Physiology of the HeartPhysiology of the HeartPhysiology of the HeartPhysiology of the Heart
Physiology of the heartPhysiology of the heart
You should understand by now that the Physiology of the Heart refers to the function of the heart
You need to be familiar with the conduction system of the heart, the cardiac cycle, sounds of the heart, and cardiac out put
You should understand by now that the Physiology of the Heart refers to the function of the heart
You need to be familiar with the conduction system of the heart, the cardiac cycle, sounds of the heart, and cardiac out put
Conduction System of the HeartConduction System of the Heart
Cardiac muscle is unique because it can contract spontaneously and independently even if all nervous connections to the heart are severed
These contractions however, are not erratic but regular and steady in rhythm
Cardiac muscle is unique because it can contract spontaneously and independently even if all nervous connections to the heart are severed
These contractions however, are not erratic but regular and steady in rhythm
Beats per minuteBeats per minute
The atrial cells of the heart beat roughly 60 times per minute
The ventricular cells of the heart beat only 20-40 times per minute
Without some unifying system to control them the heart would be an uncoordinated and inefficient pump
The atrial cells of the heart beat roughly 60 times per minute
The ventricular cells of the heart beat only 20-40 times per minute
Without some unifying system to control them the heart would be an uncoordinated and inefficient pump
Intrinsic ConductionIntrinsic Conduction
The Intrinsic Conduction System (Nodal System) of the heart is made of very specialized cardiac tissue that is a cross between muscle and nervous tissue
The Intrinsic Conduction System (Nodal System) of the heart is made of very specialized cardiac tissue that is a cross between muscle and nervous tissue
Intrinsic ConductionIntrinsic ConductionWe see 2 large ovals
which are the nodes of
the system
•The sinoatrial node (SA
Node) acts as the pace
maker of the heart
•The atrioventricular
node (AV Node) slows the
impulse before sending it
to the ventricles
We see 2 large ovals
which are the nodes of
the system
•The sinoatrial node (SA
Node) acts as the pace
maker of the heart
•The atrioventricular
node (AV Node) slows the
impulse before sending it
to the ventricles
Cardiac Cycle Cardiac Cycle
Two most important terms in understanding cardiac cycle are Systole and Diastole
Systole is heart contraction
Diastole is heart relaxation
Two most important terms in understanding cardiac cycle are Systole and Diastole
Systole is heart contraction
Diastole is heart relaxation
5 Phases of Cardiac 5 Phases of Cardiac CycleCycle
5 Phases of Cardiac 5 Phases of Cardiac CycleCycle
Cardiac sounds Cardiac sounds
In a healthy heart you should be able to hear a steady “lub-dub” sound of contraction
We have to understand that there is a sequence to the sounds
lub-dub, pause, lub-dub, pause
In a healthy heart you should be able to hear a steady “lub-dub” sound of contraction
We have to understand that there is a sequence to the sounds
lub-dub, pause, lub-dub, pause
“Lub” and “Dub” sounds“Lub” and “Dub” sounds
The “lub” sound we hear is from the the closing of the AV valves
This is then followed by a pause
The “dub” sound we hear is from the closing of the semilunar valves
The “lub” sound we hear is from the the closing of the AV valves
This is then followed by a pause
The “dub” sound we hear is from the closing of the semilunar valves
Blood flowBlood flow
It is important to realize that blood flows silently as long as the flow is smooth and un-interupted
If the flow becomes irregular we can hear murmurs
It is important to realize that blood flows silently as long as the flow is smooth and un-interupted
If the flow becomes irregular we can hear murmurs