The Cardiovascular System

Question 1

What is the heart?

Answer 1

A hollow bag of cardiac muscle.

Question 2

Where is the heart located?

Answer 2

Lies obliquely in the thoratic cacvity.

Question 3

What are the three heart wall layers called?

Answer 3

Pericardium
Myocardium
Endocardium

Question 4

What is the pericardium?

Answer 4

The outer layer.
Fibrous to protect the heart.
Formed of endothelial cells as a membrane to maintain stability.

Question 5

What is the myocardium?

Answer 5

Specialised cardiac muscle layer.
Thickest at apex, thinnest at base.
Supports heart contractions.

Question 6

What is the endocardium?

Answer 6

Inner layer.
Membrane lining the chambers and valves.
Smooth to minimise friction.

Question 7

What are the four chambers of the heart?

Answer 7

Right ventricle
Left ventricle
Right atrium
Left atrium

Question 8

What are the right and left side of the heart divided by?

Answer 8

A septum, called the muscular partition

Question 9

What is the purpose of heart valves?

Answer 9

-To seperate the ventricles and atrium
-To prevent backflow.

Question 10

What is the pulmonary valve?

Answer 10

Pumps blood from the right ventricle to pulmonary arteries

Question 11

Which valve pumps blood from the right ventricle to the pulmonary arteries

Answer 11

Pulmonary valve

Question 12

What is the aortic valve?

Answer 12

Pumps blood from the left ventricle to the aorta.

Question 13

Which valve pumps blood from the left ventricle to the aorta?

Answer 13

Aortic valve

Question 14

What is the tricuspid valve?

Answer 14

Valve between right atria and right ventricle.

Question 15

Which valve is between the right atria and right ventricle?

Answer 15

Tricuspid valve

Question 16

What is the bicuspid valve?

Answer 16

Valve between left atria and left ventricle

Question 17

Which valve is between the left atria and left ventricle?

Answer 17

Bicuspid valve

Question 18

What do the superior vena cava and inferior vena cava do

Answer 18

Bring deoxygenated blood from the body to the right atrium

Question 19

What do the valves do

Answer 19

Work to prevent backflow
Act as a one way system for blood flow

Question 20

When do the atrioventricular valves open and close

Answer 20

Open when the pressure in the atrium is greater than the pressure in the ventricles
Close when the pressure in the ventricles is greater than the pressure in the atrium
Called ventricular standstill

Question 21

Function of the CVS

Answer 21

Provides circulation of blood around the body, acting as a pump to circulate oxygen and remove carbon dioxide while providing cells with nutrients.

Question 22

Why does the conduction of the heart happen

Answer 22

Because the heart generates its own impulse

Question 23

What increases and decreases heart rate

Answer 23

Sympathetic and parasympathetic nerve fibres

Question 24

SA node

Answer 24

Located in right atria wall
Able to depolarise regularly which contribute to each heartbeat
Determines rate of HR and acts as the bodies own pacemaker

Question 25

What happens as the SA node depolarises

Answer 25

Sends impulses through the internodal pathways, which pass signals from the SA node to the AV node

Question 26

As the AV node receives the impulse…

Answer 26

Allows the AV valves to close

Question 27

The bundle of his

Answer 27

Fibres originating at the AV node, carrying impulses through the myocardium into the RBB and LBB

Question 28

Where are the RBB and LBB

Answer 28

Myocardium

Question 29

Purkinje fibres

Answer 29

Originate from the RBB and LBB Activate myocardium to pump

Question 30

Myocytes

Answer 30

Proteins in the myocardium Spread out as relaxed and overlap and muscle contracts

Question 31

What does the cardiac cycle consist of

Answer 31

Diastole and systole Diastole- the heart is at complete rest between contractions Systole- atria and ventricle contraction period

Question 32

Diastole

Answer 32

Starts as the AV valve shuts, as repolarisation occurs, and the atria begins to fill with blood. Pressure in atria becomes greater than pressure in ventricles and AV valve opens

Question 33

Systole

Answer 33

As AV valve opens, systole begins. Pressure in atria decreases, pressure in ventricles increases but volume in ventricles decreases as the ventricles fill and push the walls out.

Question 34

What constitutes to the electrophysiology of the heart

Answer 34

Myocytes and action potentials

Question 35

Phase 4

Answer 35

Refractory period Myocytes have no calcium or sodium, but lots of potassium. Needs a large action potential

Question 36

Phase 0

Answer 36

Depolarisation Voltage gated pathways allow potassium out Sodium channels open Myocyte comes to ~ +60

Question 37

Phase 1

Answer 37

Initial repolarisation Sodium channels close and calcium channels open

Question 38

Phase 2

Answer 38

Contraction Where an equilibrium is established Calcium comes in Potassium comes out Calcium acts with troponin

Question 39

Phase 3

Answer 39

Repolarisation Return to resting potential Calcium channels shut and potassium channels are open

Question 40

Represented in an ECG as

Answer 40

P= atrial depolarisation PR= delay between SA and AV node QRS= atrial repolarisation, ventricular depolarisation T= ventricular repolarisation