Heart Lecture 2 Flashcards

1
Q

Heart muscle contains numerous what for energy?

A

Mitochondria

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2
Q

Alternating bands of light and dark

A

striations

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3
Q

Heart controls itself so it is

A

involuntary

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4
Q

What hold fibres together

A

Intercalated discs

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5
Q

Tight cell junction for stability

A

Desmosome

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6
Q

Tube connecting cells, transmit substances, conduct electricity

A

Gap junctions

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7
Q

Self-excitable, beats itself

A

Autorhythmicity

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8
Q

Self-excitable fibres

A

Autorhythmic fibres

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9
Q

Network of specialized cells that cause contraction

A

Conducting system

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10
Q

Conducting system components order 1-5

A
  1. SA node
  2. Internodal pathways
  3. AV node
  4. AV bundle and branches
  5. Purkinje fibres
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11
Q

Cells that set pace of heart. SA node

A

Pacemaker cells

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12
Q

Pacemaker of heart, 60-100 bpm

A

Sinoatrial node (SA node)

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13
Q

Distributes signal to RA and LA

A

Internodal pathways

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14
Q

If SA node fails, can take over pacing. Slower. B/w atria and ventricles

A

Atrioventricular node

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15
Q

Transmit signal from AV node

A

AV bundle

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16
Q

Transmit signal to apex

A

Bundle branches

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17
Q

Conduction goes back up from Apex. Radiate upward

A

Purkinje fibres

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18
Q

Fires SA node if damaged or diseased

A

Artificial pacemaker

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19
Q

Purpose of cardiac muscle longer contraction

A

Avoid tetanic contraction (hold beat too long)

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20
Q

3 stages of cardiac muscle action potential

A
  1. rapid depolarization
  2. plateau (key)
  3. Repolarization
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21
Q

Contraction stages: sodium in, voltage-gated channels

A

Rapid depolarization

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22
Q

Contraction stages: membrane potential stays near 0 mV

A

Plateau

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23
Q

Slow calcium channels

A

slow to open/close more calcium entering

24
Q

Contraction stages: slow calcium channels close, potassium out

A

Repolarization

25
Q

Cardiac muscle energy type

A

Aerobic cellular respiration

26
Q

Cardiac fuels for power

A

Fat, glucose

27
Q

When heart uses lactic acid

A

During exercise

28
Q

Creatine phosphate blood test used for

A

presence in bloodstream - heart attack

29
Q

Recording of heart electrical currents

A

ECG

30
Q

ECG reading: Atria firing off - atrial polarization

A

P wave

31
Q

ECG: ventricular depolarization

A

QRS complex

32
Q

ECG: Ventricular repolarization

A

T wave

33
Q

Atria repolarizes when?

A

During QRS complex

34
Q

ECG: Time difference b/w P and Q

A

P-Q interval

35
Q

How much time in P-Q interval could mean damage

A

> 200msec

36
Q

ECG: Start of QRS complex to end of T-wave

A

Q-T interval

37
Q

Q-T interval too long could mean

A

Myocardial damage, ischemia

38
Q

ECG: End of QRS to beginning T wave

A

S-T segment

39
Q

S-T segment represents

A

End of depolarization, beginning of repolarization

40
Q

Abnormal heart beat called

A

arrhythmia

41
Q

Fast heart rate >100bpm

A

Tachycardia

42
Q

Slow heart rate <60bpm

A

Bradycardia

43
Q

Surprise atrial contraction

A

Premature atrial contraction

44
Q

atria keep contracting early causing raised heart rate

A

Paroxymal atria tachycardia

45
Q

Atria fluttering, not enough blood pump, ventricles working, mostly alright

A

Atrial Fibrillation

46
Q

Which is worse? ventricular or atrial issues?

A

Ventricular

47
Q

Ventricle prematurely contracts

A

Premature ventricular contractions

48
Q

Ectopic pacemaker

A

Responsible for premature ventricular contractions

49
Q

Cardiac arrest. Blood not pumping well, bad contractions

A

Ventricular fibulation

50
Q

Cardiac cycle: contraction, blood leaves chamber

A

Systole

51
Q

Cardiac cycle: Relax, chamber refills

A

Diastole

52
Q

Sequence of contractions:

A
  1. Atrial Systole
  2. Ventricular systole
53
Q

Atrial systole

A

Atria contract, push blood in ventricles

54
Q

Ventricular systole

A

Ventricles contract, push blood into circuits (lungs or body)

55
Q

typical Cardiac cycles lasts how long

A

800msec (0.8 sec)