14. Atherosclerosis Flashcards
What type of cell makes up the blood tissue interface?
Endothelial cells
What processes are regulated by endothelial cells?
Anticoagulation
Moderate vascular tone and blood flow
Regulate immune reactions
Bring lipoproteins into the cell wall to create atheroma
What is released by endothelial cells to regulate vascular tone?
NO
What is released by endothelial cells to regulate immune reactions?
Cytokines
Growth factors
What enzymes are expressed by endothelial cells?
LPL
ACE and ACE2
What is atherosclerosis?
Fibrofatty deposits accumulate in the intima of arteries
What arteries can be affected by atherosclerosis?
Elastic
Medium sized
What types of tissue gather in the intima of an artery in atherosclerosis?
Inflammatory
Immune
Smooth muscle
Connective tissue
What is the difference between arteriolar stenosis and atherosclerosis?
Arteriolar sclerosis is along the whole length of the arteriole
Atherosclerosis is found in focal points along elastic, muscular arteries
What is an atheroma?
Fibrolipid plaque that protrudes into the lumen
Describe the composition of an atheroma
Cholesterol lipid core
Fibrous cap
What are the consequences of atherosclerosis?
Infarction
Ischaemia
Embolus
Aneurysm
Describe the pathogenesis of atherosclerosis
- A chronic inflammatory response is initiated by the injury to the epithelium
- Accumulation of LDL in the vessel wall
- Invasion by monocytes and leukocytes which become macrophages
- Smooth muscle migrates from the media to the intima
- Macrophages are activated
- Macrophages and smooth muscle engulf lipid
- Smooth muscle, collagen and lipid accumulate to form a plaque
What features of a plaque make it stable?
Thick fibrous cap
Calcification
What are the risk factors for atherosclerosis?
Age Gender Genetic abnormalities Hyperlipidaemia Hypertension Smoking Diabetes
What arteries can atheroma be found in?
Abdominal aorta Coronary Popliteal Descending thoracic aorta Internal carotid and circle of willis
What is an aneurysm?
Localised abnormal dilation in a blood vessel
What is a true aneurysm?
Due to a weakened wall
What is a false aneurysm?
External haematoma with connection to a leakign artery
What are the causes of an aneursym?
Atherosclerosis
Congenital defects
infections
Trauma
What is an outpouching aneurysm known as?
Saccular
What is an aneurysm that extends the entire length of the vessel known as?
Fusiform
What are the symptoms of an abdominal aortic aneurysm?
Severe abdominal pain
Shock
Pulsatile mass
How is an abdominal aortic aneurysm diagnosed?
Ultrasound
What are the consequences of an abdominal aortic aneursym?
Rupture into peritoneal cavity Obstruction to artery Embolism from atheroma Compress ureter Erode vertebrae
How is atherosclerosis managed?
Control of hypertension, diabetes, stop smoking
Reduce obesity
Exercise and diet
Statins to reduce hyperlipidaemia
Thoracic aortic dissection is not related to atheroma. TF?
True
What is a thoracic aortic dissection?
Tear in intima
Blood goes through tear and separates layers of the blood vessel wall
What are the causes of thoracic aortic dissection?
Men aged 40-60
Hypertension
Connective tissue disorders
Complication of arterial cannulation
What are the symptoms of thoracic aortic dissection?
Sudden onset of excruciating pain
Starts in anterior chest, radiates to back and downwards
Why does atherosclerosis not happen in veins?
Veins don’t have high blood pressure
Why does smoking increase the risk of atherosclerosis?
Vasoconstriction
Free radiacals
Affects platelet function
Increase circulating fibrinogen
Why does diabetes increase the risk of atherosclerosis?
Increased risk of hyperlipidaemia
Impaired breakdown of LDL and fibrin due to glycosylation
High insulin
What effect does dystrophic calcification have?
Hardens artery
What effect does an intraplaque haemorrhage have?
Rapid enlargement of plaque
