atherosclerosis

Question 1

define atheroma

Answer 1

accumulation of intracellular and extracellular lipid in the intima and media of large and medium sized arteries

Question 2

define atherosclerosis

Answer 2

the thickening and hardening of arterial walls as a consequence of atheroma

Question 3

define arteriosclerosis

Answer 3

the thickening of the walls of arteries and arterioles usually as a result of hypertension or diabetes mellitus

Question 4

what are the macroscopic features of aatherosclerosis

Answer 4

fatty streak -represents earliest stage of atherosclerosis. lipid deposits in intimate of artery. yellow and slightly raised
the simple plaque - raised yellow/white. irregular outline. enlarge and coalesce
the complicated plaque- thrombosis, haemorrhage into plaque, calcification and aneurysm formation

Question 5

what are the common sites of atherosclerosis

Answer 5

aorta 
coronary arteries 
carotid arteries
cerebral arteries 
leg arteries

Question 6

describe normal arterial structure

Answer 6

endothelium 
internal elastic lamina
muscular media 
external elastic lamina
adventitia

Question 7

what are the early microscopic features of atherosclerosis

Answer 7

proliferation of smooth muscle cells
accumulations of foam cells
extracellular lipid

Question 8

what are the late microscopic features of atherosclerosis

Answer 8

fibrosis
necrosis
cholesterol clefts
increase/ decrease in inflammatory cells
disruption of internal elastic lamina and then damage extending to media
ingrowth of blood vessels
plaque fissuring (surface of plaque ruptures)

Question 9

how do cholesterol clefts appear in microscopy

Answer 9

needle shaped holes in tissue as cholesterol gets dissolved out when we prepare cell for microscopy

Question 10

what are the clinical affects of ischaemic heart disease

Answer 10

sudden death 
myocardial infarction 
angina pectoris -chest pain on exertion due to poor blood supply 
arrhythmias
cardiac failure

Question 11

clinical effects of cerebral ischaemia

Answer 11

transient ischaemic attack (mini stroke)
cerebral infarction (stroke)
multi-infarct dementia

Question 12

clinical effects of mesenteric ischaemia

Answer 12

ischaemic colitis - characterised by bleeding in rectum 
malabsorption (chronic form)
intestinal infarction (acute form)

Question 13

clinical affects of peripheral vascular disease

Answer 13

intermittent claudication- pain in calves on exercise
leriche syndrome -buttock pain & impotence
ischaemic rest pain
gangrene- blood flow to large areas of tissue is cut off. skin becomes greenish-black colour

Question 14

risk factors of atherosclerosis

Answer 14

age 
gender- women protected before menopause due to hormones 
hyperlipidaemia 
cigarette smoking
hypertension 
diabetes mellitus 
alcohol 
infection
obesity

Question 15

how does smoking cause atherosclerosis

Answer 15

reduced PG12

Increased platelet aggregation

Question 16

what are the theories behind atherosclerosis

Answer 16

thrombogenic theory-plaques formed by repeated thrombi, lipid derived from thrombi, overlying fibrous cap
insudation theory- endothelial injury, inflammation, increased permeability to lipid from plasma
reaction to injury hypothesis-plaques form in response to endothelial injury, hypercholestrolaemia leads to endothelial damage, injury increases permeability and allows platelet adhesion, monocytes penetrate endothelium , smooth muscle cells proliferate and migrate.
the monoclonal hypothesis- each plaque is monoclonal, might represent abnormal growth control, each plaque might be a benign tumour , viral cause ?

Question 17

what processes are involved in atherosclerosis

Answer 17

thrombosis
lipid accumulation
production of intercellular matrix
interactions between cell types

Question 18

what cells are involved in atherosclerosis

Answer 18

endothelial cells 
platelets 
smooth muscles 
macrophages 
lymphocytes 
neutrophils

Question 19

how are endothelial cells involved in atherosclerosis

Answer 19

key role in Haemostasis
altered permeability to lipoproteins
production of collagen
stimulation of proliferation and migration of smooth muscle cells

Question 20

how are platelets involved in atherosclerosis

Answer 20

key role in Haemostasis

stimulate proliferation and migration of smooth muscle cells (PDGF)

Question 21

how are smooth muscle cells involved in atherosclerosis

Answer 21

take up LDL and other lipid to become foam cells

synthesise collagen and proteoglycans

Question 22

how are macrophages involved in atherosclerosis

Answer 22

oxidise LDL (they are more damaging in oxidising form)
take up lipids to become foam cells
secrete proteases which modify matrix
stimulate proliferation and migration of smooth muscle cells

Question 23

how are lymphocytes involved in atherosclerosis

Answer 23

TNF (tumour necrosi factor) may affect lipoprotein metabolism
stimulate proliferation and migration of smooth muscle cells

Question 24

how are neutrophils involved in atherosclerosis

Answer 24

secrete proteases leading to continued local damage and inflammation

Question 25

what causes endothelial injury

Answer 25

raised LDL
toxins - cigarette smoke
hypertension
haemodynamic stress

Question 26

what does endothelial injury cause

Answer 26

platelet adhesion , PDGF release, SMC proliferation and migration
insulation of lipid , LDL oxidation, uptake of lipid by SMC and macrophages
migration of monocytes into intima

Question 27

foam cells produce cytokines what does this cause

Answer 27

further SMC stimulation

recruitment of other inflammatory cells

Question 28

how can atherosclerosis be prevented

Answer 28

no smoking 
reduced fat intake 
treat hypertension
decrease alcohol intake 
regular exercise

Question 29

atherosclerosis intervention

Answer 29

stop smoking 
modify diet 
treat hypertension 
treat diabetes 
lipid lowering drugs