The heart is a muscular organ about the size of a closed fist that functions as the body’s circulatory pump. It takes in deoxygenated blood through the veins and delivers it to the lungs for oxygenation before pumping it into the various arteries which provide oxygen and nutrients to body tissues by transporting the blood throughout the body. It is located between the lungs and the chest bone. The heart points  to the left, therefore, about 2/3 of the heart’s mass is found on the left side of the body and the other 1/3 is on the right.

Blood with oxygen [oxygenated], is taken from the heart, into the lungs, where it drop carbon dioxide, and picks up oxygen, then pumped round the body blood system, carrying oxygen and nutrients to tissues around the body.  The oxygen is used up and the resulting blood with depleted oxygen [ deoxygenated blood], is pumped back into the heart to be oxygenated again.
The sound that is felt and heard when your heart is beating , is known as the cardiac cycle. When your heart contracts it makes the chambers smaller and pushes blood into the blood vessels. After your heart relaxes again the chambers get bigger and are filled with blood coming back into the heart. Electricity going through your heart makes the muscle cells contract. The blood provides your body with the oxygen and nutrients it needs. It also carries away waste. Your heart is sort of like a pump, or two pumps in one. The right side of your heart receives blood from the body and pumps it to the lungs.

The primary responsibility of the heart is to pump blood throughout the body. It pumps blood from the body — called the systemic circulation — through the lungs — called the pulmonary circulation — and then back out to the body. This means that the heart is connected to and affects the entirety of the body. Simplified, the heart is a circuit of the Circulation.  The heart is a muscle that squeezes blood and functions like a pump. Each part of the heart is susceptible to failure or dysfunction and the heart can be divided into the mechanical and the electrical parts.

Blood flow diagram of the human heart:  Blue components indicate de-oxygenated blood pathways and red components indicate oxygenated blood pathways.
Conditions that can exist in the heart.
Heart attacks cause scar tissue to form amongst normal heart tissue, this can lead to further heart problems or even heart failure.
Heart disease is nothing to ignore, and it can strike both the old and young. Heart disease symptoms can occur at any age, and your first symptom of heart disease might be a heart attack.

INCIDENCE IN VARIOUS GROUPS:
•    Women . Although the average age of a heart attack for women is in the early seventies, don’t be fooled into thinking that heart disease will occur when you’re older.  More women in their early twenties suffer from effects  of heart disease than of breast cancer. Also, rates of heart attacks among younger women, ages 35 to 54, have been rising over the last 20 years.
•    Men . The average age of a heart attack in men is 66, but like with women, heart disease can strike at any age and must be taken seriously at all ages. Doctors recommend that all adults get a heart health screening every year by their primary doctor; this should include a check of blood pressure , blood cholesterol, blood sugar levels, and height and weight.  It is important you take note of your cigarette smoking, exercise habits, and nutrition habits every year.

What to do to lower the risk of  heart disease
•    Quit Smoking. Smoking causes your risk of heart attack to rise sharply, but one year  after quitting your risk is cut in half and continues to go down as you stay smoke-free.
•    Monitor your blood pressure. Because having high blood pressure makes your heart work harder, it raises the risk of heart disease. Exercising, losing weight, eating healthy foods, cutting down on your sodium intake, and limiting the number of alcoholic drinks to a maximum of one a day for women or two a day for men can help keep your blood pressure numbers in the healthy range.
• Get your cholesterol as low as possible. The higher your blood cholesterol (which causes plaque to build up in the artery walls), the higher your risk for heart disease. Many of the same steps that help lower blood pressure — eating healthy foods, exercising, and losing weight — also help lower your cholesterol.
• Get your weight down to a healthy level. Having excess weight makes you more likely to have high blood pressure, high cholesterol and diabetes, and raises your risk for heart disease. If you have weight to lose, set a goal of taking off about 10 percent, which can go a long way toward lowering your risk.
• Work up a sweat. Exercising at a moderate intensity for at least 30 minutes most days of the week also helps protect your heart.
When you keep a healthy heart regime, and a heart-healthy lifestyle is that it is also beneficial for your overall health. So when you keep your heart healthy, you’ll also feel great and help yourself stay that way for years to come.
It is important to know that , a cardiologist is the specialist that studies the heart and heart diseases. Therefore, when in need to see a doctor concerning any issue with your heart, it is better to see a cardiologist /Physician. While plenty is known about the healthy heart, the bulk of study in cardiology is in disorders of the heart and restoration, and where possible, of function.
Significant diseases    Heart disease, Cardiovascular disease, Atherosclerosis,  Cardiomyopathy,  Hypertension (High Blood Pressure).
Significant tests     Electrophysiology study, Cardiac imaging,  ECG,  Echocardiograms,  Stress test.
There are some simple tests that can be carried out, to assess if the heart is functioning well. These include physical exam, heart sound, pulse rate, edema, pulse quality, arthritis, skin exam, skin bulges.

VITAL SIGNS TO WATCH OUT FOR
•    Blood pressure: hypertension,  congenital heart disease, manifestations
•    Heart rate : bradycardia & tachycardia.
•    Respiratory rate :  in distress, shortness of breath, causes.
Hypertension
Hypertension is elevated blood pressure above “normal.” Blood pressure is reported as fraction of systolic blood pressure over diastolic blood pressure and typically at the brachial artery while seated and measured in mmHg. The normal blood pressure changes with age with a general trend that it increases with age. Normal pressure for newborns is around 90/60 and young adults classically being 120/80 (pronounced “120 over 80”).
Hypertension has significant impact on the cardiovascular system,  other systems too , and is the motivating reason for treatment. Reduction of morbidity from hypertension is the end-goal of therapy.

Types of hypertension
•    Essential hypertension.
Hypertension with no known cause, which is about 90-95% of people with hypertension. Often thought to be due to lifestyle. Management is through medications and blood pressure that does not respond is a red flag that it may be secondary hypertension. Due to the widespread nature of hypertension, cardiologists will end up managing or recommending treatments for essential hypertension.
•    Secondary hypertension.
Most causes of secondary hypertension are from kidney and endocrine disorders. Cardiovascular causes of hypertension include coarctation of aorta, , atherosclerosis, and aortic stenosis.

Cardiac arrest
Cardiac arrest  refers to the cessation of normal systemic circulation due to failure in proper contraction of the heart. There are several conditions that can cause cardiac arrest. Treatment of cardiac arrest includes cardiopulmonary resuscitation (CPR), defibrillation, and advanced cardiac life support  (ACLS), and treatment of the underlying cause of arrest.
HEART FAILURE :  Heart failure is failure of the heart to produce sufficient blood flow to meet metabolic demands of the body, or to do so at higher filling pressures. The hallmark signs of heart failure include shortness of breath (especially on exertion, at night, or while lying down) and leg swelling. Chest pain is rarely a feature of heart failure, which would point a diagnosis more toward angina pectoris or myocardial infarction . Perhaps confusingly, heart failure can be caused by coronary artery disease (CAD) and myocardial infarction (MI) that result in a deficiency in pumping that then leads to heart failure. Treatment of heart failure, like most secondary disorders, depends upon treatment of the primary cause which includes CAD & MI but also valvular problems like aortic stenosis and hypertension.
All these are medical jargon, so it is best that you see your cardiologist at the slightest possible sign of a heart problem.
The role of a good healthy diet to sustain and maintain your heart is extremely important. It is good to consult a nutritionist, to assist you in planning a healthy sustainable diet , to take care of you