Chapter 5: skeletal system Flashcards Preview

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Flashcards in Chapter 5: skeletal system Deck (90):
1

How many bones are in the body?

206

2

There are 2 division to the skeletal system. What are they? briefly describe them

axial: head and center of body
appendicular: movement (limbs and pelvis)

3

What are the two types of bone tissue?

compact: dense smooth bone
spongy:bone with open spaces within

4

What are the four components of the skeletal system?

bone
cartilage
ligaments
tendons

5

What are the five functions of the skeletal system?

Protection
Support (rigid structure)
Movement (bones act as levers)
Storage (Ca, P, and fat)
Blood cell production

6

cartilage consists of what two things?

cells and an extracellular matrix

7

what cells are found in cartilage and where are they located?

Chondrocytes and they are found in compartments called lacunae

8

what are the two components to the extracellular matrix of cartilage?

Collagen/elastic fibers and a ground substance made of chondrotin sulfates

9

does cartilage have arteries, veins, or lymphocytes? what does this mean?

no; it means it heals slowly

10

what are the three types of cartilage?

hyaline
elastic
fibrocartilage

11

describe hyaline cartilage and give its structure and location

Most common but weakest
Structure: chondrocytes, chondrotin sulfate, some collagen
Location: embryonic skeleton, articular surfaces, respiratory passages, nasal septum, between ribs and sternum

12

Give the structure and location of elastic cartilage

Structure: chondrocytes, chondrotin sulfate, densely packed elastic fibers
Location: auricle, tip and lateral walls of nose, epiglottis
-flexible

13

Give the structure and location of fibrocartilage

Structure: chondrocytes, chondrotin sulfate, densely packed collagen fibers
Location: intervertebral discs, public symphysis, articular cartilage in knee

14

describe the perichondrium

fibrous connective tissue that surrounds the cartilage, It provides support and protection and new chondrocytes

15

where is the perichondrium located?
absent?

Located: hyaline cartilage and elastic cartilage
Absent: articular surface and fibrocartilage

16

describe the inner and outer layers of the perichondrium

inner: for growth and maintenance
outer: binds cartilage to adjacent tissues; provides protection and support

17

describe appositional growth

-starts in the perichondrium
-Mesenchymal (stem) cells at periphery form in inner layer of perichondrium
-Mesenchyme move toward matrix to become chondrogenic cells
-Chondrogenic cells aggregate and become chondroblasts
-Chondroblasts secrete matrix --> forces cells apart
-Chondroblasts become enclosed in matrix and become chondrocytes

18

describe interstitial growth

-Chondrocytes are enclosed in matrix and divide
-As they move apart, matrix forms between them
-Growth of cartilage from within

19

what are three general traits of osseous tissue?

-supportive connective tissue
-contains specialized cells
-solid extracelliular matrix

20

what is found in the solid extracellular matrix of osseous tissue?

osteoid: organic portion, protein fibers
ground substance: Ca salts water

21

What do Osteoprogenitor cells do?

play role in initial bone growth and fracture repair

22

describe osteoblasts

-derived from osteogenic cells
-secrete osteoid
-common in growing bone
-Predecessor to osteocytes
-Increased osteoblast activity = stronger bone

23

describe osteocytes

-mature cells
-exist within matrix
-maintain Ca and PO4 homeostasis
-found in spaces called lacunae

24

describe osteoclasts

involved in osteolysis
Break down of bone
Increase osteoclast activity  weaker bone
Very large
Formed from the fusion of many white blood stem cell

25

look at slide 20

:)

26

Compact bone is arranged in______
Spongy bone is arranged in______

osteons
trabeculae

27

Osteocytes communicate through _______ that radiate outward and connect one cell to the next cell

canaliculi

28

what are osteons?

units of compact bone

29

___________ of matrix surrounding a ______________

concentric lamellae; central (Haversian) canal

30

do osteons contain blood vessels and nerves?

yes

31

Osteons connected to each other by

perforating canals

32

what are three characteristics of lamellae?

Concentric
Interstitial
Circumferential
**look at slide 24

33

What does spongy bone contain?
what does it not contain?

contains:
Trabeculae
osteocytes in lacunae
canaliculi
matrix
does not contain:
osteons
central canal

34

what is trabeculae?

Latticework of thin plates of bone oriented along lines of stress

35

the spaces in trabeculae are filled with what?

red marrow (where blood cells develop

36

where is trabeculae found?

Found in ends of long bones and inside flat bones.

37

what does trabeculae do?

Lightens the bone, allows for movement

38

what does the periosteum do?

it encloses bone

39

where is the periosteum absent?

Absent at site of attachment of muscles, tendons & ligaments; surfaces covered by articular cartilage

40

the periosteum has two layers, an inner and an outer layer. What does each layer do?

Outer fibrous: gives rise to collagen
Inner: for growth or new cells & maintenance

41

describe the edosteum. what cells are located here?

1 cell layer
Covers surfaces of spongy bone & medullary cavity
Cell types: Osteogenic, Osteoblasts, Osteoclasts

42

for long bones the shaft is known as the...

diaphysis

43

for long bones the epiphysis is ...

one end of a long bone

44

for long bones the growth plate region is known as the what?

metaphysis

45

for long bones the articular cartilage is located....

over the joint surfaces...acts as friction and shock absorder

46

for long bones the medullary cavity is the.....

marrow cavity

47

describe yellow marrow

Areolar and adipose CT
In medullary cavity of long bones
Energy storage
Absent in infants

48

describe red marrow
where is it located?

Areolar and myeloid tissue
Produces all types of blood cells
Locations:
Medullary cavities of infants
Spongy bone in adults

49

what are some of the arteries in the bone?

periosteal arteries
nutrient arteries
Metaphyseal & epiphyseal arteris

50

what do the periosteal arteries do?

supply the periosteum

51

where do the nutrient arteries enter the bone? what do they do?

enter through nutrient foramen
supplies compact bone of diaphysis & yellow marrow

52

what do the metaphyseal and epiphyseal arteries do?

supply red marrow & bone tissue of epiphyses and metaphyses

53

true or false:
ALL the arteries described that are located in bone have corresponding veins

true

54

what is ossification?

replacing CT with bone

55

what is Intramembranous ossification?

mesenchymal cells-->spongy bone

56

what is Endochondral ossification?

hyaline cartilage ->spongy bone

57

when does Intramembranous Ossification begin?
end?

week 8 in the embryo and ends in week 15

58

what does intramembranous ossification form?

Cranial flat bones
Facial bones
Dentary bones
Clavicle
Sesmoid bones

59

what is the Primary ossification center?

location where bone growth begins

60

what is important about intramembranous ossification?

-Mesenchymal cells arrange around BVs
-bone morphogenic proteins released
-mesenchymal cells become recruited, divide, and differentiate into osteoblasts

61

in intramembranous ossification, osteoblasts secrete.....

osteoid

62

when osteoblasts become isolated in intramembranous ossification they become what? what do they do?

osteocytes
Produce spicules of bone that interconnect

63

Look at slide 36

:)

64

what replaces what in Endochondral Ossification

bone replaces the cartilage model

65

when does Endochondral Ossification begin? end?

begins at week 7 in the embryo and lasts until adulthood

66

what does endochondral ossification form?

Long bones
Most short bones
Non-cranial irregular & flat bones
Middle ear ossicles

67

describe what happens in endochondral ossification

-------

68

where does bone growth elongation occur?

Occurs at epiphyseal plate

69

when does growth in length end?

Growth in length continues until 2 ossification centers meet

70

Relative thickness of epiphyseal plate (does/does not) change until growth almost complete; then:

does not; cartilage depleted & epiphyseal plate narrows to epiphyseal line

71

describe appositional bone growth

-Compact bone deposited beneath periostium
-Bone thickens
-Bone remodeling occurs throughout life due to osteoclasts & osteoblasts

72

does bone remodeling ever end? explain

bone modeling never ends, it is ongoing since osteoclasts carve out small tunnels and osteoblasts rebuild osteons. this means there is continual redistribution of bone matrix along lines of mechanical stress

73

_____% of compact bone, ___% of spongy bone remodeled per year

4%=compact
20%=spongy

74

distal femur is fully remodeled every __ months

4

75

what are the two types of breaks? describe them

Simple: break that does not penetrate skin
Compound: broken bone penetrates through skin

76

how are fractures treated?

reduction & immobilization

77

what are the four steps in bone repair?

fracture hematoma
fibrocartilage callus
Bony callus
Remodel tissue

78

within hours of an injury, a ________ forms
what is this and why does this happen?

-fracture hematoma
-it is a mass of blood
-Swelling and inflammation occur in response to dead bone cells

79

in a fracture hematoma, _________ and ______ eliminate dead cells/broken matrix

phagocytes and osteoclasts

80

A fibrocartilaginous callus consists of .....

a mass bridging the broken ends of the bone.

81

what do fibroblasts in the perisoteum produce?

collagen

82

in Fibrocartilaginous callus formation, _________ cells differentiate into _______ cells. This results in______

periosteum, chondrocytes, fibrocartilage

83

the formation of the bony callus occurs as the ________________is converted to _________________

fibrocartilaginous callus, spongy bone trabeculae.

84

The bony callus lasts about how long?

3-4 months

85

what happens in bone remodeling?

Remaining dead bone fragments are resorbed, and compact bone replaces spongy bone

86

if a bone fracture heals properly, can you tell later?

nope its virtually undetectable!

87

what are four factors that effect the growth and repair of bones?

Nutrition: Vit. D
Sunlight
Hormones: PTH, calcitonin, GH, thyroid hormone, sex hormones
Physical stress

88

what is osteoporosis?

abnormal reduction of bone mass

89

what are reasons for osteoporosis?

Loss of estrogen at menopause
Deficiency of minerals in youth
Imbalance in activity between osteoblasts & osteoclasts

90

describe Fibrodysplasia Ossificans Progressiva

Fibrous tissue becomes ossified
Genetic disorder
Injury results in inappropriate bone formation
Early adulthood: “freezing” of major joints
Early 20’s: confined to wheelchair
Starvation & pneumonia can result
No treatment