CVS

Question 1

fibrous pericardium

Answer 1

tough, inelastic around heart

Question 2

serous pericardium

Answer 2

parietal/visceral

Question 3

pericardial space

Answer 3

has serous fluid for lubrication

Question 4

heart wall

Answer 4

endocardium → endothelial tissue covering projections

myocardium → contractile muscle layer

epicardium → visceral layer of serous pericardium

Question 5

BS of heart tissues

Answer 5

opening of coronary A → cusps of aortic semilunar valve

coronary sinus (drains into RA) → drains the coronary V

Question 6

cardiac conduction system

Answer 6

ensures correct sequence, rhythm, coordination

Question 7

SA node

Answer 7

60-100bpm

• found in RA
• pacemaker
• initiates impulse without stimulation from NS
• spreads to mid/pos internodal tract ( found on floor of RA → delays impulse from A to V )

Question 8

AV node

Answer 8

40-60bpm

- can take over as pacemaker if SA compromised

Question 9

route of electrical impulse

Answer 9

SA → AV → bundle of His → R/L bundle branch → respective purkinje fibres (20-40bpm) → ventricular contraction

Question 10

ECG

Answer 10

P - atria depol
PR interval - AV node delay
QRS - v depol
T - v repol

Question 11

ventricular tachycardia

Answer 11

rapid ventricle contractions

Question 12

ventricular fibrillations

Answer 12

irregular, asynchronous contractions

- no pulse (no time to fill → no blood pumped)

Question 13

asystole

Answer 13

no electrical activity (defib works to reset nodes)

Question 14

ageing

Answer 14

• by 75 → 90% pacemaker + ~50% bundle of his are lost → leads to arrhythmias
• decrease baroreceptor response → orthostatic hypo
• decrease A wall elasticity/thickening + stiff valve → murmurs/regurgitations/increase BP
• decrease response to adrenergic stimulation

Question 15

what is lipofuscin

Answer 15

residue from lipolysis

• an increase lipofuscin → sign of ageing
• may also leads to atherosclerosis