cardiovascular system 4 Flashcards
what are people with long Q-T syndrome prone to
very rapid heartbeat therefore poor O2 to the brain
what is the treatment for long Q-T syndrome
B- blocks - decrease electrical impulses that pass through AV node
Defibrillator - depolarizes entire myocardium simultaneously
what is arrhythmia
irregular heart rhythm due to the defect in conduction system of the heart
what causes arrhythmia
drugs, anxiety, K deficiency
what are examples of arrhythmia
heart block, atrial flutter, atrial fibrillation, ventricular fibrillation
what is the cardiac cycle
all events associated with one heartbeat
what are the normal events of one heartbeat
2 atria contact while 2 ventricles relax, then the other way round
what is systole
contraction
what is diastole
relaxation
what are the 3 phases of the cardiac cycle
relaxation period after T wave - ventricular and atrial diastole
after P wave - atrial systole and ventricular diastole
after QRS - ventricular systole and atrial diastole
what causes the heart sound
the blood turbulence caused by closing of heart valves
what is the S1 of the cardiac cycle
closing of AV valves soon after ventricular systole
what is the S2 of the cardiac cycle
closure of the semilunar valves at beginning of ventricular diastole
what is S3 during the cardiac cycle
rapid ventricular filling
what is S4 of the cardiac cycle
atrial contraction
what is a heart murmur
abnormal sound before, between, after or masking normal sounds
what does a heart murmur indicate
a valve disorder
what is cardiac output
the volume of blood ejected from L (or R) ventricle into aorta (or pulmonary trunk) each minute
what is the equation for cardiac output
CO = stroke volume x heart rate
what are the 3 factors of the regulation of stroke volume
preload, contractility, afterload
what is preload
the degree of stretch
what is contractility
forcefulness of contraction of individual ventricular muscle fibres
what is afterload
pressure to exceed to eject ventricular blood
what are the 2 most important factors which contribute to the regulation of heart rate
autonomic NS
hormones
what are other factors regulating heart rate
age, gender, physical fitness, body temp
