Regulation of coronary blood flow and mechanisms of CHD Flashcards

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1
Q

What causes the development of collateral vessels? What are 3 specific stimuli for their growth?

A

Epicardial stenosis

VEGF, bFGF and PDGF

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2
Q
Among the following, hat is the major deteminant of coronary blood flow? 
• Autoregulation
• Wall tension
• Metabolic factors
• Neural regulation
• Humoral regulation
• Myogenic tone
A

Metabolic factors

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3
Q

What are 3 major determinants of myocardial oxygen consumption?

A

Contractility
Heart Rate
Wall Tension

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4
Q

What are 2 determinants of oxygen supply to the myocardium?

A

Coronary blood flow

Oxygen extraction

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5
Q

Where would wall stress be greater, the endocardium or epicardium?

A

Greater in the endocardium

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6
Q

Where would resting blood flow be greater, in the epicardium or endocardium?

A

Greater in the endocardium

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7
Q

What is the role of autoregulation in coronary blood flow?

A

Over a certain pressure, it ensures constant flow even as perfusion pressure changes

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8
Q

Where in the heart vasculature is the major site of changes in resistance?

A

Arterioles

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9
Q

What is the crux of myogenic regulation in the heart?

A

As the blood vessels stretch more, there is a greater increase in smooth muscle contraction

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10
Q

Alpha adrenergic stimulation of the heart occurs via stimulation of alpha 1 vs alpha 2 receptors. What is the effect of alpha 1 stimulation? What is the effect of alpha 2 stimulation? What is the overall effect of adrenergic stimulation on coronary blood flow?

A

Alpha 1 - Increased epicardial and resistance vessel tone
Alpha 2 - Increased release of nitric oxide
Modest decrease in coronary blood flow

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11
Q

Direct effects of beta adrenergic stimulation to the heart is mediated via _ receptors. What is the effect of this stimulation?

A

Beta 2

Decrease in epicardial and resistance vessel tone

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12
Q

Indirect effects of beta adrenergic stimulation to the heart is mediated via _ receptors. What is the effect of this stimulation? (3)

A

Beta 1

Increased HR, contractility and myocardial O2 consumption

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13
Q

What is the net effect of beta adrenergic stimulation on coronary blood flow?

A

Increased blood flow

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14
Q

What is the direct effect of parasymp stimulation to the heart? What about indirect? (3)

A

Direct - Decrease in epicardial and resistance vessel tone

Indirect - Decreased HR, arterial blood pressure and myocardial O2 consumption

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15
Q

What is the net effect of parasympathetic stimulation on coronary blood flow?

A

Decreased blood flow

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16
Q

What is the effect of reactive oxygen species on nitric oxide levels? What is the net effect on vascular tone?

A
Use up (decrease) NO
Block relaxation mediated by NO
17
Q
How do all of the following affect levels of nitric oxide? What might counter these effects?
• Atherosclerosis
• Diabetes
• Hypertension
• Angiotensin II
• Inflammation
A

All reduce levels of NO

Countered by antioxidants

18
Q

What are 3 antioxidants referenced in the notes?

A

Vit E
Vit C
SOD/catalase

19
Q

What are the 2 factors that determine contractile function of smooth muscle?

A
  • intracellular calcium concentration

- sensitivity of contractile proteins to calcium

20
Q

Regarding smooth muscle function, phosphorylated myosin light chain leads to _, while dephosphorylated myosin light chain kinase leads to _. What are the 2 enzymes that mediate this change in phosphorylation state?

A

Contraction
Relaxation
myosin light chain phosphatase
myosin light chain kinase

21
Q

What is a negative regulator of myosin light chain phosphatase? What is the drug that targets this negative regulator? Activity of the phosphatase leads to [relaxation / contraction] of smooth muscle?

A

Rho kinase
Fasudil
Relaxation

22
Q

What is a disease state where the activity of rho kinase is elevated?

A

Cardiovascular disease

23
Q

What are 2 factors / events that can lead to angina pectoris in CHD?

A

Coronary artery stenosis following plaque formation

Vasospasm

24
Q

Fixed atherosclerotic lesions is associated with what type of angina?

A

Chronic stable angina (exertional or typical)

25
Q

Angina upon vasospasm is also referred to as _? What kind of lesion is present?

A

Variant (Prinzmetal’s) Angina

No visible lesion

26
Q

Severe atherosclerosis in coronary vessels is also termed / referred to as _

A

Unstable angina