Histology

Question 1

which heart wall layer contains purkinje fibers?

Answer 1

endocardium

Question 2

how do purkinje fibers stain compared to cardiac muscle fibers?

Answer 2

larger, larger nuclei, stain pale

Question 3

what defines a portal system? what are the two portal systems?

Answer 3

when a vein or arteriole is interposed bw two capillary networks

hepatic
hypothalamic-hypophyseal

Question 4

what is the tunica intima composed of?

Answer 4

endothelium, basement membrane, subendothelial layer with CT and an internal elastic lamina

Question 5

What is the tunica media composed of?

Answer 5

circularly arranged layers of smooth muscle cells, elastic and collagen fibers, and sometimes an external elastic membrane

Question 6

what is the tunica adventitia composed of?

Answer 6

CT, with vasa vasorum and nervi vasorum

Question 7

what parts of the vessel does the vasa vasorum supply?

Answer 7

the tunica adventitia and media (intima is supplied by the vessel)

Question 8

what is the function of the nervi vascularis (nervi vasorum)?

Answer 8

contraction and relaxation of smooth muscles in the media

Question 9

what are general features of endothelial cells?

Answer 9

homeostasis
maintain selective permeability
maintain nonthrombogenic barrier
modulate BF and vascular resistance
hormonal synthesis
modification of lipoproteins by oxidation

Question 10

what are general features of smooth muscle cells?

Answer 10

maintain BP

produce elastin, reticular fibers, and proteoglycans

Question 11

what are large arteries AKA? example? features?

Answer 11

elastic arteries
aorta

media thicker than adventitia
many fenestrated sheets of elastic lamellae in media
collagen fibers in media and adventitia (prevents excessive distention of the large arteries)

Question 12

what are medium arteries AKA? features?

Answer 12

muscular arteries

more smooth muscle in media
prominent internal elastic lamina
thin subendothelial layer
little elastic material

Question 13

how many layers of smooth muscle in arterioles?

Answer 13

1-5

Question 14

how to distinguish small from medium arteries?

Answer 14

count the layers of smooth muscle nuclei (arterioles have < 5 ; medium arteries have >5)

Question 15

structure of capillary?

Answer 15

single layer of endothelium and basal lamina

Question 16

3 types of capillaries?

Answer 16

continuous, fenestrated, discontinuous

Question 17

where are continuous capillaries found?

Answer 17

muscle lung CNS

Question 18

what kind of junctions in continuous capillaries?

Answer 18

occluding junctions

Question 19

what are rouget cells?

Answer 19

pericytes that are associated with some capillaries and can give rise to endothelial and smooth muscle cells

Question 20

where are fenestrated capillaries found?

Answer 20

endocrine glands

Question 21

what are fenestrations spanned by?

Answer 21

thin diaphragms

Question 22

what are discontinuous capillaries AKA?

Answer 22

sinusoids

Question 23

Where are sinusoids found?

Answer 23

liver spleen bone marrow

Question 24

features of sinusoids?

Answer 24

larger diameter
irregular shape
incomplete basal lamina
gaps bw endothelial cells

Question 25

in the liver, sinusoidal space has what?

Answer 25

macrophages (kupffer cells

Question 26

where is the principal site of action for histamine and serotonin?

Answer 26

postcapillary venules

Question 27

what do veins contain that arteries don't

Answer 27

unidirectional valves

Question 28

in veins, adventitia is larger/smaller than media

Answer 28

larger

Question 29

in large veins, the tunic adventitia has bundles of _____

Answer 29

longitudinally disposed smooth muscle

Question 30

differences bw large artery and vein?

Answer 30

vein has less thick wall (thinner media) but larger luminal diameter (is often collapsed)

Question 31

what are AV shunts or anastamoses?

Answer 31

they regulate BF by allowing direct communication bw arterioles and venules

Question 32

what happens when AV shunts contract? relax?

Answer 32

send blood to capillaries sends blood directly from arterioles to venules

Question 33

where are lymphatic vessles numerous?

Answer 33

in loose CT under the epithelium of the skin and mucous membranes

Question 34

two large lymphatic trunks?

Answer 34

thoracic duct and right lymphatic duct