Lecture 3 - Intro to the Skeletal System Flashcards

1
Q

what are the five main functions of bone tissue?

A
  • supports and protects soft tissue
  • supports and generates the shape of the body
  • provides attachment for muscles, tendons, and ligaments
  • dynamic mineral storage
  • makes bone marrow
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2
Q

connective tissue in medullary cavity where blood formation occurs

A

red marrow

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3
Q

connective tissue in medullary cavity where adipose is stored

A

yellow marrow

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4
Q

bone is composed of:

A

calcium phosphate (minerals = inorganic) and type I collagen (protein = organic)

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5
Q

bone cells are embedded in a:

A

mineralized matrix

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6
Q

bone is covered by other connective tissue such as:

A

periosteum and endosteum

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7
Q

bone remodels itself under the influence of:

A

forces

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8
Q

bone is anisotropic, which means:

A

it has different strength depending on its orientation

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9
Q

how are bones classified?

A

by location and shape

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10
Q

what are the two main types of bone?

A

spongy (cancellous/trabecular) bone and compact (cortical) bone

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11
Q
  • open network of struts surrounded by blood
  • shape and direction depend on external forces
  • 20% of bone in all the body, 80% of bone remodelling (due to assoc. with vasculature)
    these are all characteristics of what type of bone?
A

spongy/trabecular bone

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12
Q
  • relatively dense and solid (lamellae = layers)
  • thickness and density also depends on external forces
  • 80% of bone in all the body, 20% of bone remodelling
    these are all characteristics of what type of bone?
A

compact/cortical bone

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13
Q

epiphysis

A

the end of a bone

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14
Q

diaphysis

A

the shaft of a bone

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15
Q

highly vascularized connective tissue and contain mesenchymal stem cells

A

endosteum and periosteum

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16
Q

contain many sensory nerves (where pain is felt)

A

periosteum

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17
Q

where does appositional growth occur?

A

periosteum and endosteum

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18
Q

contains red marrow and yellow marrow

A

medullary cavity

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19
Q

what is articular cartilage?

A

hyaline-like cartilage at the ends of bone, remnants of bane growth

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20
Q

what are osteoblasts?

A

immature bone cell which secretes matrix

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21
Q

what is the function of osteoblasts?

A

bone forming

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22
Q

what are osteocytes?

A

mature bone cells that live in the lacunas

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23
Q

what is the function of osteocytes?

A

to maintain the matrix

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24
Q

canals that allow osteocytes to communicate

A

canaliculi

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25
Q

what are osteoclasts?

A

bone cells which come from blood which reabsorb the matrix

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26
Q

what is the function of osteoclasts?

A

bone reabsorbing

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27
Q

secretes acidic substance whicch break down bone

A

osteoclasts

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28
Q

bone cells which come from mesenchymal cells

A

osteoblasts and osteoclasts (ossified version of osteoblasts)

29
Q

functional unit of the the bone which are oriented in the line of stress

A

osteons

30
Q

organized in concentric layers around around a central canal containing blood vessels and nerves supplying the osteon

A

osteocytes

31
Q

transmits blood vessels from the periosteum into the bone and communicates with the Haversian canal

A

perforating (transverse) canals

32
Q

bone remodelling is a dynamic process that allows:

A
  • bone reneal and microcrack repair
  • liberation of bone minerals
  • fracture healing
33
Q

what type of bone development is responsible for bone formed from the mineralization of mesenchymal tissue?

A

intramembranous ossification

34
Q

why do the circles of the osteons have alternating directions?

A

to resist forces

35
Q

what bones are formed by intramembranous ossification?

A

the clavicle, mandible, skull, and facial bones

36
Q

type of bone development where the formed bone replaces hyaline cartilage

A

endochondral ossification

37
Q

what bones are formed by endochondral ossification?

A

limb bones, vertebral coloumn, thoracic cage, and pelvic girdle

38
Q

what are the four main steps of intramembranous growth?

A

1) formation of an ossification centre
2) osteoid calcifies and osteoblasts become osteoclasts; new osteoblasts are produced and move outward
3) developing bone forms trabeculae and blood vessels supply the new bone
4) mesenchymal cells condense around outside of bone to form periosteum

39
Q

how is the ossification centre formed?

A

chemical messages to mesenchymal cells to crowd together –> cells differentiate into osteoblasts –> aggregation of osteoblasts secreting ECM

40
Q

what are the main functions of cartilage tissue?

A
  • supports and preserves soft tissues
  • provides a smooth, frictionless, shock absorbing surface at articulations (joints)
  • provide a model for the formation of the majority of the bones in the body
41
Q

how does cartilage resist compression?

A

contains a high amount of ground substance

42
Q

does cartilage have its own blood supply?

A

no, it is avascular and needs another connective tissue close by to survive

43
Q

most cartilage is covered by:

A

a connective tissue sheath (perichondrium)

44
Q

what are the three main types of cartilage?

A
  • hyaline cartilage
  • elastic cartilage
  • fibrocartilage
45
Q

type of cartilage which provides support, flexibility and resilience and is found in growth plates, costal cartilage, most respiratory cartilage, nasal cartilage, and articular cartilage

A

hyaline cartilage

46
Q

type of cartilage which maintains the shape of a structure while allowing flexibility and is found in the epiglottis and external ear

A

elastic cartilage

47
Q

type of cartilage which is highly compressed with great tensile strength and is found in the menisci of synovial joints (knee), intervertebral discs, pubic symphysis, and temporomandibular joint (TMJ)

A

fibrocartilage

48
Q

what are the steps of endochondral growth (pre-natal)?

A

1) mesenchymal cells condense to form outer covering (perichondrum)
2) large chondrocytes secrete an attractant for blood vessels and then undergo apoptosis
3) invading blood vessels stimulate cells which differentiate into osteoblasts and osteoclasts

49
Q

what are the steps of endochondral growth (post-natal)?

A

1) secondary ossification centres appear in the epiphyses
2) epiphyseal cartilage plate is formed and remains between the epiphysis and diaphysis

50
Q

does articular cartilage heal well?

A

no

51
Q

as you age, articular cartilage will be replaced by:

A

bone

52
Q

is it possible for bones to grow in length when the bone plates close?

A

no

53
Q

after growth plates close, bones can grow appositionally in response to:

A

stimuli like muscular activity and bone damage

54
Q

what are the three main factors that impact bone modelling and remodelling?

A
  • minerals
  • vitamin A and C
  • hormones
55
Q

what is appositinal bone growth?

A

a change in the shape/diameter of the bone

56
Q

what are the four main steps of bone remodelling and repair?

A

1) fracture hematoma: rupture of blood => hemorrhage
2) fibrocartilaginous callus: invasion of macrophages
3) bony callus: healthy blood vessels are produced, bringing in osteogenic cells to form osteoblasts, spongy bone laid down, cartilage replaced by bone
4) bone remodelling: osteoclast activity increases, spongy bone replaced by cortical bone

57
Q

why is the fracture hematoma necessary?

A

after 6-8 hours, the hematoma causes blood vessels to constrict to stop future bleeding

58
Q

what is the fibrocartilaginous callus made of?

A

cartilage

59
Q

what is the purpose of the fibrocartilaginous callus?

A

bridges the gap between the broken pieces of bone (immobilization)

60
Q

joints can be classified in two ways:

A
  • the connective tissue that binds the bones together and the potenial space between them
  • functionality
61
Q

what are fibrous joints?

A

type of joint where bones are held together by fibroius connective tissue

62
Q

where are fibrous joints found?

A

cranial sutures, gomphosis, interosseous membrane

63
Q

what are cartilaginous joints?

A

type of joint where bones are joined by cartilage

64
Q

what are the two types of cartilaginous joints?

A
  • primary/synchondrosis
  • secondary/symphysis
65
Q

where are synchondrosis cartilaginous joints found?

A

cartilage of growth plates

66
Q

where are symphisis cartilaginous joints found?

A

intervertebral discs, pubic symphysis

67
Q

what are synovial joints?

A

fluid-filled cavity that separates cartilage-covered joint surfaces

68
Q

the shape of the articular surfaces of a synovial joint dictates its:

A

range of motion