Connective Tissue Flashcards Preview

Histology > Connective Tissue > Flashcards

Flashcards in Connective Tissue Deck (127):
1

Lamina lucida

Has adhesion molecules: integrins and laminin

2

Lamina densa

Has type IV collagen and fibronectin

3

Basal lamina

Lamina lucida + lamina densa
Acts as a filtration system and attachment point
Made primarily by epithelial cells

4

Lamina reticularis

Made by fibroblasts
Type III collagen=reticular fibers
Type IV and VII collagen=anchoring proteins

5

Basement membrane

Lamina Reticularis + Basal Lamina

6

Tendons you can find

DRCT made of type I collagen

7

What makes collagen?

Fibroblasts

8

How to best ID fibroblasts in DRCT in tendon

Oval/flattened shaped nuclei in boxcar effect

9

Type of stain used for elastic membranes?

Weigert's resorcin fuschsin stain

10

Most abundant cell in connective tissue

fibroblast

11

DICT primary components

fibroblasts and collagen type I

12

Loose connective tissue is able to

Support tissue and provide space in ECM for occupancy of cells and passage of fluid or transport tissues

13

Which CT contains fewer fibers and more interfiber space

Loose CT

14

Fibroblasts are derived from

mesoderm

15

Connective tissue is derived from

mesoderm

16

T/F The supporting role of the stroma is usually but not always fulfilled by CT

True

17

Functions of CT (5)

Structural support
Medium for nutrient waste exchange
Defense/Proection of body (physical & mediated actions)
Energy storage
Repair after injusry

18

Classification of CT (2)

Ordinary CT

Special CT

19

Types of special CT

adipose
blood
cartilage
bone

20

What is CT primarily made of?

ECM and cells

21

Categories of cells in CT

Fixed and transient cells

22

Components of ECM in CT

ECM=intercellular substance between and around cells
-Fibers
-Ground substance

23

Fibers in CT are

Formed elements that resist tensile forces

24

Ground substance in CT are

AKA amorphous material
Resist compressive forces

25

Types of fibers in ECM

Collagen fiber
Reticular fiber
Elastic fiber

26

Collagen fibers

A part of ECM
Most abundant protein in body
Most abundant formed element (fiber) n body
White gross color

27

Example of collagen fiber

Tendons

28

How to make collagen fibers

Transcription-->Translation

After translation, preprocollagen molecule is made that's made of a polypeptide alpha chain with Gly, Pro, hydroxyproline, and hydroxylysine.

3 preprocollagen molecules will align with each other and assemble to form a tight helical structure called PROCOLLAGEN molecule

Procollagen looks like tightly wound rope with frayed ends. Each propetide allows procollagen molecule to be solube and prevents spontaneous aggregation into collagen fibers within the cell

When the procollagen is about to be secreted, the terminal protein is removed via PROCOLLAGEN PEPTIDASE. And yields TROPOCOLLAGEN

Tropocollagen polymerizes in ECM to form FIBRILS

FIBRILS polymerize to form COLLAGEN FIBERS

29

Overview of collagen synthesis

preprocollagen--> 3 preprocollagen-->procollagen-->tropocollagen-->fibrils-->collagen fiber

30

What removes terminal protein of procollagen

Procollagen peptidase

31

T/F Collagen fibers have great tensile strength

true

32

Hoe many types of collagen are there

28

33

Do collagen fibers have a long half life?

Yes-very stable

34

Type I collagen synthesizing cells

fibroblast, osteoblast, odontoblast, cementoblast

35

Type I collagen function

Resist tension

36

Type I collagen location in body

dermis, tendon, ligament, capsules of organs, bone, dentin, cementum

MOST COMMON

37

Type II collagen synthesizing cells

chonrdroblasts

38

Type II collagen function

resists pressure

39

Type II collagen location in body

Hyaline cartilage, elastic cartilage

40

Type III synethsizing cells

fibroblasts, reticular cell, smooth muscle cell, hepatocyte

41

Type III function

Forms structural framework of spleen, liver, LN, SM, and adipose tissue

42

Type III location in body

Lymphatic system, spleen, liver, cardiovascular system, lung, skin

43

Type IV synthesizing cell

Epithelial cell, muscle cell, Schwann cell

44

Type IV functinon

Forms meshwork of lamina densa of basal lamina to provide support and filtration

45

Type IV location in body

basal lamina

46

Type VII synthezising cells

epidermal ells

47

Type VII function

Forms anchoring fibrils that fasten lamina densa to underlying laminsareticularis

48

Type VII location

Junction of epidermis and dermis

49

Type III collagen AKA

reticular fibers

50

T/F reticular fibers branch into delicate tiny networks

True

51

What prevents reticular fibers from becoming large

glycoprotein coat

52

Oritenatin of reticular fibers allows what?

Abundant space allows bone marrow and lymph nodes and cells and fluids to go through

53

T/F reticular fibers are components of attachment

TRUE

See in basement membranes and external lamina

54

Reticular fibers are referred to as

Argyrophilic (silver)

55

A difference between elastic fibers and collagen

Elastic fibers can deform when stretched and return to original shape and can branch

56

Color of elastic fiber

Yellow-can see in nuchal ligament

57

Elastic fibers are made of

Elastin which is rich in Gly, Lys, Ala, Val, Pro, but NOT HYDROXYLYSINE

58

Explain orientation of elastin chains

They're held together by four Lys molecules of diff elastin chains form covalent bonds with each other and form desmosine crosslinks.

59

Dsmosine crosslinks

Found in elastic fibers. Are highly deformable and impart high degree of elasticity.

60

Elasin molecules are surrounded by

Microfibrils which are made of glycoprotein=fibrillin. Myofibirls help form elastic fibers

61

Formation of elastic fibers

Fibroblasts and smooth muscle cells secrete molecular subunits to make fibrillin microfibrils.

Elastin is deposited on scaffold of microfibrils and amorphous growing structure forms

Elastin accumulates and occupies most of the electron dense center of the single elastic fiber. Fibrillin microfibrils remain at fiber surface.

62

T/F elastin resists digestion by most proteases

T

63

What is elastin hydrolyzed by

Pancreatic elastase

64

Unlike collagen, elastin can form

"sheet" AKA elastic membrane or elastic lamina

65

Elastic membranes are prominent where

Arteries

66

Elastic membranes can be formed by?

CT cells (fibroblasts) and smooth mucles cells

67

What is ground substance made of

complex sugars: GAGs, proteoglycans, multiadhesive glycoproteins

68

Purpose of ground substance

Fills space between cells and fibers in CT and serves as lubricant and barrier to penetration of invaders

69

GAGs

-Long chains of repeating disaccharides (unbranched and (-) charge)

-Amino sugar is one repeating subunit. Sugars have (-) charge making it polar molecule and attracting water and forms HYDRATED GEL WHICH RESISTS COMPRESSION.

GAGs come close together, (-) repel them and reslts in slippery texture to resist compression

Act as diffusion barrier

70

What allows GAG to resist compression?

(-) charges

71

Proteoglycan orientation

Like a test tube brush

Core protein is handle that allows GAGs to attach covalently (the bristles) Adhesion moecules attach proteoglycan to something like hyaluranic acid.

72

Proteoglycan charge and function

Negative

Allows water attraction and repulsion of other preotglycans which forms hydrated gel and acts as diffusion barrier

73

Aggrecan found where

Proteoglycan macromoleucle in cartilage and CTP that contains GAGs and hyaluronic acid.

74

Purpose of aggrecan

Massive molecule responsible for gel state of ECM and acts as barrier to diffusion

75

How bacteria combat ECM

Secrete hyaluronidase which cleaves hyaluronic acid into fragments and gets ride of gel state of ECM. This allows for rapid spread of bacteria.

76

Glycoproteins makeup

Non-filamentous cell adhesion molecules that have binding sites for ECM components and integrin moleules of CM that facilitate attachment of cells to ECM

77

Glycoprotein purpose

Mediates interactions between cells
1-permanent=integrins (adhesion molecules), growth factors
2-Transient=Ilk, GF, tumor necrosis factors, interferons, hormones, plasma proteins, chemokines

78

Examples of glycoproteins

laminin and fibronectin

79

Laminin found

Basal lamina and external laminae

80

Fibronectin found

throughout ECM

81

Purpose of laminin and fibronectin

Help bind molecules to ECM and help with cell migration and maintaining tissue structure

82

Types of ordinary CT

DRCT/DICT

Loose CT

Reticular CT

83

DRCT made of and find in and good for

Collagen or elastic

Tendons, laigaments, cornea

Good for linear tensile strength

84

Primary producer of collagen

Fibroblast

85

DICT made of found in and good for

Collagen or elastic

Dermis, capsules of organs, periosteum

Can be pulled in all directions

86

Loose CT AKA found in

Areolar CT

Superficial fascia, lamina propria of intestine

87

Reticular CT found in/special ID

Internal frameowkr of spleen and LN, basement membranes

Has high affinity for silver

88

Ehlers Danlos type VI disorder

Faulty lysine hydroxylation-->increased skin elasticity, rupture of eyeball

89

Scurvy disorder

lack of vitamin C, a required cofactor for prolyl hydroxylase-->ulceration of gums hemmorhages

90

CT fixed cells (7)

fibroblast
fibrocyte
pericyte
adipocyte
Mast cells
Macrophages
Myofibrocytes

91

CT transient cells (7)

Plasma cells
Neutrophil
Eosinophil
Lymphocyte
Macrophage
Basophils
Monocytes

92

Fixed cell defintion

Resident population of cells that developed and remain in place within the CT where they perform their function

These cells are stable and long-lived

93

Fibroblast
fixed or transient
most numerous where
produces

Fixed

Most numerous in CT

Produces/maintains ECM (makes fibers and most components of ground substance)

94

Fibroblast
-nucleus
-shape
-cytoplasm

-open faced (euchromatin)
-Spindle/fusiform shaped
-Cytoplasm not normally apparent but is visible in healing wounds due to amplified synethesis of proteins for ECM

95

When can you see cytoplasm of fibroblast

In tendon where there's basophilic streaming

Damaged tissue needing repair

96

Myofibroblasts
-modified
-found where

Modified fibroblasts that are similar to fibrob;asts and smooth muscle cells

Found in areaus undergoing wound healing

97

How do myofibroblast help? How is it similar to fibroblast and smooth muscle

Speed wound healing by contracting the edges of wounds

Like muscle=contract with actin/myosin complex

like fibroblast=capable of creating ECM (type 1 and 3 collagen)

98

How is myofibroblast diff from muscle

Lack external lamina (basal lamina)

99

Pericytes
AKA
fixed?
found where
what kind of cell
cytoplasm

Rouget or mural cells

Fixed

In walls of capillaries and venules

is an immature mesenchymal cell

cytoplasm has actin and myosin

100

Multipotential of pericytes

Can differintiate into other types of cells (myofibroblasts, SM cell, endothelial cell)

101

Pericytes function

Help with blood-brain barrier stability and angiogensis

Helps with blood flow regulating in microvasculature

102

Diabetic retinopathy

Caused by damaging pericytes in retinal vessels

103

Alzheimer's disease

See increased number of pericytes in brain

104

Tumor vasculature

If tumor is weak and disorganized its partially due to inability of it to recruit pericytes.

105

Where to find pericytes? How do they respond?

Line small vascular vessels and respond to stimulation by constricting

106

What are pericytes very sensitive to?

Ischemia. When they die they constrict and stay constricted

107

Adipocytes
fixed?
Purpose
types

Fixed

store fat

Unilocular adipocyte and multiclocular adipocyte

108

Unilocular adipocyte
ID
fxn
prominent
metabolism
controlled by
how are they held together

Single large fat drop;et

E storage

Prominent smooth ER

Lipid metabolism

Under influence:insulin, corticosteroids, growth hormone, noepinephrine

External lamina holds cells together

109

Unilocular adipocyte AKA

Make

Endocrine tissue

Make leptin, adiponectin, adipokines, estrogen

110

Multilocular adipocyte
AKA
ID
FXN

Brown fat cell

Multiple small fat cell droplets and lots of mito (see uncoupling of oxidative phosphorylation)

Heat production ( E released as heat) see in neonatal and hibernating animals

111

Mast cells
Fixed?
Found
Most prominent in

Yes

See in CT of organs associated with body orifices, skin, and serous membranes

Prominent in LCT and blood vessels

112

Mast cells
mediate
Membrane receptor

Mediates anaphylactic shock (immediate hypersensitivity rxn)

IgE= stimulates degranulation

113

Primary mediators of Mast cells during degranulation (4)

Chondroitin sulfate
histamine
Eosinophil chemotactic factor (ECF)
Neutrophil chemotactic factor (NCF)

114

Secondary mediators of mast cells during degranulation (2)

prostaglandin
Leukotrienes

Same as histamine but 10x more powerful

115

ECF and NCF

Eosinophils limit magnitude of inflamm by mast cells by inactivating inflamm mediators like histamine and leukotrienes

116

Mastocytomas

Mast cell tumors

117

Mast cell tumors

Most common cutaneous tumors in trunks of :boxers, boston terriers, lab rets, beagles, schnauzers

Can effect HR, BP

Rx:surgery, chemo, antihistamines, tyrosinase kinase inhibitor

118

Leukocytes
fixed
include (5)
Movement
Origin

Transeient

PMN, Eosinophils, monocyte, lymphocyte, basophil

Circulate in peripheral blood and enter CT to perform special fxn

Bone marrow

119

Leukocytes are classfied as (2)

Granulocyte

Agranulocyte

120

Granulocytes
Contain
Lobes

Eosinophil
PMN
Basophil

Contain specific granules and primary granules

Lobed/segmented nucleus

121

Agranulocytes

Contain

Lymphocyte
Monocyte

Lack specific granules

Contain primary granules

122

Lymphocyte
Granulocyte?
Mediates
ID
Fxn
Where

Agranulocyte

Mediators of specific types of immune response

Small cells with round nuclei and minimal cytoplasm

Scouts and weapons

Throughout msot CT but especially common in lamina propria (CT of mucous mem), splee, thymus, LN, peyer's patches of ileum, tonsils.

123

MQ
Granulocyte?
Origin
Abundant
ID
Fxn

Agranulocyte

Origin=monocytes. Once mono leaves blood it becomes MQ

Abundant lyosomes

variable morphology, "kidney bean" nucleus or oval eccentric open face nucleus

Phagocytosis, secretes cytokines, Ag presentation

124

Eosinophils
Granulocyte?
ID
Fxn

Yes

Granules stain intensely eosinophilic, Same size as neutrophils with band/elongated nucleus. Acidophilic cytoplasmic granules=lysosomes

Phagocytosis and destroys parasits (IgE) and limits inflammation initated by mast cells by neutralizing histamine and inhibiting mas cell degranulation via Eosinophil inhibitor factor

125

Neutrophil
Granulocyte?
ID
fxn

Yes

Most numerous leukocyte. Cytoplasmic granules are present (lysosomes) but don't stain.

Acute phagocytosis of BACTERIA and creates pus. Also secretes inflam mediators and enzymes

126

Basophil
Granulocyte?
ID

Yes

Have large cytoplasmic granules that norm obscure 2 lobed nucleus. Stores histamine.

127

Plasma cell
AKA
Derived from
Make
Abundant

Plasma B cells, plasmocytes, effector B cells

From B lymphocytes

Make Ab

Abundant in RER