CV System

Question 1

what does the CV system consist of?

Answer 1

the heart and blood vessels

Question 2

artery structure

Answer 2

transport blood away from the heart, thick wall, narrow lumen

Question 3

vein structure

Answer 3

transport blood towards the heart, thin muscle layer, wide lumen, and valves to prevent backflow

Question 4

capillary structure

Answer 4

walls one cell thick

Question 5

cardiovascular circuit

Answer 5

vena cava –> right atrium –> right AV valve –> right ventricle –> pulmonary artery –> lungs –> pulmonary veins –> left atrium –> left AV valve –> left ventricle –> aorta –> body

Question 6

how is an electrical impulse generated

Answer 6

the SA node is depolarised, initiating a heartbeat

Question 7

pathway of electrical impulse

Answer 7

electrical signal generated at SA node –> travels to AV node –> passes through the bundle of His in the left and right bundle branches –> into Purkinje fibres –> fibres contract and the cycle restarts

Question 8

stages of the cardiac cycle

Answer 8

atrial systole, ventricular systole, complete cardiac diastole

Question 9

atrial systole

Answer 9

right atrium contracts, left atrium contracts, ventricles fully relaxed, pulmonary valve closed, aortic valve closed, AV valves open

Question 10

ventricular systole

Answer 10

r and l atrium relax, AV valves closed, ventricles begin to contract, pulmonary valve opens, aortic valve opens, ventricles fully contract

Question 11

complete cardiac diastole

Answer 11

ventricles start to relax, AV valves closed, aortic valve closed, pulmonary valve closed, ventricles fully relax, right atrium fills with deoxygenated blood, left atrium fills with oxygenated blood

Question 12

systole

Answer 12

period of ventricular contraction

Question 13

diastole

Answer 13

period of ventricular relaxation

Question 14

P wave

Answer 14

electrical impulse travels from the SA node to the walls of the atria, causing them to contract (atrial depolarisation)

Question 15

QRS complex

Answer 15

spread of impulse from the AV node through the AV bundle and the Purkinje fibres, and the electrical activity of the ventricular muscle (ventricular depolarisation)

Question 16

delay between completion of P wave and onset of QRS complex

Answer 16

conduction of impulse through the AV node, which is much slower than conduction elsewhere in the heart, and allows atrial contraction to finish completely before ventricular contraction starts

Question 17

T wave

Answer 17

relaxation of the ventricular muscle (ventricular repolarisation)

Question 18

aortic valve location

Answer 18

2nd intercostal space, right sternal border

Question 19

pulmonary valve location

Answer 19

2nd intercostal space, left sternal border

Question 20

tricuspid valve location

Answer 20

4th intercostal space, left sternal border

Question 21

mitral valve location

Answer 21

5th intercostal space, mid-clavicular line

Question 22

layers of the heart

Answer 22

pericardium (outside), epicardium, myocardium, endocardium (inside)

Question 23

pericardium

Answer 23

protective sack around the heart, has its own lubricant called pericardial fluid, which stops the sack from rubbing against the heart

Question 24

epicardium

Answer 24

outer surface of the heart, like another mucousy sack around the heart

Question 25

myocardium

Answer 25

middle layer of the heart wall, contains contractile fibres, conduction system and blood supply for heart muscle. this is the layer a heart attack happens in

Question 26

endocardium

Answer 26

inner most layer of smooth muscle that lines the valves and inner chambers of the heart

Question 27

properties of a cardiac muscle

Answer 27

rhythmicity, excitability, contractility, conductivity

Question 28

rhythmicity

Answer 28

ability of cardiac muscle to spontaneously depolarise and generate rhythmic impulses, independent of any external electrical signals from the nervous system

Question 29

excitability

Answer 29

ability of cardiac muscle cells to respond to adequate stimuli or electrical impulses by generating an action potential

Question 30

contractility

Answer 30

ability of cardiac muscle cells to contract or shorten and generate force when stimulated by electrical signals

Question 31

conductivity

Answer 31

ability of cardiac muscle cells to transmit cardiac impulses from one cell to another

Question 32

what is the "lub" sound caused by

Answer 32

closing of the AV valves during isovolumetric contraction of the ventricles

Question 33

what is the "dub" sound caused by

Answer 33

closing of the semilunar valves when the pressure in the ventricles falls below the pressure in the arteries

Question 34

equation for cardiac output

Answer 34

CO = heart rate x stroke volume

Question 35

cardiac output

Answer 35

amount of blood pumped by the heart in 1 minute

Question 36

stroke volume

Answer 36

volume of blood pumped by each ventricle in one contraction

Question 37

blood pressure equation

Answer 37

cardiac output x total peripheral resistance (TPR)

Question 38

blood pressure

Answer 38

force that the blood exerts on the walls of blood vessels