LEC 8: Connective Tissue - 08.21.2014 Flashcards Preview

STRUCTURES - WEEK 1 > LEC 8: Connective Tissue - 08.21.2014 > Flashcards

Flashcards in LEC 8: Connective Tissue - 08.21.2014 Deck (73):
1

From which primary germ layer does connective tissue originate

Mesoderm

2

Connective tissue

connects, binds together, and supports other tissues and organs

3

What are the two (2) components of connective tissue

1. cells

2. extracellular matrix

4

What are the four (4) functions of connective tissue

1. structural support

2. medium of exchange

3. defense and protection

4. storage of fat

5

What are the three (3) components of extracellular matrix

1. ground substance

2. fibers

3. structural glycoproteins

6

What are the two (2) components of ground substance

1. glycoaminoglycans (GAGs)

  • old term: acid mucopolysaccharides

2. Proteoglycans

7

Proteoglycan

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core protein to which molecules of glycosaminoglycans (GAGs) are covalently bound

 

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8

What is this structure and where is it found

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Proteoglycan; found in ground substance of extracellular matrix

9

Structural glycoprotein

globular protein molecules to which branched chains of monosaccharides are covalently attached

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10

Types of glycosaminoglycans (GAGs)

1. Hyaluronic aicd

  • not sulfated or bound to a protein

2. Chondroitin sulfate

3. Dermatan sulfate

4. Heparan sulfate

5. Keratan sulfate

  • 2-5: highly negative charges on these molecules

11

GAGs

GAGs are covalently bound to a core protein; together, the core protein plus the GAGs make up a proteoglycan

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12

Which GAG is not sulfated or bound to a protein

Hyaluronic acid

13

What are the four (4) GAGs that have negative charges

1. Chondroitin sulfate

2. Dermatan sulfate

3. Heparan sulfate

4. Keratan sulfate

14

What are the principal fiber types of connective tissues

1. collagen fibers

2. reticular fibers

3. elastic fibers

15

How many types of genetically distinct collagen are there

28

16

What is the difference between Types I/II/III collagen and Type IV collage

Type I/II/III collagen form fibrils, while Type I does note

17

Where is Type I collagen found

  • tendon
  • ligaments
  • bone
  • fibrous cartilage
  • dermis of skin

18

Where is Type II collagen found

  • hyaline cartilage
  • elastic cartilage

19

Where is Type III (reticular) collagen found

  • lymphoid organs
  • muscle cells
  • blood vessels
  • liver
  • endocrine glands

20

Where is Type IV collagen found

  • basement membranes of epithelium, endothelium, muscle, and nerve axons
    • do not form fibrils
    • form mesh-like structure

21

H&E stain of collagen fibers

Collagen fibers stained acidophilic (pink)

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22

Mallory Trichrome Stain of collagen fibers

Collagen fibers are stained blue (Type I and III collagens)

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23

Properties of collagen fibers (Type I/II/III)

1. mechanical support

2. confer great strength to the tissue

3. resistance to stretching when pulled

24

Fibroblasts have which two organelles in large quantities for synthesis of procollagen

1. RER

2. Golgi bodies

25

Procollagen

  • Procollagen is produced and secreted into extracellular matrix
  • Procollagen then converted into tropocollagen
  • Tropocollagen is then polymerized into fibrils

26

Silver Stain of Type III collagen (reticular fibers)

  • Type III collagen are stained black (agryrophilic)
  • Reticular fibers are thinner than Type I collagen
  • Reticular fibers are 6-12% hexose sugar residues and are PAS positive for this reason

 

NB: Type I collagen is 1% hexose sugar residues

27

What composes basement membrane of an epithelial cell

1. type IV collagen 

2. GAG (heparan sulfate)

3. laminin

4. entactin

28

Characteristics of Type IV collagen

  • do not form fibrils, but a mesh-like structure
  • PAS positive

29

Two (2) components of elastic fiber

1. elastin (desmosine and isodesmosine -- amino acid derivatives)

2. microfibrils (fibrillin)

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30

Describe this tissue

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Elastic fibers (connective tissue spread preparation)

  • fibers are thin and branched, forming irregular networks

31

Properties of elastic fibers

  • stretchable as rubber (amino acid derivatives desmosine and isodesmosine)
  • can stretch 150% of length without breaking and when tension released, snap back (eleastic recoil)

32

What three (3) structures are responsible for producing elastic fibers

1. fibroblasts (connective tissue)

2. smooth muscle cells (in blood vessel wall, especially of arteries)

3. chondroblasts and chondrocytes in elastic cartilage

33

Classification of Connective Tissues

A. Connective tissue proper

  1. Loose connective tissue
  2. Dense connective tissue
  • Dense irregularly arranged
  • Dense regular arranged

B. Specialized connective tissue

  1. Reticular tissue
  2. Elastic tissue
  3. Adipose tissue

C. Embryonic connective tissue

  1. Mesenchyme
  2. Mucous

34

What are the two (2) types of connective tissue proper

1. Loose connective tissue

2. Dense connective tissue

  • Dense irregularly arranged
  • Dense regular arranged

35

What are the three (3) types of specialized connective tissue

1. reticular tissue

2. elastic tissue

3. adipose tissue

36

What are the two (2) types of embryonic connective tissue

1. mesenchyme

2. mucous

37

What type of tissue is this and what are its characteristics

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Loose Connective Tissue (Connective tissue proper)

  • more cells than collagen fibers
  • most tissues and organs
  • lamina propria
  • largely Type III collagen

38

What type of tissue is this and what are its characteristics

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Dense irregular connective tissue

  • more collagen fibers than cells
  • largely Type I and Type III collagens
  • some elastic fibers
  • found in dermis of skin

39

What tissue is this and what are its characteristics

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Dense regular connective tissue

  • parallel bundles of collagen fibers separated by linear rows of fibroblasts
  • Type I collagen
  • Found in tendons, ligaments, aponeurosis

NB: aponeurosis are layers of flat, broad tendons; primary function is to join muscles and the body parts the muscles act upon, whether it be bone or muscle

40

What type of tissue is this and what are its characteristics

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Reticular tissue

  • composed of loose network of Type III collagen (remember, Type III collage = reticular fibers)
  • forms supportive stroma for tissues and organs

41

Where is reticular tissue most abundant

Reticular tissue is most abundant in lymphoid organs, like the lymph node or the spleen

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42

What kind of tissue is this and what stain is used

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Resorcin fuchsin stain, elastic arteries (elastic tissue)

 

43

What kind of tissue is this and what stain is used

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Resorcin fuchsin stain, elastic cartilage (elastic tissue)

44

What kind of tissue is this

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Adipose tissue (white/yellow); adipocytes (fat cells) contain one large single fat droplet

45

Characteristics of adipose tissue (fat)

  • found in subcutaneous tissue, omentum (abdomen), mesenteries, breast, and bone marrow
  • thermal insulation -- poor heat conductor
  • storage of energy in form of triglycerides
  • release of free fatty acids to distant sites as energy source
  • visceral fats = obesity

46

What kind of tissue is this and where is it found

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Mesenchyme

  • mesenchymal cells are stellate or spindle shape
  • delicate branching cytoplasmic processes surrounded by ground substance
  • unspecialized -- can differentiate into almost all cell types found in mature connective tissues

47

What kind of tissue is this and where is it found

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Mucous (mucoid) connective tissue; Wharton's Jelly

  • mucuous connective tissue is a type of embryonic connective tissue
  • found in umbilical cord

48

stroma

the connective tissue within an organ

49

parenchyma

the cells supported by the stroma

50

What are the eight (8) major cell types in connective tissue (especially loose connective tissue)

1. fibroblasts

2. mast cells

3. macrophages

4. lymphocytes

5. plasma cells

6. neutrophils

7. eosinophils

8. adipocytes

51

What kind of tissue is this and what cells are found here

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Connective tissue, with fibroblast cells

  • fibroblasts have spindle shape with elongated nucleus
  • have slightly basophilic cytoplasm (blue)
  • fibroblasts charged with continuous slow turnover of ECM (collagens, elastic fibers, ground substance)

52

What kind of tissue is this and what cells are noticeable

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Connective tissue, mast cells

  • single nucleus
  • strongly acidic cytoplasm
  • finely granular

53

What are the abundant granules in the mast cell cytoplasm

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1. heparin

2. histamine

NB: Histamine released from mast cells trigger allergic reaction "hayfever" (rx: antihistamines)

54

monocytes

precursor of macrophages (hence, monocyte-macrophage system)

55

What are the six (6) cells that make up the monocyte-macrophage system

1. Macrophages

2. Microglia

3. Osteoclasts

4. Kupffer cells

5. Langerhans cells

6. Dendritic cells

56

Where are macrophages found

connective tissue, lungs, lymphoid organs, bone marrow

57

Where are microglia found

CNS (brain, spinal cord)

58

Where are osteoclasts found

bone

59

Where are Kupffer cells found

Liver

60

Where are Langerhans cells found

Skin

61

Where are dendritic cells found

Lymphoid nodes

62

What is this cell and what are its characteristics

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Monocyte in blood circulation, precursor of macrophage

  • monocytes develop in the bone marrow and circulate in the blood
  • after leaving circulation into the connective tissue, monocyte differentiates into a macrophage

63

What are the characteristics of a macrophage

  • lysosomes (primary, secondary, tertiary)
  • lysosomal enzymes like acid phosphatase
  • phagocytosis of cell debris, inert materials, bacteria, damaged ECM
  • secrete cytokines
  • antigen presenting cells
    • processing and presentation of antigents to lymphocytes (T cells); component of immune system

64

Describe this schema

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Macrophage is an antigen presenting cell; processes antigen (Ag), presents to lymphocyte (T cell) and T cell activates

65

What kind of tissue is this and what cells are visible

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Macrophages in connective tissue showing phagocytic particles in cytoplasm

66

What kind of tissue is this and what cells are visible

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Lymphocytes in blood circulation

  • develop in the bone marrow
    • T lymphocytes
    • B lymphocytes
  • leave the circulation and enter the connective tissue

67

What kind of tissue is this and what cells are visible (X, Y); how are they related

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Loose connective tissue

  • X = lymphocytes (B lymphocytes) that differentiate into plasma cells that make antibodies (live 1-2 yrs)
  • Y = Plasma cells make antibodies (live 2-3 wks)

68

What are antibodies and how are they made

(also called immunoglobulins) are glycoproteins

  • RER = synthesis of the glycoproteins
  • Golgi = glycosylation of the glycoproteins

 

NB: antibodies do not aggregate into secretory granules

 

69

What kind of tissue is this and what cells are visible

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Neutrophils in blood circulation

  • multi-lobed nucleus (3-5 lobes)
  • slightly pinkish cytoplasm containing barely visible granules
  • approx. 6 hours in blood circulation

70

What kind of tissue is this and what cells are visible

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Neutrophils in loose connective tissue

  • acute infection
  • amoeboid movement
  • phagocytic cells
  • lysosomal enzymes
  • terminally differentiated cells (spend a few days in CT)

71

Example of dirty splinter

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  • in response to accute inflammation, increased number neutrophils leave blood circulation
  • migrate to site of bacterial infection
  • phagocytize bacteria, microorganisms, cell debris in poorly oxygenated environment (inflamed or necrotic tissue)
  • defunct neutrophils = pus cells

72

What kind of tissue is this and what cells are visible

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Eosinophil in blood circulation

  • bilobed nucleus
  • strongly eosinophilic granules in cytoplasm
  • increased number in blood in parasitic infections and in allergy reaction

73

What kind of tissue is this and what cells are visible

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Loose connective tissue, presence of eosinophils

  • bilobed nucleus
  • highly eosinophilic granules in cytoplasm
  • chronic inflammation
  • phagocytic Ag-Ab complex
  • Lysosomal enzymes
  • approx 2 weeks in tissue