Lecture 5 - Structure and Function of Blood Vessels

Question 1

What are the 3 layers of blood vessel structure?

Answer 1

Tunica intima (next to lumen) -> tunica media -> tunica adventitia/externa

Question 2

Tunica Intima Structure

Answer 2

Endothelium and simple squamous epithelium
Basal lamina of the epithelial cells
Subendothelial connective tissue

Question 3

Tunica Media Structrue

Answer 3

Smooth muscle fibres in loose connective tissue
May contain elastic fibres

Question 4

Tunica Adventitia Stucture

Answer 4

Connective Tissue
Merges with surrounding connective tissue
May contain Vaso Vasorum (vessels within the surrounding connective tissue - only for larger vessels)

Question 5

Name the 3 types of arteries (and another, more explanatory word to describe each one)

Answer 5

Elastic (Conducting) Arteries
Muscular (Distributing) Arteries
Arterioles (Resistance Vessels)

Question 6

Structural adaptations of the elastic arteries

Answer 6

Thick tunica media with many Elastic Fibres and Smooth Muscle cells

Question 7

Structural adaptations of the muscular arteries

Answer 7

MANY (+++) Smooth Muscle Cells in tunica media
Distinct Internal (IEL) and External (EEL) Elastic Laminae
Thick Tunica Externa

Question 8

Structural adaptations of the arterioles

Answer 8

One or two layers of smooth muscle cells in tunica media
Poorly defined tunica externa

Question 9

Functions of elastic arteries

Answer 9

Withstand PRESSURE CHANGES during cardiac cycle and ensure CONTINUOUS BLOOD FLOW

Question 10

Functions of muscular arteries

Answer 10

Distribute blood to muscles and organs
(Capable of vasoconstriction and vasodilation to control rate of blood flow to suit needs of an organ)

Question 11

Functions of arterioles

Answer 11

Control blood flow to organs
Involved in blood pressure control
(Capable of vasoconstriction and vasodilation)

Question 12

Name the 3 types of capillaries

Answer 12

Continuous, Fenestrated and Sinusoidal

Question 13

Where are continuous capillaries found?

Answer 13

Skeletal and smooth muscle; connective tissue; lungs

Question 14

Where are fenestrated capillaries found?

Answer 14

Kidney, Choroid Pexus and Endocrine Glands

Question 15

Where are sinusoidal capillaries found?

Answer 15

In the liver

Question 16

What do the pores in fenestrated capillaries allow?

Answer 16

Rapid exchange of water or large solutes (e.g. small peptides)

Question 17

Structure of sinusoidal capillaries

Answer 17

Spaces between endothelial cells, incomplete or absent basement membrane

Question 18

Where are metarterioles found and what do they do?

Answer 18

They branch off arterioles and supply a whole capillary bed (metarteriole -> throughfare channels -> capillaries)

Question 19

What guards the entrance to each capillary in a capillary bed?

Answer 19

Precapillary sphincter

Question 20

What do arteriovenous anastomoses do?

Answer 20

Form a direct link between arterioles and venules (bypass the capillary bed)

Question 21

Structural adaptations of veins

Answer 21

Thin walls
Tunica Externa is predominant
Valves to aid blood flow/prevent backflow