Conductivity
Domotropic Effect
Irritability/excitability
Chronotropic effect
Contractility
Inotrophic effect
Innermost layer of the heart
Endocardium
Thickest layer of the heart
Myocardium
Outermost layer of the heart
Pericardium
Adherent to the lungs
Parietal pericardium
Adherent to the heart
Visceral Pericardium
No overlapping
H zone
Area of Thin filament
I band
Thick/myosine filament
A band
“Crossbridge”
Myosine head
Node of Keith and flack
SA node
Located below the superior vena cava and right atrium
SA node
Node that has no actin and myosin and not specialized for CONTRACTION
SA node
Node of kent and tawara
AV node
Conduction rate : 0.05 per minute
AV node
Only area where we can conduct impulses from atria to ventricle
AV node
Conduction rate: 1 millisecond
Bundle of his
Has the fastest conduction velocity of 4 millisecond
Purkinje fibers
It’s conduction depolarizes the whole atrial muscle tissue
SA node
Anterior internodal pathway
Bachmann Tract
Middle internodal pathway
Wenckebach Tract
Posterior Internodal Pathway
Thorel tract
In the AV node, the only way to transmit impulses is thru the
Bundle of His
Depolarizes the interventricular septum
AV node
T or F: the Postero basal area of the ventricle will be the first to repolarize
TRUE
the last to depolarize will be the first to repolarize
Parasympathetic NS, fibers come from
Vagus nerve ( extrinsic innervation )
Right vagus is distributed to
SA node
Left vagus is distributed to
AV node
Has muscarinic / cholinergic receptors
Parasympathetic Nervous system
Sympathetic fibers mainly come from
Stellate Ganglion
Fusion between t1 and inferior cervical ganglion
Stellate ganglion
Stimulation decreases heart rate and conduction velocity
Parasympathetic NS
Increased HR, conduction velocity and atrial and ventricular conduction
Sympathetic NS
Has beta 1 receptors / adrenergic receptors
Sympathetic NS
Resting membrane potential/automaticity of the heart
Phase IV
Rapid depolarization due to sodium influx
Phase 0
Initial and brief repolarization due to potassium efflux
Phase 1
Plateau phase due to calcium influx
Phase II
Rapid repolarization phase due to potassium efflux
Phase III
Blocked by calcium blockers (Class IV anti arrhythmic drugs)
Phase II
Blocked by class 3
Phase III
Blocks sodium channels
Class 1
Beta blockers
Class 2
Potassium blockers
Class III
Calcium blockers
Class IV
More probe to heart block due to their slow response and slow conductance
SA node and AV node
Increase duration of cardiac cycle
Decrease heart rate
Decrease duration of cardiac cycle
Increase heart rate
Closure of the SL valves and opening of the AV valves
Isovolumetric Relaxation Phase
ESV
50 ml
Begins with Opening of AV valve and ends when they close
Ventricular filling phase
70% of blood goes to the ventricles very rapidly
Rapid filling phase
Also known as diastasis
Reduced filling phase
Completes the ventricular filling ( 20-25% ) and not essential to ventricular filling
Atrial systole
Ventricle is in the contraction phase
Systole
Begins with the closure of AV valves and ends with the opening of semilunar valves
Iso volumetric contraction
EDV
120ml
Begin ha with the opening of Semilunar valves and ends with its closure
Ejection phase
Has the highest pressure
Ejection phase
Shorter and rapid phase
Rapid ejection phase
Decreases ventricular volume
Increased aortic and ventricular pressure
Longer and slower phase due to increasing pressure in the great arteries and lessening pressure in the ventricles
Reduced ejection phase
Rapid fall of already falling ventricular pressure while ventricles are still contracting
Protodiastole
Caused by they push of blood from the aorta to the aortic semilunar valve
Incisura or Dicrotic notch
Condition in which there is increased atrial pressure
Jugular pulses
Corresponds to atrial systole
A WAVE
Produced by bulging of the tricuspid valve into the right atrium during isovolumetric contraction
C Wave
Rise in atrial pressure before the tricuspid valve opens
V Wave
1st heart sound
Lub
Closure of AV valves
2nd heart sound
Dub
Closure of SL valves
3rd heart sound
Rapid ventricular filling
4th heart sound
Due to atrial systole