CV Histology

Question 1

What are the layers of the wall of the heart? (name outside to inside)

Answer 1

epicardium (aka serous pericardium)
myocardium
endocardium

Question 2

What is the principal/largest cardiac muscle layer?

Answer 2

myocardium

Question 3

Describe the composition of the epicardium

Answer 3

single layer of mesothelial cells, CT, and adipose tissues

Question 4

Describe the composition of endocardium

Answer 4

inner layer of endothelium and subendo CT
middle layer of CT and smooth muscle
deeper CT layer (subendocardial) that contains Purkinje fibers and nuclei

Question 5

Describe the tissue composition of the heart valves.

Answer 5

connective tissue with overlying endocardium

Question 6

What layer of the heart wall contains the Purkinje fibers?

Answer 6

endocardium

Question 7

What structural feature do the purkinje fibers contain?

Answer 7

intercalated disks

Question 8

In what layer of the heart wall are the cardiac muscle fibers found

Answer 8

myocardium

Question 9

Which is larger, purkinje fibers or cardiac muscle fibers?

Answer 9

purkinje fibers

**nuclei are larger too

Question 10

What color do the purkinje fiber nuclei stain in H&E? Why?

Answer 10

pale pink bc they are glycogen rich

Question 11

What is sarcoplasm?

Answer 11

cytoplasm of muscle cells

Question 12

What are the structural features found in slides of cardiac muscle

Answer 12

intercalated disks

sarcoplasm (where nuclei are found)

Question 13

What pigment will cardiac muscle frequently contain?

Answer 13

lipofuscin

Question 14

What is a portal system? What are the 2 portal systems called

Answer 14

a vein or arteriole is interposed between 2 capillary networks

• hepatic portal system
• hypothalamic-hypophyseal portal system

Question 15

What is a portal vein?

Answer 15

a vessel that connects 2 capillary beds

Question 16

What is are tunics?

Answer 16

layers of the walls of arteries and veins

Question 17

What is the innermost layer of vessel wall called?
middle?
outermost?

Answer 17

tunica intima
tunical media
tunica adventitia

Question 18

Describe the composition of the tunica intima

Answer 18

• endothelium with BM
• subendothelial layer of CT and internal elastic lamina
• *FENESTRATED

Question 19

Describe the composition of the tunica media

Answer 19

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

Question 20

Describe the composition of the tunica adventitia

Answer 20

CT layer (mostly collagen) that contains vasa vasorum and nervi vasorum

Question 21

What supplies blood to the tunica adventitia and media?

Answer 21

vasa vasorum

Question 22

What supplies blood to the tunica intima?

Answer 22

the blood vessel itself

*also supplies part of media

Question 23

Where is the vasa vasorum found? What is it/does it do?

Answer 23

adventitia of large arteria and veins

it is in tunica adventitia and supplies blood to tunica adventitia and media

Question 24

What is the nervi vascularis?
What does it do?
Where is it found?
What is another name for it

Answer 24

network of automatic nerves
controls contraction and relaxation of smooth muscle
in T. adventitia
aka nervi vasorum

Question 25

What causes vasodialtion?

Answer 25

NO | **EDRF (endothelial derived relaxing factor)**

Question 26

What are 5 roles/functions of vascular endothelial cells?

Answer 26

1. maintain blood homeostasis 2. maintain selective permiabilty barrier 3. modulate Q and R 4. hormone synthesis 5. oxidation of lipoproteins

Question 27

What are the extracellular components of the T media? What makes these?

Answer 27

elastin reticular fibers proteoglycans *made by smooth muscle cells are are found in between layers of sm muscle

Question 28

Large arteries are also known as

Answer 28

elastic arteries | i.e aorta

Question 29

Describe the variations on the 3 layers in large arteries.

Answer 29

- T intima is thick and contains collagen and elastic fibers - internal elastic lamina is hard to find - T media is thicker than adventitia - T media contains multiple fenestrated sheets of elastic lamellae

Question 30

What does collagen in T media and adventita do? (in large arteries)

Answer 30

prevents excessive distention during systole

Question 31

What maintains BP during diastole? (in large arteries)

Answer 31

recoil of the elastic, distended fibers

Question 32

Medium arteries are also known as

Answer 32

muscular arteries

Question 33

How are medium arteries different than large arteries?

Answer 33

- T media has more smooth muscle - prominent internal elastic lamina - thinner subendothelial layer - less elastic material in T media - T adventia is the same size as T media (in large arteries media is thicker adventitia)

Question 34

What kind of artery has prominent internal AND external elastic membranes

Answer 34

medium (large only have prominent external)

Question 35

Describe the walls of arterioles (small arteries)

Answer 35

- 1-5 layers of smooth muscle in T media - may or may not have internal elastic lamina - tunica adventitia is thin and ill defined

Question 36

How can you distinguish between small and medium arteries?

Answer 36

count the layers of smooth muscle 1-5 = small > 5 = medium

Question 37

Describe the vascular wall of capillaries

Answer 37

they have a single layer of endothelium and basal lamina | *note: pericyte covering the basal lamina does not count as a layer

Question 38

What are the 3 types of capillaries?

Answer 38

continuous fenestrated discontinuous

Question 39

Where are continuous capillaries found?

Answer 39

muscle, CNS, lung

Question 40

In continuous capillaries, what is found between endothelial cells?

Answer 40

occluding junctions

Question 41

What are unspecialized cells that give rise to endothelial cells and smooth muscle cells?

Answer 41

pericytes (Rouget cells) | **assc with some continuous capillaries

Question 42

Where are fenestrated capillaries found?

Answer 42

endocrine glands

Question 43

What types of capillaries have a continuous basal lamina?

Answer 43

continuous and fenestrated

Question 44

What separates the fenestrations in fenestrated capillaries?

Answer 44

thin diaphragms

Question 45

Where are sinusoid capillaries found?

Answer 45

liver, spleen, bone

Question 46

T or F: the diameter of sinusoid capillaries are smaller then continuous and fenestrated

Answer 46

F: they are larger

Question 47

What are between the endothelial cells in sinusoid capillaries?

Answer 47

gaps

Question 48

In liver, what can be found in sinusoidal spaces?

Answer 48

macrophages (kupffer cells)

Question 49

Richness of capillary network is related to ____

Answer 49

metabolic activity of the tissue

Question 50

What is a slight thickening of the smooth muscle at the origin of the capillaries from an arteriole called?

Answer 50

pre-capillary sphincter

Question 51

What are the 3 categories of veins?

Answer 51

venules, small-medium veins, and large veins

Question 52

What are the 2 subtypes of venules?

Answer 52

post capillary and muscular

Question 53

What is the difference between postcapillary venules and muscular venules?

Answer 53

postcapillary receive blood from capillaries while muscular venules lie distal to postcapillary venules postcapillary venules has endothelium resting on basal lamina and pericytes there is no T media or T adventitia muscular venules have 1-3 layers of smooth muscle in T media and a thin adventitia

Question 54

What kind of vessel is the principal site of action for histamine and serotonin?

Answer 54

postcapillary venules

Question 55

Do veins or arteries have a larger lumen?

Answer 55

veins

Question 56

Where in the body do our veins have valves? What is the function of these valves?

Answer 56

in the extremities to make sure the blood flows in one direction

Question 57

Describe the 3 layers of the walls of medium sized veins.

Answer 57

T intima: endothelium, BM, subendothelial layer, and sometimes an internal elastic membrane T media: circularly arranged smooth muscle T adventitia: thicker than the T media and consists of collagen and elastic fibers

Question 58

How are medium sized arteries different than medium sized veins?

Answer 58

T media is much larger in a medium sized artery and the T adventitia is much larger in a medium sized vein

Question 59

Describe the layers large veins

Answer 59

T initma: sub endothelium, BM, and thin sub endothelial layer (**NO internal elastic lamina**) T media:is thin and has circularly arranged muscle fibers T adventitia: thickest layer and has **bundles of longitudinally arranged smooth muscle**

Question 60

How are large arteries and veins different?

Answer 60

wall of veins are much thinner | veins may have a much larger lumen

Question 61

How can you compare and contrast arteries and veins of the same size?

Answer 61

- both a and v have 3 layers - arteries have thicker walls due to inc thicknessof T media - in histological sections, veins are more collapsed than arteries after fixation

Question 62

What sized veins have valves

Answer 62

medium and large

Question 63

What is the function of arteriovenous shunts?

Answer 63

regulate blood flow

Question 64

How do AV shunts regulate blood flow?

Answer 64

contraction of arteriole smooth muscle sends blood to capillaries (inc P) relaxation of arterioles sends blood directly to venules (bypassing capillaries0

Question 65

How do the walls of lymphatic vessels compare to venules?

Answer 65

much thinner

Question 66

Is the flow in lymphatic vessels uni or bi directional? How?

Answer 66

uni | **valves

Question 67

where are lymphatic vessels most numerous?

Answer 67

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

Question 68

lymphatic vessels ultimatly end up as 2 large trunks...

Answer 68

1. thoracic duct | 2. right lymphatic duct