Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

R9 > Chapter 3 - Vessel wall biology > Flashcards

Chapter 3 - Vessel wall biology Flashcards

1
Q

Vessel wall characteristics: artery, vein, lymphatic

Collagen content
Elastic fiber content
Central pressure
Shear stress
Stretch force
Pulsatility
Compliance
Oxygen tension
Intrinsic propulsion
Valves

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

3 layers of the arterial wall

A

Tunica intima

Tunica media

Tunica adventitia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Thickness of vascular endothelium in capillaries/veins vs aorta

A

0.1 microm in capillaries/veins

1 microm in aorta

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Coating on the vascular endothelium to reduce friction

A

Glycocalix

Thickness varies across vascular tree

Sheared off in inflammation to allow leukocyte attachment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Distance of intercellular space in the vascular endothelium

A

15-20 nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define: pinocytic vesicles

A

allow movement of material from vessel lumen into the wall

primarily in muscular small blood vessels, largely in heart and lung, less in retina and brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Size of fenestrae on vascular endothelium

A

70 nm

majority have 5-6 nm nonmembranous diaphragm

Located in capillaries of exocrine/endocrine glands, GI mucosa, choroid plexus, glomeruli, renal tubules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Location of nonfenestrated continuous endothelium

A

Brain, skin, heart, lung

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Location of discontinuous endothelium

size of their fenestrations

A

Liver

100-200 nm without diaphragm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Zones of the basal lamina

A

Lamina rara (inner): laminin (glycoprotein)

Lamina densa: fibrillar, dense next to interstitial connective tissue; type IV collagen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Endothelium in normal functioning

A

Quiescent state

Cell-cell contact inhibit proliferation

Low mitotic index

Secrete ECM components (fibronectin) and basement membrane (laminin, proteoglycans, collagen IV)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Composition of basal lamina

A

glycoprotein

adhesion molecule (laminin, fibronectin, entactin, thrombospondin)

proteoglycans (heparan sulfate chains)

microfibrils of collage IV and V (5 nm in diameter)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Sublayers of the tunica intima

A

Endothelium

Basal lamina

Reticular layer

Internal elastic lamina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Reticular layer of the tunica intima

Composition

A

Collagen types I and III

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Proteoglycan: what it is, function in vascular wall, main types

A

macromolecules that influence viscoelasticity, permeability, lipid metabolism, homeostasis, thrombosis

Heparan sulfate
Dermatan sulfate
Chondroitin sulfate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Collagen: what it is, function in vascular wall, main types

A

Type IV collagen: made by EC and SMC; in the basement membrane
- high proline triple helix structure: affects flexibility and enhance cell adhesion and migration

Type V collagen: pericellular, made by EC and SMC
- bind interstitial collagen to cell/basal laminae

Type I collagen: major collagen; main type in human aorta intima and media

Type III collagen: major collagen; subendothelium of young adults

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Describe: laminin

A

noncollagenous basement membrane

pivotal role in cell-basement membrane interactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe: fibronectin

A

large glycoprotein with two disulfide-linked subunits

promote adhesion of molecules, spread of mesenchymal and epithelial cells and proliferation and migration of embryonic and tumor cells

Regulartes cell differentiation, shape, cytoskeletal organization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Thickness of internal elastic lamina

A

70-100 nm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Organization of the internal elastic lamina

A

Elastin organized into fenestrated cylindrical lamellae

Lamellae separated from neighbors by single layer SMC

Thickness and circumference can change with changes in media (in disease)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Tunica media: composition

A

Vascular SMC, elastin, collagen fibers arranged in organized fashion

SMC surrounded by basement membrane (laminin, collagen IV, heparans ulfate proteoglycan, entactin/nidogen, fibronectin)

  • prevents migration of SMC
  • maintains contractile state (not synthetic state SMC)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Synthetic state of SMC

A

Migrate to intima

proliferates

secrets ECM components

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Strength layer collagen type of SMC

A

Type III

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Average tangential tension per medial layer

A

2000 dynes/cm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Elastic arteries vs musclar arteries

A

Elastic arteries: well-defined elastic lamellae and collagen

  • aorta, brachiocephalic trunk, iliac arteries
  • lamellar units: elastin, collagen, SMCs

Muscular arteries: SMCs with fewer connective tissue fibres
- predominate in 2nd or 3rd order branches of elastic arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Average number of lamellar units in aorta

A

40-60 units

12-17 microm from arterial lumen

Number of lamellar units decrease from heart to peripheral arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Fascicles of the tunica media

A

Further organization of the SMC and branching elastic fibres

Each fascicle = sheath of basal lamina and collagen fibrils

Orientation of fascicle is in same direction of imposed tensile stress

  • circumferentially in straight segments
  • smaller and less uniform in size and orientation at bends and branching points
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Tunica adventitia: composition

A

Vasa vasorum

Nerves: control SMC function

Fibrous connective tissue (elastic + collagen fibers)

Lymphatic network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Vaso vasorum: which vessels have them

A

Arteries > 200 microm

Arteries where medial layer > 29 lamellar units

Supply outer part of media while inner part is supplied by lumenal flow

Arise from parent artery at branch junctions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Pathophysiology of vasa vasorum in diseases

A

Flow affected by hypertension, mural stresses and deformations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Anatomy: track of the aorta

A

Left ventricle (3 cm)

arch back over root of left lung

descend within thorax on L of vertebral column

through aortic hiatus

ends opposite to lower L4 (1.75 cm)

32
Q

Differences in small arteries vs larger arteries

A

Smaller arteries are musclar arteries

more innervated and principal regulators of peripheral resistance

thinner tunica intima

well defined internal elastic lamina

incomplete external elastic lamina

33
Q

Unique anatomic features of coronary arteries

A 
Thicker adventitia (collagen, elastic fibers, adipose tissue
- predominate collagen \> elastic: greater tensile strength, low stretch

Richly innervated SMC in medial and adventitia

Branching sites of artery show normal periodic thickening of intima

34
Q

Define: musculoelastic cushions

A

Thickening of intima at branching sites in coronary arteries

May contribute to atherosclerosis

May be a normal phenomenon

35
Q

What vessel type is responsible as the chief source of vascular resistance

A

Arterioles

36
Q

Composition of capillaries

A

Only tunica intima

Endothelium, basal lamina, pericytes (incomplete surrounding)

37
Q

Function of pericytes

A

Contractile properties: regulate flow in capillaries

Differentiate into endothelial or SMC in remodeling and repair

38
Q

Three types of capillaries

A

Continuous: selective filter by endothelium and lamina

Fenestrated: openings in endothelium; complete basal lamina

Discontinuous: incomplete endothelium, incomplete basal lamina
- sinusoid capillaries in liver, spleen, red bone marrow

39
Q

Diameter of capillaries

A

4-15 microm

40
Q

Size of fenestrations in fenestrated capillaries

A

50-60 nm

41
Q

Size of Intercellular gaps in discontinuous capillaries

A

0.1 - 1 microm

42
Q

Principle of vascular remodeling

A

Increase circumferential stress = increase SMC hypertrophy, collagen, elastin production

Decrease circumferential stress = vascular atrophy

43
Q

Effect of chronic shear stress

A

Enhance L-arginine/NO pathway in endothelium –> mRNA cGMP –> matrix metalloproteinases (MMP-2, MMP-9)
- apoptosis, enlargement, vascular remodeling

Upregulation Type III NO synthase

44
Q

Effect of age on arterial circumference

A

Medial thickness unchanged

Intimal thickness increased

Lumen diameter increased

Maintain consistent tensile strength

45
Q

Principle of pressure-induced arterial wall crush

A

When there is limited vascular stretch, intraluminal pressure causes crush (same as in PTA treatment)
- DNA synthesis, cell proliferation (FGF2)

46
Q

Endothelium response to shear stress

A

Align in direction of stress (elongation of cells)

Redistribution of intracellular stress fibers and quantity

Higher stress fibers (actin, myosin, contractile proteins)

*only occurs in arteries, not in veins

Activate stretch-induced ion channels, phospholipids and integrins

Upregulate PDGFs alpha and beta, TPA, TGF beta, endothelin-1, NO synthase III and ICAM-1

47
Q

Different vessel wall layer response to cyclic/circumferential stretch

A

Endothelium: Cell proliferation (max in 1st day of exposure)
- Increase total protein content

SMC: change orientation (align perpendicularly to direction of strain vector; annular)

  • increase type I and III collagen
  • increase elastin

Fibroblast: increase type II:I collagen ratio

48
Q

Venous endothelial cells produce these

A

Vasorelaxants: prostacyclin (PGI2) and NO

49
Q

Venous media differes from arteries

A

Thinner layer, less well developed

Contribute to varicosity development

SMC held in quiescent state

TGF beta reduces mitogenesis and stabilize matrix

Heparin-like molecule neutralize FGF to downregulate proliferation

50
Q

Venous adventitia differs from arteries

A

Thickest layer in large veins

can blend with the media

Vasa vasorum penetrate deeper

51
Q

Vasa vasorum in veins differ from arteries

A

Much more extensive and penetrate deeper into adventitia

Likely due to lower oxygen tension in venous blood

52
Q

Cellular signalling pathway for differentiation of artery and vein

A
53
Q

Effect of Ephrin-B2 signalling

A

Regulates mural-cell migration, spreading and adhesion during wall assembly

Absence will limit mural cell recruitment

54
Q

Effect of EphB4

A

limits cell proliferation, decreased intimal and medial thickening

55
Q

Vein composition difference with artery

A

Vein more collagen, nearly no elastic fibers

Veins has diminished internal and external elastic laminae

56
Q

Types of venules (3)

Characteristics and functions

A

Postcapillary venules: 10-50 microm in diameter

  • endothelium and pericytes, no SMC
  • loosely organized endothelium is leaky
  • thin basal lamina
  • main site for WBC diapedesis and tissue exudate

Collecting venules: similar with more pericytes

Muscular venules: clearly defined intimal layer, no elastic fibers, tunica media with 1-2 layers of SMC

57
Q

Average size range of small-medium veins

A

1-9 mm diameter

58
Q

Vessel wall anatomy of the venae cavae

A

Intima: fibroelastic tissue

Media: narrow with circumferentially oriented SMC

Adventitia: thick, longitudinally oriented collagen and SMC

Elastic fibers scattered throughout all layers; small amounts of cardiac tissue near connection to heart; extensive vasa vasorum in adventitia

59
Q

Threshold of reverse velocity for venous valve closure

A

30 cm/s

60
Q

Composition of venous valves

A

Collagen-elastic fiber core of connective tissue covered by thin endothelium

61
Q

General location of venous valves

A

Distal to confluence of minor venous branches forming larger veins

62
Q

Direction of intervenous flow in the lower extremity

A

Caudal to cephalad

Superficial to deep

Deep to superficial in dorsum of foot

63
Q

Venous valve changes in venous insufficiency

A

Reduction in valves per unit length

Infiltration by monocytes and macrophages

Increased MMP-2 and MMP-9 favoring accumulation of ECM

64
Q

Lymphatic drainage system names from extracellular back to vein

A

Extracellular matrix

Lymphatic capillaries (initial lymphatics; terminal lymphatics)

Precollecting lymphatics

Collecting lymphatics

Trunks

Ducts

65
Q

Initial lymphatics: location

A

Blind-ended vessels

  • connective tissue of skin and liver
  • mucous membrane of resp, GI, GU
66
Q

Diameter of initial lymphatics

A

10-60 microm

67
Q

Thickness of initial lymphatics and wall composition

A

50-100 nm

monolayer nonfenestrated endothelial cells

Discontinuous or absent basal lamina

68
Q

What is the endothelial microvalve

A

Gaps between endothelial cells are 10 microm

When vessels collapsed, gaps open allowing for lymphatic entry

When vessels filled, cells expand and close gaps

  • therefore unidirectional flow
69
Q

Precollecting lymphatics propulsion system

A

Secondary valves: bicuspid, irregularly spaced, sometimes single leaflet

SMC contractions

Primary valves as in initial lymphatics

70
Q

Collecting lymphatics: wall anatomy

A

No more primary valve mechanism

3 typical vessel layers

  • intimal monolayer
  • SMC, collagen, elastic fiber 1-3 layers (helicoidal manner)
  • adventitia: fibroblast, connective tissue, nerve terminals

More regularly spaced secondary valves

71
Q

Lymphangions

definition

diameter and length

A

Space between two secondary valves

In head and neck: 0.2 mm diameter, 2 mm length

Lower extremity: 1-2 mm diameter, 2 mm length

Innervated by SNS and PNS

72
Q

Lymph node anatomy

A
73
Q

Secondary valves

anatomy

A

Lymphatic vessel wall bulges at secondary valves
- causes string of pearls because of diameter changes

Monolayer of endothelial cells on a collagen matrix

74
Q

Cisterna chyli

Define

A

Confluence of lymphatic vessels from lower extremity by way of inguinal lymph nodes

75
Q

Factors involved in lymphatic propulsion

A

Primary valves

Secondary valves

Rhythmic contractions of SMC (pacemaker cells)

R9 (200 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions