The capillaries come together to form the venules, the venules come together to form the veins which carry the used blood back through the pulmonary circuit leading to the superior and inferior cava and back to the heart to be oxygenated and so the circuit continues.
In order for all the body’s systems to function well, the body requires certain substances which can be obtained from a balanced diet.
‘A balanced diet refers to intake of appropriate types and adequate amounts of foods and drinks to supply nutrition and energy for the maintenance of body cells, tissues and organs, and to support normal growth and development’ MedlinePlus Medical Enclyclopedia:balanced diet
There are two classes of food, macronutrients, which provide energy and materials for growth and repair and micronutrients which assist in the maintenance of chemical reactions in the body.
A balanced diet consists of carbohydrates, proteins, lipids (fats and oils), dietary fibre, vitamins, minerals and water to replace that lost or used by the body. All components should be adjusted to suit the individual requirements.
Carbohydrates provide energy for the body. The simplest carbohydrates are single sugars (monosaccharides) which are soluble and supply the energy required to make ATP. ATP is broken down to supply energy to parts of the body. Other carbohydrates: disaccharides, also soluble and sweet, again providing energy and polysaccharides, these are insoluble, used for energy storage.
Proteins are made of long chains of amino acids held together by peptide bonds. There are two different types of amino acids essential/non essential amino acids. Essential amino acids cannot be made by the body so must be obtained from the diet. Amino acids are used inside cells for growth, repair, formation of enzymes, membranes and some formation of hormones. Proteins are also, sometimes a source of energy.
Lipids are used for long-term stores of energy and to make cell membranes. They protect delicate organs with a cushion of fat surrounding the fragile tissue and act as heat insulators.
Minerals and vitamins keep all systems running properly. Minerals are all soluble in water and have many uses. Deficiencies lead to anaemia, slowing down of metabolic rate which causing tiredness and lack of energy, weak bones, poor blood clotting, tooth decay, and in the young cretinism.
Vitamins are required in small quantities, however deficiencies can lead to night blindness, scurvy, bleeding gums, loose teeth, anaemia, rickets and poor clotting of blood.
Fibre maintains a good flow through the digestive system, adding bulk to faeces to stimulate peristalsis, preventing constipation. Regular bowel movements reduce the risk of cancer in the bowel and diverticulitis (inflammation of the colon).
Without water we would die very quickly, water is present in blood plasma, it also surrounds and is inside all cells in the body, without it cells would cease to work.
To maintain a healthy body, we not only need to eat a balanced diet but also keep check of the amount of calories consumed and exercise regularly.
The amount of calories required by an individual varies according to age, height and weight. A calorie is ‘a unit of energy measurement used to measure heat producing value in food’.
It is important to find the right balance for the individual; this involves obtaining nutrients from all food types. ‘For the average person this maybe 55 per cent from carbohydrate foods, 15 per cent from protein foods and 30 per cent from fats’.
The consequences of a poor diet, too much or too less of any of the food types can lead to many health problems including obesity and cardiovascular diseases.
Obesity is very much a major concern for us as a nation, leading to severe consequences on the health, which can be very damaging if not fatal. ‘Obesity is the medical term used for people who have excess weight above a body mass index of 25’. This condition is a disease which promotes other diseases, including cardiovascular disease.
Obesity can be caused by three factors: heredity, lack of physical exercise and consuming more calories than are required by the body. Heredity factors cannot be altered, however we can address the other factors to try and avoid obesity and cardiovascular disease.
Individuals need to reassess their lifestyle, integrate physical activity to suit and monitor their eating habits ensuring all of the food groups, in moderation, are incorporated in their daily diet. Excess of any of the food types can lead to health problems, especially fats, sugars and salt.
Consumption of too much salt leads to high blood pressure which in turn leads to heart disease. Excess of lipids (fats) in the body, seems to be paramount in cases of obesity and cardiovascular disease.
We should note that fat cells are formed in childhood. They are formed in the foetus and then, during puberty when the sex hormones are triggered. It is these which dictate where fat cells will grow, therefore the diet of the mother-to-be and of children can have a huge impact on future health. After puberty fat cells no longer form. In Adulthood these fat cells expand or shrink to accommodate the fat inside our bodies.
Normal levels of fat are not a problem for the body. In fact, they are necessary for it to function smoothly. Cholesterol (type of lipid) is naturally occurring in the body, produced by the liver, it is when excess amounts of fats are consumed that cholesterol levels increase in the body, causing health problems.
There are two types of cholesterol:
Bad cholesterol – This is also called LDL cholesterol, excess of this cholesterol leads to various problems because it sticks to the wall of the blood vessels in the body. It is the excess or increased levels of LDL that is bad for your health.
Good cholesterol – This is also called HDL cholesterol. It clears bad cholesterol from the blood vessels and brings bad cholesterol to the liver where it is broken down. This helps blood to flow freely through the blood vessels.
Every dietary fat or oil is made up of one of four kinds of fats: monounsaturated, polyunsaturated, saturated and trans. Mono- unsaturated fat and poly-unsaturated fats are considered good fats and can contribute to a healthy diet, they include olive, canola, peanut and walnut oils.
Saturated fat is derived mainly from animal products such as red meat, butter, cheese, milk, cream, eggs and chicken skin; but is also present in palm and coconut oils. This type of fat is said to be damaging, raising bad cholesterol levels (LDL).
Also said, trans fatty acid raises bad cholesterol levels (LDL). Trans fats are created when oil is hydrogenated, but can also be found naturally occurring in small quantities, in animal products.
‘Some researchers also believe trans fats change how cells process insulin, which can lead to diabetes and have linked it to cancer. Trans fat is found in many processed, convenience and fast foods including: French fries, fried chicken, doughnuts, pastries, cookies, crackers and some breakfast cereals’. http://portland.indymedia.org/en/2002/02/7869.shtml
A diet high in fat raises cholesterol levels in the blood; this cholesterol sticks to the artery walls and over time causes narrowing and hardening of these vessels. Blood flow becomes restricted and this can lead to Coronary Artery Disease (CAD), Heart Attack or Stroke.
As we know the heart is a muscle which pumps blood continuously. Like any muscle in our body, in order for it to work at its optimum level it must be exercised to become stronger and more powerful.
Regular exercise can help protect your body and keep it running smoothly. However if you have not exercised for a long time then it is advisable to take it slowly to start with until your body becomes accustomed with the required energy output and as not to strain your body. Gradually increase exercise to a level to suit your individual needs.
Personal trainers and gyms can be very expensive, however no money is required as exercise can be undertaken in the comfort of your own home, or a jog in the park. Time restrictions can also be a problem such as work/family commitments; an adjustment to your timetable could afford you periods throughout the week for your exercise regime.
‘For the greatest overall health benefits, experts recommend that you do 20 to 30 minutes of aerobic activity three or more times a week and some type of muscle strengthening activity and stretching at least twice a week. However, if you are unable to do this level of activity, you can gain substantial health benefits by accumulating 30 minutes or more of moderate-intensity physical activity a day, at least five times a week’.
Exercise will help you to loose weight, burning off excess fat and assist in defence against many diseases including heart disease and stroke, high blood pressure, non insulin-dependent diabetes, obesity, back pain, osteoporosis, and can improve your mood and help you with stress management.
Daily exercise strengthens your heart muscle; pressure builds up in the heart during exercise which results in stimulation of stretch receptors in the carotid sinuses, these slow down cardiac frequency which lowers the speed of circulation. This together with dilation of muscle arterioles prevent the body developing high blood pressure. Exercise also raises your HDL cholesterol (good cholesterol) because it uses glycogen (muscle sugar) which is present in your muscles, keeping insulin levels balanced. Too much insulin in the blood constricts arteries, which causes heart attacks.
In conclusion, I realise that healthy living includes not only a balanced diet but also regular exercise to keep the heart strong and healthy. Improvements in these areas will have an impact on all the bodily functions and have major benefits for the cardiovascular system, protecting against many diseases that arise from malnutrition and lack of physical exercise.
Healthy living should be a part of life and not just a phase, if living in good health, to a ripe old age wants to be achieved.
Bibliography
Human Biology & health studies – Authors Peter Givens & Michael Reiss
Nutrition – A practical approach – Suzane Le Quesne
AQA Coordinated Science – Life Processes – Edited by Richard Parsons
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Nutrition – A practical approach – Suzane Le Quesne
Nutrition – A practical approach – Suzane Le Quesne.
Nutrition - A practical approach – Suzane Le Quesne.
