Topic 9 Flashcards Preview

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Flashcards in Topic 9 Deck (25)
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1
Q

Functions of skeletal system

A
  • support
  • protection of vital organisms
  • attached muscles and allows movement
  • red marrow produces rbc and wbc
  • stores Ca
2
Q

Before week 8 skeleton embryo constructed of..

A

fibrous membranes and hyaline cartilage

3
Q

Bone formation occurs

A

8 weeks to 20 years

4
Q

2 types of ossification

A
  • intramembranous

- endochondral

5
Q

Intramembranous

A

flat bones (skull, mandible, clavicle), develop from fibrous CT membrane

6
Q

Process of intramembranous ossification

A
  • oesteoblasts produce spongy bone alone CT fibres

- periosteum forms and then osteoblasts under it lay down and compact bone

7
Q

Fontanels

A

unossified membranes in the skill that remain at birth

8
Q

Endochondral

A

hyaline cartilage used as a model for bone construction then ossifies to form spongy bone. periosteum forms and the osteoblasts beneath lay down compact bone.

9
Q

articular cartilage and epiphyseal plates =

A

cartilage that has not been ossified

10
Q

Bone growth in length and process

A

=endochondral growth at epiphyseal plates
process: cartilage grows to matrix near diaphysis becomes bone then growth stops when epiphyseal plate ossifies into epiphyseal line

11
Q

Bone growth in diameter and process

A

= appositional growth
process: osteoblasts beneath periosteum secrete bone matrix. osteoclasts reabsorb bone on the endosteal surface so size of cavity keeps pace with growing bone

12
Q

Mechanical stress is due to

A

muscle action

13
Q

2 examples of of mechanical stress

A
  • moderate exercise: increase osteoblast activity in areas of stress
  • injury that restricts movement: decrease osteoblast activity and no change in osteoclast activity decrease bone mass
14
Q

Weights or electric currents may speed..

A

healing by increase osteoblast activity

15
Q

Ca and PO4 is required for

A

production of bone matrix

16
Q

Vitamin C

A

required for collagen production

17
Q

Vitamin D

A

increase absorption fof Ca from intestine (if lacking Vit D then rickets soft bone in tissue)

18
Q

Growth hormone and thyroid hormone stimulate

A

bone growth

19
Q

Estrogen and testosterone increase..

A

osteoblast activity

20
Q

Estrogen in both sexes does what

A

ossification of epiphyseal plate

21
Q

Calcitonin

A

inhibits osteoclast activity. increases Ca movement from blood to bone

22
Q

Parathyoid hormone (PTH)

A

osteoclast activity increases and osteoblast activity decreases therefore blood Ca increases

23
Q

Osteoporosis

A

decrease in bone mass

24
Q

Risk factors of osteoporosis

A
  • increasing age
  • post menopause
  • inadequate diet
  • illness, excess PTH
  • too little/excessive exercise
  • drugs or smoking
25
Q

Process of bone repair

A
  • begins with formation of a blood clot
  • clot replaced by a callus of fibrous network and fibrocartilage islets
  • callus ossifies so intramembranous and endochondral ossification
  • takes 4-6 weeks so cast required since movement can refractor new matrix