Lecture 6: Arteries and veins

Question 1

What are the three layers of blood vessel walls?

Answer 1

In to out:
1. Tunica Intima
2. Tunica Media
3. Tunica Adventitia (Externa)

Question 2

What comprises the tunica intima?

Answer 2

*Endothelium - A simple squamous epithelium which
lines the lumen of all vessels.
*Sub-endothelium - A sparse pad of loose FCT.
cushioning the endothelium.
*Internal Elastic Lamina (IEL)- a condensed sheet of
elastic tissue. The IEL is well developed in arteries
and less developed in veins

Question 3

What comprises the tunica media?

Answer 3

• Smooth muscle
• A variable content of connective tissue fibres -
  mainly elastin and collagen.
• Thickness of the media is proportional to both
  vessel diameter and blood pressure.

Question 4

What comprises the tunica adventitia (externa)?

Answer 4

• Loose FCT with a high content of collagen and variable
  amount of elastin.
• In larger vessels, the adventitia contains the vasa vasorum.
• Lymphatics and autonomic nerves are also found in this
  region.

Question 5

What is the function of arterioles?

Answer 5

The resistance vessels of the circulation - determine blood pressure.

Question 6

Function of capillaries?

Answer 6

Site of exchange between blood and tissues.

Question 7

Function of venules?

Answer 7

Start of the collecting (drainage) system

Question 8

Function of veins?

Answer 8

• Low pressure, large volume transport system
• One-way (unidirectional) flow
• Capacitance vessels

Question 9

Structure of veins?

Answer 9

Three Layers:
1. Intima
2. Media -Much thinner than arteries - a few layers of
smooth muscle (often in two distinct layers).
3. Adventitia -Often the thickest layer of a vein.

Question 10

What is the condition called when you get stretched wiggly shaped veins?

Answer 10

Called a varicose vein with a leaky valve causing the vein’s shape to loose integrity