Lecture 4

Question 1

Functions of the skeletal system:

Answer 1

-Support and protection-Mineral (calcium and phosphorus) and lipid storage (yellow marrow - fatty)-Hematopoiesis (red marrow) - creating blood cells-Movement

Question 2

Types of cartilage:

Answer 2

HyalineElasticFibrocartilage

Question 3

Dentin and enamel are derived from what specific germ layer?

Answer 3

Neural crest ectoderm

Question 4

What are cartilage cells?

Answer 4

chondrocytes

Question 5

The manner is which cartilage grows:

Answer 5

Interstitial growth (between the cells)

Question 6

The perichondrium means…and is made of what?

Answer 6

around the cartilage(dense irregular fibrous connective tissue)

Question 7

Bone cells are called…

Answer 7

Osteocytes

Question 8

Organic content of bones:

Answer 8

Osteocytes and collagen

Question 9

Mineral (inorganic) content of bones:

Answer 9

Hydroxyapatite

Question 10

Types of bones and describe each.

Answer 10

Long bones: longer than they are wideFlat bones: flatter than they are highShort bones: almost cubes (not perfectly)Sesmoid bones: look like sesame seedsSutural bones: between cranial suturesIrregular bones: unique

Question 11

If you start “attaching” minerals to the matrix of cartilage, what happens?

Answer 11

It changes into bone

Question 12

Examples of each type of boneLong bones:Flat bones: Short bones:Sesmoid bones: Sutural bones: Irregular bones:

Answer 12

-Long bones: most limb bones including phalanges-Flat bones: cranial bones, ribs, sternum, scapula-Short bones: carpal and tarsal bones-Sesmoid bones: patella, intratendonous bones-Sutural bones: between cranial structures-Irregular bones: vertebrae, pelvic bones, some cranial bones

Question 13

What is different about sesmoid bones?

Answer 13

They grow inside tendons (like patella bone)

Question 14

Elevations and projections featuresProcess:Ramus:

Answer 14

Process: generic term for a projectionRamus: a projection that forms a sharp angle

Question 15

Tendon or ligament featuresTrochanter/Tuberosity:Tubercle:Crest/Line:Spine:

Answer 15

Trochanter/Tuberosity: rough projections (usually for attachment of ligament/tendon - more surface area)Tubercle: smooth projection (smaller attachments)Crest/Line: large and small ridgesSpine: a point

Question 16

Articulation featuresHead:Neck:Condyle:Trochlea:Facet:

Answer 16

Head: expanded articular endNeck: narrow area between head and shaftCondyle: smooth, rounded articular portion (in pairs)Trochlea: grooved articular portion Facet: flat articular area (in between vertebrae)

Question 17

Depressions and openings featuresFossa:Sulcus:Foramen vs. canal:Fissure:Sinus:

Answer 17

Fossa: a depressionSulcus: a groove (elongated depression)Foramen vs. canal: single hole vs. 2 connecting holesFissure: a cleftSinus: a hollow area (usually air-filled)

Question 18

Parts of a boneDiaphysis:Epiphysis:Metaphysis:

Answer 18

Diaphysis: shaft (single; unpaired)Epiphysis: expanded end (paired)Metaphysis: transitional zone between the diaphysis and epiphysis

Question 19

What is the actual growth plate?

Answer 19

Metaphysis

Question 20

Structure of boneCompact bone:Spongy bone:Marrow cavity:

Answer 20

Compact bone: dense shell around marrow cavitySpongy bone: at the ends; lots of holes; meshworkMarrow cavity: hollow center in the diaphysis

Question 21

The marrow cavity is also referred to as…

Answer 21

the medullary cavity

Question 22

The compact bone is also referred to as…

Answer 22

cortical bone (cortex)

Question 23

The spongy bone is also referred to as…

Answer 23

trabecular bone (“beam”)

Question 24

What kind of tissue is bone?

Answer 24

connective tissue

Question 25

What does the matrix of a bone consist of?

Answer 25

-Extracellular fibers (most collagen with inorganic crystals)-Ground substance (the fluid - minimal)

Question 26

Most of the mass of bone is...

Answer 26

Inorganic; hydroxyapatite mineral

Question 27

Hydroxyapatite mineral structure:

Answer 27

Hard, inflexible, brittle; will break

Question 28

What hold the hydroxyapatite crystals in place?

Answer 28

Collagen fibers

Question 29

Combination of ______ and _______ makes bone strong and slightly flexible.

Answer 29

Organic content and inorganic content

Question 30

Osteocytes:

Answer 30

Mature bone cells that occupy lacunae

Question 31

What are lacunae?

Answer 31

Little spaces in the matrix that hold one osteocyte per lacuna

Question 32

Osteocytes are connected via what?

Answer 32

Canaliculi (tiny little channels)

Question 33

Functions of osteocytes:

Answer 33

-Maintain the matrix environment-Repair damaged bone

Question 34

Osteochondral progenitor cells:Located:

Answer 34

-Stem cells that will become osteoblasts-Located on the interior endosteum (lining the inside of the bone in the marrow cavity)-And periosteum (outside of marrow cavity)

Question 35

Osteoblasts:

Answer 35

-Produce new bone-Secrete the organic matrix (osteoid)-Promote deposition of hydroxyapatite

Question 36

Osteiod is...

Answer 36

Organic component of matrix before it becomes mineralized

Question 37

Osteoclasts:

Answer 37

-Large cells that break down/dissolve bone matrix-Multi-nucleated

Question 38

Where are osteoclasts derived from?

Answer 38

macrophages

Question 39

What is the very middle of bone? And what can you find?

Answer 39

Central canalBlood vessels

Question 40

What has layers and surrounds the central canal?

Answer 40

Osteon

Question 41

Where do you find circumferential lamellae?

Answer 41

The outer and inner surfaces (circumference) of the bone, where they are covered by the periosteum and endosteum

Question 42

Structure of a periosteum:

Answer 42

Fibrous outer layerCellular inner layer

Question 43

Basic biomechanics Force:Load:Stress:Strain: Elasticity:Stiffness:

Answer 43

Force: mass x accelerationLoad: a force applied to an objectStress: force/areaStrain: deformation resulting from stressElasticity: ability to experience strain and return to original shapeStiffness: resistance to bending

Question 44

2 main types of bone and characteristics:

Answer 44

Compact (cortical) bone: dense; stress from limited directions; resists compression & tension; heavySpongy (trabecular) bone: resists stress from many directions; stress lines; light

Question 45

Functional unit of compact bone....

Answer 45

Osteon

Question 46

Perforating canals allow what?

Answer 46

Blood to come from outside and go from one central canal to another, all the way to the innermost portion of the bone (medullary cavity)

Question 47

Other names for...Central canal:Perforating canal:

Answer 47

Central canal: Haversian canalPerforating canal: Volkmann's canal

Question 48

Where is spongy bone located?What happens at these locations?

Answer 48

-At the ends of long bones-Articulation with other bones

Question 49

Spongy bone helps to do what?

Answer 49

Receives stress and helps to distribute loads from the articular condyles to the cortical (inner) bone where it is the strongest

Question 50

Compact bones and spongy bones work together to...

Answer 50

Most efficiently handle the load placed on it