Cardiovascular System
Anatomy Physiology Disorders and Diseases Treatment
Cardiovascular Anatomy
The Heart is made of four chambers, two atria (singular atrium) and two ventricles. When looking at an image of the four chambers of the heart the chambers on the right are referred to as the left atrium and ventricle while the chambers on the left are referred to as the right atrium and ventricle. This is because while inside a persons body the right atrium and right ventricle would correspond with their right side of the body, when looking at these images we are seeing a mirror image.
When looking at blood flow through the body we begin with oxygen-deprived blood entering the right atrium via the superior and inferior vena cavas. The blood then goes through the tricuspid valve, which is an atrioventricular valve, and enters the right ventricle. The right ventricle contracts, pumping the blood through the pulmanary valve, a semilunar valve, and through the pulmonary arteries to the lungs. In the lungs, oxygen diffuses into the blood which then returns to the heart's left atrium by way of the pulmonary veins. Contraction of the left atrium pushes the blood through the bicuspid (mitral) valve, also an atrioventrical valve, and into the left ventricle. The left ventricle is the largest chamber and is required to pump the blood through the semilunar aortic valve into the aorta which disperses the blood throughout the body.
Systemic Circulation is the route in which oxygenated blood is pumped from the left ventrical to all tissues in the body. This is responsible for delivering nutrients to the body cells and removes waste.
Pumonary Circulation brings deoxygenated blood from the right ventricle to the lungs for gas exchange in which the deoxygenated blood becomes oxygenated.
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Blood Vessels
Arteries are the largest blood vessels, followed by veins and then capillaries.
Arteries
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Three Layers, they are thick and elastic- Connective Tissue, a thick muscular layer and an endothelial layer. Strength required to support pressure
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Blood is pumped away from the heart
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Blood contains oxygen (except in the case of the pulmonary artery)
Veins
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Three Layers, they are thinner and less muscular.
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Valves prevent backflow of blood
Capillaries
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Single-celled layer, suitable for gas and nutrient exchange.
The heart walls are made of three layers:
Endocardium- the innermost layer. It is made of epithelial tissue and forms the lining of the entire circulatory system.
Myocardium- the middle layer. This layer is the thickest of the three and is made up of cardiac muscle.
Epicardium- the outer layer. The epicardium is the thin, external membrane.
The Cardiac Cycle
The cardiac cycle is the flow of blood through the heart. Electrical impulses of the heart cause the chambers to contract, forcing the blood through valves in a continuous cycle around the body.
In a regular cardiac cycle the process begins with the two atria simultaneously contracting and the ventricles are relaxed. As the atria relax, the ventricles contract. All four chambers remain relaxed and then the cycle repeats.
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Cardiac Muscle cells are either contractile cells or autorhythmic cells. The majority are contractile.
Examples of autorhythmic cells:
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Sinoatrial (SA), or Sinus, Node
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Atrioventricular (AV) Node
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Atrioventricular (AV) Bundle (occasionally referred to as the bundle of His)
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Right and Left Bundle Branches
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Purkinje Fibers
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**Provided by Eastern Kentucky University
Cardiovascular Physiology
Cardiac
Electrical Conduction
The SA Node is the hearts natural pacemaker. The autorhythmical cells generate electrical impulses which depolarize the atria, initiating the contraction of the atrial myocardial and stimulating the AV Node. The AV Node is connected to the Atrioventricular bundle which delivers impulses to the left and right bundle branches and eventually the purkinje fibers. This results in the depolarization and contraction of the ventricals.
The Electrocardiogram (ECG/EKG)
An electrocardiogram is a record of the heart's electrical activity. 12 leads, external skin sensors, are placed on the body to record the electrical impulses of the heart that cause it to contract. The depolarization of the cells causes the cardiac muscle to contract.
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*University of Utah
**Eastern Kentucky University
Cardiovascular Disorders and Diseases
When researching Cardiovascular Disorders and Diseases the first topic that tends to come to mind is "Heart Attack." A Heart Attack is caused by the blockage of a coronary vessel, that is a vessel responsible for supplying the heart with blood. Coronary Artery Disease is a serious problem in the United States, despite heightened awareness and medical capabilities.
Arteriosclerosis, the hardening of the arteries, is the collective term for many diseases of the arteries. The most common of these diseases is Atherosclerosis. This is responsible for the build-up of plaque in arteries which leads to clots and eventually may result in a heart attack.
A visit to the doctor for a regular check-up always examines a few "vital" pieces of information. One of these factors is blood pressure. There are two disorders accompanied by blood pressure.
Hypertension - Around 25% adult Americans have high blood pressure, also known as hypertension. Hypertension increases the risk of heart and kidney disease, as well as stroke. High blood pressure is defined as a systolic pressure of 140 or higher and a diastolic pressure of 90 or higher.
Average blood pressure is considered 120/80 mm hg for an adult.
Hypotension - Chronic low blood pressure, hypotension, is generally not a health concern. When blood pressure drops suddenly an inadequate supply of blood, and respectively oxygen, to the brain and other vital organs may result in medical issues.
Treatment for Heart Problems
There are a few ways, regardless of race, gender, age and hereditary conditions, that will help prevent high blood pressure.
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Acquire and maintain a healthy weight
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Be more physically active
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Choose foods lower in salt and sodium
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Only drink alcoholic beverages in moderation
The healthiest way to lose weight as a means of lowering your blood pressure is to do it slowly for a long period of time. Increasing your physical activity is also in relationship to whether you participate in vigorous, moderate or light activities and the amount of time spent. Physical activity may also reduce risk of heart disease and stroke, lowering the blood's LDL cholesterol levels and strengthening the heart. After all, the heart is nothing more than a muscle acting as a pump. Salty foods increase blood pressure, respectively a decrease in the consumption of these foods will lower blood pressure. Stress also has the ability to increase blood pressure; creating a calm lifestyle and reducing some stress will help this problem.
As is shown, physical fitness and nutrition play a major role in treatment for heart problems that can be done without medical intervention. Heart attacks, strokes and extreme arteriosclerosis patients should seek professional medical help.
In the case of a severe heart attack, nearby people may be able to perform CPR to help the victim until emergency medical technicians arrive. CPR, Cardiopulmonary Resuscitation, is a technique used to sustain an individuals heart and breathing when they are unable to do it themselves. It is recommended that the general public learn how to perform this, as well as the Heimlich Maneuver, to help other civilians in a time of need.
To learn about where you can become certified in these contact the American Heart Association or the American Red Cross.