The cardiac cycle

Question 1

What are the heart sounds?

Answer 1

Lub and dub

Question 2

What is lub?

Answer 2

The first heart sound (S1)

Question 3

What causes lub?

Answer 3

The turbulence causes by the closing of the bicuspid and tricuspid valves when ventricles are full and start contracting

Question 4

When does lub occur?

Answer 4

At the start of systole

Question 5

What is dub?

Answer 5

The second heart sound (S2)

Question 6

What causes dub?

Answer 6

The closure of the semi-lunar valves

Question 7

When does dub occur?

Answer 7

At the end of systole

Question 8

How is heartbeat regulated?

Answer 8

The pacemaker

Question 9

What is the pacemaker in the heart?

Answer 9

The sino atrial node

Question 10

What is the pacemaker made of?

Answer 10

A patch of myogenic tissue in the right atrium

Question 11

What is the effect of the pacemaker?

Answer 11

It generates electrical signals so heart muscles contract

Question 12

What regulates the heart relate?

Answer 12

The two nerves attached to the sino trial nerve

Question 13

What are the 2 nerves attached to the SAN?

Answer 13

The accelerator nerves and vagus nerve

Question 14

What causes the atria to contract?

Answer 14

A wave of electrical excitation that spreads over the heart muscle of the atria

Question 15

What separates the atria from the ventricle?

Answer 15

A disc of non-contractile tissue

Question 16

Where does electrical excitation gather?

Answer 16

At the atrio-ventricular node before passing down the Purkinje fibres into the bundle of His at the apex

Question 17

What is the delay at Q?

Answer 17

When the signal is gathering at the atrioventricular node

Question 18

What do all cells have?

Answer 18

An electrical charge difference across their membrane

Question 19

What is depolarisation?

Answer 19

Sending out electrical charge

Question 20

What is repolarisation?

Answer 20

Charge is built up again it can send out signal

Question 21

What are the waves on the sinus rhythm?

Answer 21

PQRST

Question 22

What is the p wave?

Answer 22

The small hump before the wave

Question 23

What does the p wave represent>

Answer 23

The depolarisation of the atria where the atria contract

Question 24

What is the QRS complex?

Answer 24

The main wave

Question 25

What does the QRS complex represent?

Answer 25

The depolarisation of the ventricles

Question 26

What does the QRS complex require?

Answer 26

A much stronger electrical signal because of the large size of the ventricular cardiac muscle

Question 27

What is the T wave?

Answer 27

The small hump after the big wave

Question 28

What does the T wave represent?

Answer 28

The repolarisation of the ventricles which occurs during the QRS complex which masks it on an ECG

Question 29

What are types of heart conditions?

Answer 29

Tachycardia, bradycardia, ectopic heartbeat and atrial fibrillation

Question 30

What is tachycardia?

Answer 30

When the heartbeat is very rapid

Question 31

When is tachycardia normal?

Answer 31

When you exercise, have a fever or are frightened/angry

Question 32

What causes tachycardia?

Answer 32

Problems with electrical control of heart so may need treatment with medication or surgery

Question 33

What is bradycardia?

Answer 33

When the heartbeat slows below 60 bpm

Question 34

When is bradycardia normal?

Answer 34

In many active people as long as it isn’t severe

Question 35

How is bradycardia treated?

Answer 35

An artificial pacemaker to keep heart beating steadily

Question 36

What is ectopic heartbeat?

Answer 36

Extra heartbeats that are out of normal rhythm

Question 37

What is atrial fibrillation?

Answer 37

Abnormal rhythm of the heart

Question 38

What causes atrial fibrillation?

Answer 38

Rapid electrical impulses are generated in the atria causing them to contract very fast

Question 39

What is the effect of atrial fibrillation?

Answer 39

Some impulses are passed on and heart doesn’t pump blood effectively

Question 40

What is the use of a defibrillator?

Answer 40

To electrically shock the heart to restore the normal rhythm when cardiac output is lost

Question 41

How do you calculate cardiac output?

Answer 41

Stroke volume (ml/beat) x heart rate

Question 42

What is stroke volume?

Answer 42

Amount of blood put out by the left ventricle of the heart in one contraction