Lecture 5 Blood vessels

Question 1

Describe the structure of the tunica intima

Answer 1

• Endothelium lining made of simple squamous epithelial cells.
• contains a basal lamina of the epithelial cells.
• Subendothelial connective tissues.

Question 2

Describe the structure of the Tunica media

Answer 2

Smooth muscle fibres in loose connective tissue.

Contains elastic fibre sometimes.

Question 3

Describe the structure of the Tunica externa/adventitia

Answer 3

Connective tissue
Merges with surrounding connective tissue
Can contain vaso vasorum.

Question 4

Examples of the elastic conducting arteries

Answer 4

Brachiocephalic and common carotid and aorta.

Question 5

Name two examples of muscular distributing arteries

Answer 5

Brachial and femoral

Question 6

State the structural adaptations of elastic conducting arteries

Answer 6

Thick tunica media
Many elastic fibres
few smooth muscle cells

Question 7

State the strucural adaptations of the muscular distributing arteries

Answer 7

thick tunica media 
thick tunica externa. 
Lots of smooth muscle cells. 
Distinct internal and external elastic laminae
Diameter = 0.5mm

Question 8

What is the diamter of the muscular distributing arteries

Answer 8

0.5-0.4cm

Question 9

State the diameter of the elastic conducting arteries

Answer 9

diameter can be up to 2.5 cm

Question 10

State the diameter of the arterioles

Answer 10

<30uM

Question 11

Which of the 3 arteries has the largest diameter

Answer 11

The elastic conducting arteries.

Question 12

What are the structural adaptations of the aterioles

Answer 12

one to two layers of smooth muscle in the tunica media

poorly defined tunica externa

Question 13

What is the size of the capillaries

Answer 13

8 micrometers in diameter

Question 14

State the general features of capillaries

Answer 14

connects arterioles and venules via microcirculation

sites of gaseous exchange

thin walls facilitate diffusion

blood blow through capillaires is slow

Structure permits 2 way exchange

8 micrometers

found near every cell.

Question 15

What does the capillary sphincter do, and what does contractiona and relaxation of the capillary do.

Answer 15

Capillary sphincter guards the entrance to each capillary
contraction narrows the entrance
relaxation dilates the entrance

Question 16

What is the arteriovenous anastomoses and what does this structure permit

Answer 16

Forms direct communication between the arteriole an the venule.

When dilated blood bypasses the capillary bed and flows directly to venous circulation.