See Atherosclerosis. * "Smooth Muscle" * Smooth muscle histology photomicrographs Myosin II contains two heavy chains which constitute the head and tail domains. Each of these heavy chains contains the N-terminal head domain, while the C-terminal tails take on a coiled-coil morphology, holding the two heavy chains together (imagine two snakes wrapped around each other, such as in a caduceus). Thus, myosin II has two heads. In smooth muscle, there is a single gene (MYH11 ) that codes for the heavy chains myosin II, but there are splice variants of this gene that result in four distinct isoforms.
smooth muscle cellssmooth musclessmooth muscle cell
serum cholesteroldietary cholesterolcholesterol level
Elevated levels of the lipoprotein fractions, LDL, IDL and VLDL are regarded as atherogenic (prone to cause atherosclerosis). Levels of these fractions, rather than the total cholesterol level, correlate with the extent and progress of atherosclerosis. Conversely, the total cholesterol can be within normal limits, yet be made up primarily of small LDL and small HDL particles, under which conditions atheroma growth rates would still be high.
coronary arteriescoronarycoronary artery
These relatively narrow vessels are commonly affected by atherosclerosis and can become blocked, causing angina or a heart attack. The coronary arteries that run deep within the myocardium are referred to as subendocardial. The coronary arteries are classified as "end circulation", since they represent the only source of blood supply to the myocardium; there is very little redundant blood supply, that is why blockage of these vessels can be so critical. If the posterior descending artery is supplied by the right coronary artery (RCA), then the coronary circulation can be classified as "right-dominant".
atherosclerotic plaqueplaqueatheromatous plaque
Atherosclerosis. Atherothrombosis. Coronary circulation. Coronary catheterization. EBT. Hemorheologic-Hemodynamic Theory of Atherosclerosis. Lipoprotein. LDL, HDL, IDL and VLDL.
carotid endarterectomiesendarterectomy, carotidsurgery to open up the arteries to the brain
Need for open heart surgery within 30 days. Left ventricular ejection fraction of ≤30%. Recent (≤30-day) heart attack. Severe lung disease or COPD. Severe renal disease. High cervical (C2) or intrathoracic lesion. Prior radical neck surgery or radiation therapy. Contralateral carotid artery occlusion. Prior ipsilateral CEA. Contralateral laryngeal nerve injury. Tracheostoma.
plaque ruptureplaque rupturesobviously symptomatic
Repeated atheroma rupture and healing is one of the mechanisms, perhaps the dominant one, that creates artery stenosis. Researchers have found that accumulation of white blood cells, especially macrophages, termed inflammation, in the walls of the arteries leads to the development of "soft" or vulnerable plaque, which when released aggressively promotes blood clotting.
congenital heart diseaseheart defectcongenital heart defects
Common defects include pulmonic stenosis, aortic stenosis, and coarctation of the aorta, with other types such as bicuspid aortic valve stenosis and subaortic stenosis being comparatively rare. Any narrowing or blockage can cause heart enlargement or hypertension. The septum is a wall of tissue which separates the left heart from the right heart. Defects in the interatrial septum or the interventricular septum allow blood to flow from the right side of the heart to the left, reducing the heart's efficiency. Ventricular septal defects are collectively the most common type of CHD, although approximately 30% of adults have a type of atrial septal defect called probe patent foramen ovale.
Any pathology which constricts blood flow, such as stenosis, will increase total peripheral resistance and lead to hypertension. Arteriolosclerosis is the term specifically used for the hardening of arteriole walls. This can be due to decreased elastic production from fibrinogen, associated with ageing, or hypertension or pathological conditions such as atherosclerosis. The muscular contraction of arterioles is targeted by drugs that lower blood pressure (antihypertensives), for example the dihydropyridines (nifedipine and nicardipine), which block the calcium conductance in the muscular layer of the arterioles, causing relaxation.
transient ischaemic attacktransient ischemic attacksmini-stroke
Also, carotid stenosis secondary to atherosclerosis narrowing the diameter of the lumen and thus limiting blood flow is another common cause of TIA. Individuals with carotid stenosis may present with TIA symptoms, thus labeled symptomatic, while others may not experience symptoms and be asymptomatic. Risk factors associated with TIA are categorized as modifiable or non-modifiable. Non-modifiable risk factors include age greater than 55, sex, family history, genetics, and race/ethnicity. Modifiable risk factors include cigarette smoking, hypertension (elevated blood pressure), diabetes, hyperlipidemia, level of carotid artery stenosis (asymptomatic or symptomatic) and activity level.
drug eluting stentdrug-eluting stentsdrug-eluting
With PCI, the requirement for emergency CABG has markedly decreased since the days of balloon angioplasty, such that in some communities, coronary stenting is permitted in hospitals without on-site cardiac surgery facilities, though this remains highly controversial in the United States, not the least because of the rare but largely unpredictable risk of coronary artery perforation. Rarely, a type of allergic reaction to the drug may occur; episodes of fatality have been reported.
IVUSIntravascular ultrasound systemsultrasound
In the early 1990s, IVUS research on the re-stenosis problem after angioplasty lead to recognition that most of the re-stenosis problem (as visualized by an angiography examination) was not true re-stenosis. Instead it was simply a remodeling of the atheromatous plaque, which was still protruding into the lumen of the artery after completion of angioplasty; the stenosis only appearing to be reduced because blood and contrast could now flow around and through some of the plaque. The angiographic dye column appeared widened adequately; yet considerable plaque was within the newly widened lumen and the lumen remained partially obstructed.
Diabetes mellitus (DM), commonly referred to as diabetes, is a group of metabolic disorders in which there are high blood sugar levels over a prolonged period. Symptoms of high blood sugar include frequent urination, increased thirst, and increased hunger. If left untreated, diabetes can cause many complications. Acute complications can include diabetic ketoacidosis, hyperosmolar hyperglycemic state, or death. Serious long-term complications include cardiovascular disease, stroke, chronic kidney disease, foot ulcers, and damage to the eyes.
Second World WarwarWWII
World War II (often abbreviated to WWII or WW2), also known as the Second World War, was a global war that lasted from 1939 to 1945. The vast majority of the world's countries—including all the great powers—eventually formed two opposing military alliances: the Allies and the Axis. A state of total war emerged, directly involving more than 100 million people from over 30 countries. The major participants threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources.
Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue, causing it to harden. Calcifications may be classified on whether there is mineral balance or not, and the location of the calcification. Calcification may also refer to the processes of normal mineral deposition in biological systems, such as the formation of stromatolites or mollusc shells (see Mineralization (biology) or Biomineralization).
mitral stenosismitral valvuloplastymitral atresia
Although the immediate results of PBMV are often quite gratifying, the procedure does not provide permanent relief from mitral stenosis. Regular follow-up is mandatory, to detect restenosis. Long-term follow-up data from patients undergoing PBMV indicates that up to 70-75% individuals can be free of restenosis 10 years following the procedure. The number falls to about 40% 15 years post-PBMV. Heart failure symptoms, such as dyspnea on exertion, orthopnea and paroxysmal nocturnal dyspnea (PND). Palpitations. Chest pain. Hemoptysis. Thromboembolism in later stages when the left atrial volume is increased (i.e., dilation).
mitralbicuspid valvemitral annulus
In abnormal conditions, blood may flow backwards through the valve (mitral regurgitation) or the mitral valve may be narrowed (mitral stenosis). Rheumatic heart disease often affects the mitral valve; the valve may also prolapse with age, and be affected by infective endocarditis. The mitral valve is named after the mitre of a bishop, which resembles its flaps. The mitral valve is typically 4 to 6 cm2 in area, and sits in the left heart between the left atrium and the left ventricle. It has two leaflets (or 'cusps'), an anteromedial leaflet, and a posterolateral leaftlet. The opening of the mitral valve is surrounded by a fibrous ring known as the mitral annulus.
pulmonic valvepulmonarypulmonary (or pulmonic) valve
The pulmonary valve (sometimes referred to as the pulmonic valve) is the semilunar valve of the heart that lies between the right ventricle and the pulmonary artery and has three cusps. Similar to the aortic valve, the pulmonary valve opens in ventricular systole, when the pressure in the right ventricle rises above the pressure in the pulmonary artery. At the end of ventricular systole, when the pressure in the right ventricle falls rapidly, the pressure in the pulmonary artery will close the pulmonary valve.
blood clotblood clotsclot
Arterial thrombosis resulting from hypertension or atherosclerosis can become mobile and the resulting emboli can occlude any artery or arteriole downstream of the thrombus formation. This means that cerebral stroke, myocardial infarction, or any other organ can be affected. 3) Dissolution occurs when the fibrinolytic mechanisms break up the thrombus and blood flow is restored to the vessel. This may be aided by fibrinolytic drugs such as Tissue Plasminogen Activator (tPA) in instances of coronary artery occlusion.
blood clottingblood coagulationclotting
Coagulation, also known as clotting, is the process by which blood changes from a liquid to a gel, forming a blood clot. It potentially results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair. The mechanism of coagulation involves activation, adhesion, and aggregation of platelets along with deposition and maturation of fibrin. Disorders of coagulation are disease states which can result in bleeding (hemorrhage or bruising) or obstructive clotting (thrombosis).