Intro to heart

Question 1

Cardiovascular system includes

Answer 1

Heart & blood vessels

Question 2

Heart main function:

Answer 2

Pump O2 blood into systemic circulation

Pump de O2 blood to pulmonary circulation

Question 3

Systole

Answer 3

Contraction

Question 4

Diastole

Answer 4

Relaxation

Question 5

Arterial system

Answer 5

Oxygenated blood

Question 6

Venous system

Answer 6

deoxygenated blood

Question 7

Systemic circulation

Answer 7

Arterial & Venous

Blood pumped from left ventricle around body and into right ventricle

Question 8

Pulmonary circulation

Answer 8

blood pumped from right ventricle to pulmonary artery to lungs

Question 9

What size are arterioles?

Answer 9

300-10um

Question 10

What size are capillaries?

Answer 10

8-10um

Question 11

why is there a parallel arrangement of capillary beds?

Answer 11

Ensures all tissues get arterial blood

Enables redistribution of blood flow between capillary beds

Question 12

Variable resistance

Answer 12

placed at precapillary part of circulation

enables redistribution of blood flow between capillary beds

Question 13

Function of Arteries

Answer 13

to distribute blood from heart to tissues

dampens pulse pressure

Question 14

Arterioles

Answer 14

Offer max resistance to flow in systemic circulation

Control flow of blood to different tissues

Question 15

Pressure drop

Answer 15

As blood flows from arteries to veins the BP decreases

Greatest drop in arterioles and greater in systemic compared to pulmonary circuit

Question 16

Function of capillaries

Answer 16

Site of gaseous exchange

Nutrient and waste product exchange

Question 17

Venues and Veins

Answer 17

Collect drainage from capillaries for return back to heart

Contains valves to prevent backflow of blood

Question 18

How much does the heart weigh?

Answer 18

300g

Question 19

Heart chambers

Answer 19

4 chambers

Atria & ventricles

Question 20

Why is left ventricle wall thicker than right?

Answer 20

bc it has to pump blood all around the body whereas the right ventricle just pumps to heart

Question 21

What do heart valves do?

Answer 21

Aid unidirectional flow of blood

Question 22

Blood flow through Right side of heart

Answer 22

Blood flows through veins into right atrium.
Through Tricuspid valve to fill Right Ventricle.
RV contracts and blood flows through pulmonary valve to lungs.

Question 23

Blood flow through left side of heart

Answer 23

Blood comes from pulmonary vein through left atrium through the mitral (bicuspid) valve into the left ventricle
LV contracts and blood flows through aortic valve to aorta to the body.

Question 24

What is myocardium?

Answer 24

Cardiac muscle

Question 25

Conduction of AP through heart

Answer 25

Sino Atrial node (SAN) generates electrical impulse
AP propagates across atria and excites muscle
AP reaches AV node (only electrical connection between atria and ventricles)
AP is delayed at AV node to ensure atria contract before ventricles
AP propagates down Purkinje fibres
Rest of ventricular myocardium activated by cell to cell spread of impulse through gap junctions

Question 26

What is an ECG?

Answer 26

Electrocardiogram is a record of overall spread of electrical activity through heart

Question 27

ECG recording represents

Answer 27

Recording of overall spread of activity throughout heart during depolarisation and repolarisation

Question 28

P wave

Answer 28

Atrial depolarisation

Delayed at AV node

Question 29

Impulse originates:

Answer 29

at SAN

Question 30

QRS complex

Answer 30

when ventricles invaded by impulse

Question 31

ST segment

Answer 31

when ventricles are uniformly depolarised

Question 32

T wave

Answer 32

Ventricles repolarise

Question 33

P-R interval

Answer 33

0.12-0.2 seconds

Question 34

QRS width

Answer 34

0.08-0.12 seconds

Question 35

QT interval

Answer 35

0.35-0.43 seconds

Question 36

How is heart rate measured?

Answer 36

PR interval can be used