LATEST ARTICLES
Hypertension problems
Hormones and a cell receptor in the kidneys may explain why premenopausal women have fewer problems than men with salt-sensitive hypertension, a new study says.
Systolic And Diastolic Blood Pressure
Pressure increases due to an increase in cardiac output or increasing vascular tone, an important role in the regulation of which belongs to the kidneys...
Atherosclerosis
Hypertension is not just one illness but a syndrome with multiple brings about.
Skin Wart
Produced by a viral infection of the human papillomavirus (HPV), a wart is a skin condition that many people are experiencing. Most of the time warts are not painful and people usually want to get rid of them because they are not very attractive in appearance.
Anti-aging skin care creams
More and more people begin to investigate natural, organic-based products for skin care. Natural anti-aging skin care certainly falls into this category. With the rising popularity of natural beauty, natural anti-aging skin care creams and other products are a rapidly developing line for many health and beauty companies.
|
Atherosclerosis
Atherosclerosis - is characterized by patchy subintimal thickening (atheromas) of medium and large arteries, which can reduce or obstruct blood flow.
Arteriosclerosis - definition A generic term for several diseases in which the arterial wall becomes thickened and loses elasticity. Large elastic arteries carry blood from the heart, they divide into medium sized, muscular arteries branching throughout the body. Medium sized arteries divide into small arteries which divide further into smaller arteries called arterioles.
Arterioles entering tissues branch into many very small blood vessels called capillaries which, through their very thin walls allow exchange of substances between the blood and tissues.
Inside tissues, groups of capillaries unite to form small veins or venules. These venules merge to form veins. The veins return blood to the heart. Blood vessels, like all tissues, also need nutrients plus O2. The larger vessels are served by their own blood vessels terms vasa vasorum (vasculature of vessels). These are located within the walls of the major vessels.
The endothelium lies in the inner surface of the entire cardiovascular system and is a continuous layer of cells. It is the only tissue that under normal conditions, makes contact with the blood inside the lumen (hollow centre of the vessels).
Contraction and Dilation of Arteries Neurons of the autonomic nervous system innervate vascular smooth muscle causing vasoconstriction - narrowing of vessels. The smooth muscle fibres relax when sympathetic stimulation decreases or when some chemicals are present such as NO, K+, H+ and lactic acid.
Elastic arteries or large diameter arteries. The tunica media contains a large amount of elastic fibres. The arteries help propel the blood while the ventricles of the heart relax before the next cycle. The elastic fibres store mechanical energy for a short time and function as a pressure reservoir. The elastic arteries recoil and continue to deliver blood while the ventricles relax by converting potential energy to kinetic energy.
Blood keeps moving through the arteries even while the ventricles are relaxed. Cholesterol is a key player in the formation of arterial plaques. A diet high in fats results in the reabsorption of cholesterol-containing bile back to the blood, so less of the cholesterol is lost in faeces. Also, when saturated fats are broken down, hepatocytes (in the liver) use some of the breakdown products to make cholesterol. |