Histology

Question 1

Where is most of the blood in the body held?

Answer 1

Peripheral veins

Question 2

What is the inner layer of blood vessels?

Answer 2

Tunica intima - a single layer of squamous epithelial cells supported by a basal lamina and a thin layer of connective tissue

Question 3

What is the middle layer of blood vessels?

Answer 3

Tunica media - made up predominately of muscle (in some areas there is a significant amount of elastic tissue) - this layer varies tremendously and in some cases virtually disappears

Question 4

What is the outer layer of blood vessels?

Answer 4

Tunica adventitia - supportive connective tissue

Question 5

Why are the largest arteries termed “elastic arteries”?

Answer 5

They have many elastic sheets in their tunica media to allow elastic recoil

Question 6

What is the vascular supply to the large arteries called?

Answer 6

Vasa vasorum

Question 7

What are pericytes and where are they found?

Answer 7

Connective tissue cells that have contractile properties that are found at intervals just outside the basal lamina of capillaries

Question 8

What are fenestrated capillaries and where are they found?

Answer 8

Capillaries with ~50nm pores in the walls

Found in mucosa of gut, endocrine glands, glomeruli of kidneys

Question 9

What are sinusoidal capillaries and where are they found?

Answer 9

They have large gaps through which macromolecules, and in some cases even cells, can pass
Found in liver, spleen and bone marrow

Question 10

Which type of capillary lacks a basal lamina?

Answer 10

Sinusoidal capillaries

Question 11

What structures at the beginning of capillaries help control blood flow through the network?

Answer 11

Precapillary sphincters

Question 12

What is the structure of the endocardium of the heart?

Answer 12

Endothelium
Basal lamina
Thin layer of collagen fibres
Layer of denser connective tissue

Question 13

What is the structure of the myocardium of the heart?

Answer 13

Bundles and layers of contractile cardiac muscle fibres

Individual muscle fibres are surrounded by delicate, collagenous connective tissue with a rich network of capillaries

Question 14

Histologically, what is the fibrous pericardium?

Answer 14

A sac of tough fibrocollagenous connective tissue

Question 15

What does the serous pericardium consist of?

Answer 15

Made up of a layer of simple squamous epithelium (termed mesothelium), backed by a basal lamina and connective tissue

Question 16

What is the function of the serous pericardium?

Answer 16

Lines the inner surface of the fibrous pericardium (where it is termed the parietal serous pericardium), and covers the surface of the heart (where it is termed the visceral serous pericardium)

Question 17

What is the name given to the core of dense connective tissue in the heart valves and what structure is it related to?

Answer 17

Lamina fibrosa, in continuation with the cardiac skeleton

Question 18

Where are the Purkinje fibres found?

Answer 18

The subendocardial layer, just deep to the endocardium