Special Connective Tissue

Question 1

What are the components of the Extracellular Matrix?

Answer 1

(MEG C.) Collagen, Tropoelastin–> Elastin (elastic fibers), Mircrofibrils, Ground Substance

Question 2

What is the precursor to collagen?

Answer 2

Tropocollagen

Question 3

What is the function of collagen?

Answer 3

provide tensile strength to tissue

Question 4

What are the major types if collagen and where are they found?

Answer 4

Type 1: Dermis, ligaments, bone, cornea
Type 2: Hyaline cartilage (i.e., Articulating surfaces of bones, nose, trachea)
Type 3: Reticular collagen; Meshwork in highly cellular organs (i.e,. liver, spleen, kidney)

Question 5

What is the most abundant protein in the human body?

Answer 5

collagen

Question 6

What are the two components of mircofibrils?

Answer 6

fibrillin and fibronectin

Question 7

What is fibrillin?

Answer 7

Elastic fiber component (scaffold for elastin deposition)

Question 8

What is fibronectin?

Answer 8

deposition and orientation of collagen as well as binding of CT cells to extracellular matrix, including linking actin cytoskeleton to matrix

Question 9

Describe ground substance?

Answer 9

transparent, viscous, semi-fluid gel

Question 10

What is the function of ground substance?

Answer 10

influence fluid transport and metabolic exchange

Question 11

What are proteoglycans? What part of the extracellular matrix are they a part of?

Answer 11

GAG + core protein (binds to GAG) +linker protein (binds core protein and GAG to hyaluronic acid backbone

Ground Substance

Question 12

What is proteoglycan aggregate composed of?

Answer 12

proteoglycan + hyaluronic acid + some collagen

Question 13

Name 2 types of specialized Connective Tissues.

Answer 13

Cartilage and bone

Question 14

Where is cartilage developed from?

Answer 14

paraxial mesoderm

Question 15

Cartilage: what is perichondrium; what are the layers?

Answer 15

Fibrous layer- fibroblasts, vasculature

Chondrogenic layer- chondroblasts and chondrocytes

Question 16

What is lucunae?

Answer 16

space occupied by a cell (in cartilage- a chondrocyte as it has walled itself by extreting ECM

Question 17

What is the first type of cartilage?

Answer 17

1st type: Hyaline Cartilage

Question 18

What is the second type of cartilage?

Answer 18

2nd type: Elastic Cartilage

Question 19

What is the third type of cartilage?

Answer 19

3rd type: Fibrous Cartilage

Question 20

Does Hyaline Cartilage have perichondrium?

Answer 20

YES, but not found in articulating surface joints to keep growth at a minimum

Question 21

Does Elastic Cartilage have perichondrium?

Answer 21

YES

Question 22

Does Fibrous Cartilage have perichondrium?

Answer 22

NO

Question 23

What is the only difference between elastic and hyaline cartilage?

Answer 23

there are elastic fibers in elastic cartilage but NOT in hyaline

Question 24

Where is hyaline cartilage located?

Answer 24

tracheal bands, bronchi, nasal septum, joints, growth plates of long bones, site of initial bone repair following a fracture, embryonic template for the formation of long bones

Question 25

Where is elastic cartilage located?

Answer 25

external ear lobe, epiglottis, pharyngotympanic tube (Eustachian tube)

Question 26

Where is firbous cartilage located?

Answer 26

intervertebral discs (annulus fibrosis) and symphyses (joints between bones of breastbone and joint b/w left and right pubic bones in the hip)

Question 27

What type of collagen is found in hyaline and elastic cartilage?

Answer 27

Type 2 (elastic cartilage) predominantly [Type 1 in outer fibrous layer of perichondrium]

Question 28

Where is bone derived from?

Answer 28

paraxial mesoderm

Question 29

Are bone and cartilage derived from the same thing? If so, from what?

Answer 29

paraxial mesoderm

Question 30

Name the outer and inner layers on the most EXTERNAL portion of bone. What do these layers contain?

Answer 30

fibrous (fibroblasts) and osteogenic periosteum (osteoblasts mostly but also can have osteocytes)

Question 31

extensions of periosteum into compact bone:

Answer 31

Sharpey's fibers (allow for better adherence of periosteum to underlying bone given that periosteum serves as attachment site for muscle tendons)

Question 32

What cells are in bone? (hint: 3)

Answer 32

Osteoblasts, osteocytes, osteoclasts

Question 33

What are osteoblasts?

Answer 33

main builder of bone

Question 34

What are osteocytes?

Answer 34

secondary builder of bone; bone maintenance

Question 35

What are osteoclasts?

Answer 35

maintenance--> dissolve bone

Question 36

Name the seven structures of bone?

Answer 36

lamellae, cancliculi, lacunae, Haversian system/osteon, Haversian canal, Volkmann canal, Howship's lacunae

Question 37

Name two steps of bone development:

Answer 37

intramembraneous ossification and endochondral ossification

Question 38

What is intramembraneous ossification?

Answer 38

formation of FLAT bones (like in the skull, face)

Question 39

What are the two steps of intramembraneous ossification?

Answer 39

1. CT replaced with bone matrix | 2. Mesenchymal cells differentiate into bone cells (osteoblasts)

Question 40

What is endochondral ossification?

Answer 40

formation of LONG bones (like arm and legs)

Question 41

Where is endochondral ossification derived from?

Answer 41

miniature hyaline cartilage template

Question 42

What are the three steps of endochondral ossification?

Answer 42

Epiphysis, Metaphysis, Diaphysis

Question 43

What is epiphysis?

Answer 43

Secondary ossification site (contains the RED BONE MARROW--important for hemopoesis)

Question 44

What is metaphysis?

Answer 44

location of the GROWTH PLATE; closes at adolescence

Question 45

What are the zones of metaphysis?

Answer 45

``` Reserve cartilage (R) Proliferation (P) Maturation (M) Hypertrophy/calcification (H) Degeneration (D) Ossification (O) ``` RPMH DO- Run past my house DO it

Question 46

What is reserve cartilage (R)?

Answer 46

typical hyaline cartilage with chondrocytes in small clusters

Question 47

What is proliferation?

Answer 47

mitotic activity of chondrocytes increases, ECM rich in proteoglycans

Question 48

What is maturation?

Answer 48

mitosis has STOPPED and chondrocytes have INCREASED in size

Question 49

What is Hypertrophy/calcification (H) ?

Answer 49

chondrocytes continue to INCREASE in size; Matrix becomes calcified--trapped chondrocytes in lacunae

Question 50

What is degeneration?

Answer 50

chondrocytes DEGENERATE and are invaded by osteogenic cells and capillaries that will FORM bone marrow of the shafts of long bone, the diaphyses

Question 51

What is ossification?

Answer 51

bone becomes CALCIFIED in increase strength--allowed to maintain a small amount of flexibility

Question 52

What is diaphysis?

Answer 52

bone shaft; primary ossification site

Question 53

What type of bone tissue is present during bone repair and during bone development?

Answer 53

Primary bone tissue

Question 54

what is primary bone tissue?

Answer 54

has a random organization of collagen fibers--not as dense as mature bone

Question 55

Describe the first bone of development/after fracture:

Answer 55

unorganized or woven

Question 56

Why is bone after a fracture unorganized or woven?

Answer 56

because a fracture causes destruction of bone matrix and death of bone cells. Damaged blood vessels form a clot and the clot, cells and damaged matrix removed by macrophages

Question 57

What is the role of periosteum and endosteum in bone fracture?

Answer 57

it responds with intense proliferation, surrounding the fracture and penetrating the fracture

Question 58

What two things are formed at the same time? (hint: a bone and a cartilage)

Answer 58

primary bone and hyaline cartilage

Question 59

What do primary bone and hyaline do during a fracture?

Answer 59

they are replaced with bone as well as CT is formed and replaced. They form irregular trabeculae or bone calluses

Question 60

What replaces Callus?

Answer 60

Secondary bone tissue