Introduction to Blood Vessels and Circulation

Learning Objectives

  1. Identify the structural characteristics (composition of tunics) and functions of the three major types of blood vessels.
  2. Identify the three major types of arteries. Describe the structure and function of each.
  3. Describe the basic structure and function of all three of the major capillary types.
  4. Describe capillary beds. Include the following terms in your discussion: true capillaries, vascular shunt, and precapillary sphincters. Identify the triggers for precapillary sphincter contraction and relaxation.
  5. Compare veins with arteries in terms of the following: size and composition of the tunics, elasticity, distensibility, pressure, resistance, valves, and volume.
  6. Define blood flow, blood pressure, and total peripheral resistance.
  7. Explain how each of the following can affect resistance, pressure, and flow: blood viscosity, total blood vessel length, and blood vessel radius.
  8. Define systolic pressure and diastolic pressure and explain why arterial pressure is pulsatile and how arterial pressure varies with distance from the heart.
  9. Explain how venous return is affected by respiratory and skeletal muscle pumps.
  10. Describe the location and function of the vasomotor center.
  11. Describe the baroreceptor reflex response to a high rise in arterial BP.
  12. Identify the primary adrenal medulla hormones and discuss their site of production, triggers for release, and effect on blood pressure.
  13. Describe the relationship between blood volume and blood pressure and explain how the rate of urine production can alter blood volume and blood pressure.
  14. Describe the renin-angiotensin system and its effect on BP. Include the following in your discussion: renin, angiotensin II, aldosterone, and antidiuretic hormone.
  15. Define tissue perfusion and explain why adequate tissue perfusion is essential.
  16. Describe how total cross-sectional area differs in arteries, capillaries, and veins and describe the relationship between blood velocity and total vessel cross-sectional area.
  17. Identify and describe the four forces that affect the bulk flow of fluid between blood and the interstitial fluid. Explain how those forces affect net filtration pressure and filtration and reabsorption.
This photo shows a forearm with the veins bulging.

Figure 1. While most blood vessels are located deep from the surface and are not visible, the superficial veins of the upper limb provide an indication of the extent, prominence, and importance of these structures to the body. (credit: Colin Davis)

In this chapter, you will learn about the vascular part of the cardiovascular system, that is, the vessels that transport blood throughout the body and provide the physical site where gases, nutrients, and other substances are exchanged with body cells. When vessel functioning is reduced, blood-borne substances do not circulate effectively throughout the body. As a result, tissue injury occurs, metabolism is impaired, and the functions of every bodily system are threatened.