CV3

Question 1

what conducts action potentials into the left atrium

Answer 1

Bachmanns bundle

Question 2

what is the speed of atrial conduction

Answer 2

it is relatively slow (80ms-100ms)

Question 3

where is the important delay during conduction in the heart

Answer 3

conduction slows down during the AV node to allow blood from atria to empty into the ventricles

Question 4

what does slow conduction through the AV node allow

Answer 4

allows for completion of ventricle filling

Question 5

how does ventricular contraction occur (direction)

Answer 5

from the bottom to the top

Question 6

what is the speed of ventricle contraction

Answer 6

more rapid than atria contraction (60ms-100ms)

Question 7

what is the hearts muscle arrangement to ensure blood is squeezed upwards

Answer 7

spiral arrangement

Question 8

what is a complete conduction block

Answer 8

its caused by damage in conduction pathway

Question 9

what does the electrocardiogram represent

Answer 9

the summed electrical activity of all cells recorded from the surface of the body

Question 10

what does electrocardiogram record

Answer 10

electrical changes in the extracellular fluid

Question 11

is the extracellular fluid a good conductor of electrical energy

Answer 11

yes

Question 12

what is einthovens triangle

Answer 12

three leads (pair of electrodes). 3 separate recordings that give their own readings

Question 13

what happens if the electrical activity of the heart is moving towards the positive electrode

Answer 13

an upward reflection would be recorded

Question 14

if electrical energy is moving away from the positive electrode

Answer 14

a downward deflection is recorded

Question 15

if the electrical energy is moving perpendicularly to the axis of the electrodes, what is the deflection

Answer 15

there is no deflection

Question 16

what do leads measure (3)

Answer 16

current
how much its moving
and what direction its moving in

Question 17

what are ECG’s

Answer 17

combination of waves and segments

Question 18

what is the P wave

Answer 18

atrial depolarization

Question 19

what is the P-R segment

Answer 19

conduction through AV node and AV bundle

Question 20

what is the QRS complex

Answer 20

ventricular depolarization

Question 21

what is the T wave

Answer 21

ventricular repolarization (Ca channels close)

Question 22

what happens at the ST segment

Answer 22

ventricle contract and pump blood

Question 23

what does the Q wave represent

Answer 23

the depolarization of the intraventicular septum

Question 24

what does the R section represent

Answer 24

the depolarization of most of the ventricular walls

Question 25

whats considered the plateau phase in cardiac cycle

Answer 25

S-T segment (ventricular contraction)

Question 26

what does the S phase represent

Answer 26

last phase of ventricular depolarization at the base of the heart

Question 27

what is the heart rate on an ECG

Answer 27

P wave - P wave

Question 28

which wave is often very small and not seen

Answer 28

Q

Question 29

what is arrhythmia

Answer 29

abnormal rhythm

Question 30

what are premature ventricular contractions? what is it perceived as?

Answer 30

purkinje fibres randomly kicking in as a pacemaker perceived as a skipped beat or palpitation

Question 31

what are the 2 arrhythmia examples he lists

Answer 31

premature ventricular contractions Long QT syndrome

Question 32

what is long QT syndrome

Answer 32

delayed repolarization of the ventricles due to a mutation

Question 33

what is the cardia cycle

Answer 33

one complete contraction and relaxation

Question 34

what are the 2 primary phases of cardiac cycle

Answer 34

systole diastole

Question 35

what is systole

Answer 35

the time when the cardiac muscle contracts

Question 36

what is diastole

Answer 36

the time in which cardiac muscle relaxes

Question 37

why are diastole and systole discussed separately ?

Answer 37

the atria and ventral do not contract and relax at the same time

Question 38

whats the order of the cardiac cycle

Answer 38

late diastole atrial systole EDV isovolumetric ventricular contraction ventricular ejection ESV isovolumetric ventricular relaxation

Question 39

what happens in late diastole

Answer 39

ventricles are filling passively

Question 40

what happens in atrial systole

Answer 40

atrial contraction (just a little more blood goes into the ventricle)

Question 41

what is EDV

Answer 41

the maximum amount of blood in the ventricles after ventricular diastole

Question 42

what happens during isovolumetric ventricular contraction

Answer 42

ventrial starts contracting but no change in volume yet AV valve close first heart sound

Question 43

what happens during ventricular ejection

Answer 43

blood flows into major artery

Question 44

what is ESV

Answer 44

the amount of blood left in the ventricle after ventricular systole

Question 45

what happens during isovolumetric ventricular relaxation

Answer 45

ventricles are relaxing semilunar valve close second heart sound

Question 46

what causes the heart sounds

Answer 46

first is vibrations of the ventricular walls second is the vibrations of the large arteries

Question 47

what does the a-a' segment represent

Answer 47

late diastole

Question 48

what does the a'-b segment represent

Answer 48

atrial systole

Question 49

what does the b-c segment represent

Answer 49

isovolumetric contraction

Question 50

what does the c-d segment represent

Answer 50

ventricular ejection

Question 51

what does the d-a segment represent

Answer 51

isovolumetric relaxation

Question 52

whats on the x axis of the pressure loop for cardiac cycle

Answer 52

left ventricular volume

Question 53

whats on the y axis of the pressure loop for cardiac cycle

Answer 53

left ventricular pressure