A glance at the cardiovascular system
The circulatory system is a body organ system which allows blood to circulate and the transport of nutrients, gases (oxygen, carbon dioxide), hormones and blood cells to and from the cells to ensure they can support cell nutrition and functions. The circulatory system is often seen to involve two systems: the cardiovascular system, engaged to distribute blood, and the lymphatic system, which circulates the lymph.
We will focus on the cardiovascular system and its relevance for health.
The cardiovascular system comprises the blood, heart, and blood vessels; and it includes two essential loops: the pulmonary circulation through the lungs where the blood is oxygenated; and the systemic circulation, which involves the rest of the body to provide oxygenated blood. Indeed, all cells in the body need to have oxygen and nutrients, and they need their wastes removed. The heart, blood and blood vessels work together to provide such service to the cells of the body. The cardiovascular system of humans is closed, so that the blood never leaves the network of blood vessels. Oxygen and nutrients, however, diffuse across the blood vessel layers and enter interstitial fluid (fluid between cells), which carries oxygen and nutrients to the target cells, and carbon dioxide and wastes in the opposite direction.
Blood is a fluid that consists of red blood cells; white blood cells, platelets, and plasma. Red blood cells carry oxygen from the lungs to the rest of the body, and carry waste products to be released by the lungs or the kidneys. Red blood cells contain haemoglobin, which is the protein that binds and releases oxygen. White blood cells are part of the immune system. They detect and fight with infections and/or foreign molecules that enter the body. Platelets are small blood cells that help the blood clot, being essential for coagulation. Plasma is the fluid that carries the cells and nutrients obtained from the diet such as sugars, fats, proteins, vitamins and minerals. As well as carrying cells, nutrients, oxygen and waste, blood also helps to regulate body temperature.
Blood circulates by the heart through the vascular system, carrying oxygen and nutrients to and waste materials away from all body tissues. From the small intestine, the blood gathers food nutrients and delivers them to every cell.
What the heart and blood vessels do?
The heart pumps blood around the body, and actually it is a double pump made up of four chambers, with the flow of blood going in one direction due to the presence of the heart valves.
Blood vessels (arteries, capillaries and veins) are assembled like a network whereby blood carries carbon dioxide to the lungs (for exhalation) and picks up oxygen. There are different types of blood vessels, with different roles and structures. Blood vessels are elastic tubes that carry blood to every part of the body.
Arteries are blood vessels engaged in the transportation of oxygenated blood from the heart. Oxygenated blood is pumped from the heart along arteries, which are muscular. Arteries divide like tree branches until they are slender. The largest artery is the aorta, which connects to the heart and picks up oxygenated blood from the left heart ventricle. The only artery that picks up deoxygenated blood is the pulmonary artery, which runs between the heart and lungs. So, arteries carry blood away from the heart
Capillaries represent the smallest blood vessels. The arteries eventually divide down into the capillary. Oxygen and food nutrients pass from these capillaries to the cells. Capillaries are also connected to veins, so wastes from the cells are transferred to the blood.
The veins have one-way valves instead of muscles, to stop blood from running back the wrong way. Generally, veins carry deoxygenated blood from the body to the heart, where it can be sent to the lungs. Indeed, veins return blood back to the heart. The exception is the network of pulmonary veins, which take oxygenated blood from the lungs to the heart.
Blood leaves the heart in large arteries, then moves through progressively smaller ones to the capillaries in tissues. It leaves in veins that get larger as they get closer to the heart. The arteries can expand and contract to lower or increase blood pressure, according to body needs.
Healthy blood vessels do the job they are supposed to do efficiently. Less-than-healthy blood vessels may have obstructions or weaknesses that restrict the circulation and delivery of nutrients. In light of its functions, the relevance of the cardiovascular system becomes obvious and keeping it in good health is essential to avoid potential vascular problems.
Vascular Disease is a term that includes any condition that affects the cardiovascular system, which ranges from diseases of arteries (artery diseases), and veins (vein diseases). This term can apply also to diseases of lymph vessels to blood disorders that affect circulation.
Atherosclerosis is a common artery disease which involves inflammatory events within the artery wall that lead to build plaque deposits that cause narrowing of the arteries and that tend to become unstable causing unstable, prone to rupture plaques. Atherosclerosis is the root cause of serious health issues such as heart attacks, stroke, and peripheral artery disease. Other examples of artery problems include aneurysms (weak spots in an artery wall), while vein diseases include venous insufficiency – where a faulty valve in a vein leads to blood flowing the wrong way or ‘leaking’ – or varicose veins – problems with the valves that stop blood from running backwards-
Controlling blood cholesterol can help keep healthy arteries and cardiovascular system
Cholesterol often gets a bad rap in our culture, but in fact is an essential substance for humans.
Cholesterol is an insoluble fat substance involved in many metabolic processes, such as the building of cell membrane structures; the production of hormones like estrogens, testosterone and adrenal hormones, the production of Vitamin D, and the production of bile acids, which help the body digest fat and absorb important nutrients. So, cholesterol is necessary for life and health.
Most of our cholesterol comes from our own synthesis. The body makes its own cholesterol; it is produced mainly in the liver, and is also made in other body’s cells, such as bowel cells.
Since cholesterol is a lipid (fat) structure and blood is essentially aqueous, it is carried around in the blood by little ‘couriers or carriers’ called lipoproteins. These lipoproteins include chylomicrons, very low-density (VLDL); low-density (LDL) and high-density (HDL) lipoproteins, the two last ones the most relevant for understanding the balance needed to have healthy arteries preventing atherosclerosis and consequences.
The cholesterol carried by LDL and HDL are currently named LDL-C (‘bad’ or atherogenic cholesterol) and HDL-C (“good” cholesterol)
Problems can occur however when the LDL-C level is too high, so that it is easily oxidized and trigger a series of inflammatory events, leading to build the plaques that can clog the arteries. By opposite, HDL plays a role in removing excess cholesterol, and also exhibit anti-oxidant and anti-inflammatory effects.
Consequently, lowering LDL-C and increasing HDL-C, thus lowering LDL-C to HDL-C ratio, can help in lowering the risk of heart disease and stroke.
According to the Better Health Channel, the recommendation from health authorities in Australia is to have total blood cholesterol levels of no more than 5.5mmol/L if there are no other risk factors present.
If there are other cardiovascular risk factors such as smoking and high blood pressure or pre-existing cardiovascular (heart) disease, then the aim for the LDL levels would be below 2 mmol/L. In a 2013 health survey, the Australian Bureau of Statistics defined abnormal HDL-C as being less than 1.0 mmol/L for men and less than 1.3 mmol/L for women.
To evaluate your cardiovascular health consult with your general practitioner. There are a number of risk factors associated with cardiovascular disease and risk. Some risk factors cannot be changed, such as increasing age, male gender and family history of premature CVD. Other risk factors, however, can be controlled or modified and such control is the key strategy to prevent cardiovascular issues and to have a good cardiovascular health.
High values of blood cholesterol, blood pressure and blood sugar are among major cardiovascular risk factors, but they can be managed through a healthy lifestyle, which may be enough for many cases, while others can require medications recommended by the doctors.
Lifestyle and healthy blood cholesterol values
For many of us, our lifestyles can be a contributing factor in high cholesterol. This means changing our habits can help improve our cholesterol profile. Healthy recommendations include:
- Eat a healthy diet. From a dietary standpoint, the best way to lower your cholesterol is reduce saturated fat and trans
- Exercise regularly. Routine physical activity can lower LDL-C and triglycerides (another blood fat) and raise HDL-C level.
- Weight management. Reduce your bodyweight if you are overweight or obese. These factors contribute to raise blood LDL-C and triglyceride levels.
- Don’t smoke. Smoking increases the ability of LDL-C to get into artery cells and cause damage; and also lowers HDL-C values.
- Cease alcohol consumption or reduce your alcohol intake to no more than one or two drinks a day.
In some cases, in addition to lifestyle measures (and never replacing or ignoring them) treatments may be necessary to help control cholesterol levels. These may include medications or complementary medicine.
For your own wellbeing, it pays to take steps to keep your blood vessels in good health, through maintaining the right cholesterol levels, and living a healthy active lifestyle.
Keeping arteries healthy is vital for wellbeing. Read how controlling cholesterol can help keep them in good shape.
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Piepoli MF, Hoes AW, Agewall S, Albus C, Brotons C, Catapano AL, et al. Authors/Task Force Members 2016 European Guidelines on cardiovascular disease prevention in clinical practice: The Sixth Joint Task Force of the European Society of Cardiology and Other Societies on Cardiovascular Disease Prevention in Clinical Practice (constituted by representatives of 10 societies and by invited experts) Developed with the special contribution of the European Association for Cardiovascular Prevention & Rehabilitation (EACPR) Eur Heart J. 2016; 37(29):2315–2381.