Faculty of allied medical sciences Histopathology and cytology (MLHC-201)

DISEASES OF BLOOD VESSELS Supervision: Prof.Dr. Noha Ragab

Outcomes By the end of this lecture the student will understand the Atherosclerosis , causes and complication .

ARTERIOSCLEROSIS Definition: This is thickening and hardening of arterial walls. Arteriosclerosis includes: Atherosclerosis Mockenberg's sclerosis (medial calcification) arteriolosclerosis

ATHEROSCLEROSIS (ATHEROMA) Definition: Atherosclerosis; this is patchy thickening of the intima of arteries by lesions composed of deposited lipids surrounded by proliferating connective tissue. Each of these lesions is called atheroma

Risk factors: High levels of plasma lipids (hypercholesteriamia) cause endothelial damage Hypertension : is a major risk factor Smoking : causes endothelial damage Diabetes mellitus Life style: lack of exercise, stress, obesity Familial hereditary factors

Pathological features Sites of atherosclerosis: Large arteries: aorta and its main branches Small arteries : coronaries, cerebral and renal arteries Medium sized arteries as femoral artery

Pathogenesis: The pathogenesis of disease is according to two theories Chronic Endothelial Damage Theory Thrombogenic Theory

Chronic endothelial damage Caused by: Vascular stress (hypertension) Toxic products of cigarette Endothelial injury  allows trapping of LDL (cholesterol) in the sub-endothelial part of the intima Also endothelial injury  enhance the adherence of platelets  release of platelet factors  stimulation of proliferation of connective tissue & smooth muscles

Thrombogenic theory: Fibrosis of an arterial thrombus can give rise to atheromatous plaque (lipids within the blood involve the thrombus)

Atheroma of Aorta

Effects and Complications: (A) Ischemic effects: Ischemia may be incomplete i.e. narrowing or complete i.e. occlusion Small arteries Coronaries: Narrowing  arteriosclerosis heart diseases Occlusion  myocardial infarction Femoral artery: Narrowing  intermittent claudication Occlusion  dry gangrene of leg Large arteries: Aorta Thrombosis may develop over atheromata and this may be detached to form thrombo-emboli which can cause systemic embolism leading to infarctions in different organs

Angiogram - Embolism Infarction

Narrowing of coronaries by atheroma

Occlusion of coronaries by atheroma

(B) Aneurysms formation: A local enlargement of an artery They are due to stretch of the atrophic media The most common are: The cerebral arteries The aorta

HYPERTENSION

HYPERTENSION Definition: Hypertension is persistent elevation of blood pressure above normal. The normal adult pressure is 140/90

Types of hypertension: Primary (essential) hypertension: (90%) Secondary hypertension: (10%)

Questions Define Atherosclerosis and Hypertension ? What is the risk factor for developing atherosclerosis ? Explain with drawing the aneurysms formation ?