S1L2 - Histology of Blood Vessels

Question 1

Describe the general stucture of tunica intima

Answer 1

Consists of endothelium and supporting connective tissue

Question 2

Describe the general structure of tunica media

Answer 2

Consists of elastic tissue and smooth muscle

Question 3

Describe the general structure of tunica adventitia

Answer 3

Principally collagen

Question 4

How does the aorta differ to the vena cava?

Answer 4

The aorta has a larger tunica media and a smaller tunica adventitia than the vena cava.

The vena cava has a larger internal diameter and thinner wall.

Question 5

What is the internal diameter and thicknes of the wall of the aorta?

Answer 5

Internal diameter = 24ml

Wall thickness = 2mm

Question 6

What is the internal diameter and thicknes of the wall of the muscular arteries?

Answer 6

Internal diameter = 2mm

Wall thickness = 1mm

Question 7

What is the internal diameter and thicknes of the wall of the arterioles?

Answer 7

Internal diameter = 30µm

Wall thickness = 20µm

Question 8

What is the internal diameter and thicknes of the wall of the veins

Answer 8

Internal diameter = 5mm

Wall thickness = 0.5mm

Question 9

What is the internal diameter and thicknes of the wall of the vena cava

Answer 9

Internal diameter = 30mm

Wall thickness = 1.5mm

Question 10

Tha autonomic nervous system controls the diameter of arteroles. What factors help determin the diameter (also of muscular arteries in general)?

Answer 10

Local metabolites (eg. O2/CO2)
Nervous action - sympathetic nerve fibres
Circulating vasoactive hormones
Factors secreted by endothelial cells (including NO)
Mechanical factors: strech of walls`

Question 11

What are the tree types of capillaries? Where would you find each?

Answer 11

Continuous - normal tissue
Fenestrated - brain (blood-brain barrier)
Discontinuous (sinusoids) - Liver, spleen and bone marrow

Question 12

What are the histological characteristics of small and medium veins?

Answer 12

Similar to that of arteries, but with a larger lumen and thinner and irregular wall. They have a thin tunica media annd a large tunica adventitia.

They also usually contain semilunar paired valves.

Question 13

Smooth muscle is a major component of the tunica media. What are its characteristics?

Answer 13

Smallest type of muscle cells.
Spindle shaped cells with a single, central nucleus.
Not striated in appearance.
May show intrinsic activity, modified by various factors eg. ANS.

Question 14

Cardiac muscle pumps blood throught the circulation. What are its characteristics?

Answer 14

Cylindrical cells, often branched, with a single, central nucleus.
Striated in appearance.
Has intrinsic rhythmicity, modified by various factors eg. ANS.

Question 15

What are the characteristics of skeletal muscle?

Answer 15

Largest type of muscle cell.
Recieves ~20% of blood supply, even at rest.
Cylindrical fibre cells with a multiple peripheral nuclei.
Striated in appearance.
Requires motor nerve activity; no intrinsic activity.

Question 16

Blood vessels reach almost every part of our body. What are the three main sites where this is not true?

Answer 16

Cartilage; epithelia; cornea. (Also a few other structures)