HeartThe Heart is an organ vital to survival.

It is involved in controlling and improved function of the  Circulatory, Respiratory, and Endocrine systems.

This is a muscular organ comprised of Cardiac muscle that provides blood throughout the body.

Cardiac muscle is an involuntary muscle that contracts on its own.

The heart beats (contracts) around 70 times a minute.


The Heart is made up of 4 Chambers or Cavities

1.)  Right Atrium
2.)  Right Ventricle
3.)  Left Atrium
4.)  Right Atrium


Heart Contraction or Pulmonary Circulation

Step 1:  Blood (without oxygen) returns to the heart and enters the Right Atrium

Step 2:  Blood from the Right Atrium is pushed into the Right Ventricle.

Step 3:  Blood from the Right Ventricle is pushed into the lungs where it is oxygenated.

Step 4:  Blood returns from the Lungs (with oxygen) and enters the Left Atrium.

Step 5:  Blood from the Left Atrium is pushed into the Left Ventricle.

Step 6:  Blood from the Left Ventricle is pushed out of the heart and around the entire body.

This entire system is referred to as Pulmonary Circulation.


4 major Valves of the heart

1.)  Tricuspid Valve

2.)  Pulmonary Valve

3.)  Mitral Valve

4.)  Aortic Valve


Blood flow with valve involvement

The blood enters the right atrium and enters the right ventricle through a valve called the tricuspid valve.

It then is pumped from the right ventricle to the pulmonary arteries through the pulmonary valve.

Within the – carbon dioxide is released and oxygen enters the blood stream.

The blood is pumped back to the heart by the pulmonary veins and enters the left atrium.

It then enters the left ventricle via the mitral valve.

Blood leaves the heart through the last valve via the aortic valve and is pumped throughout the body.

Coronary circulation is the vessels that supply the heart itself with blood

When blood leaves the heart it passes through arteries.

From arteries blood enters arterioles and finally into capillaries.

These are the thinner aspects of the blood vessels. Capillaries allow blood or nutrients to get into the tissues and cells.

Carbon dioxide and other wastes are collected into venules which flows into veins.

The blood is then returned to the heart.


The heart itself is enclosed in a sac referred to as the Pericardium

Two aspects of the pericardium include:

1.)  Fibrous pericardium
2.)  Serous pericardium



Electrical system of heartElectrical system

How does the heart beat at a constant rate?

This answer lies within the specific cells of the heart.

There is a specific area in heart called the sinoatrial node (SA node) that regulate heartbeat.

The cells involved are called pacemaker cells.

These cells send an electrical pulse throughout the heart that tells it to contract.


The impulse travels the following route:

First, the impulse begins in the SA node

Second, It travels from the SA node to the right and left atria within milliseconds.

Then the impulse travels to the AV node

Next to the Bundle of His

Then to the Right and Left bundle branches

Finally to the Purkinje fibers to the Right and Left ventricles.


If the SA node has lost function either temporarily or permanently then cells from the atrioventricualar node (AV node) will then become the “pacemaker” cells.


Examination of the Heart or its Electrical System

Echocardiogram also called EKG

Thallium Stress Test


Valve problems of the heart

Aortic Stenosis

Tricuspid Regurgitation

Tricuspid Stenosis

Mitral Regurgitation

Mitral Stenosis

Tricuspid Regurgitation

Tricuspid Stenosis

Pulmonary Stenosis


Other Disorders of the Heart


Angina Pectoris



Atrial Fibrillation

Coarctation of the Aorta

Congestive Heart Failure [CHF]

Coronary Artery Disease

Coronary Heart Disease

Dilated Cardiomyopathy

Dressler’s Syndrome

Elevated Blood Pressure

Heart Attack


Hypertrophic Cardiomyopathy

Myocardial Infarctions


Patent Ductus Arteriosus [PDA]

PEA or Pulseless Electrical Activity



Restrictive Cardiomyopathy

Secondary Hypertension


Genetic problems with the heart

Tetralogy of Fallot

Atrial Septal Defect

Ventricular Septal Defect

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