Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Cardiovascular Systems > Heart Rhythms > Flashcards

Heart Rhythms Flashcards

1
Q

Cardiac Muscles are myogenic - what does this mean?

A

generating own action potential spontaneously

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where is the action potential for spontaneous contraction in cardiac muscles come from?

A

this is done by the sino-atrial node - the pacemaker

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does SA node action potential cause contraction of lots of muscle cells?

A

Action potentials come from SA node and conduct from cell to cell by intercalated discs which have a gap junctions

This causes contraction as it goes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How do Skeletal muscles contract?

A

Is neurogenic which means it needs a nerve impulse to initiate contraction this can come from the neuromuscular junction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is sinus rhythm caused by?

A

Sinus rhythm is caused by the SA node

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How does the SA node make an action potential in terms of repolarisation and depolarisation?

A

Calcium influx to cell causing depolarisation and potassium efflux from cell causes repolarisation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do cardiac muscle cells join and what type of junctions allow signals to pass between them?

A

Cardiac muscles cells join in rows to wrap around heart - the gap junctions allow signal to pass between cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does the SA node signal travel around the heart and where does it pause? What fibres contract vesicles?

A

Signal goes from SA node to atria which allows the atria to contract. The signal is paused at AV-node which leads to a delay in ventricle contraction. The AV-node then activates the purkinje fibres which contract the ventricles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Why does the action potential plateau in the ventricles?

A

the ventricles have more muscles and need more calcium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Phase order - 4,0,2,3

What is Phase 4 of the action potential for the heart after receiving a cardiac output?

A

When you get a cardiac output Na moves into the cell slowly depolarises it (phase 4).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does Electrocardiogram measure?

A

Measures automatically - HR, rhythmicity, pacemake
Measure conductivity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does the ECG work?

A

Leads placed on skin and measures electrical signals between them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the P wave of the ECG monitoring?

A

SA node action potential and depolarisation of the atria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Arrhythmias: abnormal impulse generation: What is bradycardia and Tachycardia?

A

Bradycardia - slow rate
Tachycardia - fast rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Arrhythmias - Abnormal impulse conduction: What does a heart block cause and how if this overcome?

A

blockage of action potential at some point in pathway, may lead to pacemaker activity below SA node

Need to shock them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the steps of the cardiac cycle?

A

Ventricles relax leading to pressure difference and blood flow from the atria to the ventricle.

Ventricles contract but the valves haven’t opened yet due to incorrect pressure to get the correct pressure.

When correct pressure generated blood released from ventricles

Relax again and blood flows into the atria but there isnt enough pressure to put the blood in the ventricle

17
Q

Where do heart sounds come from?

A

heart sounds come from valves closing and opening

18
Q

What is stroke volume

A

The volume of blood pumped out by each ventricle after one contraction (is more when you excersise)
Determined by venous return and heart contractility

19
Q

What is cardiac output?

A

Amount of blood pumped out by each side of the heart in 1 minute
Determined by heart rate x stroke volume

20
Q

What is ejection fraction?

A

percentage of the blood volume that is pumped out by the ventricle
Determines by contractilty (can increase during excersise (80%) and dereases (20%) in heart failure

21
Q

What is the main nerve which goes to the heart?

A

The vagus nerve is the main nerve to the heart.

22
Q

What does the Sympthetic nervous system do to the heart?

A

Increase heart rate, increase rate of conduction, increase force of contraction and dilates coronary arteries

23
Q

What does the parasympathetic nervous system do to the heart?

A

decreases the heart rate and reduces force of contraction

24
Q

What is the average normal resting heart rate?

A

70bp

25
Q

What does the parasympathetic nervous system release into the heart?

A

release ACh into heart

26
Q

What does the sympathetic nervous system release into the heart and what does it act on?

A

NA to act of Beta 1 receptors (muscarinic receptors).

27
Q

What does the autonomic nervous system do to the heart?

A

modify the rate of activation of the SA node and the contraction force

28
Q

Phase order - 4,0 - What happens in phase 0 of the action potential?

A

When NA reaches threshold it causes a sodium channels to open leading to massive increase of NA into cell. This is rapid.

29
Q

Phase order - 4,0,2,3 - What is phase 2 of the action potential graph

A

This rapid increase of NA into the cell causes repolarisation due to K leak out. This creates a plateau (phase 2) and calcium can enter.

30
Q

After phase 2 of the action potential calcium enters the cell. What does this cause?

A

Ca entering cells cause intracellular stores to open (sarcolasmic reticulum) - this causes contraction.

31
Q

Phase order - 4,0,2,3 - What is phase 3 in the action potential? (takens place after repolarisation starts)

A

Further repolarisation as k leaves cell.

32
Q

What happens after all the phases of action potential has finished and what does it lead to?

A

The heart still contracts due to high calcium levels leading to Na and K not being in the correct place for a action potential. This leads to the refractorys period where no action potential can be generated

33
Q

How does the cell get sodium and potassium into the correct place to start the action potential again?

A

Na needs to be removed and K added to cell - does this by Na/K pump. (3 na out, 2k in).

34
Q

How does calcium leave the cell to stop contraction?

A

The NA which is now in the cell participates in the NA/Ca exchanger which exchanges Na for the Ca in the cell.
Ca can also be moved back into its storage area

35
Q

What does an ECG reveal?

A

Revelas hypertrophy - cardiac cells get bigger due to hypertension
Reveal ischemic damages -e.g heart attach

36
Q

What does the QRS complex show on an ECG?

A

QRS complex - depolarisation of ventricles - movement of signal through the muscles.

37
Q

What does the T wave show on an ECG?

A

repolarisation

Cardiovascular Systems (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions