Blood vessels Flashcards
In relation to atherosclerosis, which of the following statements is correct?
A Risk is reduced by homocystinuria
B Plaques have 2 principle components, cells and lipids
C Is characterised by thickening of the tunica media of arteries
D Predominantly affects large and medium elastic arteries
D
Explanation
Atherosclerosis literally means hardening of the arteries. The dominant pattern is characterised by the formation of intimal fibrous plaques that often have a central granulomatous core, rich in lipid. It is characterized by thickening of Tunica Intima. Atherosclerotic plaques have three components:
1-cells including smooth muscle cells, macrophages and other leucocytes.
2-connective tissue extracellular matrix- including collagen, elastic fibres and proteoglycans.
3-intracellular and extracellular deposits.
Update: hyperhomocystinaemia. Serum homocysteine levels correlate with coronary atherosclerosis. Homocystinuria due to inborn errors of metabolism results in elevated homocysteine levels and is associated with premature vascular disease. Although low folate and vit B12 levels can increase homocysteine, supplemental ingestion of these vitamins does not effect the incidence of cardiovascular disease
Which of the following combinations represents the major risk factors for atherosclerosis?
A Hypertension, obesity, male, family history
B Increased lipids, cigarette smoking, hypertension, diabetes mellitus
C Hypertension, sedentary lifestyle, obesity, family history
D Hypertension, male, age, family history
B
Explanation
The major risk factors are lipids, smoking, hypertension and diabetes, no matter what age group. Male gender is a risk factor, but only if all other risks are equal. As women age and stop having their menses, their “age risk” equals that of men. Family history is important- the most independent risk factor for atherosclerosis, but it only accounts for a small percentage of cases. Most familial risk is related to multifactorial traits that go hand in hand with atherosclerosis, including hypertension, and diabetes
Which of the following statements is correct in relation to atherosclerosis?
A There are 2 components: cells and connective tissue matrix
B Lesions in the thoracic aorta are more common than in the abdominal aorta
C Coronary arteries have the worst lesions
D The severity of a lone lesion does not predict severity elsewhere
D
Explanation
The abdominal aorta is the most heavily involved vessel followed by the coronary arteries, popliteal artery, descending thoracic aorta, the internal carotid artery and the branches of the circle of Willis
Atherosclerotic plaques have three components:
1-cells including smooth muscle cells, macrophages and other leucocytes
2-connective tissue extracellular matrix including collagen, elastic fibres and proteoglycans
3-intracellular and extracellular deposits
The major risk factors for atherosclerosis are contained in which of the following options?
A Hypertension, obesity, male and family history
B Hypertension, male sex, smoking and hypercholesterolaemia
CHypertension, diabetes, smoking and hyperchoesterolaemia
D Hypertension, hypercholersterolaemia, smoking and sedentary lifestyle
C
Explanation
The major risk factors are lipids, smoking, hypertension and diabetes, no matter what age group. Male gender is a risk factor, but only if all other risks are equal. As women age and stop having their menses, their “age risk” equals that of men. Family history is important- but the family risk factor becomes less relevant with age.
Extra:
I have left this question as is, but understand that it is confusing. The current text book divides the risk factors (RF) into non-modifiable and modifiable.
Non modifiable= genetic abnormalities, family history, increasing age and male gender
Modifiable= hyperlipidaemia, hypertension, cigarette smoking, DM and inflammation
Genetic is the most independent RF for atherosclerosis- but this applies to only a small percentage of cases. A family history of atherosclerosis outside of true genetic issues (FH hypercholesterolaemia, both homo and heterozygous), are often related to a familial clustering of other established risk factors e.g. hypertension or DM or to other inherited variants that influence other pathophysiologic processes, such as inflammation.
I suspect that if you modify your lifestyle, and keep healthy, your family history (outside of true genetic abnormalities) will be less of a risk factor. Also, if you are elderly and haven’t developed IHD or the like, then you FH of atherosclerosis will again be less of a factor.
In atherosclerosis, the cells at the centre of the plaque are?
A Smooth muscle cells
B Leukocytes
C Foam cells
D Macrophages
C
Explanation
The atherosclerotic plaque consists of a superficial fibrous cap which is comprised of smooth muscle cells with a few leukocytes and relatively dense connective tissue. There is a cellular area beneath and to the side of the cap consisting of macrophages, smooth muscle cells and T lymphocytes, along with a deeper necrotic core in which there is a disorganised mass of lipid material, cholesterol clefts, cellular debris and lipid laden foam cells. Fibrin and thrombin are also contained in this area.
All of the following are major risk factors for atherosclerosis, with the exception of?
A Diabetes
B Hypertension
C Smoking
D Obesity
D
Explanation
The major risk factors are lipids, smoking, hypertension and diabetes, no matter what age group. Male gender is a risk factor, but only if all other risks are equal. As women age and stop having their menses, their “age risk” equals that of men. Family history is important- but the family risk factor becomes less relevant with age.
Obesity per se is not a major risk factor
Which of the following statements regarding malignant hypertension is correct?
A Occurs mainly in the older population
B Affects 1 to 5% of chronic hypertension sufferers
C Is associated with low levels of renin
D 75% recover with no loss of renal function
B
Explanation
Malignant hypertension affects 1-5% of chronic hypertension sufferers. Risk factors include: younger individuals, men, black and those with a diastole of >130mmHg. It is associated with abnormally high levels of renin. 75% will survive 5 years and 50% will survive with a pre-crisis renal function
Regarding a hypertensive crisis which of the following options is correct?
A Occurs more commomly in the older age group
B There are 2 morphological features: fibrinoid necrosis of arterioles and hypoplastic arteriolitis
C More common in the african population
D 75% will recover if treated promptly
C
Explanation
Malignant hypertension affects 1-5% of chronic hypertension sufferers. Risk factors include younger individuals, men, African descent and those with a diastole of >130mmHg. It is associated with abnormally high levels of renin. 75% will survive 5 years and 50% will survive with pre-crisis renal function. Hypertension is associated with 2 forms of small blood vessel diasease: hyaline arteriolosclerosis and hyperplastic arteriolosclerosis
Which of the following statements is correct regarding atherosclerotic plaques?
A Thoracic aorta is more frequently affected than the abdominal aorta
B Coronary arteries are the most often affected
C Rarely causes micro emboli
D They contain a mixture of cells and connective tissue matrix
D
Explanation
The abdominal aorta is the most heavily involved vessel, followed by the coronary arteries, popliteal, descending thoracic, the internal carotid and the branches of the circle of Willis.
Atherosclerotic plaques have three components:
1-cells including smooth muscle cells, macrophages and other leucocytes.
2-connective tissue extracellular matrix including collagen, elastic fibres and proteoglycans.
3-intracellular and extracellular deposits
Which of the following antithrombotic properties of the endothelium is false?
A Endothelial cell production of nitric oxide inhibits platelet adhesion
B Endothelial cell production of t-PA cleaves fibrinogen to fibrin
C Endothelial cell production of thrombomodulim coverts thrombin into an anticoagulant
D Endothelial cell production of ADPase inhibits platelet aggegation
B
Explanation
Normally, the endothelial cells actively prevent thrombosis by producing factors that block platelet adhesion and aggregation, inhibit coagulation and lyse clots.
Antiplatelet effects: Intact endothelium prevents platelets and clotting factors from adhering to the thrombogenic extracellular matrix (ECM). PGI2 (prostacyclin) and nitric oxide produced by the endothelial cells inhibit adhesion. Both of these mediators are vasodilators and inhibit platelet aggregation. Endothelial cells release ADPase that degrades ADP further inhibiting platelet aggregation.
Anticoagulant effects: mediated by heparin like molecules, thrombomodulin and tissue factor pathway inhibitor. Thrombomodulin binds to thrombin and converts it form a procoagulant to an anticoagulant via its ability to activate protein C. Protein C inhibits factors Va and VIIIa. Endothelium also produces co-factors for protein C and tissue factor pathway inhibitor (TFPI), which inhibits factors VIIa and Xa
Fibrinolytic effects: endothelial cells synthesise tissue plasmin activator (t-PA) that cleaves plasminogen to plasmin which inturns cleaves fibrin to degrade thrombi
What is responsible for binding of platelets to exposed extracellular matrix?
A Thromboxane A2
B Leukotriene B4
C VWF
D Factor X
C
Explanation
Platelets bind to exposed subendothelial matrix via VWF.
A 55-year-old man with chest pain undergoes a CT aortogram and is found to have an aortic dissection of his ascending thoracic aorta, extending to just proximal to the subclavian artery. His DeBakey classification is:
A I
B IV
C III
D II
D
Explanation
Stanford classification:
Type (A) (A)ffects (A)scending (A)orta, whereas
Type B (B)egins (B)eyond (B)rachiocephalic vessels
DeBakey classification - Dissections are BAD:
I = (B) - Both ascending/descending aorta
II = (A) - Ascending aorta
III = (D) - Descending aorta
Note: the picture in the textbook of a DeBakey type II seems to reflect a dissection only up to the brachiocephalic artery. However, reviewing the words in the textbook and other sources a DeBakey II involves the whole of the ascending aorta but not the descending aorta.
What is the most significant early mechanism involved in increased vascular permeability?
AEndothelial cell contraction
B Endothelial cell detachment
C Chemotaxis of inflammatory mediators
D Vasodilation
A
Explanation
Mechanisms of increased vascular permeability in acute inflammation include: Contraction of venule endothelium to form intercellular gaps (most common; immediate transient response) Direct endothelial injury Increased transcytosis (transendothelial channels)
A male presents with a pulsatile mass in his abdomen. Which of the following conditions MOST predisposes to this?
A Infections
B Vasculitis
C Atheroscleorisis
D Hypertension
C
Explanation
The two most important causes of aortic aneurysms are atherosclerosis and hypertension; atherosclerosis is a greater factor in AAAs, while hypertension is the most common aetiology associated with ascending aortic aneurysms.
Other factors that weaken the vessel walls and lead to aneurysms include trauma, vasculitis, congenital defects (fibromuscular dysplasia) and berry aneurysms typically in the circle of Willis and infections (mycotic aneurysms)
