Connective Tissue

Question 1

Connective Tissue

Answer 1

supporting tissue

primarily structural

often the stroma of organs

includes cushioning CT found almost everywhere

cells organized in specialized ECM

classified based on ECM, not cells

Question 2

Types of Embryonic Connective Tissue

Answer 2

Mesenchymal

Mucous

Question 3

Types of Adult Connective Tissue

Answer 3

• CT Proper (Collagenous/Elastic)
  
  • loose
  • Dense Irregular
  • Dense Regular
  • Reticular (not elastic)
• Specialized
  
  • Supporting (Bone/Cartilage)
  • Adipose
  • Blood

Question 4

Ground Substance

Answer 4

in all CT except Blood

water and salts (primary cation is sodium)

complex carbohydrates (water retention)

proteoglycans (water retention)

Question 5

Connective Tissue Cells

Answer 5

mostly fibroblasts and immune cells

other specialized cells for specific functions (adipose tissue → adipocytes)

arrangement gives terminology

Question 6

What makes up collagen?

Answer 6

Fibroblasts

it is a triple helix structural protein

collagen fibril → collagen fiber → proteoglycan

Question 7

What are the types of collagen?

Answer 7

Type I

Type II

Type III

Type IV

Type V

dif types of collagen do different things

Question 8

What cell types make up collagen?

Answer 8

Fibroblasts

Reticular cell

epithelia cells (IV)

Equivalents

Question 9

Making Collagen: Fibroblasts

Answer 9

inactive fibrocytes

Question 10

Making Collagen: Reticular Cell

Answer 10

make reticular fibers (III)

Question 11

Making Collagen: Smooth Muscle Cells

Answer 11

in particular places

type I and III

Question 12

Making Collagen: Equivalents

Answer 12

bone - osteoblasts

Cartilage - chondroblast

Teeth - ondotoblast

Question 13

Elastic Fibers

Answer 13

elastin with microfibrillar proteins (fibrillins)

Question 14

What makes elastic fibers detectable?

Answer 14

orcein (black or dark purple)

Question 15

How are elastic fibers elastic?

Answer 15

Modification of two lysine residues in elastin protein (Lysyl oxidase, extracellular)

Form new amino acid: desmosine

ring structure linkes tropoelastin proteins

allows stretching and recoil

Question 16

Other cells found in CT

Answer 16

Resident immune cells (macrophages, mast cells, plasma cells)

Non-resident immune cells (neutrophils/eosinophils, transit into CT upon stimulation, produced in bone marrow, travel through blood)

Question 17

What is the function of macrophages?

Answer 17

phagocytosis of complement-bound particles

turnover of fibers and ECM

antigen presenting cells (lymphocytes)

produce cytokines (include chemokines to bring in other immune cells)

Question 18

How do macrophages get to the CT?

Answer 18

enter blood as monocytes

not called macrophages until mature (resident)

Question 19

What is the structure of macrophages?

Answer 19

kidney shaped nucleus

large

indent of one side

Question 20

Macrophage histology

Answer 20

Question 21

What is the function of mast cells?

Answer 21

release proteases, proteoglycans, leukotrienes

respond to chemical signals (cytokines, chemokines)

vasoactive mediators - leukotrienes, heparin

produce histamine, chemotactic

Question 22

Where are mast cells produced?

Answer 22

Travel through blood

activate immune (response to allergies)

Question 23

What is the structure of mast cells?

Answer 23

many granules

Question 24

Mast cell histology

Answer 24

Question 25

What is the function of plasma cells?

Answer 25

make/release antibodies respond to immune challenge produce IgAs (and other immunoglobulins)

Question 26

Where are plasma cells produced?

Answer 26

travel through blood Mature B lymphocyte

Question 27

What is the structure of plasma cells?

Answer 27

clockface or wagon wheel nucleus (clumped chromatid around edge) basophilic alot of rough ER off center nucleus alot of golgi comet like appearance

Question 28

Plasma Cell Histology

Answer 28

Question 29

Embryonic CT: Mucous

Answer 29

found in umbilical cord and teeth pulp larger spaces between fibers jelly is thicker rich in proteoglycans

Question 30

Embryonic CT

Answer 30

Question 31

Mucous CT Histology

Answer 31

Question 32

where is Mesenchymal CT found?

Answer 32

In embryo → cells give rise to all cells found in CT in adult → dental pulp, pluripotent pericytes (can act like stem cells) mesenchymal cells reticular fiber

Question 33

Mesenchymal CT (Mouse) Histology

Answer 33

Question 34

What is the function of CT proper: Loose CT?

Answer 34

supports epithelial function information nutrients/waste transport barrier (including surveillance) bring nutrients to avascular epithelium mesentery that holds organs in place

Question 35

Where is CT Proper: Loose CT found?

Answer 35

often found under epithelium

Question 36

What does CT proper: Loose CT contain?

Answer 36

fibroblasts and resident immune cells nerve bundles blood vessels fibers: collagen ± elastic (loose elastic CT)

Question 37

Loose CT Histology

Answer 37

Question 38

Loose CT Histology

Answer 38

Question 39

What is the function of CT Proper: Dense Irregular CT?

Answer 39

supports tissue function information nutrients/waste physical support

Question 40

Where is CT Proper: Dense Irregular CT found?

Answer 40

often found under loose CT

Question 41

What does CT Proper: Dense Irregular CT contain?

Answer 41

fibroblasts and resident immune cells (fewer than Loose CT) nerve bundles (larger) blood vessels (larger) more fibrocytes and fewer plasma cells fibers: collagen ± elastic

Question 42

What is Dense Irregular CT often associated with?

Answer 42

adipose

Question 43

Dense Irregular CT Histology

Answer 43

Question 44

Dense Irregular vs. Loose CT

Answer 44

loose → fewer fibers (nuclei) → darker dense → more fibers, fewer nuclei → lighter

Question 45

What is the function of CT Proper: Dense Regular CT

Answer 45

supports tissue function physical support connection between tissues

Question 46

What does CT Proper: Dense Regular CT contain?

Answer 46

fibroblasts thick collagen bundles in regular array (same direction) usually contains elastic fibers typically no immune cells unless sick

Question 47

Where is CT Proper: Dense Regular CT found?

Answer 47

mostly tendons or ligaments

Question 48

Dense Regular CT Organization

Answer 48

Question 49

Dense Regular CT Histology

Answer 49

Question 50

CT Proper: Elastic CT

Answer 50

Subcategory of Loose, Dense Irregular, or Dense Regular CT contains: above/elastic fibers supporting tissue function → stretching special stains typically required

Question 51

Elastic CT Organization

Answer 51

Question 52

Elastic CT Histology

Answer 52

Question 53

Elastic CT Histology: Silver Stain

Answer 53

Question 54

What is the function of CT Proper: Reticular CT?

Answer 54

supports tissue function → cells in a fibrous matrix

Question 55

What stains are required to see reticular fibers?

Answer 55

silver staining reticulin (uses silver and other heavy metals)

Question 56

What does Reticular CT contain?

Answer 56

specialized fibroblasts (reticulocytes) reticular fibers (stroma) hepatocytes - perinchyma only reticular fibers and ground substance

Question 57

Reticular CT Organization

Answer 57

Question 58

Reticular CT Histology

Answer 58

Question 59

Reticular CT Histology: Silver Stain

Answer 59

Question 60

What does Adipose CT contain?

Answer 60

adipose cells (adipocyte) very little ground substance

Question 61

What is the function of adipose CT?

Answer 61

supports tissue function → cushioning, energy storage (in form of lipids)

Question 62

What stain is required to see lipids?

Answer 62

fixation with osmium

Question 63

Adipose CT Organization

Answer 63

Question 64

Adipose CT Histology

Answer 64

Question 65

How does ground substance contribute to the function of CT?