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Flashcards in Connective Tissue Deck (81):
1

two groups of CT

nonspecialized - loose and dense CT

specialized - adipose, cartilage, bone, blood

2

components of CT

ECM
Nonpolarized cells

3

what properties does ECM impart on connective tissue

elasticity (elastic fibers)
tensile strength (fibrous collagens)
resilience (proteoglycans)

4

what are the three major functions of CT

defense
support
nutrition, transport, storage

5

What are the two components of ECM

ground substance
fibrous proteins

6

What are the two components of ground substance?

proteoglycans
glycoproteins

7

what is the ground substance three functions

retain water
matrix between cells and fibers
anchor cells to matrix and allow them to move

8

what is the general structure of proteoglycans

core p
negatively charged, long disaccharides

9

what is unique about hyaluran (a glycoprotein)

no core p

linker p binds many HA to a core p

giant aggregates bind fibrous elements of ECM (collagen fibers)

10

what are the three functions of glycoproteins

cell-to-cell recognition
adhesion
migration

11

what is the general structure of glycoproteins

mostly protein
short polysaccharides, branched, diverse

12

what are the three main binding sites on glycoproteins?

integrins (cells)
collagen fibers (ECM)
proteoglycans (ECM)

13

what are two types of glycoproteins

laminin
fibronectin

14

what does laminin do and what secretes it?

binds proteoglycans, epithelial cell membrane, collagen IV (in lamina dense of basal lamina)

epithelial cells

15

what does fibronectin do and what secretes it?

mediates attachment of fibroblasts (or other cells) to collagen fibers, proteoglycans

16

give the general scheme for collagen formation

alpha chains in RER..

procollagen sent to golg, exocytosed..

terminal peptides cleaved giving tropocollagen..

self assembly

17

which collagen types form fibrils?

I, II, III

18

what collagen types form fibers?

I, III

19

what collagen type forms reticular fibers?

III

20

Type I: what cells synthesize it, where is it found? what is its function? what form does it take?

fibroblasts, osteoblasts

dermis, tendons, ligaments, bone, fascia, organ capsule, loose CT

resist force, tension, stretch

fibers

21

type 1 is also found in fibrocartilage. what cells synthesize it, what form does it take, and what is its function?

chondroblasts/cytes

fibers

resist force, tension, stress

22

Type II: what cells synthesize it, where is it found? what is its function? what form does it take?

chondroblasts

hyaline, elastic cartilage

resists intermittent pressure

fibrils

23

Type III: what cells synthesize it, where is it found? what is its function? what form does it take?

fibroblasts, smooth muscle, reticular cells, schwann cells, liver cells

soft tissue support network, lamina reticularis of basement membrane, hepatocyte support, lymph nodes

structural support, elasticity, wound repair

fine fibers, reticular fibers

24

what do reticular fibers do? (III)

delicate for support of lymph nodes, bone marrow, spleen

slow fluid flow so Ag can be recognized and phagocytosed

25

Type IV: what cells synthesize it, where is it found? what is its function? what form does it take?

epithelial cells, muscle cells, schwann cells

lamina densa of basal lamina, external lamina

support and filtration

no fibers, no fibrils

26

elastic fibers: what cells synthesize them, where are they found?

fibroblasts

lungs, walls of large arteries, elastic ligaments between vertebrae

27

discuss the general structure and composition of elastic fibers

elastin deposited on microfibril bed of fibrillin.

cross-link to form elastic fiber

relaxed -- randomly coiled
stretched -- organized

typically associate with collagen fibers

28

what are the four cells of CT

fibroblasts
macrophages
mast cells
adipocytes

29

what are the four functions of CT cells

defense, support, metabolism, tissue repair

30

function of fibroblasts

synthesize collagen fibers
elastic fibers
proteoglycans
hyaluronan
glycoproteins
organize

31

what are fibroblasts called in cartilage? bone?

chondroblasts
osteoblasts

32

fibroblast morphology?

nucleus - large, oval, pale, nucleolus

irregular shape
solitary
abundant cytoplasm (active), non-abundant (inactive)

33

fibroblast origin?

mesenchymal cells form fibroblasts, osteoblasts, chondroblasts, or adipocytes

34

what is unique about myofibroblasts?

take on contractile properties when activated from tissue damage

35

function of macrophages?

acute inflammation, phagocytosis

36

what do macrophages do in acute inflammation?

release IL-1 --> chemotactic for neutrophils and proliferation of fibroblasts

proliferation of B cells

37

what triggers phagocytosis

recognizes Fc and C3b (opsonized pathogen)

38

what are macrophages called in liver, lymph nodes/spleen, cartilage, and bone?

kupffer cells
reticuloendothelial cells
chondroclasts
osteoclasts

39

macrophage morphology?

bipolar
darkened nucleus
infoldings in plasma membrane
irregularly sized phagocytic vacuoles
electron dense granules

40

macrophage origin?

when monocytes leave bone marrow and circulate, become macrophage

41

what is the function of mast cells?

detect Ag entry in lamina propria and elicit local inflammatory response

42

what 6 substances do mast cells release?

histamine
heparin
slow reacting substand of anaphylaxis
eosinophil chemotactic factor
neutrophil chemotactic factor
tumor necrosis factor-alpha

43

how do mast cells detect pathogen and respond?

on first exposure, IgE component of Fc binds to mast cell

on second exposure, Ag binds and crosslinks w/ mast cell IgE --> release of factors

44

mast cell origin and location?

bone marrow then migrates to CT and stays

45

mast cell morphology/

discrete cell boundaries
round oval cell
uniformly sized secretory granules

46

what are the three types of non-specialized CT

Loose
Dense irregular
dense regular

47

what is the predominant collagen in non-specialized CT

type I

48

loose CT: where is it found, what is it's composition and characteristics? (5)

Beneath epithelia
Binds different tissue types
Large proportion of cells
Sparse elastic and coll fibers
Abundant ground substance

49

dense irregular: where is it found, what is it's composition and characteristics? (3)

where more mechanical stress or required support

irregular orientation of abundant collagen fibers

fewer cells, ground substance

50

dense regular CT: where is it found, what is it's composition and characteristics? (5)

Mechanical stress greatest
Regular orientation of abundant coll fibers
Minimal ground substance
Fibroblasts squeezed between fibers
Tendons, aponeuroses, ligaments

51

what are the four types of specialized CT

adipose tissue
cartilage
bone
blood

52

three functions of adipose tissue

lipid storage
heat production
hormone secretion

53

adipocyte origin?

mesenchymal cells

54

two types of adipocytes?

unilocular white
multilocular brown

55

5 functions of unilocular white adipocytes

energy storage
shock absorption
insulation
hormone secretion
organ positioning

56

how are white adipocytes shaped and organized?

intracellular - single fat droplet surrounded by intermediate filaments

polyhedral cells bound by reticular fibers

each cell surrounded by external lamina

57

what are 4 substances released by white adipocytes for their endocrine function?

leptin (appetite, energy balance)

resistin (insulin resistance)

plasminogen activator inhibitor 1 (predicts typeII diabetes)

pro-inflammatory cytokines (TNFalpha, IL-6, IL-8)

58

brown adipocyte morphology?

many fat droplets
numerous mitos, capillaries
polyhedral but smaller than white
centrally located nucleus, rounded

59

white adipocyte morphology?

thin cytoplasm surrounding empty fat vacuole (on histo)
elliptical, flat nucleus squished to edge of cell

60

function of brown adipocytes

nonshivering thermogenesis

61

5 functions of cartilage?

support soft tissues
shock absorption
structural framework of organs
allow smooth movement of skeletal elements at joints
lay down skeletal model in embryogenesis

62

composition of cartilage?

ECM
chondroblasts, chondrocytes

63

what is lacking in cartilage?

nerves, blood vessels, lymphatic vessels

64

how does cartilage get nutrients

diffusion of surrounding fluids facilitated by negatively charged proteoglycans

65

how is cartilage organized?

surrounded by perichondrium which contains perichondrial fibroblasts embedded in dense irregular CT of collagen I and proteoglycans

66

what is the glycoprotein that connects chondrocytes to ECM?

chondronectin

67

what are the two steps in appositional growth?

1. perichondrial fibroblasts and mesenchymal cells differentiate into chondroblasts
2. chondroblasts synthesize cartilage matrix

68

what is the cartilage matrix composed of?

hyaluronan
collagen II
chondroitin sulfate
keratin sulfate

69

how does interstitial growth work?

deep chondrocytes divide giving isogenous groups and synthesize cartilage

as isogenous groups synthesize cartilage the chondrocytes separate

70

what are the two identifying characteristics of hyalin cartilage?

1. composition: hyaluronan, collagen II, chondroitin sulfate, keratin sulfate giving amorphous appearance
2. perichondrium, isogenous groups

71

what is lacunae?

space in cartilage for chondrocytes

72

where is hyalin cartilage found?

articular surface of joints
costal (ribs) locations
structural elements of trachea and larynx

73

what is unique about elastic cartilage?

has elastic fibers

74

where is elastic cartilage found?

pinna of ear, external auditory meatus, nose, epiglottis

75

what are identifying characteristics of fibrocartilage?

1. collagen I in bundles. run parallel, woven
2. chondrocytes, isogenous groups in lacunae
3. no well-defined perichondrium, scarce ECM
4. resembles and merges with dense CT

76

where is fibrocartilage found and what does it do?

in intervertebral disks, replaces damaged hyaline cartilage

77

what causes scurvy?

vitamin C deficieny which is needed for hydroxylation of collagen residues

78

what is the symptoms of scurvy?

abnormal bone growth
poor fracture healing
tendency to bleed

79

what is the cause of marfan syndrome?

fibrillin defective/missing

80

what is the consequence of marfan syndrome?

progressive dilation of ascending aorta and subluxation of lens.

eventually get a ruptured aorta from defective elastic membranes

81

what is the cause of osteoarthritis?

degenerative disease of hyalin cartilage
-cracks and tears in articular surface
-proteoglycan content decreases
-chondrocyte proliferation decreases