Histo Exam 2-Blood & lymph vessels study guide Flashcards Preview

Histology Fall 2014 > Histo Exam 2-Blood & lymph vessels study guide > Flashcards

Flashcards in Histo Exam 2-Blood & lymph vessels study guide Deck (72)
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1

What classifies a macrovasculature?

>0.1mm in diameter

2

What are examples of macrovessels?

elastic and muscular arteries, large arterioles and veins

3

What classifies a microvessel?

<0.1mm in diameter

4

What are examples of microvessels?

arterioles, capillaries, and post-capillary venules

5

What is the order of blood flow in the heart?

heart>aorta>arteries>aterioles>capillaries>venules>veins>vena cava

6

How are blood vessels organized?

according to type and size

7

what is the purpose of smooth muscle in arteries?

it's important in maintaining high hydrostatic pressure

8

Why is there little to no smooth muscle in veins?

due to lower pressure in venules

9

What does smooth muscle do in association with capillary beds?

regulates how much blood can be in capillary beds

10

What are the basic layers of the vascular wall?

Intima, Media, Adventitia

11

What is the tunica intima?

single layer of simple squamous epithelia called endothelium.plus a basal lamina and subendothelial layer of loose connective tissue

12

What is another layer that might be found in the Tunica intima?

internal elastic lamina beneath the subendothelium

13

What types of vessels would this internal elastic lamina be found?

most prominent in muscular arteries

14

What is the tunical media?

concentric layer of smooth muscle fibers with interspersed elastic fibers and type 3 collagen

15

What is found in the tunica media of arteries?

external elastic lamina

16

What is the tunica adevenitia?

fibroblasts, type 1 collagen, and elastic fibers oriented along the longitudinal axes

17

What do arteries do?

transport blood away from the heart

18

What are the two types of arteries?

elastic and muscular

19

What are examples o elastic arteries?

aorta and its branches

20

What are the characteristics of elastic arteries?

very thick high walls with high elasticity

21

What is the purpose of elasticiy in elastic arteries?

elasticity helps stabilize and maintain blood flow during systole and diastole

22

What are weibel-palade bodies?

rodlike inclusions within the tightly packed endothelial cells specific for elastic fiber

23

What does the media of elastic arteries consist of?

mostly elastic fibers and concentrically arranged fenestrated elastic lamellae

24

What happens to the fibers of media in elastic arteries with age?

increase with age

25

What are the multiple layers of tunical media in elastic arteries?

multiple layers of concentrically arranged smooth muscle fibers and vasa vasorum

26

What is a vasa vasorum?

small vessesl within the wall of larger vessels

27

What is adventitia like in elastic arteries?

thin and underdeveloped with mainly fibrocytes, type 1 collagen, elastic fibers, and some vasa vasorum

28

What do the Weibel-Palade bodies do?

contain secretory granules used for post-synthesis storage of endothelial proteins involved in hemostasis and inflammation

29

What do WPBs contain?

P-selectin and von Willebrand Factor

30

What is the purpose of P-selectin?

recruits circulating leukocytes to site of injury

31

What is he purpose of von Willebrand Factor?

plays a major role in blood coagulation

32

What is the purpose of vasa vasorum?

supply the thick vessel layers with oxygen and nutrients

33

What are nervi vasorum?

small unmyelinated sympathetic nerve fibers that stimulate vasoconstriction through release of norepinephrine

34

What are muscular arteries?

Distributing branches of elastic arteries

35

What is the purpose of muscular arteries?

control blood flow to organs by contracting and relaxing smooth muscle within the tunica media

36

What is the tunica intima in muscular arteries like?

prominent internal elastic lamina that sometimes appears undulated/wavy

37

What is the tunica media like in muscular arteries?

contains up to 40 concentric layers of smooth muscle fibers enveloped by their own basal lamina, type III collagen and may have outer external elastic lamina

38

What is the tunica adventicia like in muscular arteries?

thin consisting of loosely arranged collagen and elastic fibers, fibrocytes and nerves

39

What is an aneurysm?

abnormal widening of a portion of an artery due to weakness within the vessel wall

40

What are common locations for aneurysms?

aorta, popliteal, mesenteric spenic and cerebral arteries

41

What are characteristics of an arteriole?

endothelium with flat to rounded nuclei and thin subendothelium

42

What are the tunics like in arterioles?

generally only 1-2 smooth muscle layers thick, no internal or external laminal and sparse adventitia

43

What are capillaries composed of?

single layer of endothelial cells rolled into a tube and pericytes

44

What are pericyts?

specialized contractile cells with rounder nuclei that can differentiate into smooth muscle cells in arterioles and venules

45

What is the purpose of capillaries?

allow for exchange of molecules between blood and tissues

46

What portion of blood vessels do capillaries comprise?

90%

47

What are continuous capillaries?

smooth, continuous endothelium with no gaps or pores

48

How are these continuous capillary cells connected?

through tight occluding junctions with a continuous basal lamina

49

How do continuous capillaries transport molecules?

Only through transcytosis or diffusion across endothelial cell membranes

50

Where are continuous capillaries found?

muscle, brain, peripheral nerves, exocrine glands

51

What are fenestrated capillaries?

endothelial cells held together by tight junctions but have perforated pores with a continuous external basal lamina

52

Where are fenestrated capillaries found?

kidneys, intestines, endocrine glands

53

What are discontinuous capillaries?

gaps between endothelial cells that are large enough to allow cells to pass through

54

Sinusoidal capillaries have_____ fenestrations with _________basal lamina.

large, discontinuous

55

Where are sinusoidal capillaries found?

liver, spleen, some endocrine glands, bone marrow

56

What are postcapillary venules?

resemble large capillaries, lumens are much larger than capillaries or arterioles

57

What are the puprose of postcapillary venules?

sites at which white blood cells leave circulation and move into tissues

58

What is the purpose of venules?

allow for gradual transition from capillary to venule

59

What are characteristics of arterioles?

large lumen diameter with very thin wall

60

Where do you find veins in relation to arteries?

usually travel near arteries and are sometimes parallel

61

How do veins differ from arteries?

lumen is less spherical and more irrgularly shaped appear collapsed

62

What is the reason for the difference in veins vs arteries?

lower blood pressure in veins

63

How are veins classified?

small, medium, and large depending on their diameter

64

What are the three tunics in veins?

same as arteries just not well defined

65

What do the valves in veins consist of?

consist of fibroelastic connective tissue covered on both sides by endothelium

66

What is the purpose of vein valves?

prevent backflow of blood due to low pressure

67

Why are valves more prominent in large veins?

wider and under the least amount of pressure

68

What are varicose veins?

weakness in the media caused by increased intraluminal pressure or a defect in the structure or function of a valve

69

Where are varicose veins typically found?

hemorrhoids, esophageal varices and spermatic cord

70

What is the purpose of lymphatic vessels?

transport lymph which flows in one direction toward the heart

71

What do lymph capillaries consits of?

a single layer of endothelium and a thin incomplete basal lamina

72

How do lymphatic vessels resemble veins?

thin intima, thin medial layer mostly longitudinal smooth muscle fibers, thin adventitia and contain valves