WEEK 3 - CARDIO Pt2

Question 1

Have you used objectives to practise essay qs?

Answer 1

yuppp

Question 2

Arterial flows:

Answer 2

away from the heart

Question 3

venous flows:

Answer 3

towards the heart

Question 4

the heart is:

what circuits?

Answer 4

2 pumps and 2 circuits

Systemic circuit and pulmonary circuit

Question 5

what happens when atria contract?

Answer 5

blood is pushed into ventricles. AV valves open, SL closed

Question 6

how do muscles contract?

Answer 6

thick myosin filament and thin filament actin work together through cross bridges to contract the muscles. To do this, calcium levels are increased.

Question 7

what is relaxation (muscular)?

Answer 7

the opposite of contraction - calcium is taken back into storage (still everything is recruited in relaxation)

Question 8

what is diastole?

Answer 8

relaxation - falling pressure

Question 9

what is systole?

Answer 9

contraction - rising pressure

Question 10

what are the 5 steps of the cardiac cycle (basic)?

Answer 10

1. ventricles filling from atria
2. atrial diastole
3. ventricular systole
4. ventricular diastole
5. ventricular diastole, passive filling

Question 11

what happens during the first step of the cardiac cycle?

Answer 11

full heart, ventricles filling with blood, pressure and blood moving from atria to ventricles, AV valves open,

Question 12

what happens during the atrial diastole step?

Answer 12

2nd: atrial relaxation/diastole, AV valves, ventricles in isometric contraction, pressure is building because the blood is trapped in the shut contracting ventricles.

Question 13

how does pressure build in the heart?

Answer 13

when the atria/ventricles contract with all valves closed and full of blood. Systole

Question 14

what happens in the ventricular systole step?

Answer 14

third step: ventricular systole. not alllll blood leaves.

Question 15

what happens in the ventricular diastole step?

Answer 15

fourth step: SL valves shut, AV valves shut, low pressure and relaxed muscles, isovolumetric relaxation phase.

Question 16

what happens in the last step of the cadiac cycle?

Answer 16

AV vales open, passive filling phase, ventricular diastole.

Question 17

systolic pressure is:

Answer 17

the highest pressure that your arteries will be under during the cardiac cycle.

Question 18

what is a/b and what is pulse pressure?

Answer 18

a = systolic pressure
b = diastolic pressure
pulse pressure is a/b

Question 19

which circuit is higher pressure?

Answer 19

systemic

Question 20

explain mean pressure:

Answer 20

the mean pressure of the heart is usually lower than the midpoint because the heart spends more time in relaxation than contraction.

Question 21

what is hypertension?

Answer 21

above average systolic pressure

Question 22

what is hypotension?

Answer 22

diastolic and systolic prsssure are low so the brain won’t be able to get enough oxygen.

Question 23

what is the L/min for pulmonary and systematic circuit?

Answer 23

5L/min

Question 24

what percentage of contractile and electrical cells in the heart? and what do they do?

Answer 24

99% contractile cells: striated

1% electrical cells: low actin/myosin - spreads electrical signal/impulse throughout the heart.

Question 25

what does the sa node do?

Answer 25

passes electrical signal into electrical cells which pass it throughout the heart. As it goes through it is also passed into contractile cells along the way which makes them contract. The SA node tells the heart to beat.

Question 26

what are intercalated discs?

Answer 26

they connect most cells of the heart to each other. they contain gap junctions
they allow flow between adjacent cells through pores

Question 27

what is a gap junction?

Answer 27

pores with low resistance to ions

Question 28

what is a function syncytium?

Answer 28

millons of cardiac cells acting as one because of shared signals through gap junctions.

Question 29

what is the 5 step flow of electrical signal through the heart?

Answer 29

1. SA node aka pacemaker
2. sends electrical energy into left atrium (across interatrial bundle) and then the right atrium (intermodal bundle).
3. AV node pauses the signal until atrium is relaxed
4. AV bundle brings the signal down the inner wall of the heart
5. signal goes up the left and right sides through purkinji fibres)

Question 30

in regards of electrical signals, what is depolarisation?

Answer 30

the signal arriving and telling the cells in that part to contract.

Question 31

in regards to electrical signals, what is repolarisation?

Answer 31

the signal leaving the area and the the cells relaxing.

Question 32

what are the three main parts of the ecg?

Answer 32

p wave - atrial depolarisation
QRS complex - atrial rp and vent dp
t wave - vent rp

Question 33

what is ecg?

Answer 33

electrocardiogram - how we track the signal through the heart. Measures change in the electrical state.

Question 34

What are the sounds of the heart?

Answer 34

lubb - AV valves shutting

dupp - SL valves shutting

Question 35

what are the 6 steps of electrical signal’s impact on parts of the heart?

Answer 35

1. relaxation is ended by excitation spreading from SA node (P Wave)
2. atria are fully dped and contract
3. atria rp and relax, av node sends excitation to ventricles (QRS complex)
4. ventricles fully dped and contract
5. ventricles rp and relax (T Wave)
6. ventricles repolarised and relaxed so heart is back in quiescence

Question 36

what does quiescence mean?

Answer 36

inactivity