The Heart as a Pump

Question 1

Why does the heart have a double pump

Answer 1

2 ventricles which each supply different circulations

Question 2

What is the systemic circuit

Answer 2

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

Question 3

What is the pulmonary circuit

Answer 3

Blood vessels that carry blood to and from the lungs

Question 4

What does the right hand side of the heart do

Answer 4

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

Question 5

What does the left hand side of the heart do

Answer 5

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

Question 6

Where is the heart located

Answer 6

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

Question 7

Where is the apex of the heart loacted

Answer 7

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

Question 8

What is the heart surrounded by

Answer 8

A pericardium

Question 9

What are the chambers of the heart

Answer 9

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

Question 10

Describe the atria and their functions

Answer 10

Superior “receiving chambers”, blood from the veins enters the atria

Question 11

What divides the two atria

Answer 11

The interatrial septum

Question 12

Describe the ventricles and their functions

Answer 12

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

Question 13

What divides the two ventricles

Answer 13

Interventricular septum

Question 14

Why is the LV thicker than the RV

Answer 14

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

Question 15

Why are the atria thin

Answer 15

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

Question 16

What are the 3 tricsupid valves

Answer 16

Triscupid, pulmonary, aortic

Question 17

What is the bicuspid valve

Answer 17

Mitral valve

Question 18

What valve is between the RA -> RV

Answer 18

Tricuspid valve

Question 19

What valve is between the LA -> LV

Answer 19

Mitral valve

Question 20

What valve is between the RV-> pulmonary artery

Answer 20

Pulmonary valve

Question 21

What valve is between LV -> aorta

Answer 21

Aortic valve

Question 22

What are the atria -> ventricles valves called

Answer 22

Atrioventricular valves

Question 23

What are the ventricles -> arteries valves called

Answer 23

Semilunar valves

Question 24

Describe chordae tendineae in relation to their function

Answer 24

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

Question 25

Define heart beat

Answer 25

A single sequence of atrial contraction followed by ventricular contraction

Question 26

What is normal heart rate

Answer 26

60-100 bpm

Question 27

What is bradycardia

Answer 27

Slow heartbeat

Question 28

What is tachycardia

Answer 28

Fast heartbeat

Question 29

What are the two periods that make up the cardiac cycle

Answer 29

Diastole and systole

Question 30

What is diastole

Answer 30

A period of relaxation where the heart fills with blood

Question 31

What is systole

Answer 31

A period of contraction

Question 32

What sounds does that heart make

Answer 32

Lub Dub

Question 33

What is S1

Answer 33

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

Question 34

What is S2

Answer 34

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

Question 35

What is the resting HR of athletes

Answer 35

40-60 bmp

Question 36

What is the sinoatrial node

Answer 36

The heart's pacemaker

Question 37

Describe the stages involved in a heartbeat

Answer 37

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

Question 38

What does an EGC do

Answer 38

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

Question 39

Describe an ECG

Answer 39

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

Question 40

What factors affect the heart rate/ rhythm

Answer 40

Autonomic nervous system, Hormones, Activity, Pathology,

Question 41

Which hormones affect heart rate/ rhythm

Answer 41

Adrenaline, noradrenaline, thyroid hormones

Question 42

How does activity affect heart rate/ rhythm

Answer 42

Rest, exercise, stress etc.

Question 43

How does coronary heart disease occur

Answer 43

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

Question 44

What is angina

Answer 44

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

Question 45

How does a heart attack occur

Answer 45

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.

Question 46

What is requires within 20 minutes after a heart attack

Answer 46

Medication or intervention otherwise the heart muscle will die without oxygen

Question 47

What is stroke volume

Answer 47

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

Question 48

What is cardiac output

Answer 48

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

Question 49

What does cardiac output equal?

Answer 49

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