Untitled Quiz

Learning Objectives

• Identify major arteries in the body.
• Describe structure and function of blood vessels in the cardiovascular system (CVS).
• Understand microscopic structure of blood vessels.
• Explain mechanisms controlling blood vessel diameter.
• Recognize risk factors for coronary artery disease (CAD) and their relation to atherosclerosis.
• Describe progression steps of atherosclerosis.

Overview of Blood Vessels

• Heart propels blood at high pressure through arteries, then low pressure in veins.
• Types of blood vessels include:
  • Arteries: Includes large arteries, small arteries, arterioles.
  • Capillaries: Site for substance exchange.
  • Veins: Comprised of venules, small veins, and large veins.

Blood Vessel Structure

• Comprised of three layers known as tunics:
  • Tunica intima: innermost layer.
  • Tunica media: middle muscle layer, responsible for vasoconstriction and vasodilation.
  • Tunica externa: outermost layer.

Types of Arteries

• Arteries serve as pressure reservoirs with three main types:
  • Elastic arteries:
    • Large and thick-walled, e.g., aorta and femoral artery.
    • Composed of elastin, allowing distension and recoil as blood moves.
  • Muscular arteries:
    • Medium size (1 cm - 0.3 mm), involved in blood distribution.
    • Control via extrinsic mechanisms; less elastic, more muscular.
  • Arterioles:
    • Smallest arteries (diameter 0.3 mm - 10 µm).
    • Regulate blood flow to capillary beds through hormonal, neural, and local influences.

Mechanisms Controlling Blood Flow

• Intrinsic control: adjusts blood flow independently of nerves/hormones through myogenic and metabolic autoregulation.
• Extrinsic control: redirects blood flow efficiently to maintain blood pressure and direct it to vital areas via neural and hormonal signals.

Atherosclerosis

• Common form of arteriosclerosis characterized by plaque formation in tunica intima.
• Risk factors include:
  • Hypertension
  • Dyslipidaemia (high cholesterol)
  • Hyperglycaemia (high blood sugar)
  • Sedentary lifestyle
  • Obesity
  • Smoking
  • Chronic stress
• Complications can lead to stroke, heart attack, and chronic conditions affecting various arteries.

Coronary Artery Disease Treatment

• Coronary angioplasty is a procedure to widen obstructed coronary arteries using a balloon.

CVD Prevalence & Mortality

• Higher prevalence of cardiovascular disease (CVD) among younger indigenous populations.
• CVD is a leading cause of death, particularly among indigenous males.

Key Terms

• Atheroma: raised lesion formed in the tunica intima.
• Vasoconstriction: narrowing of blood vessels to reduce blood flow.
• Vasodilation: widening of blood vessels to increase blood flow.