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Flashcards in The Heart as a Pump Deck (49):
1

Why does the heart have a double pump

2 ventricles which each supply different circulations

2

What is the systemic circuit

The blood vessels that transport blood to and from all the body tissues

3

What is the pulmonary circuit

Blood vessels that carry blood to and from the lungs

4

What does the right hand side of the heart do

Receives oxygen-poor blood from the body and pumps it to the lungs

5

What does the left hand side of the heart do

Receives oxygen-rich blood from the lungs and pumps it to the body's tissues

6

Where is the heart located

In the mediastinum behind the sternum between the 2nd and 6th ribs and T5-T8

7

Where is the apex of the heart loacted

At the 5th intercostal space in the left mid-clavicular line

8

What is the heart surrounded by

A pericardium

9

What are the chambers of the heart

Right atrium -> right ventricle -> left atrium -> left ventricle

10

Describe the atria and their functions

Superior "receiving chambers", blood from the veins enters the atria

11

What divides the two atria

The interatrial septum

12

Describe the ventricles and their functions

Inferior "pumping chambers", thick muscular walls to increase the force of the pumping action

13

What divides the two ventricles

Interventricular septum

14

Why is the LV thicker than the RV

Because it forces blodo out against more resistance as the systemic circulation is much longer than the pulmonary circulatrion

15

Why are the atria thin

Because ventricular filling is done by gravity, requiring little atrial effort

16

What are the 3 tricsupid valves

Triscupid, pulmonary, aortic

17

What is the bicuspid valve

Mitral valve

18

What valve is between the RA -> RV

Tricuspid valve

19

What valve is between the LA -> LV

Mitral valve

20

What valve is between the RV-> pulmonary artery

Pulmonary valve

21

What valve is between LV -> aorta

Aortic valve

22

What are the atria -> ventricles valves called

Atrioventricular valves

23

What are the ventricles -> arteries valves called

Semilunar valves

24

Describe chordae tendineae in relation to their function

Have low tension when valves are open but high tension when valves are shut in order to ensure valves remain closed

25

Define heart beat

A single sequence of atrial contraction followed by ventricular contraction

26

What is normal heart rate

60-100 bpm

27

What is bradycardia

Slow heartbeat

28

What is tachycardia

Fast heartbeat

29

What are the two periods that make up the cardiac cycle

Diastole and systole

30

What is diastole

A period of relaxation where the heart fills with blood

31

What is systole

A period of contraction

32

What sounds does that heart make

Lub Dub

33

What is S1

"Lub"- closing of the atrioventricular valves at the start of ventricular systole

34

What is S2

"Dub"- closing of the semilunar valves at the end of ventricular systole

35

What is the resting HR of athletes

40-60 bmp

36

What is the sinoatrial node

The heart's pacemaker

37

Describe the stages involved in a heartbeat

  1. From SA node excitation is spread across both atria via connective tissue
  2. Passes to atrioventricular node
  3. Conduction to AV node is slow and excitation to ventricles is delayed (0.1s), ensures filling of ventricles with blood
  4. Conduction through rest of heart is rapid- via bundle of His (atrioventricular bundle)
  5. Divides to supply LV RV via purkinjie fibres Purkinjie fibres spread excitation to ventricular myocytes (fast)
  6. Ventricles excite at the same time

38

What does an EGC do

Records the heart;s electrical activity. Excitation thorugh the heart is generated by small electrical currents in the ECF which is detected by electrodes on teh surface of the body which record small voltage changes

39

Describe an ECG

P wave- depolarisation of the atria (prior to contraction) triggers atria to contract.

QRS complex- ventricular depolarisation, triggers ventricles to contract (includes atrial repolarisation).

T wave- repolarisation of the ventricles

40

What factors affect the heart rate/ rhythm

Autonomic nervous system, Hormones, Activity, Pathology,

41

Which hormones affect heart rate/ rhythm

Adrenaline, noradrenaline, thyroid hormones

42

How does activity affect heart rate/ rhythm

Rest, exercise, stress etc.

43

How does coronary heart disease occur

In the coronary arteries. Atherosclerosis due to cholesterol and WBC's result in coronary vessels becoming heard and stiff

44

What is angina

A result of 75% occlusion of at least one coronary artery, so lack of oxygen to the heart (hypoxic) when the heart needs to work harder during exercise. Can be stable/ unstable

45

How does a heart attack occur

Clotting factors and plaque result in a thrombus/ blood clot. The clot gets so big it blocks off the blood vessel or breaks off (embolisation). If embolisation occurs the clot floats downstream and blocks off a smaller vessel resulting in a heart attack.

46

What is requires within 20 minutes after a heart attack

Medication or intervention otherwise the heart muscle will die without oxygen

47

What is stroke volume

The amount of blood pumped by the LV of the heart in one contraction

48

What is cardiac output

It is a measure of the amount of blood pumped out of the heart in one minute

49

What does cardiac output equal?

CO= SV x HR cardiac output = stroke volume x heart rate