Session 1

Question 1

What is the total perfusion rate in an average 70kg male at rest?

Answer 1

5 litres per minute

Question 2

How is blood flow to different tissues controlled?

Answer 2

Using resistance vessels: arterioles and pre-capillary sphincters

Question 3

What is capacitance in relation to blood vessels?

Answer 3

Ability to cope with changes in cardiac output; a store of blood that can be used to cope with temporary imbalances in blood flow to and from the heart

Question 4

What are the layers of artery and vein walls from inside to outside?

Answer 4

Tunica intima, tunica media, tunica adventitia

Question 5

Describe the contents of the tunica intima of an artery

Answer 5

Endothelial calls with long axes orientated parallel to the long axis of the artery; narrow sub-endothelium of connective tissue with discontinuous elastic lamina

Question 6

Describe the contents of the tunica media of an artery

Answer 6

Fenestrated elastic membranes with smooth muscle cells and collagen between the lamellae; may also have a thin external elastic lamina

Question 7

Describe the contents of the tunica adventitia of an artery

Answer 7

Layer of fibroblast if tissue containing vasa vasorum, lymphatic vessels and nerve fibres

Question 8

What structural differences exist between arteries and arterioles?

Answer 8

Layers of smooth muscle in the tunica media decrease; thin elastic lamina only present in larger arterioles; external elastic lamina is absent in arterioles

Question 9

What structural differences exist between arterioles and metarterioles?

Answer 9

Smooth muscle layer isn’t continuous in metarterioles

Question 10

What are the features of continuous capillaries?

Answer 10

Pericytes form a branching network on the outer surface of the endothelium

Question 11

What are the features of fenestrated capillaries?

Answer 11

Fenestrations in the endothelium; pericytes present

Question 12

What are the features of sinusoid capillaries?

Answer 12

Fenestrated capillaries with larger openings to allow RBCs and WBCs to pass through

Question 13

What is the function of pericytes in capillaries?

Answer 13

Can divide into muscle cells or fibroblasts during angiogenesis, tumour growth and wound healing

Question 14

Which veins have a well defined muscle wall and why?

Answer 14

Superficial veins of the legs; allows them to resist distension due to gravity

Question 15

What are the features of the structure of large veins?

Answer 15

Well developed longitudinally oriented smooth muscle in tunica adventitia; circularly arranged muscle in the tunica media

Question 16

What are the features of the structure of veins?

Answer 16

Larger diameter than any accompanying artery; thinner wall with more connective tissue and fewer elastic & muscle fibres than any accompanying artery

Question 17

What differences are there in the structure of postcapillary venules and venules?

Answer 17

Smooth muscle fibres begin to be associated with the endothelium in venules

Question 18

What factors affect diffusion rate in capillaries?

Answer 18

• Area: determined by capillary density
• Diffusion resistance
• Concentration gradient