Lecture Notes on Blood Vessels and Circulation

Introduction to Blood Vessels

• The science of blood vessels is called Angiology.
• Focus on systemic circulation:
  • Heart with four chambers: left ventricle, right atrium.
  • Blood flow sequence: Arteries → Arterioles → Capillaries → Venules → Veins.

Structure of Blood Vessels

• Blood vessels have three layers (except capillaries):
  • Capillaries have endothelium and basement membrane (or basal lamina).

Types of Arteries

Elastic Arteries

• Elastic arteries come out from the heart and need elasticity for expansion.
• Layers in elastic arteries:
  • Tunica intima: Endothelial cells + elastic connective tissue.
  • Tunica media: Elastic fibers + smooth muscle.
  • Tunica adventitia: Elastic and collagenous fibers, contains vasa vasorum (blood vessels of blood vessels).
• Examples of elastic arteries:
  • Ascending aorta, right and left coronaries, brachiocephalic, arch of aorta, left subclavian, right and left common carotids.

Muscular Arteries

• Known as distributing arteries.
• Layers in muscular arteries:
  • Tunica intima: Endothelial cells + internal elastic membrane.
  • Tunica media: Predominantly smooth muscle.
  • Tunica adventitia: Collagenous fibers + external elastic membrane.
• Examples: Internal carotid (supplies 75% of the brain), first branch is the ophthalmic artery, terminal branches: anterior and middle cerebral arteries.

Blood Vessel Health and Conditions

Coronary Artery Disease

• A third of US deaths are from heart attacks (blockage of coronary arteries).
• Atherosclerosis: Plaques in arteries begin in the tunica intima, often cholesterol-rich.
• Angioplasty:
  • Inject radiopaque material into femoral artery.
  • Localize obstruction with x-ray.
  • Insert catheter with balloon and stent (wire mesh tube) to press plaque against wall.
  • Laser can also vaporize plaques.
• Importance of monitoring cholesterol: Dangerous levels >200.

Carotid Artery Plaques

• Common carotid bifurcation is a common site for plaques.
• Use ultrasound to detect plaques.
• Endarterectomy: Procedure to remove plaques in the common carotid.
• Importance of carotid body and carotid sinus for regulating blood pressure and respiration.

Summary

• Elastic arteries are crucial for supplying blood right from the heart, while muscular arteries distribute blood to the rest of the body.
• Understanding the structure and function of arteries helps in managing cardiovascular diseases and improving surgical interventions.

Visual Aids

• Slides showing different types of arteries and their structures were used to explain the concepts better.