Blood Vessels

Coordinator: Rachel Cherian, M.D.

Normal blood vessel structure

• Arteries
  • elastic arteries
    • tunica intima
    • tunica media
    • tunica adventitia
  • muscular arteries
• Arterioles
• Capillaries
• Veins
• Functions of endothelial cells (Fig 10-3)

Hemostasis and Thrombosis

• Hemostasis
• Blood coagulation (Fig. 10-6)
• Platelet aggregation (Fig. 10-7)
• Endothelial factors (Fig. 10-5)
• Clot lysis (Fig. 10-9)

Atherosclerosis

• Pathogenesis:
  • Interaction of endothelium
  • Arterial smooth muscle cell
  • Mononuclear phagocyte
  • Inflammatory cells
• Hypotheses regarding pathogenesis:
  • Insudation theory
  • Encrustation theory
  • Reaction to injury
  • Monoclonal concept
  • Intimal cell mass concept
  • Hemodynamic hypothesis
  • Unifying hypothesis (Fig. 10-10)
• Initial lesion of atherosclerosis:
  • Fatty streaks (Fig 10-11)
    • Aorta of a young man
    • Histology
  • Intimal cell mass
• Characteristic lesion of atherosclerosis
  • Fibrofatty (atherosclerotic) plaque
  • Fibrous cap and atheroma (Fig 10-12)
    • Aorta of a middle aged man
    • Atheroma, histology I
    • Atheroma, histology II
  • Complicated lesions of atherosclerosis (Fig. 10-13)
  • Thrombosis (Fig 10-16)
    • Severe arthrosclerosis
    • Mural thrombi
    • Narrowing and thrombosis
  • Calcification
  • Ulceration
• Mechanism of lesion progression
  • Cytokines
  • T lymphocytes
  • Endothelium
  • Thrombosis
  • Risk factors:
    • Hypertension
    • Blood cholesterol level
    • Cigarette smoking
    • Diabetes
    • Increasing age and male sex
    • Physical inactivity and stressful life patterns
    Lipid metabolism and atherosclerosis
    • Major classes of lipoprotein particles
      • Chylomicrons
      • Very-low-density lipoproteins (VLDL)
      • Low-density lipoproteins (LDL)
      • High-density lipoproteins (HDL)
    Exogenous metabolic pathway (Fig 10-19)
    • Endogenous metabolic pathway (Fig 10-19) - HDL
    • Oxidized LDL

  Hereditary disorders of lipid metabolism and atherosclerosis

  • Familial hypercholesterolemia
    • Apo E
    • HDL
    • Lipoprotein (a)

  Complications of atherosclerosis

  • Acute occlusion
  • Chronic narrowing of the lumen
  • Aneurysm formation
    • Abdominal aortic aneurysm
    • Aneurysm of the aorta with a thrombus
    • Ruptured aneurysm
    • Dacron prosthesis of the aorta
  • Embolism
    • Thromboembolus
    • Cholesterol crystal embolus

  Hypertensive vascular disease

  • Definition and epidemiology
  • Secondary hypertension, causes:
    • Renal disease:
      • increased renin secretion
      • sodium and fluid retention
    • Endocrine causes:
      • aldosteronism
      • Cushing syndrome
      • oral contraceptives
      • pheochromocytoma
      • thyrotoxicosis
    • Vascular causes:
      • coarctation of the aorta
      • vasculitis
    • Neurogenic causes
  • Primary (essential) hypertension
    • Benign arteriolosclerosis (Fig. 10-24)
      • Hypertensive arteriosclerosis
      • Benign arteriolosclerosis
    • Malignant (accelerated) hypertension
    • Fibrinoid necrosis of small arteries
      • Malignant hypertension I
      • Immunofluorescence
    • Smooth muscle hyperplasia"onion skin appearance"(Fig 10-26)

  Monckeberg medial sclerosis

  Raynaud phenomenon (Fig 10-15)

  Vasculitis (Table 10-9)

  • Polyarteritis nodosa (Fig 10-28)
    • Slide I
    • Slide II
  • Hypersensitivity angiitis
    • Histology of the skin
    • Immunofluorescence
  • Allergic granulomatosis and angiitis (Churg-Strauss syndrome)
  • Giant cell arteritis (temporal or granulomatous arteritis) (Fig. 10-29)
  • Wegener granulomatosis (Fig. 10-30)
  • Takayasu Arteritis
  • Kawasaki disease (Fig 10-31)
  • Thromboangiitis obliterans (Buerger disease) (Fig 10-32)

  Aneurysms

  • Classification by configuration
    • Fusiform
    • Saccular
    • Dissecting
  • Classification by etiology
  Atherosclerotic aneurysm (Fig. 10-34)
  • Abdominal aortic aneurysm
  • Aortic aneurysm with a thrombus
  • Ruptured aneurysm
  • Dacron prosthesis of the aorta
  • Congenital (Berry) aneurysms of cerebral arteries
    • Berry aneurysm
  • Dissecting aneurysm (Fig 10-353)
    • Aorta I
    • Intimal tear of the aorta in Marfan syndrome
    • Cystic medial necrosis
    • Aorta II
    • Thoracic aorta
    • Syphilitic aneurysms(Fig. 10-36)
      • Arch of the aorta I
      • Arch of the aorta II
      • Intimal surface of previous slide
      • Micro I
      • Micro II
    • Mycotic aneurysms

Veins

• Varicose veins of the legs
  • Pathogenesis, (risk factors):
    • age
    • sex
    • heredity
    • posture
    • obesity
  • Pathology
  • Clinical
    • Varicose veins of the leg
    • Stasis ulcer
• Varicose veins at other sites:
  • Hemorrhoids
  • Esophageal varices
  • Varicocele
• Deep venous thrombosis:
  • Thrombophlebitis
  • Phlebothrombosis

Lymphatic vessels:

• Lymphangitis
• Lymphatic obstruction: lymphedema, lymphangiectasia

Tumors of blood vessels

• Benign tumors
  • Hemangiomas: capillary hemangioma, cavernous hemangioma (Fig 10-38)
  • Glomus tumor (Fig 10-39)
• Malignant vascular tumors
  • Hemangioendothelioma, (intermediate malignancy)
  • Angiosarcoma
  • Hemangiopericytoma
  • Kaposi sarcoma, sporadic and epidemic forms, association with AIDS
    • Back
    • Nose
    • Palm
    • Micro
• Miscellaneous vascular lesions
  • Bacillary angiomatosis: a reactive tumor like vascular proliferation seen in patients with AIDS. The etiologic agent is Bartonella henselae. The lesion responds to antibiotics, and therefore should be distinguished from Kaposi sarcoma.