Heart Anatomy and its Disease
The human heart is a highly evolved, complex organ acting essentially as the plumbed pump for the body. It is a muscular organ, roughly the size of a closed fist, resting in the chest just left of center. The heart beats more or less 100,000 times a day and pumps approximately 8 pints of blood throughout the body 24/7. The heart delivers the oxygen- and nutrient-rich blood to cells and organs, and carries away waste and deoxygenated blood toward the lungs.
Put together, the heart, blood, and blood vessels-arteries, capillaries, and veins-make up the circulatory system.
In humans known as double circulation.
Anatomy of Hearts
○ The heart is made up of four chambers:
○ Atrial: These are the two upper chambers receiving blood.
○ The ventricles: These are the two lower chambers, which discharge blood.
○ The left and right atria, and the left and right ventricle, are separated by a wall of tissue known as the septum. Atria are separated from ventricles by valves.
The walls of the heart are made up of three layers of tissue:
● Myocardium: The myocardium is the muscular tissue of the heart.
● Endocardium: This tissue lines the interior of the heart and covers the valves and chambers.
● Pericardium: The other parts are enclosed in a thin, smooth protective cover.
● Epicardium: The outermost layer serving as protection is comprised primarily of connective tissue and forms the innermost layer of the pericardium.
How the heart works
● Left and right sides
The left and right side of the heart works as a team. Both the atria and ventricles squeeze and relax.
This generates the rhythmic heartbeat in turn.
● Right side
The right side of the heart receives the return of deoxygenated blood and sends it to the lungs.
It is through this right atrium that the deoxygenated blood of the body returns via the veins, which include the superior and inferior vena cava; these are also the largest veins in the body.
The right atrium contracts and blood passes to the right ventricle.
Once the right ventricle is full, it contracts and pumps the blood to the lungs via the pulmonary artery. The blood collects oxygen from, and off-loads carbon dioxide, into the lung.
● Left side
It is the left side of the heart that receives blood from the lungs and pumps it to the rest of the body.
The newly oxygenated blood returns to the left atrium through the pulmonary veins. Contraction of the left atrium pushes the blood into the left ventricle.
When the left ventricle is full, it then contracts and pumps the blood back out to the body through the aorta.
Diastole, systole, and blood pressure.
Each heartbeat comprises two parts:
● Diastole: Ventricle relaxation is a result of the contraction and therefore total emptying of blood from the atria into the ventricles.
● Systole: It is the contraction of the ventricles; the atria are in their relaxation phase again, refilling themselves with blood.
If a person is checking their blood pressure, for instance, the machine will give both a high and a low number: the high number being the systolic blood pressure, the lower number being the diastolic blood pressure.
Systolic pressure: It refers to the extent of pressure the blood exerts against the wall of the artery during systole.
Diastolic pressure: The extent of pressure that occurs in the arteries during diastole.
Valves
There are four one-way valves in the heart to allow blood flow only in one direction: the aortic valve between the left ventricle and the aorta, the mitral valve between the left atrium and the left ventricle, the pulmonary valve between the right ventricle and the pulmonary artery, and the tricuspid valve between the right atrium and right ventricle.
Most of us are familiar with the sound of the heart. The heart generates many forms of sound, and physicians can train their ears to distinguish these and assess the health of the heart.
Blood Vessels
Now there are three types of blood vessels:
Arteries: These carry oxygenated blood from the heart to the other parts of the body. The arteries are strong, muscular, and stretchy, which helps in the movement of blood in the circulatory system, and they also help in regulating the level of blood pressure. Arteries have small branches known as arterioles.
Veins: These carry deoxygenated blood back to the heart. They get larger towards the heart and the walls of the veins are thinner than those of arteries.
Capillaries: these are vessels that link the smallest arteries with the smallest veins; they are thin-walled to allow exchange between them and any surrounding tissues of compounds such as carbon dioxide, water, oxygen, waste, and nutrients.
The circulatory or cardiovascular system includes the heart, blood, and blood vessels.
Cardiac arrest: When the heart stops
The heart is the life-enabler; because if it stops beating, blood will not reach the brain and other organs, and the person can die within minutes. It is called cardiac arrest. If the person is under cardiac arrest, he will fall short of speaking or breathing, let alone having a heartbeat. Anyone present must call in immediately to 108 if a person is having a heart attack, and should begin cardiopulmonary resuscitation by pressing hard and fast with locked hands on the center of the victim’s chest. The best prevention against cardiac arrest is to live a heart-healthy lifestyle: a healthy, balanced diet containing plenty of fruits, vegetables, whole grains, and lean proteins. Limit your intake of saturated fats and sodium. Stay active, by doing at least 150 minutes of moderate-intensity aerobic physical activity, such as brisk walking, every week. Do not smoke tobacco, and limit alcoholic beverages. Manage stress with mindfulness techniques. Get regular health check-ups that include screening of your blood pressure, cholesterol levels, and diabetes. Maintain a healthy weight. Learn CPR and the warning signs of a heart attack so you can act if one happens.
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