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Question 1

3 structures of a vessel

Answer 1

tunica intima (inner most)
tunica media
tunica adventitia (outer)

Question 2

tunica intima is composed of

Answer 2

endothelium
subendothelium
internal elastic lamina (IEL)( in arteries)

Question 3

the tunica media is composed of

Answer 3

smooth muscle

external elastic layer (EEL) in arteries

Question 4

the tunica adventitia is composed of

Answer 4

Connective tissue and fibroblasts
Longitudinal smooth muscle in veins
Vasovasorum in large vessels

Question 5

in a large artery which layer is the thickest

Answer 5

tunica media

Question 6

endothelium of vessels

Answer 6

Composed of single layer of squamous cells, provides a permeable barrier, angiogenesis, release of single molecules.

Question 7

Medium Artery

Answer 7

Also called muscular artery because the wall is dominated by smooth muscle.
Similar to large artery but internal and external elastic lamina are well defined and lack prominent vasovasorum.

Question 8

small arteries

Answer 8

Generally have same structure as medium artery but have a smaller diameter and no external elastic lamina. The tunica media also has fewer layers of smooth muscle cells

Question 9

arterioles

Answer 9

The smallest arteries, lead blood flow into capillary beds. Only two layers of smooth muscle cells. Internal elastic lamina, external elastic lamina, and subendothelial layers usually absent.

Question 10

differences in the tunica media in larger, medium, small arteries, and arterioles

Answer 10

large: Smooth muscle cells + Large quantity of elastic fibers
medium: Dominated by multiple layers of smooth muscle cells (6-40)
small: 2-6 layers of smooth muscle
arterioles: 1-2 layers of smooth muscle cells

Question 11

Capillary

Answer 11

Smallest vessels
Connect arterioles and venules
One layer of endothelial cells with a basal lamina

Question 12

fenestrated capillary

Answer 12

have holes in endothelial layer

Question 13

discontinuous capillary

Answer 13

holes in both the endothelial layer and basolamina

Question 14

continuous capillaries

Answer 14

both the basolamina and endothelial layers are intact

Question 15

small veins structure

Answer 15

Small veins may have slightly larger lumen and more visible smooth muscle layer

Question 16

venules

Answer 16

have small lumens, thin walls, and only single layer of endothelum. Have surrounding connective tissue

Question 17

tunica adventitia in a medium or large vein

Answer 17

which is at least as wide as the media, and often even wider. With many longitudinal smooth muscle bundles and vasa vasorum.

Question 18

valves

Answer 18

Folds in the intima seen in medium and larger veins
Number of valves increase with size of vessel
Prevent backflow of blood
present in the lymphatic vessels and veins

Question 19

differences in the lumen of veins and arteries

Answer 19

arteries: Smaller, rounder. Prominent internal elastic lamina
veins: larger and flatter

Question 20

lymphatic system

Answer 20

Composed of lymphatic capillaries, vessels, and ducts
Collect and drain interstitial fluid from tissue in the large veins
Have large lumens and relatively thin walls
Single layer of endothelium
Connective tissue outer layer with few smooth muscle cells
Also have valves

Question 21

what are the 3 layers of the heart

Answer 21

endocardium, myocardium, epicardium

Question 22

define intercalculated disks

Answer 22

Junctional complexes that contain fascia adherens, desmosomes, and gap junction to provide connection and communication.

Bind myocytes and allow ion exchange to facilitate electrical impulses to pass

Question 23

Name the layer of the heart in which Purkinje fibers are found and describe their function

Answer 23

in the subendocardium of the endocardial layer

Impulse conducting fibers

Large modified muscle cells
Cluster in groups together
1-2 nuclei and stain pale due to fewer myofibrils
Terminal branches of the AV bundle branches

Question 24

Explain which chamber of the heart has the thickest layer of myocardium vs the thinnest

Answer 24

Thickest in left ventricle because must pump hard to overcome high pressure of systemic circulation

Right atrium the thinnest because of low resistance to back flow

Question 25

Explain the general histologic structure of a cardiac valve

Answer 25

Composed of connective tissue layers covered by endothelium on each side; 3 layers

Spongiosa: loose collagen (atrial side)
Fibrosa: dense core of connective tissue
Ventricularis: dense connective tissue with many elastic and collagen fibers (ventrical side)

Question 26

Differentiate cardiac, skeletal and smooth muscle on H&E stained slides citing the key distinguishing morphologic features

Answer 26

Cardiac: central round nuclei, intercalculated discs, striated, branching

skeletal: striated, Fibers with cross-striations and peripheral nuclei.

smooth muscle: Long, slender central nuclei, lying within narrow, fusiform cells. No cross striations

Question 27

endocardium is composed of

Answer 27

Innermost layer
Composed of:
• Simple squamous epithelium (endothelium)
• Connective Tissue
• Subendocardium: in contact with cardiac muscle and contains small vessels, nerves, and Purkinje Fibers.

Question 28

Myocardium consists of

Answer 28

cardiac muscle cells = myocytes

Question 29

Epicardium characteristics

Answer 29

Outermost layer of the heart
Composed of connective tissue with nerves, vessels, adipocytes and an outer layer of mesothelium
Mesothelium secretes pericardial fluid
Covers and protects the heart