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1.  Draw the human heart and the main blood
vessels in/out of the heart.
 Label the following on your diagram:
 4 chambers
 4 valves
 All blood vessels going into/out of heart
 Using a blue pencil, indicate oxygen-poor blood
flow
 Using a red pencil, indicate oxygen-rich blood
flow

3.  Cardiac muscle cells can contract spontaneously and
independently
 Regulation of heart activity:
1. Autonomic nervous system
▪ Epinephrine, thyroxine: ↑ heart rate
▪ Low Ca2+
levels: ↓ heart rate
1. Intrinsic conduction system
▪ Built into heart tissue & sets basic rhythm
▪ Pacemaker = Sinoatrial (SA) NodeSinoatrial (SA) Node

4. Sequence of action:
1. Sinoatrial (SA) node – right atrium
▪ Generates impulses  Starts each heartbeat
1. Atrioventricular (AV) node – between atria &
ventricles
▪ Atria contract
1. Bundle of His (or AV bundle)
2. Bundle branches – interventricular septum
3. Purkinje fibers – spread within ventricle walls
▪ Ventricles contract

7.  Records the electrical activity of the heart
 Electrocardiograph: graphic record of heart activity

8.  P wave: atria contact
 QRS complex: ventricles
contract
 T wave: ventricles relax

12.  Cardiac cycleCardiac cycle = events of one heartbeat
 SystoleSystole: contraction of ventricles
 DiastoleDiastole: relaxation of ventricles
 Cardiac Output Animation

13.  ““Lub”:Lub”: closing of AV
valves
 ““Dub”:Dub”: semilunar
valves close at end of
systole

14.  Angina pectoris: heart muscle
deprived of O2,crushing chest
pain
 Myocardial infarction (Heart
Attack): prolonged angina,
heart cells may die

15.  Ischemia: Lack of adequate blood supply to heart
 Fibrillation: uncoordinated shuddering of heart
muscle, useless pump
 Major cause of death from heart attacks

16.  Damage to SA node  slower heart rate
 Install artificial pacemaker
 Damage to AV node  Heart block: ventricles beat
at own rate (slower or not at all)
 Tachycardia: rapid heart rate (>100 beats/min)
 Bradycardia: very slow heart rate (<60 beats/min)
 Heart murmur: abnormal or unusual heart sounds
 Often valve problems

17.  Cardiac Output (CO) = Heart Rate (HR) x Stroke Volume
(SV)
 Stroke volume: volume of blood pumped out by
one ventricle with each best
Average adult:
CO = HR (75 beats/min) x SV (70 ml/beat)
CO = 5250 ml/min

18.  Progressive weakening of heart
 Low heart efficiency  circulation inadequate to
meet tissue needs
 Caused by:
 Coronary atherosclerosis – clogged coronary
vessels
 Persistent high blood pressure
 Multiple heart attacks – scar tissue