Brainscape's Knowledge GenomeTM

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


See full index

Bio 7: Run For Your Life > The Heart > Flashcards

The Heart Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What type of muscle is the heart muscle?

A

Myogenic

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

Explain what myogenic means

A
  • Contracts without nervous stimulation

- Even if removed from nervous system it still beats

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

What causes heart muscle contraction? 4

A
  • Electrical charge changes in cardiac muscle
  • As polarity changes spread from cell to cell
  • Stimulate contraction of cardiac muscle
  • Pattern of contractions co-ordinate regular heartbeat
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How is a cell polarised?

A

If it is slightly positive on the outside

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

How is a cell depolarised?

A

If it is slightly negative on the outside

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

What is the sinoatrial node [SAN]? 2

A
  • Small group of specialised muscle fibres known as the pacemaker
  • Set rhythm of the heartbeat by sending regular waves of electrical activity to atrial walls
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Explain the electrical activity of the heart - 6

A
  • SAN initiates depolarisation
  • passes through wall of atria
  • causes atrial systole
  • AVN conducts to ventricles
  • conducts to Purkyne fibres - bundle of His
  • ventricular systole follows from apex
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Where is the AVN located?

A

Right and left ventricle walls

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

What is the AVN?

A

Group of large specialised muscle fibres conducing impulses rapidly to apex of ventricles

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

Where is the SAN located?

A

Right atrium wall under the superior vena cava opening

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

What is an ECG?

A

Graphic record of electrical activity in the cardiac cycle

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

How is an ECG formed?

A
  • The heart depolarises - loses electrical charge - when it contracts
  • The heart polarises - regains electrical charge - when it relaxes
  • Changes in polarisation cause small electrical currents to be detected on skin’s surface by chest electrodes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What are the 4 parts of an ECG from order of left to right? 4

A
  • P wave
  • PR interval
  • QRS complex
  • T wave
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does the P wave indicate?

A

Contraction and depolarisation of atria in atrial systole

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

What does the PR interval indicate?

A

Time for conduction of impules from SAN across atria to ventricles through AVN

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

Why is there a time delay between the conduction of impulses from the atria to the ventricles?

A

Ensures ventricles contract after atria have emptied

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What does the QRS complex indicate?

A

Contraction/depolarisation of ventricles in ventricular systole

18
Q

What does the T wave indicate?

A

The repolarisation/relaxation of the ventricles in cardiac diastole

19
Q

What is bradycardia?

A

Heart rate of less than 60bpm

20
Q

What condition is indicated by a heart rate of less than 60bpm?

A

Bradycardia

21
Q

What is tachycardia?

A

Heart rate of more than 100bpm

22
Q

What condition is indicated by a heart rate of more than 100pm?

A

Tachycardia

23
Q

What can cause bradycardia? 4

A
  • Athlete at rest
  • Hypothermia
  • Heart disease
  • Drugs
24
Q

What can cause tachycardia? 4

A
  • Anxiety
  • Heart disease
  • Exercise
  • Anemia
25
Q

What does a low QRS complex indicate? 2

A
  • Muscle damage

- AVN not conducting impulses to ventricles properly

26
Q

What does an early/odd P wave indicate? 2

A
  • Ecoptic heartbeat

- Early contraction of atria

27
Q

What is fibrillation?

A

Ventricles and atria completely lose rhythm and eventually stop contracting completely - could lead to death

28
Q

Label an ECG diagram

A

SEE NOTES

29
Q

Define cardiac output

A

Total volume of blood pumped out of ventricle every minute

30
Q

Give the formula for calculating cardiac output

A

cardiac output : heart rate x stroke volume

31
Q

What are the units of cardiac output?

A

cm3min-1

32
Q

What are the units of stroke volume?

A

cm3

33
Q

Define stroke volume

A

The volume of blood pumped out by a ventricle each time it contracts

34
Q

How does increased exercise increase stroke volume and cardiac output? 4

A
  • During exercise there is a greater venous return: more blood returning to heart because more respiration
  • Muscle stretched to greater extent
  • Comes into contact with greater force
  • More blood is expelled
35
Q

What is residual blood?

A

When body is at rest ventricles don’t completely empty with each beat

36
Q

How does exercise affect residual blood?

A

Stronger contractions eject more residual blood from the heart

37
Q

What 2 things influence heart rate?

A
  • Heart size

- Amount of training

38
Q

How does heart size lower heart rate? 2

A
  • Increased stroke volume with each beat

- So need to beat less frequently to circulate same volume of blood around the body

39
Q

The larger the heart, the x the resting heart rate

A

Lower

40
Q

What 2 things affect heart size?

A
  • Genetics

- Body size

41
Q

How does training reduce heart rate? 4

A
  • Increase in heart size
  • Due to thickening of heart muscle walls
  • Increased stroke volume with each beat
  • So need to beat less frequently to circulate same volume of blood around the body
42
Q

How is heart rate increased? 4

A
  • increased impulses to SAN
  • via sympathetic nervous system
  • stimulates more frequent depolarisation in SAN
  • increases heart rate

Bio 7: Run For Your Life (11 decks)

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