Bones, Cartilage & Joints 1

Question 1

what are the different types of connective tissue

Answer 1

Question 2

what cells are in cartilage

Answer 2

chondroblasts –> produces the matrix

chondrocytes –> same cell that contains matrix

Question 3

what is the extracellular matrix (ECM) in cartilage

Answer 3

unique biomechanical properties

fibres (depends on type of cartilage) –> rigidity

ground substance (abundant) –> resiliency

generally avascular (cells are reliant on diffusion for nurishment)

Question 4

what are the 3 types of cartilage

Answer 4

1. hyaline
2. elastic
3. fibrocartilage

Question 5

what type of cartilage is this

Answer 5

hyaline

Question 6

what type of cartilage is this

Answer 6

elastic

Question 7

what type of cartilage is this

Answer 7

fibrocartilage

Question 8

what is the most common type of cartilage

Answer 8

hyaline cartilage

Question 9

what makes up hyaline cartilage

Answer 9

abundant ground substance plus few type II collagen fibres

Question 10

what does hyaline cartilage form in the embryo

Answer 10

temporary skeleton in embyro –> gradually replaced by bone

responsible for growth of long bones

Question 11

where is hyaline cartilage in adults

Answer 11

limited distribution

ex. articular surface of moveable joints, walls respiratory passages, costal cartilage (trachea)

Question 12

how does hyaline cartilage grow

Answer 12

appositional and interstitial growth –> added to outer surfaces and growth within (unique to cartilage, bone is only appositional)

Question 13

where is elastic cartilage found

Answer 13

ear pinna, epiglottis

Question 14

what is in elastic cartilage

Answer 14

high content of elastic fibres + collagen type II

less ground substance

Question 15

how does elastic cartilage grow

Answer 15

appositional and interstitial growth

Question 16

where is fibro-cartilage found

Answer 16

limited distribution

inter-vertebral discs

intra-articular discs (menisci)

attachment ligament and tendons to bones

Question 17

how is fibro-cartilage arranged

Answer 17

cells (chondroyctes) arranged in columns between bundles of collagen (type I)

minimal ground substance

no identifiable perichondrium (no CT between them)

Question 18

how does fibro-cartilage grow

Answer 18

interstitial growth only (no bounding surface to allow growth from surfaces)

Question 19

what is appositional growth

Answer 19

process begins with perichondrium (fibroblasts-chondroblasts synthesis matrix–> chondrocytes)

growth continues at the edges of a pre-existing cartilage model

Question 20

what is interstitial growth

Answer 20

occurs within existing

chondrocytes become chondroblasts

isogenous groups form and produce mroe extracellular matrix

Question 21

what are the cells

Answer 21

P- perichondrium

Cg- chondrogenic zone

Cb- chondroblasts

C- chondrocytes

Question 22

what type of growth is shown here

Answer 22

green - appositional

red - interstitial

Question 23

what is an example of hyaline cartilage where only interstitial growth occurs

Answer 23

articular cartilage and synocial joints

Question 24

what is the origin of synovial fluid

Answer 24

synovial membrane or synovium –> specialized connective tissue with secretory capacity

Question 25

what is the intima

Answer 25

2-4 cells deep type A macrophage - maintenance and "clean up" type B fibroblast (synoviocytes) - secretes hyaluronan (hyaluronic acid)

Question 26

what is subintima

Answer 26

loose connective tissue capillaries --\> important for maintenance of articular cartilage which is avascular

Question 27

what are the 3 components of synovial fluid

Answer 27

1. interstitial fluid - blood plasma 2. hyaluronan - fibroblast-like cells in the synovial membrane (synoviocytes) 3. lubricin (proteoglycan 4; PRG4) - chondrocytes

Question 28

what is the function of synovial fluid

Answer 28

fills the gap 1. lubrication 2. shock absorption 3. nutrient transport

Question 29

how does synovial fluid lubricate

Answer 29

forms lubricating film forms on synovial membrane and seeps into articular cartilage and spaces squeeze film --\> weeping lubrication --\> fluid held in the cartilage is squeezed out mechanically to maintain a layer of fluid on the cartilage surface

Question 30

how does synovial fluid provide shock absorption

Answer 30

becomes thick and viscous returning to normal viscosity

Question 31

how does synovial fluid aid in nutrient transport

Answer 31

most articular cartilage in close apposition to synovial membrane

Question 32

what are the functions of bone

Answer 32

1. rigid and hard support 2. protects vital organs 3. contains bone marrow (hematopoiesis) 4. reservoir for calcium, phosphate and other ions 5. transforms forces of skeletal muscle contraction into bodily movements

Question 33

what is the structure of bone

Answer 33

cells and fibres embedded in hard unbending calcified matrix

Question 34

how is bone different than cartilage

Answer 34

dynamic tissue --\> capable of remodelling and repairing itself --\> unlike cartilage it is very vascular --\> nourish cells

Question 35

what are the 3 structures of bone

Answer 35

1. epiphysis 2. metaphysis 3. diaphysis

Question 36

what is compact bone

Answer 36

compact bone forms the outer wall

Question 37

what is trabecular bone

Answer 37

interior of bone

Question 38

what is another name for trabecular bone

Answer 38

spongy or cancellous bone

Question 39

what are the types of lamellar bone

Answer 39

compact and trabecular

Question 40

what are the structures

Answer 40

Question 41

what is lamellar bone

Answer 41

specific orientation of collagen fibres --\> biochemical function

Question 42

what are the two types of lamellar bone

Answer 42

1. compact (cortical) bone: diaphysis 2. spongy, cancellous or trabecular bone: spicules are aggregated into bony trabeculae (plates)

Question 43

what is woven bone

Answer 43

random orientation collagen fibres temporary form association developing bone, fracture repair, bone tumours replaced by lamellar bone in most cases

Question 44

what is the basic unit of compact (cortical) bone

Answer 44

osteone or haversian system

Question 45

what are the bone cell types

Answer 45

1. osteoblasts 2. osteocytes 3. osteoclasts

Question 46

what are osteoblasts associated with

Answer 46

periosteum/endosteum which covers external and internal

Question 47

where are osteoblasts found

Answer 47

surfaces all bony surfaces

Question 48

what is the function of osteoblasts

Answer 48

function is to form osteoid (organic part of ECM) become osteocytes - maintenance

Question 49

where are osteocytes

Answer 49

located within calcified "osteoid" ECM

Question 50

what is the function of osteocytes

Answer 50

communicate with each other by special cellular extensions --\> canaliculi maintain the bony matrix

Question 51

where osteoclasts

Answer 51

located on external and internal surfaces of boney surfaces

Question 52

what are the characteristics of osteoclasts

Answer 52

large, motile, multinucleated cells

Question 53

what is the functions of osteoclasts

Answer 53

characteristic ruffled border enzymatic digestion of ECM --\> important for remodelling of bone

Question 54

name these cells

Answer 54

osteocyte - maintiains bone tissue osteoblast - forms bone matrix osteogenic cell - stem cell (osteoprogenitor cell, associated with periosteum or endosteum) osteoclast - resorbs bone

Question 55

what is the organic component (osteoid) of the bone ECM produced by

Answer 55

produced by osteoblasts fibres - predominantly collagen type I (spiral arrangement)

Question 56

when does the inorganic component of bone ECM form

Answer 56

after the osteoid laid down hydroxyapatite crystals Na, Mg, Fe

Question 57

how is the calcified matrix impermeable

Answer 57

all connected through extensions surrounded by hard bone the lacunar-canalicular system allows osteocytes embedded within the matrix to communicate with each other

Question 58

what cartilage is responsible for growth of long bones

Question 59

identify the histological cells of trabecular bone

Answer 59

Question 60

what is shown here

Answer 60

calcified matrix very impermeable lacunar-canaluclar system allows osteocytes embedded within the matrix to communicate