Cardiac Conduction System

Question 1

Cardiac conduction system:

Answer 1

> A network of nodes, cells, and signals that control your heartbeat

Question 2

3 layers of the heart:

Answer 2

1) Pericardium (outer layer)
2) Myocardium (second layer)
3) Endocardium (inner layer)

Question 3

Myocardium:

Answer 3

> Middle, muscle layer (thick and large)
Facilitates contraction and relaxation of the heart walls to receive and pump blood
A cardiac impulse is transmitted throughout - activating all muscle tissue (myogenic)
The septum is myocardial tissue which divides the heart into its double pump

Question 4

Atria:

Answer 4

Top chambers of the heart - receive blood from the lungs and body

Question 5

Ventricles:

Answer 5

Bottom chambers of the heart - pumps blood to lungs or body

Question 6

Atrioventricular valves: (Bicuspid and Tricuspid)

Answer 6

Control blood flow from the atria to ventricles

Question 7

Semi-lunar valves: (Aortic and Pulmonary)

Answer 7

Prevent back flow of blood into ventricles

Question 8

Septum:

Answer 8

The muscular wall that separates the sides of the heart

Question 9

Aorta:

Answer 9

Main artery of the system - transport oxygenated blood to the body

Question 10

Vena Cava:

Answer 10

Main vein of the system - transports deoxygenated blood to the heart

Question 11

Pulmonary artery:

Answer 11

Specialised artery - carries deoxygenated blood from the right atrium to the lungs

Question 12

Pulmonary vein:

Answer 12

Specialised vein - carries oxygenated blood from the lungs to the left atrium

Question 13

Sinoatrial Node: (SA)

Answer 13

Pacemaker of the heart, generates electrical impulses

Question 14

Atrioventricular Node: (AV)

Answer 14

Distributes nerve signals from the SA node, delaying age contractions between the atria and ventricles

Question 15

Bundle of HIS:

Answer 15

Carries the electrical signals from the AV node to the septum, the walls of the heart, and the purkinjie fibres

Question 16

Purkinjie Fibres:

Answer 16

A network of fibres that receive conductive signals from the AV node, which then activates the ventricles causing them to contract and eject blood

Question 17

Conduction system (5 steps):

Answer 17

1) The cardiac impulse originates at the SA node
2) The impulse travels down the atrial myocardium to the AV node
3) The impulse spreads to the bundle of HIS
4) The bundle connects the AV node to the septum via purkinjie fibres
5) The purkinjie fibres are connected to cardiac muscle fibres - the ventricles contract (systole)