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Anatomy > Cardiac Cycle > Flashcards

Flashcards in Cardiac Cycle Deck (29):
1

What is a cardiac cycle

The sequence of events that occur and repeat with every heart beat

2

What are the phases of a cardiac cycle

Systole and diastole

3

Alternative name for systole

Ventricular contraction

4

Alternative name for diastole

Ventricular relaxation

5

When does an AV open ?

When the atrial pressure is higher than the ventricular pressure

6

When does semilunar valves open

When the ventricular pressure is higher than the aortopulmonary pressure

7

When is cardiac cycle initiated

When there is a firing of the SA node from the right atrium

8

Explain the mechanism after which SA node Is fired

Depolarisation of atria

9

What represents the Depolarisation of the atria

P- wave

10

Does P- wave and atria contraction happen at the same time

No, atria contraction happen earlier to increase pressure in the atria to force blood into the ventricles

11

Can atrial contraction only cause the filling of the ventricles? And why?

No, the ventricles become partially fully due to a passive flow of blood through the AVN

12

What happens prior to the end of atria contraction

Atrial pressure fall reversing the pressure gradient

13

The first heart sound is produced by

Closing of the AV valves

14

The first heart sound is called

S1 which is the beginning of systole

15

What happens at S1

Ventricular Depolarisation halfway (QRS complex )

16

What is the effect of ventricular Depolarisation

Contraction of ventricles to increase pressure

17

Which possible valve will be closed when there is Depolarisation of the ventricle

Semilunar valves

18

Define iso volumetric contraction

It is when the ventricles contract within a closed space

19

Why isovolumetric contraction ?

No blood is ejected and the ventricular volume is unchanged

20

When does ventricular ejection occur

When ventricular pressure exceeds aorta and pulmonary valves causing blood to be ejected from the ventricles

21

Ventricular repolarisation is reflected by

T waves

22

Consequences of ventricular repolarisation

Ventricular pressure reduce

23

Relation between ventricular pressure and force of ejection

Directly proportional

24

Effects of pulmonary and aortic reduced pressure as ventricular pressure is reduced

It cause the semilunar valves to close causing the end of systole

25

What produces the second heart sound(S2)

Closure of the semilunar valves

26

Why is the first part of diastole isovolumetric

The ventricles relax with all valves closed

27

As atrial pressure rise slowly,ventricular pressure....

Drops to cause ventricular filling because of lower ventricular pressure than atrial pressure

28

Effects of lower ventricular pressure compared to atrial pressure

AV valve open to allow blood flow to the ventricles passively

29

Phases of cardiac cycle

1. Atrial Depolarisation
2. Isovolumetric contraction
3. Rapid ejection
4. Reduced ejection
5. Isovolumetric relaxation
6. Ventricular filling