cardiovascular week 3 Flashcards
Describe the body’s response to exercise
when local tissue blood vessels dilate, venous return increases and cardiac output raises above normal to prevent the blood pressure to fall dramatically
What is atherosclerosis?
A disease characterised by the formation of focal elevated lesions in the intima of large and medium sized arteries.
When does atherosclerotic plaques become life threatening/
when an occlusive thrombus forms on a spontaneously disrupted plaque
Describe the beginning of the formation of lesions
starts in young children
earliest significant lesion is called a fatty streak
yellow linear elevation of the intimated lining and is composed of masses of lipid-laden macrophages.
no clinical significance
Describe a fully developed plaque
central lipid core
cap of fibrous tissue covered by arterial endothelium
connective tissues in cap such as collagens provide structural integrity and are produced from smooth muscle cells
Inflam cells such as macrophages, T lymphocytes and mast cells also reside in the cap
these are recruited from arterial endothelium or in advanced plaques from newly formed micro-vessels
Describe atheromatous lesions
rich in cellular lipids and debris
they are soft, semi-fluid, highly thrombogenic lesions often bordered by a rim of “foam cells”
What are foam cells?
macrophages which have phaogcytosed oxidised lipoproteins via a specialised membrane-bound scavenger receptor
they have large amounts of cytoplasm with a foamy appearance
What can happen to plaques in the late stages?
calcification
Where do plaques have a tendency to form and why?
arterial branching points and bifurcations
the important role of turbulent blood flow in the pathogenesis of atherosclerosis
What are risk factors for atherosclerosis?
hypercholesterolaemia is by far the most important
smoking
hypertension
male gender
increasing age
less strong risk factors;
obesity
sedentary lifestyle
low socio-economic status
low birth weight
What is the process by which lesions usually develop?
injury to the endothelium of the arterial wall
tissue response of the vascular wall to injurious agents
chronic or episodic exposure to of the arterial wall to these processes leads over many years to the formation of plaques
What are the typical symptoms of angina?
constricting discomfort in the front of chest, arms, neck and jaw
provoked by physical exertion, especially after meals and in cold, windy weather or by anger or excitement
relieved (usually in minutes) by rest or glycerol trinitrate
What is stable angina?
when it is not a new symptom and when there is no change in the frequency or severity of attacks
What is unstable angina?
recent onset or a deterioration in previously stable angina with symptoms frequently occurring at rest
What are some of the clinical manifestations of atherosclerosis?
progressive lumen narrowing leading to high-grade plaque stenosis
acute atherothrombonic occlusion
embolisation to distal arterial bed
ruptured abdominal atherosclerotic aneurysm
