Histology

Question 1

Sinusoids

Answer 1

Non true capillaries: vascular channels, much larger
discontinuous endothelium with discontinuous basement membrane

Think liver, spleen, bone marrow

allow for direct communication b/w parenchymal cells and endothelial spaces
associated with phagocytes (Kupferr cells)

Question 2

Tunica Intima

Answer 2

deepest layer

• endothelium
• BM
• subendothelial CT
• IEL (more visible in larger vessels)

Question 3

Tunica Media

Answer 3

• Smooth muscle
• CT fibers
• EEL

muscle organized in spiraling orientation
EEL more prominent in medium sized vessels
Largest layer in arteries

Question 4

Tunica adventitia

Answer 4

mostly dense CT with lots of collagen from fibroblasts

Question 5

Arterioles

Answer 5

Thin intima, no CT, no IEL
controls flow to capiliaries–> controls BP
no EEL

Question 6

Medium (muscular) arteries

Answer 6

small amount of CT, IEL present

40 layers of smooth muscle, ANS controls blood flow. EEL present but hard to see

Question 7

Large (elastic) arteries

Answer 7

lots of CT, limited IEL
lots of smooth muscle with high elastic fibers
elasticity allows you to decrease pulsatility of blood flow during delivery to peripheral vessels

tunica adventitia prevents over-distension of inner layers
contain vaso vasorum

Question 8

Vein structure

Answer 8

large lumen, thinn intima and media with very small amount of elastic lamina

adventitia is thickest with lots of fibrous CT and no smooth muscle

valves made of intima +endothelium

Question 9

Arteries vs. veins

Answer 9

Veins always have greater CSA than artery that it runs with
Arteries have more smooth muscle and more elastic fibers and IEL

veins have more collagen, less smooth muscle and valves

Question 10

Endocardium

Answer 10

continuous with tunica intima of great vessels

• endothelium + BM
• Subendothelial CT
• Subendocardial CT (binds endocardium with myocardium)
• Purkinje fibers: impulse conducting system

Question 11

Purkinje fibers

Answer 11

cardiac muscle made for impulse conduction

specialized myofiber with high glycogen content

Question 12

Myocardium

Answer 12

bundled cardiac muscle fibers
thickets in ventricles
supported by thin CT networks that carry vessels and nerves

Question 13

Epicardium

Answer 13

visceral layer of pericardial sac
fluid filled
carries nerves and ganglia
lots of adipose

Question 14

heart valves

Answer 14

evagniations of endocardium

supported by fibrous rings

Question 15

IEL

Answer 15

Most prominent in Medium (muscular) arteries

- may not be visible in arterioles or large (elastic) arteries

Question 16

EEL (OEL)

Answer 16

Most prominent in Medium muscular arteries
-also present in large (elastic) arteries)
not visible in arterioles