C14. Histology of heart and blood vessels

Question 1

what does the cardiovascular system consist of

Answer 1

heart, arteries (elastic/muscular), arterioles, meta arterioles, capillaries, venules, post capillary venule, veins

Question 2

name the 3 blood vessel layers

Answer 2

Tunica - Intima, media, adventitia

Question 3

describe the inner layer of a blood vessel

Answer 3

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

Question 4

describe the middle layer of a blood vessel

Answer 4

tunica media
made up of smooth muscle
thickness varies

Question 5

describe the outer layer of a blood vessel

Answer 5

tunica adventitia made of supporting connective tissue

Question 6

tunica intima and media are separated by a layer of what?

Answer 6

elastic tissue called internal elastic membrane

Question 7

tunica media and adventitia are separated by a layer of what?

Answer 7

elastic tissue called external elastic membrane

Question 8

when elastic fibres are specially stained, what colour do they stain

Answer 8

black

Question 9

why are large arteries like the aorta termed elastic arteries

Answer 9

because they have many sheets of elastic fibres in their tunica media to provide elastic recoil

Question 10

Large vessels, only the inner part of the wall can obtain nutrients from the lumen, therefore these vessels will have their own vascular supply called what?

Answer 10

Vasa Vasorum

Question 11

describe arterioles structure

Answer 11

Arterioles have only one or two layers of smooth muscle in their tunica media and almost no adventitia.

Question 12

arterioles have an important role of what

Answer 12

These are particularly important in controlling blood flow in a tissue.

Question 13

what is interesting an different about meta arterioles

Answer 13

smooth muscle is replaced by discontinuous contractile cells called pericytes

Question 14

where are capillaries absent

Answer 14

epithelial cells resting on basement membrane
epidermis of skin, hair and nail
cornea of eye
hyaline cartilage

Question 15

what are capillaries composed of

Answer 15

endothelial cells and a basal lamina

Question 16

what cells are often on capillaries at intervals just outside the basal lamina. And what type of cells are they

Answer 16

pericytes - connective tissue cells with contractile properties

Question 17

name the 3 types of cappilaries

Answer 17

continuous
fenestrated
discontinuous (or sinusoidal)

Question 18

where are continuous capillaries found

Answer 18

muscle, connective tissue, lung, skin, nerve

Question 19

where are fenestrated capillaries found

Answer 19

mucosa of the gut, endocrine glands, glomeruli of the kidney

Question 20

one type of capillary has large gaps and another has 50nm pores. which is which?

Answer 20

fenestrated have 50nm pores
discontinuous has large gaps

Question 21

where are discontinuous capillaries found

Answer 21

liver, spleen and bone marrow

Question 22

which type of capillary lacks a basal lamina

Answer 22

discontinuous

Question 23

blood getting from a small arteriole to a post capillary venule has to go through other vessels to get there. Which vessels are these?

Answer 23

Metarterioles (MT)
Throughfare channels (TC)
Capillaries (C)
Precapillary sphincters (PS)

Question 24

Post capillary venules are made up of what?

Answer 24

endothelial lines and have a thin layer of connective tissue and occasional pericytes

Question 25

what are post capillary venules important for?

Answer 25

sites of exchange eg. cells moving into the tissue in inflammation

Question 26

once post capillary venules gain more smooth muscle cells in their tunica media they become...? and what size are these generally?

Answer 26

venules >50um

Question 27

Vein have a thin/thick continuous/discontinuous tunica intima/media/adventitia choose from the options to complete the sentence

Answer 27

thin, continuous, tunica media

Question 28

name the two largest veins

Answer 28

vena cava and hepatic portal vein

Question 29

The largest veins (e.g. vena cava or hepatic portal vein) have a ........ tunica adventitia which incorporates bundles of ......... ........ smooth muscle.

Answer 29

thick longitudinally oriented

Question 30

which vessels contain the most blood in the body

Answer 30

veins

Question 31

veins contain what structure

Answer 31

valves

Question 32

what are valves

Answer 32

inward extensions of the tunica intima that prevent backflow of blood

Question 33

name the 3 layers of the heart

Answer 33

endocardium, myocardium and epicardium

Question 34

what is the endocardium made from

Answer 34

endothelium basal lamina thin layer of collagen fibres layer of denser connective tissue

Question 35

what area of the heart is made of loose connective tissue, small blood vessels and nerves, and branches of the impulse conducting system (Purkinje fibres)

Answer 35

subendocardium

Question 36

what is the myocardium made of

Answer 36

bundles and layers of contractile cardiac muscle fibres Individual muscle fibres are surrounded by delicate, collagenous connective tissue with a rick network of capillaries

Question 36

cardiac muscle cells have how many nuclei

Answer 36

single central nucleus (sometime 2)

Question 37

what specialised structures are in cardiac muscle cells

Answer 37

intercalated discs

Question 38

what is the external layer of the heart called

Answer 38

epicardium

Question 39

what is the epicardium made of

Answer 39

-single layer of flattened epithelium called mesothelium -basal lamina -fibroelastic connective tissue and in some places adipose tissue

Question 40

what is the pericardium

Answer 40

a sac of tough fibrocallagenous connective tissue

Question 41

name the part of the pericardium that is made up of a layer of simple squamous epithelium (mesothelium), basal lamina and connective tissue

Answer 41

serous pericardium

Question 42

what are the 2 types of serous pericardium

Answer 42

visceral and parietal

Question 43

visceral serous pericardium covers where?

Answer 43

surface of the heart

Question 44

what is the space between the visceral and parietal serous pericardium

Answer 44

pericardial cavity

Question 45

what does the pericardial cavity contain

Answer 45

small amount (15-50ml) of pericardial fluid

Question 46

what does the pericardial fluid aid?

Answer 46

lubrication for heart movement

Question 47

what is the fibrous 'skeleton' of the heart and valves made of

Answer 47

thick bands of fibrous connective tissue around the valves and between the atria and ventricles

Question 48

what does the fibrous 'skeleton' do

Answer 48

the fibrous connective tissue supports the valves and provides attachment for the cardiac muscle fibres

Question 49

A core of dense connective tissue is called what

Answer 49

A core of dense connective tissue, called the lamina fibrosa, that is in continuity with the fibrous skeleton.

Question 50

The leaflets of the valves separating the atria from the ventricles (the mitral and tricuspid) are anchored to ..............in the wall of the ventricle by collagenous strands called the chordae tendineae, which merge with the lamina fibrosa.

Answer 50

papillary muscles

Question 51

leaflets of the mitral and tricuspid valves are anchored to papillary muscles in the wall of the ventricle by collagenous strands called the ...................., which merge with the lamina fibrosa.

Answer 51

chordae tendineae

Question 52

leaflets of the mitral and tricuspid valves are anchored to papillary muscles in the wall of the ventricle by collagenous strands called the chordae tendineae, which merge with the ............

Answer 52

lamina fibrosa.

Question 53

what type of blood vessels are in valves

Answer 53

none - there are no blood vessels in valves

Question 54

what is at the core of a heart valves

Answer 54

lamina fibrosa

Question 55

The lamina fibrosa is the core of a heart valve and is '............ ............' connective tissue that is continuous with the fibrous skeleton of the hear. What kind of connective tissue is described here?

Answer 55

dense irregular

Question 56

name the 3 types of cardiac muscle cells:

Answer 56

contractile pacemaker conducting