The Articular System

Question 1

The articular system is comprised of:

Answer 1

Bone
Cartilage
Synovial Fluid
Synovial Membrane

Question 2

Highly vascularlized, mineralized connective tissue that is living and constantly changing in response to external stress

Answer 2

Bone

Question 3

Consists of cells and extracellular matrix

Answer 3

Bone

Question 4

Compact bone on the shaft of a bone that surrounds the marrow cavity and provides strength

Answer 4

Cortical bone

Question 5

_______ bone always surrounds cancellous bone (below) but the relative quantity of each type varies among bones and within individual bones according to functional requirements

Answer 5

Cortical

Question 6

Can only deform 2% before fracture occurs

Answer 6

Compact bone

Question 7

Dense bone

Answer 7

Compact bone

Question 8

Spongy Bone

Answer 8

Cancellous Bone

Question 9

Does not contain osteons, always located in the interior of the bone

Answer 9

Cancellous bone

Question 10

Facilitates cellular action of adding to or withdrawing from calcium and phosphate reservoir within the body

Answer 10

Cancellous bone

Question 11

Tough outer connective tissue sheath and its associated blood supply that surrounds bone surface

Answer 11

Periosteum

Question 12

Hollow, cylindrical space within the diaphysis (shaft) that contains fatty yellow bone marrow and blood vessels

Answer 12

Medullary cavity

Question 13

The periosteum is attached to underlying bone by perforating fibres – thick bundles of collagen that extend from the periosteum into the bone extracellular matrix known as:

Answer 13

Sharpey’s fibers

Question 14

Protects the bone, assists in fracture repair, helps nourish bone tissue, serves as an attachment point for ligaments and tendons

Answer 14

Periosteum

Question 15

Thin membrane that lines the medullary cavity, contains single layer of bone-forming cells and small amount of connective tissue

Answer 15

Endosteum

Question 16

Mature bone cells, main cells in bone tissue and maintain its daily metabolism

Answer 16

Osteocytes

Question 17

in the bone matrix: Fibre direction is random in the young but highly-ordered and parallel in the older population and consists mainly of collagen fibre bundles

Answer 17

Organic component

Question 18

There is a greater loss of the ______ fibres in osteoporosis

Answer 18

transverse fibres

Question 19

Compression strength and modulus of elasticity is the greatest in bones when the fibres are mainly _______ and lowest when the fibres are mainly _______

Answer 19

transverse

longitudinal

Question 20

Composes 70% of the bony matrix; made up of inorganic component (55%) and water (15%)

Answer 20

Ground substance

Question 21

consists of salts and minerals which impregnate the collagen fibres and crystallize to provide tissue hardness and rigidity

Answer 21

Inorganic component (of ground substance)

Question 22

The remaining 15% of bone; provides the flexibility (distortion tolerance) of the bone

Answer 22

Water

Question 23

The _________ allows bone to increase in length until adulthood, bone is added on to diaphysis side

Answer 23

epiphyseal plate

Question 24

__________ cartilage remains between the diaphysis and epiphysis as the epiphyseal growth plate

Answer 24

hyaline

Question 25

bone can resist _______ load better than a torsional or longitudinal load

Answer 25

compressive

Question 26

Loss of ______ strength causes the bones to become very brittle and susceptible to fracture

Answer 26

tensile

Question 27

________ fractures occur when the high energy from a high load can not be dissipated fast enough through a single crack in the bone

Answer 27

comminuted

Question 28

_______ fracture occurs when the remodeling process is outpaced by the load frequency

Answer 28

fatigue

Question 29

Bone is laid down where needed and reabsorbed where not needed

Answer 29

Wolff's Law

Question 30

When bone is placed under _________ bone tissue becomes stronger through increased deposition of mineral salts and production of collagen fibres by osteoblasts

Answer 30

stress (weight bearing exercise)

Question 31

Bone loss begins after 30 in females, accelerates greater around 45 as levels of _______ decrease and continues until as much as 30% of the calcium in bone is lost by age 70

Answer 31

estrogen

Question 32

In males, bone loss typically does not begin until age _______

Answer 32

60

Question 33

Loss of ______ from bones is one of the problems in osteoporosis

Answer 33

calcium

Question 34

Brittleness results from a decrease rate of _________

Answer 34

protein synthesis

Question 35

the two principle effects of aging on bone tissue are:

Answer 35

loss of bone mass and brittleness

Question 36

What are the functions of bone?

Answer 36

Supports soft tissue Protects internal organs Serves as levers for movement Contains red bone marrow which produces blood cells Stores mineral salts, calcium, phosphate Contains yellow bone marrow which stores triglycerides

Question 37

________ are responsible for building articular cartilage during development and maintaining the integrity of the tissue in adulthood

Answer 37

chondrocytes

Question 38

provides the structural framework of the tissue giving the tissue its shape and tensile stiffness and therefore provides resistance to tensile loads; it additionally anchors the cartilage to the subchondral bone

Answer 38

collagen fibrils (mainly type II)

Question 39

Consists of proteoglycans and water

Answer 39

Interfibrillary matrix

Question 40

Provides resilience, lubrication, elasticity, and resists compression

Answer 40

interfibrillary matrix

Question 41

metabolism of chondrocytes is dependent upon diffusion of oxygen and nutrients from the synovial fluid and subchondral bone through the tissue matrix and this diffusion is aided by ________ , which create the flow of extracellular fluid in and out of the tissue

Answer 41

joint motion and load

Question 42

What type of articular cartilage is found over the ends of long bone

Answer 42

Hyaline cartilage

Question 43

Which type of cartilage affords flexibility and strength

Answer 43

Hyaline

Question 44

Which type of cartilage provides strength and rigidity

Answer 44

Fibrocartilage

Question 45

Found in annulus fibrosis of the IV disc, symphysis pubis, knee menisci, TMJ disc

Answer 45

Fibrocartilage

Question 46

Compression of the articular cartilage tissue forces large volumes of _______ to exit the middle zone towards the superficial zone and into the ________ space; this fluid returns after removal of compression

Answer 46

water | synovial

Question 47

The only vascularized region of articular cartilage

Answer 47

calcified zone

Question 48

Articular cartilage has a low capacity for regeneration except in _________ with a delicate balance of synthesis and breakdown

Answer 48

perichondrium

Question 49

What are the functions of articular cartilage?

Answer 49

Protection: collagen provides tensile strength; matrix provides smoothness and firmness Reduced Friction: provides a smooth and gliding surface with a very low coefficient of friction Resistance to Compression and Shear Forces: afforded by the elastic and viscoelastic properties of cartilage

Question 50

Immobilization of joints leads to atrophy of the articular cartilage and therefore continuous ______ motion is believed to be beneficial to healing

Answer 50

passive

Question 51

What are the functions of synovial fluid?

Answer 51

Nutrition of articular cartilage, discs, menisci Lubrication: all apposed surfaces that have movement are lubricated by synovial fluid Heat dissipation

Question 52

What are the reactions to injury to the synovium?

Answer 52

Post-traumatic synovitis -- increased white blood cells; increased proteins results in decreased viscosity due to fall in concentration of hyaluronate Hemmorhage effusions

Question 53

lines the non-articular components of synovial joints, as well as bursae and tendon sheaths Is absent from intra-articular discs or menisci

Answer 53

synovial membrane