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Flashcards in Skeletal System (KT) Deck (114):
1

What are the 2 divisions of the skeletal system?

1. Axial
2. Appendicular

2

What components make up the axial skeleton?

Head, center of body, skull, ribs, vertebral column

3

What components make up the appendicular skeleton?

Movements, limbs, pelvis

4

2 types of bone tissue

1. Compact
2. Spongy

5

How much percent of total body mass are the bones?

20%

6

Components of the skeletal system? (4)

1. Cartilage
2. Bone
3. Tendons
4. Ligaments

7

Functions of skeletal system? (5)

1. Protection
2. Support (rigid support)
3. Movement (bones act as levers)
4. Storage (Ca, P, and fat)
5. Blood cell production

8

Cartilage cells are called...

Chondrocytes

9

Where are chondrocytes found...?

Chondrocytes are found in compartments called lacunae

10

What is the extracellular matrix of cartilage?

-Collagen and elastic fibers
-Ground substance of chondroitin sulfates

11

Does cartilage have arteries, veins, or lymphocytes?

No.
- That's why it heals slowly- because not a lot of nutrients getting in

12

What types of cartilage are there...? (3)

1. Hyaline
2. Elastic
3. Fibrocartilage

13

Cartilage that...
- is the most common
- weakest concerning tensile strength
- found in places that can be compressed
-lack fibers

Hyaline Cartilage

14

Hyaline Cartilage Structure (3)

1. Chondrocytes
2. Chondroitin
3. Some collagen

15

Location of Hyaline Cartilage (5)

1. Embryonic Skeleton
2. Articular surfaces
3. Respiratory passages
4. Nasal Septum
5. Between ribs and sternum

16

Cartilage that...
-is elastic yet still needs compression
- flexible, maintains shape but recoils and pushes back
-Ex. nose, ear, epiglottis

Elastic Cartilage

17

Elastic Cartilage Structure (3)

1. Chondrocytes
2. Chondroitin Sulfate
3. Densely packed elastic fibers

18

Locations of Elastic Cartilage

-nose,
-ear
-epiglottis

19

Cartilage that...
- is very strong
-need tensile resistance AND compression resistance

Fibrocartilage

20

Structure of Fibrocartilage (3)

1. Chondrocytes
2. Chondrotin Sulfate
3. Densely packed collagen fibers

21

Location of Fibrocartilage (3)

1. Intervertebral Disc
2. Pubic Symphysis
3. Articular Cartilage in Knee

22

Fibrous connective tissue that surrounds cartilage

Perichondrium

23

What does perichondrium provide...? (2)

1. Support & Protection
2. New Chondrocytes

24

Locations of Perichondrium (2)

1. Hyaline Cartilage
2. Elastic Cartilage

25

Where is perichondrium absent from...? (2)

1. Articular surfaces
2. Fibrocartilage

26

How many layers does the perichondrium have?

2

27

What are the layers of the perichondrium?

1. Outer
2. Inner

28

Binds cartilage to adjacent tissues; provides support and protection

Outer layer of perichondrium

29

Layer for growth and maintenance

Inner layer

30

-Have cartilage, it expands outward by growing from its own ledge
-this is facilitated by the perichondrium

Appositional Growth

31

Appositional Growth Steps (6)

1. Starts in the Perichondrium
2. Mesenchymal (stem) cells at periphery form in inner layer of perichondrium
3. Mesenchyme move toward the matrix to become chondrogenic cells
4. Chondrogenic cells aggregate and become chondroblasts
5. Chondroblasts secrete ,matrix and force cells apart
6. Chondroblasts become enclosed in matrix and become chondrocytes

32

Is Appositional Growth a Fast or a Slow Process?

Slow- because there is no blood supply, oxygen, and glucose

33

-Internal cartilage growth
-Chondrocytes are enclosed in matrix and divide
-As they move apart, the matrix forms between them

Interstitial Growth

34

Characteristics of Osseous Tissue (3)

1. Supportive CT
2. Contains specialized cells
3. Solid extracellular matrix

35

Solid Extracellular Matrix
(fibrous)

-Osteoid

36

What components make up the osteoid? (2)

1. Organic Portion
2. Protein fibers

37

Ground Substance of Osseous Tissue

-Ca salts (forms mineralized salts
- water

38

-Mesenchyme bone cell
-Predecessor to osteoblasts
-Play a role in initial bone growth and fracture repair

Osteoprogenitor

39

Bone cell that...
-Is derived from osteogenic cells
-secrete osteoid
-common in growing bone
-predecessor to osteocytes
-Increased osteoblast activity=stronger bone

Osteoblasts

40

Bone cells that...
-Are mature cells
-Exist within matrix
-Maintain Ca and PO4 homeostasis
-

Osteocytes

41

Bone cells that...
-involved in the breakdown of bone
- very large
- increased osteoclast activity --> weaker bone

Osteoclast

42

How are osteoclasts formed?

Formed by the fusion of many white blood stem cells

43

Inorganic Materials of Bone Matrix

-65%
-Brittle Salts
-Na, K, Mg

44

Organic Materials of Bone Matrix

- Osteoid
-35%
-Flexible Fibers aka collagen, glycoproteins, and proteoglycans

45

How are compact bones arranged?

Osteons

46

How are spongy bones arranged?

Trabeculae

47

-Communicate through canaliculi that radiate outward and connect one cell to the next cell

Osteocytes

48

A unit of compact bone

Osteon

49

Osteons consist of... (2)

1. Concentric lamellae of matrix surrounding a central (Haversian) canal
2. Contains blood vessels and nerves

50

How are osteons connected to eachother?

Perforating Canals

51

Types of Lamellae (3)

1. Concentric
2. Interstitial
3. Circumferential

52

-Layers of bone surrounding the central canal
-Make up osteons

Concentric Lamellae

53

-Found between the osteons
-Represents older osteons partially removed during tissue remodeling

Interstitial Lamellae

54

-Surround the compact bone
-Directly produced from periosteum

Circumferential Lamellae

55

What does spongy bone contain? (4)

1. Trabeculae
2. Osteocytes in lacunae
3. Canaliculi
4. Matrix
(Does NOT contain osteons and central canal)

56

-Lattice work of thin plates of bone oriented along lines of stress
-Spaces are filled with red marrow where blood cells develop
-Found in ends of long bones and inside flat bones
-Lightens the bone, allows for movement

Trabeculae

57

-Encloses bone
-Absent at site of attachment of muscles, tendons, ligaments, surfaces covered by articular cartilage

Periosteum

58

2 Layers of the Periosteum

1. Outer Fibrous- gives rise to collagen
2. Inner- for growth of new cells or maintenance

59

-One cell layer
-Covers all surfaces of spongy bone & medulla
-Cell types are osteogenic, osteoblasts, and osteoclasts

Endosteum

60

Shaft of long bone

Diaphysis

61

One end of the long bone

Epiphysis

62

Growth plate region

Metaphysis

63

Over joint surfaces... acts as friction and shock absorber

Articular Cartilage

64

Marrow cavity

Medullary Cavity

65

2 Types of Bone Marrow

1. Red Marrow
2. Yellow Marrow

66

-Areolar and myeloid tissue
-Produces all types of blood cells
-Located in the medullary cavities of bebes and spongy bone of adults

Red marrow

67

-Areolar and Adipose CT
-In medullary cavity of long bones
-Energy storage
-Absent in bebes

Yellow marrow

68

KT

I figured I would put this in here to give you a break from studying and hopefully put a smile on your face! I want you to know that I am very thankful that Janelle introduced me to you in spring semester last year. If it wasn't for her I would have never met the amazing person you are and I would be short one of my best friends. Well that is all I have right now.
Until next time,
Connor :)
P.S. get back to work now

69

When does intramembranous ossification begin?

At about 8 weeks in embryo.

70

When does intramembranous ossification end?

About week 15.

71

What does intramembranous ossification form? (5)

Cranial flat bones, facial bones, dentary bones, clavicle, and sesmoid bones.

72

What is the primary ossification center?

Location where bone growth begins.

73

When does endochondral ossification begin?

7 weeks of embryo.

74

Does endochondral ossification end?

No, it continues throughout adulthood.

75

What does endochondral ossification form?

Long bones, most short bones, non-cranial irregular & flat bones, and middle ear ossicles.

76

This forms the model of future bone?

Hyaline cartilage.

77

Artery that supplies the periosteum

Periosteal Arteries

78

-Artery that enters through the nutrient foramen
-Supplies compact bone of diaphysis and yellow marrow

Nutrient arteries

79

Artery that supplies red marrow and bone tissue of epiphyses and metaphyses

Mataphyseal and Epiphyseal Arteries

80

Replacing Connective Tissue with bone

Ossification

81

2 Types of Ossification

1. Intramembranous
2. Endochondral

82

Ossification that goes from...
Mesenchymal cells to spongy bone

Intramembranous

83

Ossification that goes from... Hyline cartilage to spongy bone

Endochondral

84

When does intramembranous Ossification occur?

-Begins at about week 8 in embryo
-Mainly finished by week 15

85

What does Intramembranous Ossification form...? (5)

1. Cranial Flat Bones
2. Facial Bones
3. Dentary Bones
4. Clavicle
5t. Sesmoid Bones

86

What is the primary ossification center of Inframembranous Ossification?

-Location where bone growth begins

87

What arrange around blood vessels in Intramembranous Ossification?

Mesenchymal Cells

88

What kindof protiens are realeased in Intramembranous Ossification?

Morphogenic Proteins

89

What do mesenchymal cells undergo during intramembranous ossification? (3)

1. Become recruited
2. Divide
3. Differentiate into osteoblasts

90

Steps of Intramembranous Ossification... (6)

1. Osteoblasts then secrete osteoid
2. Osteoblasts become isolated and turn into osteocytes
3. Produce spicules of bone that interconnect
4. Mesenchymal cells at the surface from inner layer of periosteum
5. Calcified matrix is degraded by osteoclasts to form spongy bone
6. Ended up with spongy bone covered in thin layer of compact bone

91

In this type of ossification...
-Bone replaces a cartilage model
-Begins at week 7 of embryo
- Continues to adulthood

Endochodral Ossification

92

What does endochondral ossification from? (4)

1. Long Bones
2. Most Short Bones
3. Non cranial Irregular and flat bones
4. Middle ear ossicles

93

In endochondral ossification, this type of cartilage forms model of future bone...?

Hyaline Cartilage

94

What happens during endochondral ossification? ()

1. Chondrocytes near center hypertrophy
2. Matrix reduced to struts
3. Chondrocytes deprived of nutrients and die
4. Blood vessels grow around and penetrate cartilage
5. Cells differenciate into osteoblasts
6. Compact bone forms around the diaphysis
7. Spongy bone forms in center of model (primary ossification center)

95

What happens during endochondral ossification? (3)

1. Remodeling of the shaft
2. Formation of the medullary cavity
3. Length increases

96

What forms at both epiphyses?

Secondary Ossification Centers
(and Blood vessels penetrate the ends of the model)

97

How does endochondral ossification end?

-Ends with incomplete ossification of epiphysis
- Some cartilage remains

98

What 2 kinds of cartilage remain after endochondral ossification?

1. Articular Cartilage (contact points of bone)
2. Epiphyseal Plate (growth plate)

99

Where does bone elongation occur and when does it end?

1. Occurs at epiphyseal plate
2. Growth in length continues until 2 ossification centers meet

100

About the Epiphyseal Plate (3)

1. Relative thickness of epiphyseal plate does not change until growth is almost complete, then...
2. Cartilage is depleted
3. Epiphyseal plate narrows to epiphyseal line

101

Type of Bone growth that...
-Compact bone deposited beneath periostium
-Bone thickens
- Bone remodeling occurs throughout life (due to osteoclasts and osteoblasts)

Appositional

102

-Ongoing, since osteoclasts carve out small tunnels and osteoblasts rebuild osteons
-Continual redistribution of bone matrix along lines of mechanical stress

Bone Remodeling

103

Percentage of remodeling? (3)

1. 4% of compact bone remodeled per year
2. 20% of spongy bone remodeled per year
3. Distal femur is fully remodeled every 4 months

104

Break in bone

Fractures

105

2 Types of fractures...

1. Closed (simple) break that does not penetrate the skin
2. Open (compound) broken bone that penetrates the skin

106

How are fractures treated?

Reduction and immobilization

107

4 Steps of Fracture Repair

1. Fracture Hematoma
2. Fibrocartilage Callus
3. Bony Callus
4. Remodel Tissue

108

Fracture hematoma formation (4)

1. 1. Forms within hours of the injury
2. A mass of blood
3. Swelling and inflammation occur in response to dead bone cells
4. Phagocytes and osteoclasts elimate dead cells and broken matrix

109

Fibrocartilaginous Callus Formation (5)

1. A fibrocartilaginous callus consists of a mass bridging the broken ends of the bone
2. Fibroblasts in periosteum produce collagen
3. Periosteum cells differentiate into chondrocytes
4. Results in fibrocartilage
5. Takes about 3 weeks

110

Bony Callus Formation (2)

1. Formation of the bony callus occurs as the fibrocartilaginous callus is converted to spongy bone trabeculae
2. The bony callus last about 3 to 4 months

111

-Remaining dead bone fragments are resorbed and compact bone replaces spongy bone
-A well handled fracture is virtually undetectable

Bone Remodeling

112

Factors Affecting Growth, Repair, and Development (4)

1. Nutrition aka Vitamin D
2. Sunlight
3. Hormones: PTH, calcitonin, GH, thyroid hormone, sex hormones
4. Physical Stress

113

-Abnormal reduction of bone loss
-Loss of estrogen at menopause
-Deficiency of mineral in youth
-Imbalance in activity between osteoblasts and osteoclasts

Osteoporosis

114

-Fibrous tissue becomes ossified
-Genetic Disorder
-Injury results in inappropriate bone formation
-No treatment

Fibrodysplasia Ossificans Progressiva