THE HUMAN HEART
THE HUMAN HEART IS THE ENGINE that keeps you alive, just like the engine in your car, your heart needs looking after. If you don’t maintain the engine in your car, it could let you down. Likewise, if you don’t look after and maintain your heart it could let you down. Plus, if you put the wrong fuel in your car, the pipes taking fuel to the engine can cause things to clog up, likewise if you don’t maintain a healthy blood supply, your arteries can start to block causing heart problems.
THE HEART IS A MUSCLE, to be medically correct the muscle tissue is called the myocardium, more commonly referred to as the cardiac muscle. There are three muscles in the human body, skeletal muscles, smooth muscles and cardiac muscle, albeit, the is only one cardiac muscle. Skeletal muscles are one of many muscles that are used in walking, lifting weights and many more functions, every movement of the muscle is voluntary. Smooth muscles are found in organs such as the stomach, lungs, and intestines, smooth muscles are involuntary. More on skeletal muscles in other sections.
The Cardiac Muscle works totally different to the other muscles in your body. Although the brain can speed up or slow down your heartrate, due to release of hormones and other factors, providing the is a supply of oxygenated blood from the lungs, the heart muscle can continue to beat without any connection to the brain. The heart will beat on its own, this is referred to as automaticity, the heart will beat at a set rate called the intrinsic heart rate, around 100 beats per minute.
The Heart is able to function on its own as it’s own pacemaker, totally independent from the brain, its possible for the human body to still have a heartbeat even if the brain has died.
WHERE IS YOUR HEART?
WHERE IS YOUR HEART? It’s located between your lungs, around 80% of the heart is close to the left lung, sitting just above your stomach and liver behind the breast bone. The size of your heart is roughly the size of a large grapefruit and weighs around 10 ounces (283 grams) .
HOW DOES YOU HEART WORK?
The walls of the heart are muscle and like other muscles in your body it needs to be exercised to keep it strong and healthy. A sedentary life style and no physical activity may double your chances of heart disease, possibly dying. People don’t need to be super athletes to keep the heart muscle exercised, just 30 minutes a day of brisk walking, maybe running up the stairs instead of taking the lift can make a difference. Exercise helps to strengthen the heart muscle, this can make it more efficient and able to pump more blood to the organs in your body, the brain senses more blood than is needed is reaching the body’s organs, in turn the brain tells the heart to beat slower, this also reduces blood pressure.
Your Heart, your Circulatory System
The cardiac muscle (Your Heart) has four sections and two pumps that squeezes and pumps blood around your Circulatory System. The right atrium receives blood from your veins, people call this ‘Blue Blood’ which is now deoxygenated, the blue blood from your lower body enters the right atrium of your heart via the Inferior Vena Cave, the blue blood from your upper body enters the right atrium of your heart via the Superior Vena Cava.
This blue blood passes through a one-way valve into the right ventricle, the heart then pumps blood in need of oxygen through another one-way valve to the pulmonary artery which in turn divides into the right and left pulmonary arteries that connect to the left and right side of your lungs.
Your lungs then removes the carbon dioxide when you breath out, when you then breath in fresh air comes into your lungs and then taken back to the heart via the left and right pulmonary veins into the left atrium of your heart, you heart pumps fresh blood via a one way valve into the left ventricle of your heart which in turn pumps fresh oxygenated blood via another one way valve into your main artery called the aorta, supply fresh blood to your brain and every organ in your body.
If you have a normal heart beat around 70 beats per minute, every action detailed above happens in less than a second, that’s 100,800 every day, around 3.7 Billion times a year, even more when your heart rate increases.
Life2Moro ®'s Interactive Heart Diagram
Interactive Heart Diagram
1. Please hover your mouse over each section in the diagram of the heart.
2. Certain areas will become highlighted.
3. Each area that becomes highlighted is then clickable.
4. Click the highlighted area to reveal that part of the hearts particular function.
5. If clicked in alphabetical order the whole process of a single heartbeat is described step-by-step.
THIS DIAGRAM abbreviates what I’ve detailed. It shows how your blood has travelled through your arteries around your body and then returns via your veins to the Right Atrium, to receive a fresh supply of oxygen. It is explained in each step by step click from (A) to (P)...
(A) Right Attrium
Deoxygenated blood from the upper body enters the Right Atrium (A).
(B) Superior Vena Cava
The deoxygenated blood from the upper body comes in from through the Superior Vena Cava (B).
(C) Inferior Vena Cava
Blood from the lower body enters the right atrium through the Inferior Vena Cave (C).
(D) Triscupid Valve & (E) Right Ventricle
As the heart contracts a valve opens (D) and forces blood into the Right Ventricle (E).
(F) Pulmonary Valve
All the valves in your heart only allow blood to pass in one direction. Then valve (F) opens and blood is ejected into the Pulmonary Artery, which then divides into the Left Pulmonary Artery (G) and Right Pulmonary Artery (H).
(G) Left Pulmonary Artery
When valve (F) opens it forces blood out into the Left Pulmonary Artery (G) and to the left lung, where the blood expels the Carbon Dioxide and receives freshly oxygenated blood.
(H) Right Pulmonary Arteries
When valve (F) opens it forces blood out into the Right Pulmonary Artery (G) and to the Right lung, where the blood expels the Carbon Dioxide and receives freshly oxygenated blood.
(J) Left Pulmonary Veins
The oxygenated blood returns to the heart via the two Left Pulmonary Veins (J) entering the ...
(K) Left Atrium
... the Left Atrium (K) ...
(L) Right Pulmonary Veins
... and the two Right Pulmonary Veins (L) also entering the Left Atrium (K).
(M) Mitral Valve
Oxygenated blood from the Left Atrium (K) is then passed through the Mitral Valve (M) ...
(N) Left Ventricle
... to the Left Ventricle (N).
(O) Aortic Valve
Freshly oxygenated blood from the Left Ventricle is then pumped out through valve (O) into the Aorta (P) and throughout the body to start its journey again.
... via the Aorta (P) to start its journey ending up back at Right Atrium (A).
It’s hard to believe that all of what I’ve described above happens in one heartbeat.
WHAT IS A HEART ATTACK?
A heart attack, medically referred to as a myocardial infarction is a serious medical emergency. In simple terms your heart will start to fail if there is a blockage in your arteries, stopping oxygen rich blood reaching your heart, causing the heart muscle to start dying. Should this happen immediate treatment is required, a fast response is required to stop or minimise damage to heart muscle otherwise scar tissue will form.
Sudden Cardiac Arrest is a heart condition, sometimes referred to as a heart attack, this is wrong. Sudden Cardiac Arrest (SCA), is not a heart attack. SCA starts when the electrical system inside the heart becomes faulty. The human heart has its own built in pacemaker called the SA Node, this node sends out electrical impulses in a continuous rhythm, to the AV Node conducting the impulses to the ventricles causing heart muscle to contract, resulting in your heart beating around 70 beats per minute. It’s worth mentioning that the human brain is not responsible for the beat of your heart, however the brain together with hormones influence the heart rate.
It’s when the rhythm of the heart becomes abnormal, medically called an arrhythmia, that causes the heart to beat too fast (called tachycardia) or too slow, (called bradycardia). The most common side effect of an arrhythmia, which is life threatening is referred to as ventricular fibrillation, when this happens it can stop the ventricles in the heart from pumping blood, blood pressure drops, resulting in loss of consciousness to the brain and organs. Without immediate treatment of CPR and a defibrillator, the brain dies causing death.
Some research indicates a high proportion of sudden cardiac arrest cases occurs in the age bracket between mid-thirty’s and fifty. On many times there’s been no history of heart disease.
It’s worth remembering:
Heart conditions can cause high blood pressure.
High blood pressure can cause heart disease.
SYMPTOMS OF A HEART ATTACK
Unfortunately people can mistake a heart attack and believe it’s indigestion, some symptoms can be similar, especially a chest pain or a discomfort in the chest, a chest pain appertaining to the heart normally affects the centre and left side of the chest, however indigestion can also cause similar symptoms.
Another indication of a heart attack is a discomfort in the left arm, possibly both arms, also a tight feeling in the jaw, other areas affected are the neck and shoulder.
More common symptoms include, a cold sweat, possibly a shortness of breath, a feeling of nausea, feeling dizzy. If chest pain is accompanied by any of these common symptoms medical assistance should be your first priority.
What is Angina?
Medically referred to as angina pectoris is a chest pain due to the lack of oxygen to the heart muscle. This condition can feel like pressure on your chest and due to the lack of oxygen, feel like being suffocated. Any of these symptoms should be checked, it’s possible it could lead to a heart attack. Angina is also related to blood pressure, the higher the blood pressure will cause more symptoms. Higher than normal blood pressure puts a strain on the heart wall requiring more oxygen.
All our organs which include the kidneys, liver, gall bladder, stomach, and others, require oxygenated blood to function correctly, however people with Coronary Heart Disease (CHD) have arteries which have plaque within their arteries, the plaque can be caused by fatty deposits, the plaque causes your arteries to narrow.
Because your arteries are now partially blocked, when you exercise or do anything to increase your heartrate the arteries can’t get enough fresh oxygenated blood to your organs, the medical term for this condition is called ‘Cardiac Ischemia’ it means the volume of blood flowing through your arteries is reduced resulting in your heart not receiving enough oxygen, this condition is referred to as Angina. When you rest, your heartrate goes down and the pain can subside.
Danger of Stress!
Although there are many obvious causes of high blood pressure and heart disease, another cause of heart problems can be caused by stress. If you are a person who occasional has a stressful situation, then this section is not so important.
However, if you’re a person who leads a busy life at work, spends time driving to work and encountering traffic jams, maybe have personal problems, may have money worries, you’re a Mum looking after children but still must work, cook and manage the house. Then it’s possible people can be stressed to a level that it affects their health, I’ve written below some of the information I’ve discovered about the possible dangers of a stressful life.
There is a lot of information on stress in section 19, below I’ve included some information on hormones and the effect they have on the body.
Linking Stress to high blood pressure and heart disease is not straight forward. From research, there is no evidence that stress alone causes long term high blood pressure and in-turn heart disease. However, when the human body gets into a stressful situation it produces different hormones, below are a few examples:
Adrenaline, Norepinephrine, Cortisol
Adrenaline also known as Epinephrine is often referred to as the “Fight or Flight Hormone”. For interest only, the word Adrenalin without an ‘e’ was originally the trade mark of the Parke Davis & Co a pharmaceutical company founded in 1860 in Detroit USA.
Adrenaline is also known as epinephrine is produced in the Adrenal Glands having received a message from the brain that the body is under stress in some way. People have been known to be able to lift weights far heavier when adrenaline gets into the blood stream, adrenaline also gives you the energy to run away from danger, plus adrenaline will raise your blood pressure while a stressful situation remains. There is more about Epinephrine and Adrenaline in section 26.
Norepinephrine, is a hormone that reacts in a similar way to adrenaline, should the body become stressed or threatened, the brain releases norepinephrine into the blood stream, this hormone focuses your mind, makes you alert and ready to react to whatever stressful situation you’re faced with. And like adrenaline your heart rate increases, glucose is released into the blood stream and again your blood pressure rises.
Cortisol is a steroid hormone, when it’s used for medication it’s called hydrocortisone, this has many uses including, inflammation, arthritis, immune disorders and a lot more.
Cortisol is released into the blood stream under stressful situations, this hormone increases blood sugar but suppresses the body’s immune system. Cortisol is always present in the blood stream, the level of cortisol is higher in the morning, lower towards the end of the day, reducing even lower when we sleep. More on sleep in section 25.
The levels of cortisol in the body shouldn’t be too low nor should they be too high, it’s when the levels are outside accepted levels the may kick in.
Cortisol plays an important part when the body is stressed, cortisol manages stress in the body by shutting down important functions such as the reproduction and immune system, this assists our bodies to direct our energy and cope with stressful situations.
So far all is good, your body is coping with the stressful situation, your blood pressure will have risen and should reduce once the stressful situation is resolved and you are relaxed and in control.
However, should stress levels continue, even at a lower level day in day, cortisol can start to cause many problems, some of which are:
- Cortisol causes ‘Gluconeogenesis which is responsible for making glucose in your liver.
- Cortisol can stop insulin from getting into the cells in your body, this results in glucose remaining in the blood stream, not good.
- Cortisol can also shut down parts of the immune system which can leave your body open to infection.
- Cortisol can cause the body to retain salt (Sodium) causing blood pressure to rise.
- Cortisol can cause problems with the supply of thyroid hormones.
- Cortisol can cause an increase in gastric acid with in turn can give problems with the intestines.
- Cortisol in levels higher than normal can cause you to feel hungry and binge food.