cardiovascular system: cardiac structure and function- week 5

Question 1

how does the heart get its blood supply ?

Answer 1

the coronary arteries

Question 2

what is myocardial infarction?

Answer 2

blockage in the coronary blood flow which causes cell damage

exercise training protects against heart damage during MI

Question 3

what is the epicardium ? (3)

Answer 3

the outer layer of the heart

function:lubricative outer covering

membrane containing capillaries and nerve fibres

Question 4

what is the myocardium? (3)

Answer 4

middle layer of the heart

function: provides muscular contractions ejecting blood from chambers

connective tissues with capillaries and nerve fibres

Question 5

what is the endocardium ? (3)

Answer 5

inner layer of the heart

function: protective lining of chambers and valves

thick subendothelial layer of elastic and collagenous fibres

Question 6

how does branching of muscle fibres in the heart benefit it ?

Answer 6

allows simultaneous contraction

Question 7

what is the SA node?(3)

Answer 7

sinoatrial node

pacemaker

imitates depolarisation - generates AP

Question 8

what is the AV node? (3)

Answer 8

atrioventricular node

passes depolarisation to ventricles

causes brief delay of Ap to allow ventricle filling

Question 9

what are bundle fibres ?

Answer 9

connect atria to left and right ventricle

Question 10

what are purkinje fibres ?

Answer 10

spread depolarisation through ventricles

Question 11

what is meant by automaticity ?

Answer 11

heart can generate its own AP

Question 12

what is an ECG and what does it do?

Answer 12

electrocardiogram

records heart electrical activity

Question 13

what is the P wave in an ECG?

Answer 13

shows atrial depolarisation

Question 14

what is the QRS complex in an ECG?

Answer 14

shows ventricular depolarisation and atrial repolarisation

Question 15

what is the T wave in an ECG?

Answer 15

shows ventricular repolarisation

Question 16

what is meant by EDV?

Answer 16

end diastolic volume

max volume of blood in the ventricle

Question 17

what is systolic volume ?

Answer 17

blood left in the heart post contraction

Question 18

what is stroke volume ?

Answer 18

amount of blood ejected from the left ventricle per beat

Question 19

what is atherosclerosis ?(3)

Answer 19

can be found through ECG

plaque narrows coronary arteries

reduces blood flow to myocardium

Question 20

how is regular exercise cardioprotective ?

Answer 20

more pathways for coronary arteries which can increase O2 supply to myocardium

increased survival from heart attack

Question 21

how does exercise reduce the amount of myocardial damage from heart attack ?

Answer 21

improves heart antioxidant capacity - fights free radicals

improved function of ATP sensitive potassium channels

Question 22

how does the parasympathetic nervous system affect HR?

Answer 22

release of acetylcholine
- increasing K+ , decreasing AP + HR

slows HR by inhibiting the SA and Av node

Question 23

how does the sympathetic NS affect HR?

Answer 23

release of norepinephrine
- increases Ca+ and increases HR

increases hR by stimulating the SA and AV node

Question 24

what do exercise stress tests examine ?

Answer 24

can detect restricted coronary flow due to coronary artery disease

if they get blocked there’s no coming back due to no blood supply to the heart

Question 25

what is meant by chronotropic ?

Answer 25

HR increases

Question 26

what is meant by inotropic ?

Answer 26

contractility increases

Question 27

what is the main metabolic vasodilator? (by product. of atp)

Answer 27

adenosine

by product of ATP

Question 28

where/when does more coronary flow take place?

Answer 28

diastole 80%