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Anatomy & Physiology 200 > Osseous Physiology > Flashcards

Flashcards in Osseous Physiology Deck (91):
1

Medullary cavity

"Marrow" cavity
Hollow cavity in diaphysis. Contains yellow bone marrow for adipose storage

2

Greenstick fracture

Usually seen in kids.
Partial fracture.
Once side broken, other side bent.

3

Osteoclasts

Cells that destroy bone as a natural part of growth and repair.

4

Haverian System

aka Osteon

Repeating units of all the components of compact bone around one central canal.

Includes canal, blood and lymph vessels, lacunas, canaliculi, oseocytes and concentric lamellae

5

Osteoblasts

Bone builders
Synthesize collagen fibres and initiate calcification.
Take Ca+ from blood for use in cells

6

Under what circumstances does ossification a occur?

1. As an embryo (beginning in 6th week)
2. Childhood and adolescence
3. Normal remodelling of bone through adulthood
4. Fracture repair.

7

Metaphyseal arteries/veins

Enter at the metaphysis to supply blood to the metaphysis and red bone marrow

8

Six key functions of the skeletal system:

1. Support
2. Protection
3. Movement
4. Control of mineral content (Ca+, P, Fe+)
5. Hemopoesis
Storage of triglycerides.

9

Articular cartilage

Covers epiphysis. Reduces friction and allows movement at joints.

Most commonly composed of hyaline cartilage.

10

Pott's fracture

Occurs only in legs. Closed fracture with damage to ankle articulation.

11

Stress fracture

Microscopic tears in the fissures of the bone.
Usually caused by repetitive and strenuous activities.

12

Diaphysis

Main portion of the bone (the shaft)

13

Development of Marrow Cavity

Part of endochondral ossification.
Occurs through osteoclast activity.

14

Osteocytes

Mature bone cells
Maintain daily metabolic activities of the bone

15

Perforating canals

aka Volkmann's canals
Perpendicular canals that run superficial to deep.
Carry blood, lymphatic vessels, nerves, from periosteum.

16

Spongy bone

No osteons
Appears spongy due to lattice and irregular pattern of bone tissue distribution.
Greater blood supply than compact bone

17

Periosteum

The "skin" surrounding bones.
Made of irregular sense connective tissue.
Merges with tendons
Contains nerve endings which detect irregularities/pathologies

18

Osteogenic cells

AKA osteoprogenitors
Unspecified stem cells serviced from mesenchyme cells

19

Hypertrophic cartilage zone

In metaphysis, in between proliferating and calcified cartilage zone.
Large mature chondrocytes situated in columns.

20

X Rays

aka radiography

developed by William C. Roentgen

Electron beam shot through object and reflect off of hard objects. Use ionizing radiation.

Digital X-rays 50% more efficient and less harmful than traditional cathode tubes

21

What are the two types of canals found in compact bone?

Perforating (Volkmann's) and Central (Haversian)

22

What are the two type of bone formation?

Intramembranous and endochondrial

23

Crystallized mineral salts in the ECM of the bone

Calcium phosphate Ca3(PO4)2 most abundant
Calcium hydroxide second most abundant.

24

What are the stages of Endochondral Ossification?

1. Development of cartilage model

2. Growth of cartilage model

3. Development of primary ossification centre

4. Development of the marrow cavity

5. Development of secondary ossification centres

6. Formation of articular cartilage and epiphyseal plate

25

Calcitriol

A form of Vitamin D which increases absorption of Ca+ from the GI tract.

26

Reparative Phase 2.0

Osteogenic cells become osteoblasts, which convert fibrocartilage into spongy bone. (bony callus formation)

Lasts 3-4 months

27

Epiphysis

Proximal and distal ends of bones.
Tend to have projections and fossa that articulate with other bones

28

What are some of the key roles of Ca+?

1. act as a cofactor in numerous chemical reactions in the body
2. deeply involved in blood clotting
3. involved in muscle contractions

29

What are the stages of Intramembranous Ossification?

1. Development of ossification centre
-- chemical messages cause mesenchymal cells to develop into osteoblasts, which secrete bone ECM
2. Calcification
-- osteoblasts --> osteocytes
3. Formation of trabelculae
-- matrix continues to harden and trabeculae form.
-- development of spongy tissue, red bone marrow
4. Development of periosteum
-- periosteum forms. Compact bone replaces spongy bone where appropriate.

30

Deposition

The process by which osteoblasts will lay down minerals and collagen fibres to create ECM

31

Two main portions of bone tissue

Spongy and compact

32

Concentric lamellae

Concentric rings surrounding each central canal.

AKA osteon

33

Factors that affect bone growth

Minerals (Ca+, P, F, Mg, Mn)
Vitamins
Vit A -- promotes osteoblasts
Vit C -- collagen formation
Vit D -- absorption of Ca+
Vit K & B12 -- build bone proteins
Hormones (T3 & T4 from thyroid and IGF in response to hGH -- promote bone growth)

34

Proliferating cartilage zone

In the metaphysis, next to resting cartilage zone.
Contain large chondrocytes that replicate and divide to replace old/dying chondrocytes.
Appear like a stack of coins.

35

Epiphyseal arteries/veins

Enter at epiphyseal portion to supply blood to the epiphysis and red bone marrow

36

Development of secondary ossification centres.

Part of endochondral ossification
-- epiphyseal place formed from penetration of epiphyseal arteries

Growth occurs outwards from epiphysis.
Cartilage continues to be converted into bone.

37

Parathyroid Hormone

Secreted by parathyroid cells. Increases Ca+ levels in the blood
Effects:
1. increases activity of osteoclasts; reduces activity of osteoblasts. (increases resorption)
2. increases formation of calcitriol
3. stimulates kidney cells to retain Ca+ from urine

38

Canaliculi

Small channels that radiate in all directions from each lacunae.
Filled with ECF.
Arms of metaphoric snow angels

39

What cells are produced in spongy bone?

White blood cells
Red blood cells
Platelets

40

What are the four layers of hyaline cartilage in the metaphysis?

Resting cartilage zone
Proliferating cartilage zone
Hypertrophic cartilage zone
Calcified cartilage zone

41

Growth of cartilage model

Part of endochondral ossification.
-- Chondroblasts --> chondrocytes. Model grows longer. Interstitial growth and appositional growth occurs

42

Avulsion

Forceful tearing of muscles and tendons that pull portions of bone with it.

43

What is the composition of the bone extracellular matrix?

25% water
25% collagen fibre
50% crystallized mineral salts

44

Periosteal arteries/veins

Enter through Volmann's/perforating canals
Carry blood to and from outer portion of compact bone and periosteum

45

Endosteum

Layer of dense irregular connective tissue that lines medullary cavity.

46

Reactive phase of fracture repair

Clots form around broken vessels, creating a fracture hematoma.

Blood flow stops, local bone cells dies.

Inflammation occurs in response; phagocytes and osteoclasts move in to clean up.

Lasts several weeks.

47

Lacunae

Areas/spaces within lamellae where osteocytes can be found.

Snow angel bodies.

48

Impacted fracture

One bone if forced into another bone

49

Interstitial growth

replication of chondrocytes accompanying new matrix --> lengthening
Part of Growth of cartilage model

50

Circumferential lamellae

Surround the medullary cavity or lie underneath the periosteum, along circumference of the bone. Tends to circle around interstitial and concentric lamellae.

51

What are the stages of apposition cell growth?

1. Periosteal cells differentiate into Osteoblasts, which turn into osteocytes, which create ridges on either side of blood vessel.

2. Ridges fuse and become tunnel.

3. Osteoblasts in (new) endosteum create new concentric lamellae

4. As osteon forms, osteoblasts under periosteum create new circumferential lamellae.

5. All the while, osteoclasts are destroying bone lining medullary cavity to enlarge it as well.

52

Metaphysis

Portion in between diaphysis and epiphysis.
Weakest portion.
Contains epiphysial plate --> epiphysial line

53

Trabeculae

Lamellae of spongy bone
Coral-like appearance

54

Bone Remodelling

Final stage of fracture repair.

Osteoclasts move in to resorp any remaining fragments. Compact bone eventually replaces spongy bone around the periphery.

55

Nutrient arteries/veins

Enter through nutrient foramen in the diaphysis
Supplies blood to the inner portion of the compact bone and also proximal parts of the spongy bone

56

What is the normal levels of Ca+ in the blood?

9-11 mg/100ml
More that than, heart stops.
Less than that, respiration stops.

57

Cole's fracture

Occurs in hands and wrist, often as a result of a FOOSH.
Fall drives carpals posteriorly.

58

Wolf's Law

Bone tissue will lay down along lines of stress
ex. trauma, infection, cancer, aging

59

Development of cartilage model

Part of endochondral ossification.
-- mesenchyme --> chondroblasts, which secrete ECM, producing a cartilage model consisting of hyaline cartilage, surrounded by perichondrium

60

Closed fracture

aka simple fracture
doesn't break skin

61

Bone scan

Radioactive tracer in injected and taken up by bone. Hot spots show increased metabolism (i.e. cancer) and cold sports suggest healed fractures.

62

Ca+ concentration is controlled by:

1. Parathyroid hormone (PTH)
2. Calcitonin

63

Development of Primary Ossification Centre

Part of endochondral ossification.
-- nutrient artery penetrates into the middle of the cartilage, initiating activity of osteoblasts. Perichondrium --> periosteum. Local cartilage --> bone

64

Resorption

The process by which osteoclasts breakdown and destroy portions of bone ECM.
Part of normal bone growth and of healing after fractures.

65

Calcification

Calcium phosphate + calcium hydroxide --> hydroxyapatite

Which will combine with Fl-, K+, (So4)2- and Mg2+.

Adhere to collagen fibres and harden.

66

Reparative Phase 1.0

Fibroblasts invade site and lay down collagen fibres.

Chondroblasts invade from periosteum and produce fibrocartilage.

Fibrocartilaginous Callus is formed.

67

Calcified cartilage zone

In metaphysis.
Mostly dead chondrocytes. Calcified.
Osteoblasts invade to lay down new extracellular bone matrix to convert it from calcified cartilage to new diaphysis and new blood vessels are formed.

68

Osteomalacia

Called rickets in kids
Failure of bones to calcify.
Organic matrix is present but calcium salts not deposited.
Often due to Vitamin D deficiency

69

Intramembranous Ossification

Simpler method. Flat bones of skull, facial bones, mandible, medial clavicle.

70

Four main types of bone cells

1 osteogenic
2 osteoblasts
3 osteocytes
4 osteoclasts

71

Three types of lamellae

Concentric
Interstitial
Circumferential

72

Interstitial lamellae

Located between osteons

73

When does ossification occur?

Begins in 6th week of embryonic development and continues into maturity,

74

Osteoporosis

Loss of bone mass associated with deterioration of the micro-architecture of bone tissue

75

Ossification/Osteogenesis

bone formation

76

Central canals

aka Haversian canals
Parallel canals that run deep and longitudinally. Carry blood, lymphatic vessels, nerves.

77

Comminuted fracture

Bone splinters and pieces are trapped between main fragments

78

Resting cartilage zone

The zone of the metaphysis nearest to the epiphysis.
Consists of small chondrocytes that anchor epiphyseal plate to the bone.
"Resting" because cells not involved in bone growth

79

Lamellae

The matrix of bone, arranged in thin, platelike structures.

80

Sharpey's fibres

Perforating fibres that mesh with bone matrix and help keep periosteum in place.

81

Appositional growth


Deposition of ECM on cartilage surface and periphery.
Part of Growth of Cartilage Model

82

Endochondral Ossification

A method of bone formation where cartilage is developed fires, then replaced by bone. Most bones of the body formed this way.

83

Where is spongy bone found?

In long bone, mostly concentrated in ends.
Flat bones, some irregular and all cuboidal bones are predominantly spongy.

84

Calcitonin

A hormone, produced by thyroid parafollicular cells. Released in response to elevated Ca+ levels.

Decreases activity of osteoclasts; increases activity of osteoblasts (bone formation increases)

85

How do hormones regulate blood Ca+ levels?

Controlled condition (decreased Ca+ levels) -->
Receptor (parathyroid gland) --> Releases PTH --> bone resorption increases/ kidneys retain Ca+/ increased absorption of Ca+ in GI tracts --> increase in blood Ca+ level --> homeostasis achieved. High five!

86

Open fracture

aka compound
broken ends of bone protrude through skin.

87

Why is compact bone compact?

Because there is little space between cells. Composed mostly of calcium, phosphate, collagen and other minerals.

88

What are the steps of fracture repair in bones?

1. formation of fracture hematoma (reactive phase)
2. fibrocartilaginous callus formation (reparative phase 1.0)
3. bony callus formation (reparative phase 2.0)
4. bone remodelling

89

Resorption

The breaking down of bones by osteoclasts. Ca+ is taken from the bone and put in the blood.

90

Where is extra Ca+ stored?

Muscle and liver cells, in smooth endoplasmic reticulum

91

Formation of articular cartilage and epiphyseal plate

Last stage of endochondral ossification
hyaline cartilage becomes articular cartilage