Exam 2: Bone Flashcards Preview

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Flashcards in Exam 2: Bone Deck (70)
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1
Q

Pressure to bone results in

A

bone resorption (breakdown)

2
Q

Tension to bone results in

A

bone deposition (addition)

3
Q

Long bones

A

Contain 2 epiphyses, a diaphysis, marrow cavity in core

4
Q

Epiphyses

A

2 bulbous ends of long bone

5
Q

epiphyseal growth plate

A

consist of hyaline cartilage plates that allow bone growth in length. Disappear around age 18-20

6
Q

Metaphysis

A

angulation between epiphyseal plate and diaphysis

7
Q

Diaphysis

A

long cylindrical shaft between two epiphyses

8
Q

Periosteum

A

external connective tissue capsule of bone - 2 layers outer fibrous and inner cellular
Does not cover articulating surfaces of bones and where tendons attach to bones

9
Q

Outer fibrous layer

A

dense collangeous CT, blood vessels and nerves

10
Q

Sharpey’s fibers

A

anchor periosteum to bone

Found in outer fibrous layer

11
Q

Inner cellular layer

A

covers actively growing bone - contains osteoprogenitor cells

12
Q

Endosteum

A

internal CT capsule of bone
thin CT layer with a single row of osteoprogenitor cells
Line bone marrow cavity, and Haversian and Volkman canals
Cover bony spicules and trabeculae of spongy bone

13
Q

Bone Matrix is made of

A

inorganic minerals (hardness) and organic fibers/ground substance (prevent bone from becoming brittle)

14
Q

Bone fibers are mainly

A

type I collagen (acidophilic)

15
Q

Proteoglycans (with hyaluronan, chondroitin sulfate, and keratan sulfate)

A

bind growth factors

16
Q

Osteonectin

A

serves as glue between collagen and hydroxyapatite crystals

17
Q

sialoproteins (osteopontin and sialoproteins I & II)

A

bind cells to bone matrix

begins calcium phosphate formation during mineralization

18
Q

osteocalcin

A

traps calcium from blood stream

stimulates osteoclasts to remodel bone

19
Q

Osteoprogenitor cells

A

arise from mesenchymal stem cells
located in inner layer of mature periosteum and in endosteum
Differentiate into osteoblasts

20
Q

Osteoblasts

A
arise from osteoprogenitor cells
Cuboidal-columnar shaped
basophilic
synthesize organic component of bone matrix
Has high levels of alkaline phosphatase
21
Q

Osteoid

A

newly formed non-mineralized bone

collagen type I and bone matrix proteins

22
Q

When bone is being synthesized, what is high in blood

A

alkaline phosphatase

23
Q

Osteocytes

A

osteoblasts that are enclosed within matrix they produce

Enclosed in lacuna

24
Q

Rickets

A

calcium or vitamin D deficiency

Bone softening

25
Q

Osteoporosis

A

reduction in bone mass - porous bones that fracture easily

26
Q

Bone-lining Cells

A

cover bone surface, protecting it from osteoclasts

nutritional support of osteocytes

27
Q

Canaliculi

A

cytoplasmic processes that radiate from osteocytes

form gap junctions with other osteocytes to transfer nutrients

28
Q

Osteocyte is surrounded by

A

fluid in periosteocytic space

29
Q

The periosteocytic space is surrounded by

A

osteoid - nonmineralized bone matrix (osteoid is surrounded by mineralized bone)

30
Q

Osteoclasts

A

motile, acidophilic due to lysosomes
derived from mononuclear hemopoietic progenitor cells in bone marrow
resorb bone

31
Q

An osteoclast in the process of bone breakdown has what 3 regions?

A

ruffle border, clear zone, basolateral regions

32
Q

ruffled border

A

associated with bone resorption
cell membrane is thickened with infoldings
exocytosis of hydrolytic enzymes and endocytosis of broken down bown

33
Q

Clear zone

A

lacks organelles
has actin microfilaments
sealing zone that isolates acidic resorption compartment

34
Q

Basolateral region

A

contains organelles

functions in exocytosis of broken down matrix

35
Q

Compact Bone

A

dense, solid bone that forms a shell around the exterior of long bones
Contains Haversian systems

36
Q

Skull cap consists of

A

an outer table of compact bone covered by periosteum and an inner table of compact bone that is lined by periosteal layer of cranial dura mater

37
Q

Cancellous bone

A

spongy bone that lines marrow cavity of long bones
bony trabeculae and spicules protrude from inner surface of compact bone toward marrow cavity
Contains mainly an irregular arrangement of bone lamellae

38
Q

Primary bone

A

forms during fetal development and bone repair
contains irregular bundles of collagen
Temporary tissue, resorbed by osteoclasts and replaced by secondary bone

39
Q

Secondary Bone

A

parallel or concentric bone lamellae
collagen fibers parallel
more mineral content than primary bone

40
Q

Outer circumferential lamellae

A

deep to periosteum
surround bone
Sharpe’s fibers anchor periosteum to underlying bone

41
Q

Interstitial lamellae

A

lamellar fragments, remnants of former osteons

42
Q

Haversian canal systems (osteons)

A

vascular space that encloses a neurovascular bundle - No Lymphatics!
Helical arrangement

43
Q

Volkmann canals

A

connect osteons that are next to each other

not have to be concentric

44
Q

Inner circumferential lamellae

A

around marrow cavity

45
Q

Ankylosis (arthritis)

A

trauma induced to a joint that damages hyaline cartilage

Cartilage becomes calcified, die, then replaced by bone - two articulating bones fuse = no joint movement

46
Q

Rheumatoid arthritis

A

autoimmune disease that attacks synovial joints, damaging articular cartilages, producing disfigurement of joints and severe pain

47
Q

Gouty arthritis

A

accumulation of uric acid crystals in joints

48
Q

Intramembranous ossification

A

bone forms directly within a membrane of highly vascular mesenchyme
Flat bones of skull, face, mandible, clavicle, and other flat bones form this way

49
Q

The first bone laid down is

A

primary bone

50
Q

The soft osteoid of primary bone undergoes

A

mineralization, trapping osteocytes in lacunae

51
Q

Primary bone is resorbed by ____ and replaced with____

A

osteoclasts; secondary bone

52
Q

Newly formed secondary bone occurs as

A

spongy bone, which can remain spongy or become compact bone

53
Q

Endochondral Ossification

A

cartilage model of bone-to-be is formed first, than becomes calcified, eroded, and replaced by bone

54
Q

Long bones and vertebrae of spine form via

A

Endochondral Ossification

55
Q

Primary ossification center is located in

A

diaphysis (hyaline cartilage model of bone)

56
Q

As bony collar forms in Endochondral ossification, cartilage cells

A

hypertrophy (accumulate glycogen and form vacuoles) and produce alkaline phosphatase - cartilage matrix becomes calcified

57
Q

Secondary center of ossification is located in

A

the epiphysis, forms shortly after birth

58
Q

Cartilage is continuously being replenished at _____ side of growth plates and being replaced by bone at the ______ side.

A

epiphyseal; diaphyseal

59
Q

Zones of epiphyseal plate

A

Zone of Reserve Cartilage, Zone of proliferation, Zone of hypertrophy, zone of calcified cartilage, zone of resorption and ossification

60
Q

Zone of reserve cartilage

A

hyaline cartilage

mitotically active

61
Q

Zone of proliferation

A

intense mitosis here - chondrocytes produce new organic matrix - cartilage grows interstially
form parallel columns of isogenous cells
Chondrocytes appear in stacks (like pennies) parallel to long axis of bone

62
Q

Zone of hypertrophy

A

chondrocytes accumulate glycogen and become vacuolated

Individual chondrocytes swell in size

63
Q

Zone of Calcified cartilage

A

lacunae coalesce, calcification of cartilage matrix, chondrocytes die

64
Q

Zone of resorption and ossification

A

calcified cartilage remnants form long spicules, blood vessels bringing osteoprogenitor cells invade, differentiate into osteoblasts

65
Q

Calcified cartilage stains

A

blue - basophilic

Does not contain cells

66
Q

Mineralized bone stains

A

pink - acidophilic

contains living cells

67
Q

Bone growth in width occurs by

A

appositional growth - osteoblasts secrete bone matrix on subperiosteal bone surface

68
Q

Neutrophils

A

arrive at site of bone injury first, then macrophages arrive to clean up debris

69
Q

Soft callus

A

formed by granulation tissue and cartilage to cover injured bone, eventually dies and is replaced by bony callus

70
Q

Achondroplasia

A

most common cause of dwarfism

Cartilage in growth plates is replaced by bone at a very slow rate - results in short bones in upper and lower limbs