Cartilage/Bone

Question 1

what 2 compounds help retain water?

Answer 1

1) proteoglycans

2) glycoproteins

Question 2

what does collagen provide to cartilage?

Answer 2

• flexibility
• resiliency
• diffusion thru the membrane
• tensile strength

Question 3

what do elastic fibers help collagen to do?

Answer 3

regain original shape

Question 4

what are the 2 types of cartilage growth?

Answer 4

1) appositional

2) interstitial

Question 5

what is appositional cartilage growth?

Answer 5

new cartilage forms at the surface of existing cartilage (so cartilage grows from outer edges)

Question 6

what is interstitial cartilage growth?

Answer 6

when new cartilage forms WITHIN existing cartilage

Question 7

what are the 3 types of cartilage?

Answer 7

1) fibrocartilage
2) elastic cartilage
3) hyaline cartilage

Question 8

what are some characteristics of fibrocartilage?

Answer 8

• has visible fibers; NO perichondrium
• associated with dense regular CT
• more collagen fibers

Question 9

where is fibrocartilage found in?

Answer 9

• tendon-bone junction
• intervertebral discs
• menisci (knee)

Question 10

what cell types make collagen?

Answer 10

• fibroblasts
• reticular cell
• smooth muscle cells
• epithelial cells
• osteoblasts (bone)
• chondroblasts (cartilage)

Question 11

why is there a lacuna around chondrocytes?

Answer 11

matrix is more rigid than other types of CT, so matrix is retained upon fixation, but cell shrink a little (leaving an empty space around them)

Question 12

what is a chondrocyte?

Answer 12

a chondroblast that is fully surrounded by matrix

Question 13

describe characteristics of hyaline cartilage

Answer 13

• glassy appearance
• perichondrium
• high proteoglycan content & water content (gives glassy appearance)

Question 14

where is hyaline cartilage found?

Answer 14

• fetal skeletal tissue
• epiphyseal plates
• articular surface (no perichondrium)
• respiratory system

Question 15

describe some characteristics of elastic cartilage

Answer 15

• elastic stain
• perichondrium
• often continuous w/ hyaline cartilage

Question 16

where is elastic cartilage found?

Answer 16

• ear (pinna, meatus, tube)

- epiglottis/larynx

Question 17

what is the difference between dense regular CT and fibrocartilage visually?

Answer 17

• fibrocartilage has lacuna around cells

- dense regular CT contains fibrocytes with no lacuna

Question 18

what are the 3 parts of a long bone?

Answer 18

1) epiphysis
2) metaphysis
3) diaphysis

Question 19

what is the structure and function of bone?

Answer 19

• structural = protection of internal organs; mechanical movement with skeletal muscle
• metabolic = hematopoiesis; calcium/phosphate storage

Question 20

what are osteoprogenitor cells?

Answer 20

• line marrow cavity
• differentiate into osteoblasts
• are not distinctive histologically

Question 21

what are bone-lining cells?

Answer 21

• inactive osteoblasts

- cover static bone where bone is not being laid down

Question 22

what are osteoblasts?

Answer 22

• line marrow cavity
• deposit (BUILD) matrix
• also found in periosteum

Question 23

what are osteocytes?

Answer 23

• mature bone cell
• maintain matrix (SIT)
• surrounded by matrix

Question 24

what are osteoclasts?

Answer 24

• phagocytic bone cell (CLEAVE)
• bone reabsorption
• breaks down bone to release calcium & phosphate

Question 25

what do parathyroid hormone & calcitonin do in bone?

Answer 25

• parathyroid hormone = inhibits osteoblasts to reduce bone matrix production; reduced bone matrix production means more calcium available in blood, less calcium for bone
• calcitonin = inhibits osteoclasts to slow bone resorption; DECREASES blood calcium

Question 26

where is calcitonin produced?

Answer 26

in thymus gland

Question 27

what are the steps in bone mineralization?

Answer 27

1) increase local calcium & phosphate concentrations
2) secretion of vesicles that accumulate additional calcium & phosphate
3) increase in local isoelectric point crystallizes calcium phosphate
4) additional crystallization into hydroxyapatite crystals (initial deposit is called osteoid)

Question 28

what are the 2 methods of bone formation?

Answer 28

1) intramembranous ossification (initial development)

2) endochondral ossification (growth plates/epiphyseal plates)

Question 29

what are the steps of endochondral ossification?

Answer 29

1) proliferation
2) hypertrophy
3) calcification
4) reabsorption of cartilage

Question 30

what are the steps in bone remodeling?

Answer 30

1) osteoclasts (CLEAVE) bore through tissue
2) osteoblasts (BUILD) lay down new matrix
3) lamellar reach minimum circumference
4) Haversian canal is lined by bone-lining cells (endosteal cells)

Question 31

what are the 2 types of synoviocytes?

Answer 31

1) phagocytic = digests debris in synovial fluid

2) productive = makes synovial fluid

Question 32

what is synovial fluid and what does it do?

Answer 32

• contains hyaluronan for cushioning, lubricin for lubrication, nutrients
• function: cushioning impact, lubrication of articular cartilage, support of articular cartilage

Question 33

what is the healing process of a broken bone?

Answer 33

1) blood clot forms in area of break due to blood vessels in Haversian canals
2) space will be filled up with fibrocartilage along w/ loose CT with a lot of immune cells (macrophages to clean up debris) = new blood vessels forming
3) converted to spongy bone
4) new compact bone will form thru remodeling