Week 4 - Chapter 7

Front 1

Define osseous:

Back 1

bone tissue

Front 2

Define mineralization:

Back 2

crystallization process in which ions(calcium, phosphate & others) are removed from blood plasma & depositedin bone tissue

Front 3

Define calcifitaion

Back 3

calcium deposits in the bone

Front 4

Define compact bone:

Back 4

external and internal surfaces of flat bone are composed of compact bone

•Osteon (haversian system) = basicstructural unit –cylindersof tissue formed from layers (lamellae) of matrix arranged around central canalholding a blood vessel

Front 5

Define Medullary cavity

Back 5

marrow cavity in a bone

Front 6

Define spongy bone:

Back 6

Middlelayer of a flat bone is spongy bone (diploe). No marrow cavity in a flat bone.

•Spongelikeappearance formed by rods and plates of bone called trabeculae

–spacesfilled with red bone marrow

•Trabeculaehave few osteons or central canals –noosteocyte is far from blood of bone marrow

•Providesstrength with little weight

–trabeculaedevelop along bone’s lines of stress

Front 7

Define diaphysis:

Back 7

Shaft (diaphysis) is cylinder of compactbone containing marrow cavity (medullary cavity) & lined with endosteum(layer of osteogenic cells and reticular connective tissue)

Front 8

Define epiphysis:

Back 8

Epiphyseal plate

•Non-maturebones increase in length by interstitial growth of epiphyseal plate (addingmore matrix internally)

Front 9

Define articular cartilage:

Back 9

Joint surfaces are covered with articular cartilage for lubrication (at the end of long bones)

Front 10

Define periosteum:

Back 10

–outerfibrous layer of collagen fibers continuous with tendons orperforating(Sharpey’s) fibers that penetrate into bone matrix

–innerosteogenic layer important for growth & healing

Front 11

Define Sharpey fibers

Back 11

fibers that penetrate into bone matrix

Front 12

Define endosteum:

Back 12

layer of osteogenic cells and reticularconnective tissue

Front 13

Define Epiphyseal plate

Back 13

in children and adolescents and epiphysealplate of hyaline cartilage separates the marrow spaces of the epiphysis anddiaphysis. The epiphyseal plate is azone where the bones elongate by a growth process. There are no ephiphyseal plates inadults.

Front 14

Define Lamellae

Back 14

–cylindersof tissue formed from layers (lamellae) of matrix arranged around central canalholding a blood vessel

lamellae encircle haversian canals.

Front 15

Define Haversian canal

Back 15

Anosteon or haversian system is the central canal and its lamellae.

Front 16

Define Osteon

Back 16

•Osteon (haversiansystem) = basic structural unit of a compact bone

contains lamellae and haversian canal

Front 17

Define Volkmann canals

Back 17

•Perforating canals or Volkmann canalsvascularcanals perpendicularly joining central canals

They enhance the strength of bone.

Front 18

Define Trabeculae

Back 18

•Spongelikeappearance formed by rods and plates of bone called trabeculae

–spacesfilled with red bone marrow

•Trabeculaehave few osteons or central canals

–noosteocyte is far from blood of bone marrow

•Providesstrength with little weight

–trabeculaedevelop along bone’s lines of stress

Front 19

Define metaphysis

Back 19

each side of epiphyseal plate has a metaphysis

•Theregion of transition from cartilage to bone at each end of the primary marrowcavity is called a metaphysis.

•Thisis where cartilage in converted into bone and it is responsible for boneelongation and a person’s increase in height.

Front 20

What are the 5 histological zones of transformation from cartilage to bone in metaphysis?

- begin with farthest from the marrowcavity.

What is the function of each zone?

Back 20

•Zone of reserve cartilage

–Hyalinecartilage, no transformation into bone.

•Zone of cell proliferation

–Chondrocytesmultiply and line up.

•Zone of cell hypertrophy

–Enlargementof chondrocytes.

•Zone of calcification

–Temporarycalcification of cartilage.

•Zone of bone deposition

–Deathof chondrocytes; bone deposition; trabeculae forming

Front 21

Define hypertrophy:

Back 21

The enlargement of an organ or tissue from the increase in size of its cells.

Front 22

Define Appositional growth

Back 22

•Bonesalso increase in width by appositional growth (adding more matrix to thesurface)

Front 23

Define Ectopic ossification

Back 23

abnormal calcification

–mayoccur in lungs, brain, eyes, muscles, tendons or arteries (arteriosclerosis)

Front 24

Define Hypocalcemia

Back 24

–isdeficiency of blood calcium

•causesexcessive excitability of nervous system leading tomuscle spasms, tremors or tetany

Front 25

Define hypercalcemia

Back 25

•excessivecalcium binding to cell surface makes sodium channels less likely to open,depressing nervous system

Front 26

Define tetany

Back 26

Tetanyis the inability of a muscle to relax due to a fall in calcium concentration.

Front 27

Define Granulation tissue

Back 27

•fibroustissue formed by fibroblasts & infiltrated by capillaries

Front 28

Define callus formation

Back 28

•softcallus of fibrocartilage replaced by hard callus of bone in 6 weeks

Front 29

Define Close and open reduction

Back 29

•Closedreduction

–fragmentsare aligned with manipulation & casted

•Openreduction internal fixation (ORIF)

–surgicalexposure & repair with plates & screws

Front 30

Bones are a ____________ tissue that continually remodels itself.

Back 30

dynamic

Front 31

What are the functions of the skeletal system?

Back 31

–support,protection, movement, blood formation, mineral reservoir, pH balance &detoxification

Front 32

What is the difference between endochondrial ossification and intramembranous ossification?

Back 32

intramembranous ossification produces flat bones of the skull and clavical

Endochondrial ossification produces most other bones, like the vertebrae, pelvic bones and moves of the limbs.

•Aprocess by which a bone develops from a pre-existing model composed of hyalinecartilage.

•Beginsat the 6thweek of fetal development and continues into the early 20’s.

Front 33

What are the steps of intramembranous ossification?

Back 33

–Mesenchyme(embryonic connective tissue) condenses into a sheet of soft tissue

•transformsinto a network of soft trabeculae

–osteoblastsgather on the trabeculae to form osteoid tissue (uncalcifiedbone)

–calciumphosphate is deposited in the matrix transforming the osteoblasts intoosteocytes

–osteoclastsremodel the center to contain marrow spaces & osteoblasts remodel thesurface to form compact bone

–mesenchymeat the surface gives rise to periosteum

Front 34

What are the steps of endochondrial ossification?

Back 34

•Primaryossification center forms in cartilage model–chondrocytesnear the center swell to form primary ossification center–matrixis reduced & model becomes weak at that point–Somecells of the perichondrium become osteoblasts, which produce a bony collar–Thebony collar acts like a splint it also cuts off diffusion of nutrients andhastens their death (becomes periosteum)

Front 35

What is the structure of a long bone?

(Long Bone Blank Picture Here)

Back 35

Long Bone Picture Here

Front 36

Where do osteogenic cells reside?

Back 36

endosteum

periosteum

or central canals

Front 37

What do ostoblasts do?

Back 37

form and help mineralize organic matter of matrix

Front 38

What are osterocytes?

Back 38

Mature bone cells, that have become trapped in the matrix they formed.

Front 39

What are osteoclasts? What is their function?

Back 39

They develop in bone marrow, formed by the fusion of several stem cells so that they are unusually large. They break down bone.

Front 40

All of the following are functions of the skeletal system, EXCEPT:

To protect viscera

To produce blood To release hormones

To store and release minerals

To aid in respiration launch

Back 40

To release hormones

Front 41

These cells are responsible for the breakdown of bone:

Back 41

Osteoclasts

Front 42

Most of the bones of the extremities are made up of ________________ bones.

Back 42

long bones

Front 43

If a thyroid tumor secretes excessive Calcitonin, which of the following would happen?

Elevated osteoclast activity

Elevated osteoblast activity

Reduced rate of endochondral ossification

Increase in blood calcium concentration

Increase in brittle bones

Back 43

Elevated osteoblast activity

Front 44

A/an __________________ fracture is when a body part is completely severed.

Back 44

Avulsion fracture

Front 45

The shaft of a long bone is called the __________.

Back 45

diaphysis

Front 46

Hemopoiesis typically occurs in

Back 46

the red bone marrow

Front 47

A/an ___ covers most parts of a bone except for its articular cartilage.

Back 47

periosteum

Front 48

Most bones develop from

Back 48

hyaline cartilage

Front 49

The cells primarily responsible for the breakdown of bone are

Back 49

osteoclasts

Front 50

Appositional growth of a long bone has the effect of

Back 50

increasing the diameter of the bone.

Front 51

A soft callus forms during

Back 51

the healing of a fracture.

Front 52

____________ provide(s) hardness to bones, whereas ____________ provide(s) some degree of flexibility.

Back 52

Hydroxyapatite and other minerals; proteins

Front 53

What is the matrix of osseous tissue?

Back 53

1/3 organic and 2/3 in organic

organic matter consists of - collagen,glycosaminoglycans,proteoglycans & glycoproteins

inroganic material consists of

–85%hydroxyapatite (crystallized calcium phosphate salt)

–10%calcium carbonate

–otherminerals (fluoride, sulfate, potassium, magnesium)

Front 54

___________ have a ruffled border with many deep infoldings of the plasma membrane, whereas ____________ have long, thin, fingerlike cytoplasmic processes.

Back 54

Osteoclasts; osteocytes

Front 55

Red marrow

Back 55

–meshof reticular fibers and immature blood cells

–hemopoieticmeans produces blood cells

–foundin vertebrae, ribs, sternum, pelvic girdle and proximal heads of femur and humerusin adults

Front 56

yellow marrow

Back 56

fatty marrow of long bones

Front 57

What are the two methods of ossification prior to birth?

Back 57

intramembranous

endochondral

Front 58

Primary ossification center

Back 58

The region of chrondrocyte enlargement, bony collar and periosteum.

Front 59

Endochondrial ossification

Back 59

A process in which the bone is preceded by a hyaline cartilage "model" that becomes replaced by osseous tissue. It begins around the 6th week of fetal development and continues into a person's 20's. Most bones in the body develop this way, including yhe vertebrae, ribs, sternum, scapula, pelvic girdle, and bones of the limbs

Front 60

Secondary ossification center during fetal development

Back 60

When chrondrocyte enlargement and death occur at the same time in the epiphysis

•Beginto form in the epiphyses near time of birth

•Samestages occur as in primary ossification center

–resultis center of epiphyseal cartilage being transformed into spongy bone

•Hyalinecartilage remains on joint surface as articular cartilage and at junction ofdiaphysis & epiphysis (epiphyseal plate)

–eachside of epiphyseal plate has a metaphysis

Front 61

What is appositional growth?

Back 61

Increase in width by adding more matrix to the surface of the bone

Front 62

What is interstitial growth?

Back 62

Increase in length by by growth of the epiphyseal plate (adding more matrix internally)

Front 63

What is Wolff's law of bone?

Back 63

Thearchitecture of a bone is determined by the mechanical stresses placed upon it,and the bone thereby adapts to withstand those stresses.

Front 64

What is achondroplastic dwarfism?

Back 64

•Shortstature but normal

-sized head and trunklongbones of the limbs stop growing in childhood but other bones unaffected

Front 65

If a bone is fully formed does it remain a metabolically active organ?

Back 65

yes

Front 66

________ exchanges minerals with the tissue fluid and help to maintain calcium homeostasis

Back 66

osseous (bone) tissue

Front 67

Mineralization is crystallization process

Back 67

in which ions (calcium, phosphate &others) are removed from blood plasma & deposited in bone tissue

Front 68

What are the steps in the mineralization process?

Back 68

–osteoblastsproduce collagen fibers that spiral along the length of the osteon inalternating directions

–fibersbecome encrusted with minerals hardening matrix

•ionconcentration must reach the solubility product for crystal formation to occur& then positive feedback forms more

Front 69

Mineral reabsortion

Back 69

-process of dissolving bone and releasing minerals into blood and plasma

Front 70

What is ectopic ossification?

Back 70

abnormal calcification

–mayoccur in lungs, brain, eyes, muscles, tendons or arteries (arteriosclerosis)

Front 71

Calcium and phosphate are found in the bones at what percentages?

Are they both present in blood as well?

Back 71

•99%of calcium is in the bones.

•85%- 95% of phosphate is in the bones.

yes

Front 72

Phosphateis a component of:

Back 72

DNA, RNA, ATP, phospholipids, & acid-base buffers

Front 73

Why is calcium needed?

Back 73

for communicationbetween neurons, muscle contraction, blood clotting & exocytosis

Front 74

What keeps calcium and phosphate in the blood steam?

Back 74

Calciumphosphate homeostasis depends on calcitriol, calcitonin & Parathyroidhormone (PTH)

Front 75

The parathyriod hormone has the ability to _____ or _________ bone mass.

Back 75

increase or decrease

Front 76

What is a carpopedal spasm?

Back 76

hypocalsemia causing overexcitability of nervous system and muscle spasm of hands and feet.

Front 77

What are the effects of calcitriol on bone?

Back 77

behaves as a hormone (blood-born messenger)

raises blood calcium concentration; can promote bone reabsorption or deposition.

The net effect is that it makes our bones stronger.

Front 78

What does calcitonin do?

Back 78

stimulates osteoblast and bone deposition

Front 79

What is a stress fracture?

Back 79

a break caused by abnormal trauma to a bone

Front 80

What is a pathological fracture?

Back 80

a break/fracture in a bone weakened by some other disease.

Front 81

How are fractures classified?

Back 81

•bytheir structural characteristics -- causing a break in the skin, breaking intomultiple pieces, etc

Front 82

Name these bone fractures:

Back 82

(Answer to bone fracture picture here)

Front 83

What is a non-displaced fracture?

Back 83

Where bones remain in proper anatomical alignment.

Front 84

What is a displaced fracture?

Back 84

at least one piece of bone is shifted out of alignment.

Front 85

How does the healing of a fracture take place?

What are the four stages?

Back 85

•Normallyhealing takes 8 - 12 weeks (longer in elderly)

•Stagesof healing:

–fracturehematoma (1) •brokenvessels form a blood clot

–granulationtissue (2)•fibroustissue formed by fibroblasts & infiltrated by capillaries

–callusformation (3)•softcallus of fibrocartilage replaced by hard callus of bone in 6 weeks

–remodeling (4) occurs over next 6 months as spongy boneis replaced with compact bone

Front 86

What is a comminuted fracture?

Back 86

bone is broken into three or more pieces

Front 87

What is a greenstick fracture?

Back 87

bone is incompletely broken on one side but merely bend on the opposite side.

Front 88

What is an open fracture?

Back 88

bone is piercing through skin.

Front 89

What is a closed fracture?

Back 89

bone does not pierce through skin.

Front 90

What is a closed reduction treatment?

Back 90

–fragmentsare aligned with manipulation & casted

Front 91

What is a open reduction internal fixation (ORIF)?

Back 91

–surgicalexposure & repair with plates & screws

Front 92

What is orthopedics?

Back 92

prevention & correction of injuriesand disorders of the bones, joints & muscles

Front 93

What is osteoporosis?

Back 93

most common bone disease, bones lose mass & become brittle dueto loss of both organic matrix & minerals

–riskof fracture of hip, wrist & vertebral column

–leadto fatal complications such as pneumonia

–widow’s(dowager’s) hump is deformed spine

Front 94

Who is most at risk of osteoporosis?

Back 94

•Postmenopausal white women at greatestrisk

–byage 70, average loss is 30% of bone mass

Front 95

How is osteoporosis best treated?

Back 95

•Estrogen Replacement Therapy slows bone resorption, but besttreatment is prevention -- exercise & calcium intake (1000 mg/day) betweenages 25 and 40

•Therapies to stimulate bone depositionare still under investigation