2.3.1　Atherosclerosis

The term atherosclerosis is derived from the Greek word“athera”meaning“soft gruel-like（porridge-/mush-/paste-like）fatty deposit”and“sclerosis”meaning“hardening”.This hardening results from a build-up of a plaquelike substance composed of cholesterol，lipids and cellular debris（atheroma）.Over time，it builds up on the inside lining of the arterial walls.Eventually，the plaque hardens，causing the vessel to lose elasticity.The lumen narrows as the plaque becomes larger.After a while，it becomes difficult for blood to pass through the blocked areas.Tissues distal to the occlusion become ischemic.In many instances，blood hemorrhages into the plaque and forms a clot（thrombus）that may dislodge.When a thrombus travels through the vascular system，it is called an embolus（plural，emboli）.Emboli in venous circulation may cause death.Emboli in arterial circulation commonly lodge in a capillary bed and cause localized tissue death（infarct）.Sometimes plaque weakens the vessel wall to such an extent that it forms a bulge（aneurysm）that may rupture.

Atherosclerosis occurs most often in the lumen of medium-sized and large arteries.Prominent risk factors of consideration are hypertension，diabetes，dyslipidemia，obesity，sedentary lifestyle，family history and smoking.Intraplaque rupture，bleeding，thrombosis and stenosis cause symptoms.The definitive diagnosis of the clinical syndromes caused by atherosclerosis usually depends on imaging tests for direct visualization of atherosclerosis in addition to medical history and physical examination.Atherosclerosis can be managed through one or all of the following interventions：lifestyle modifications（physical activity with low caloric diet），administration of antiplatelet and antiatherogenic drugs，and surgical procedures.

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Task 3　Define the meaning of each medical term given below.