A MATTER OF THE HEART: THE CIRCULATIONYou begin to marvel at the way it continues to beat 100000 times a day, continuously pumping about 5 litres of blood per minute around the circulatory system, handling some 7000 litres of blood every 24 hours. That means that, in the average lifetime, nearly 200 million litres are circulated around the body.The basic route of the blood’s remarkable journey is this. Fresh blood (i. e., blood saturated with oxygen (O2) and bright red in colour) is pushed from the left ventricle through the aortic valve into the aorta. It then flows through the arteries to all parts of the body, where it supplies the various tissues with essential oxygen and other nutrients. Once these life-giving nutrients have been expended, leaving in their stead carbon dioxide (CO2), water and other waste-products, the blood, now dark purplish-red (it is often called ‘blue’ or venous blood) flows through the veins back to the heart, entering the right atrium (or receiving area). It then passes through the tricuspid valve into the right ventricle; from here it is pumped through the pulmonary valve into the pulmonary artery, which leads to the lungs. In the lungs the blood is oxygenated and water and CO2 are extracted; it then flows through the pulmonary veins to the left atrium, ready to begin the cycle again.There is, then, a strict route taken by the blood: from the body via the veins to the right side of the heart, from there to the lungs, from the lungs to the left side of the heart and from there back to the body via the arteries. This is where those one-way valves become important, ensuring that the blood does not seep back. And, of course, in order to maintain sufficient driving force the heart has to keep going – the body cannot wait for fresh supplies of oxygenated blood. The wastes soon become toxic unless they are removed and replaced by fresh oxygen.The blood is carried by three kinds of vessels: arteries, which take blood from the heart to the body’s tissues and lungs; veins, which carry it on its return journey to the heart; and capillaries, which act as link roads, as it were, connecting the smaller arteries to the smaller veins. (Note that, while normally veins carry ‘blue’ blood and arteries carry oxygenated blood, the pulmonary vessels are the exception – the pulmonary vein carries red blood and the pulmonary artery carries ‘blue’.) Thus when an artery reaches a muscle, for example, it will branch out into tiny capillaries so that the blood can enter the muscle itself. After being deprived of its oxygen and loaded with waste products, the blood then leaves the muscle through a similar network of capillaries which then join up at a vein. Think of the capillaries as the smallest twigs of a tree, carrying nourishment from the main boughs and larger branches to all the leaves.*5/353/5*
Archive for February, 2011
INCIDENCE OF CANCESex does not affect the incidence of the disease. However, proportion of cancer in males and females is roughly 10:12. It also affects the site of growth. In men, cancer is usually found in the intestines, the prostate and the lungs. In women, it occurs mostly in the breast tissues, uterus, gall-bladder and thyroid.Cancer occurs at all ages, from infancy to old age. There is a close relationship between cancer and aging. In the United States, over one-half of all cancers occur in 11 per cent of the population over the age of 65. At the age of 25, the probability of developing cancer within five years is one in 700, while at the age of 65, it is one in 14. The peak incidence and mortality of cancer is in the 60-70 age range.Although deaths attributable to cancer decrease from 30 per cent at age 50 to 10 per cent or less at age 85, this is largely due to rapid increase in death due to other causes with advancing age, and not due to non-prevalence of cancer. Despite the marked increase in cardiovascular related deaths with age, cancer remains the second leading cause of death in those over 65.Cancer is not contagious or infectious. This is clearly evident from the fact that a large number of members of the medical profession and technicians come in close contact and handle cancer tissues in the course of treating patients, but they do not get cancer any more than other sections of the people. No infective agent has so far been detected from cancer tissues.*5/355/5*
JUVENILE RHEUMATOID ARTHRITIS AND CHILDRENAre autoimmune antibodies evident in these children?Yes, for some reason the antibodies found in lupus and other autoimmune disease are found in these children. This does not mean that they have lupus, just that this syndrome is likely to be an autoimmune disorder, like adult RA. The occurrence of these antibodies in children with these diseases can sometimes cause scary confusion.A good pediatric rheumatologist knows the importance of eliminating other illnesses as causes of symptoms.
What are the lifelong consequences in children?Many patients require lifelong therapy with anti-arthritic drugs. The anti-inflammatory agents and the new disease-modifying anti-rheumatic drugs (DMARDs) are very useful in the later life treatment of JRA patients. Problems like stunted limbs or a shortened jaw are only a few side effects of JRA. Today, these skeletal deformities are not as prevalent since early diagnosis and treatment are much more common. Unlike many other aspects of the disease, these growth changes can be irreversible.
What type of doctor should my child with JRA see?Specialists called pediatric rheumatologists would examine, diagnose, and treat your child. They are experts in the childhood forms of arthritis.*21/141/5*