11.21 B Flashcards

1
Q

What kind of epithelium lines blood vessels?

A

simple squamous

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2
Q

White blood cells typically exit the vascular system at what point?

A

in the post-capillary venules

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3
Q

Elastic arteries are also known as what?

A

larger arteries

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4
Q

Muscular arteries are also known as what?

A

medium-sized arteries

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5
Q

Where in the vascular system does hydrostatic pressure drop the most?

A

in the arterioles

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6
Q

The innermost of the three layers of arterial walls is called what?

A

tunica intima

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7
Q

The outermost of the three layers of arterial walls is called what?

A

tunica externa or tunica adventitia

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8
Q

The middle layer of arterial walls is called what?

A

tunica media

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9
Q

Describe the tunica intima.

A
  • the endothelial lining as well as the subendothelial basement membrane
  • loose connective tissue
  • a dense layer of elastic fibers
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10
Q

The dense layer of elastic fibers in the tunica intima is called what?

A

the internal elastic lamina

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11
Q

Describe the tunica media.

A

concentric layers of smooth muscle, collagen fibers, and discontinuous elastic sheaths

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12
Q

The discontinuous elastic sheaths that help constitute the tunica media are called what?

A

the external elastic lamina

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13
Q

Describe the tunica externa.

A

connective tissue with it’s own vascular supply and innervations

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14
Q

What are vasa vasorum?

A

blood vessels supplying the tunica externa of larger vessels

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15
Q

What are nervi vasorum?

A

nerves that innervate the tunica externa of large blood vessels

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16
Q

What are conducting arteries?

A

large (aka elastic) arteries that conduct blood from the heart

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17
Q

What are distributing arteries?

A

medium-sized arteries that allow selective distribution of blood to different organs in response to functional needs

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18
Q

What feature of the vascular system ensures continuous blood flow despite intermittent pumping of the heart?

A

the elastic recoil of large arteries during diastole

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19
Q

When do large arteries recoil?

A

during diastole

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20
Q

How does the histology of elastic arteries compare to those of muscular arteries?

A

muscular arteries often have a more prominent internal elastic lamina as well as fewer elastic sheaths and more smooth muscle fibers

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21
Q

What are resistance vessels?

A

arteries that regulate the distribution of blood to different capillary beds by vasoconstriction and vasodilation

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22
Q

What type of blood vessel is a major determinant of overall systemic blood pressure?

A

arterioles

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23
Q

How thick is the tunica media of arterioles?

A

they typically have 2-5 concentric layers of vascular smooth muscle

24
Q

Why do veins tend to appear more irregularly shaped than arteries?

A

because they have less smooth muscle and elastic tissue because they aren’t under the hydrostatic force generated by the heart

25
Q

What are the three types of capillaries?

A

continuous, fenestrated, and discontinuous

26
Q

Where are continuous capillaries found?

A

muscle, brain, thymus, and lung

27
Q

Where are fenestrated capillaries found?

A

sites of fluid transport like intestine and kidney

28
Q

Where are discontinuous capillaries found?

A

sites of macromolecule exchange like liver, spleen, and bone marrow

29
Q

Which types of capillaries have an intact basement membrane?

A

continuous and fenestrated

30
Q

What are caveolae?

A

vesicles that transport substances through the cytoplasm of endothelial cells lining capillaries

31
Q

What are sinusoids?

A

the gaps found in discontinuous capillaries

32
Q

Caveolae are coated with what protein?

A

caveolin

33
Q

What are pericytes involved in?

A
  • tight junction formation
  • vesicle trafficking in endothelial cells
  • regulation of blood flow
  • angiogenesis
34
Q

Loss of pericytes in the CNS result in what?

A

loss of the blood brain barrier and neurodegenerative disorders

35
Q

What types of blood vessels tend to be lined by pericytes?

A

arterioles and venules

36
Q

How do the tunica of veins compare to those of equal sized arteries?

A
  • no distinct internal elastic lamina in veins

- tunica media of veins are typically thinner

37
Q

What is prostacyclin?

A

a compound produced by endothelial cells to limit adhesion of platelets to the cells, preventing clotting

38
Q

How do endothelial cells modulate smooth muscle activity?

A

by producing nitric oxide (a muscle relaxant) and endothelin 1 (a muscle contractor)

39
Q

What is endothelin 1?

A

a muscle contractor produced by endothelial cells to regulate smooth muscle activity

40
Q

What is Tissue Factor?

A

a compound that initiates blood clotting

41
Q

What are some active roles of endothelial cells?

A
  • modulate smooth muscle activity
  • produce prostacyclin
  • trigger blood coagulation
  • traffic inflammatory cells
  • control vascular cell growth
42
Q

How does oxidative stress result in atherosclerosis?

A

it causes endothelial dysfunction and thus reduced NO availability, which leads to lipid deposition, vasoconstriction, platelet aggregation, luekocyte adhesion, etc.

43
Q

What are some risk factors for atherosclerosis?

A

smoking, diabetes, aging, obesity, dyslipidemia, hypertension

44
Q

What is atheroscelerosis?

A

deposition of fatty material in the wall of the vessel to form a lesion

45
Q

Atheroscelerosis typically involves what sorts of blood vessels?

A

large arteries

46
Q

Atheromas are responsible for what health issues?

A

MI, cerebral infarction or stoke, and gangrene

47
Q

Atheromas in the peripheral vasculature can lead to what problem?

A

gangrene

48
Q

How do cells and macromolecules enter lymphatic capillaries?

A

muscular contractions open spaces between lymphatic endothelial cells which lack tight junctions

49
Q

What is vasculogenesis?

A

creation of a new vascular network

50
Q

What is angiogenesis?

A

sprouting of new vasculature from an existing network

51
Q

What is VEGF?

A

vascular endothelial growth factor, required for vasculogenesis and angiogenesis

52
Q

What are angiopoietins?

A

compounds required for vasculogenesis and angiogenesis

53
Q

What is the main regulator of hypoxia-induced angiogenesis and vasculogenesis?

A

HIF-1

54
Q

What is HIF-1?

A

a transcription factor that regulates hypoxia-induced angiogenesis

55
Q

What are the target genes of HIF-1?

A

EPO, VEGF, IGF2, and GLUT

56
Q

HIF-1 binds what element of DNA?

A

the hypoxia response element, HRE