can cause valve incompetence?

A

Inflammed heart muscles and valves due to bacteria e.g. gum disease or dental procedures

15
Q

What 2 factors influences stroke volume?

A

Energy of contraction of ventricles

Left ventricular resistance to outflow

16
Q

What decides the energy of ventricular contraction?

A
Diastolic stretch (preload)
Sympathetic innervation
17
Q

Which equation is diastolic stretch linked to?

A

Frank Starling law

18
Q

What does resistance to outflow mean?

A

The pressure the heart is working against in the arteries during ventricular systole to eject the blood- total peripheral resistance (afterload)

19
Q

What does an increased preload do? (2)

A

Increases ventricular pressure and contraction force

20
Q

What is Frank Starling’s law?

A

Heart contraction force increases due to diastolic stretching
The energy released in contraction depends on the initial fibre length and how much these have become stretched during filling

21
Q

What happens if the heart is over stretched?

A

Reduce contractile force and so SV

22
Q

What happens with increased sympathetic stimulation?

A

EDP stays the same but SV increases

23
Q

On the starling graph what are the axis?

A

SV vs EDP

24
Q

Can the 2 halves of the heart have different SV?

A

No we have a closed system so if one side spits out more and increases the SV the other side will just have to receive that increased amount and also increase its SV

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