Lecture 31: Blood Vessels

Question 1

What are the three components to blood vessel walls?

Answer 1

Tunica interna, tunica media, tunica externa

Question 2

Describe the structure of the tunica intima

Answer 2

Made of simple squamous epithelium (endothelium)

Question 3

Describe the structure of the tunica media

Answer 3

Made of smooth muscle and elastic fibres

Question 4

Describe the structure of the tunica externa

Answer 4

Made of connective tissue with collagen and elastic fibres

Question 5

What tunica contributes to the artery’s elasticity?

Answer 5

The tunica media

Question 6

What are the three groups of arteries?

Answer 6

Elastic, muscular, and arterioles

Question 7

Describe elastic arteries

Answer 7

• Large arteries near the heart
• Large lumen
• Tunica media has more elastic fibres than smooth muscle
• Exhibits stretching and recoil characteristics
• AKA the conducting arteries

Question 8

Describe muscular arteries

Answer 8

• Delivers blood to the various regions and organs of the body
• Tunica media is mostly smooth muscle
• Exhibits contractile characteristics
• AKA the distributing arteries
• Contains an internal and external elastic membrane

Question 9

Describe arterioles, specifically their tunica media

Answer 9

• Tunica media has only a few layers of smooth muscle; 3-5

Question 10

Describe capillaries

Answer 10

• Small diameter of 8-10 um
• Consist of only the tunica intima

Question 11

What are the three types of capillaries?

Answer 11

Continuous, fenestrated, sinusoidal

Question 12

Describe continuous capillaries

Answer 12

• Most common
• Have an uninterrupted endothelial lining
• Common in skin and skeletal muscle

Question 13

Describe fenestrated capillaries

Answer 13

• The endothelial lining has small holes in it
• Found in tissues where rapid exchange of fluids and solutes is needed (endocrine glands, kidneys, small intestine)

Question 14

Describe sinusoidal capillaries

Answer 14

• Have larger pores than fenestrated
• Thin or no basement membrane
• Leaky
• Large and irregular shaped lumen
• Found in liver, bone marrow, lymphatic tissue
• Found in spaces that require extensive exchange

Question 15

List the vessels in the venous system

Answer 15

Venules, veins

Question 16

Describe venules

Answer 16

Diameter of 8-100um
- Consist of only the tunica interna
- Resemble capillaries when still super small

Question 17

Describe veins

Answer 17

• Have 3 tunics
• Larger lumen than arteries
• Thicker tunica externa than arteries
• Have no elastic membrane
• Contain valves in medium-sized veins

Question 18

Is distribution of cardiac output higher in the arterial system or venous system?

Answer 18

The venous system is 65-70%, whereas the arterial system is 30-35%