What keeps us up and running
HEALTH
In this series of articles every Friday I will explain your body to you, and how you can use this understanding to improve your health, and hopefully live a longer and more enjoyable life. You will learn how your body works, and how you can avoid damage to it. You will also learn how we doctors examine you and treat illnesses. And most importantly, you will learn how you can change your lifestyle to stay healthy.
This articles will help you to know more about your body, about health and disease. I will answer your questions in a column every Thursday. Send your questions to: [email protected]
OUR circulatory system, also known as the cardiovascular (heart and blood vessel) system, moves blood and lymph through our bodies and acts both as a delivery and waste removal system.
It assists in regulating body temperature and helps maintain to maintain the water and electrolyte balance.
This circularly system delivers nutrients, oxygen and hormones to every cell and removes waste products such as carbon dioxide, among other functions.
Our circulatory system keep our cells healthy and keeps us alive and moving. Our body constantly sends signals to our heart how hard it should pump depending on our activities. When asleep our heart slows down, during heavy exercise our heart pumps harder to deliver extra oxygen and fuel to our muscles.
How the circulatory system works
The heart lies at the center of the circulatory system and pumps blood through the rest of the network. The heart is a hollow muscle consisting of four chambers: there are two chambers at the top, the left and right atriums, and there are two chambers at the bottom, the left and right ventricles. These chambers are separated by one-way valves (like doors that only open to let traffic through in one single direction) to ensure that blood flows in the correct direction.
The rest of the circulatory system consists of two independent networks that work together: the pulmonary (lung) and the systemic (body) network.
The pulmonary network pumps blood through the lungs, through smaller arteries and capillaries (the tiniest form of blood vessels). The tiny capillaries facilitate the exchange of carbon dioxide and oxygen. When you smoke a cigarette, poisons from this cigarette are distributed via the circulatory system throughout your body, and damage every part of your body.
Oxygen feeds the fuel burning process in our cells. Arteries distribute nutrients and oxygen-rich blood coming from the lungs and heart through your body and which is red in colour. You normally cannot see them through your skin. They end up in the capillary system where the oxygen exchange takes place.
Carbon dioxide and other waste products are picked up as the blood flows through the capillaries and into the veins.
Blood low in oxygen returns from the capillary network via the vein system back to the right hand side of the heart. You can see some of your veins through your skin, they are blue lines just below your skin for example on your arms and legs. The returning oxygen depleted blood is pumped through the right side of the heart and again through the lungs.
The motor that keeps us moving and alive
The contraction and relaxation of the heart – the heartbeat – is controlled by the sinus node, which is a cluster of cells situated at the top of the right atrium. The sinus node sends electrical signals to the heart that direct the muscle to contract or relax. These are the zigzags or spikes the cardiac doctor analyses when he performs an ECG (ElectroCardiogram).
Heartbeat is divided into two phases: the systole and diastole phases. In the first, the ventricles contract and push blood out into the pulmonary artery or the aorta. At the same time, the valves separating the atria and ventricles snap shut to prevent blood from flowing backwards. In the diastole phase, the valves connecting to the atrium open, and the ventricles relax and fill with blood. The sinus node controls the pace of these two phases.
Some amazing numbers
Adult humans have a total of about five to six liters of blood pumping through their bodies. On average, the heart pumps about 100,000 times per day, pushing about 2,000 gallons (7,570 liters) of blood through a total of 60,000 miles (96,560 kilometers) of blood vessels. It only takes about 20 seconds for blood to travel through the entire circulatory system.
Circulatory system diseases – What can go wrong?
Cardiovascular (or heart and blood vessel) disease of the circulation system is the leading cause of death for both men and women in most parts of the world, also in Papua New Guinea.
Heart and circulation system disease is a broad term that covers a wide range of diseases and disorders, including stroke (the blockage of blood to the brain), heart attack (the flow of blood to the heart muscle is blocked), hypertension (high blood pressure causing the heart to work harder), arteriosclerosis (the arteries become thick and stiff) and aneurysm (a damaged blood vessel that enlarges like a balloon and may rupture and that can lead to deadly bleeding).
Risk factors
Risk factors for heart disease include age, gender, family history, poor diet, smoking and stress, as well as high blood pressure and elevated cholesterol levels, according to the PIH heart specialists. There are many ways that heart disease can be prevented, including keeping all health conditions under control, maintaining a healthy diet and a healthy life style, participating in regular physical activity and keeping stress levels at a minimum. But most importantly, you should have your health checked regularly, best once a year so that any problems are found early and can be cured before they become more serious. You should have your risk factors checked regularly. These are blood sugar levels, blood lipid levels, blood pressure and get an ECG done to check on your heart.
Most important, when you feel chest pain or heart burn, every minute counts! Every minute can make the difference between life and death. If you feel chest pain or heart burn, you should drop everything you are doing, and see your heart specialist and doctor immediately !
When to see your doctor
Talk to a doctor if you think you’re at risk of a circulatory system disease. They can help develop a treatment or management plan for your condition.
Heart attacks, strokes, and ruptured abdominal aortic aneurisms are life-threatening. When someone has the symptoms of these conditions – take them to the emergency room immediately.
Outlook
Not all risk factors for coronary artery disease are avoidable. But at least one quarter of all deaths due to heart disease and stroke are preventable, according to the heart specialists at PIH. Many conditions can be reversed or controlled with a combination of lifestyle changes and, in some cases, medication.
Tips for circulatory system health
If you’re at risk for a circulatory system disease, work with your doctor to control conditions such as high blood pressure, high cholesterol, and diabetes. You can also take steps and make lifestyle changes to prevent these conditions.
Next article next week: Circulation diseases – Hypertension/high blood pressure