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The Skeletal System

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Tissues/organs of the skeletal system. Histology of osseous tissue. Bone development ... enlarged to strengthen joint and attach ligaments ... – PowerPoint PPT presentation

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Title: The Skeletal System


1
The Skeletal System
  • Chapter 7

2
Bone Tissue
  • Tissues/organs of the skeletal system
  • Histology of osseous tissue
  • Bone development
  • Physiology of osseous tissue
  • Bone disorders

3
Bone as a Tissue
  • Connective tissue with a _____________
    ________________ (_________________)
  • Bones ? bone tissue, marrow, blood, cartilage and
    _____________________
  • Continually ________________________
  • Functions of the skeletal system
  • _____________________________________,
    electrolyte balances, acid-base balance and blood
    formation

4
Shapes of Bones
  • ________ bones levers acted upon by muscles
  • Short bones glide across one another in
    multiple directions
  • _________ bones protect soft organs
  • Irregular

5
General Features of Bones
  • _________ (___________) cylinder of compact
    bone
  • marrow cavity (____________ cavity) lined with
    ______________ (osteogenic cells and reticular
    connective tissue)
  • ________________? collagenous fiber and
    osteogenic cells
  • Enlarged ends (_________________)
  • spongy bone covered by compact bone
  • enlarged to strengthen joint and attach ligaments
  • Joint surface covered with articular cartilage
  • Epiphyseal plate (_______________)

6
Match the Columns
  • As long as it is wide with flat articular
    surfaces
  • Longer in one direction
  • Even, parallel surface separated by spongy bone
  • Unusual processes
  • Long bone
  • Irregular bone
  • Flat bone
  • Short bone

7
Structure of a Flat Bone
  • Surfaces composed of _______________
  • Middle layer is _________________ and bone marrow
  • Skull fracture may leave inner layer of compact
    bone unharmed

8
Cells of Osseous Tissue
  • ______________ cells in endosteum, periosteum or
    central canals give rise to new _____________
  • Osteoblasts _______________________________
  • Trapped osteoblasts become ________________
  • cells in lacunae connected by gap junctions
    inside ________________________________

9
Matrix of Osseous Tissue
  • Organic matter (___________ of mass)
  • collagen, glycosaminoglycans, proteoglycans and
    glycoproteins
  • Inorganic matter
  • 85 ___________________________
  • 10 ___________________________
  • other minerals (fluoride, potassium, magnesium)
  • Combination ? strength and resilience
  • minerals resist ______________________ collagen
    resists ________________
  • bone adapts by varying proportions

10
Compact Bone
  • _______________ basic structural unit
  • cylinders formed from layers (__________) of
    matrix around central canal (_____________________
    _)
  • osteocytes connected by processes in canaliculi
  • ______________________ ______________________
  • vascular canals perpendicular to central canals

11
Spongy Bone
  • Spongelike appearance formed by plates of bone
    called ____________________
  • spaces filled with _______________________
  • __________ - few osteons or central canals
  • Provides strength with little weight
  • trabeculae develop along bones lines of stress

12
Bone Marrow
  • In _____________________ (long bone) and among
    trabeculae (_________________________)
  • in vertebrae, ribs, sternum, pelvic girdle and
    proximal heads of femur and humerus in adults
  • Red marrow like thick blood
  • _________________________ (produces blood cells)
  • ________________________
  • fat long bones (medullary cavity)

13
Intramembranous Ossification
  • Osteoblasts on trabeculae lay down osteoid tissue
    (uncalcified bone)
  • __________________________________________________
    ________________________
  • Osteoclasts create ____________________
  • _________________ form compact bone at surface
  • Surface mesenchyme produces periosteum

14
_____________ Ossification
  • Bone develops from ______________________________
  • perichondrium and ____________________________
  • Most bones develop this process
  • Form _______________________ centers and marrow
    cavity in shaft of model

15
Endochondrial Ossification
  • Secondary ossification centers ? ______________
  • Cartilage ? __________________ and __________
    (growth) plates
  • Bone length increases during childhood and
    adolescence
  • by early twenties, growth plates are gone and
    primary and secondary marrow cavities united

16
The Metaphysis
  • Zones
  • of ___________________
  • hyaline cartilage
  • of ___________________
  • chondrocytes multiply form columns of flat
    lacunae
  • of _______________ cell enlargement
  • of calcification
  • mineralization of matrix
  • of ____________________
  • chondrocytes die and columns fill with
    osteoblasts
  • osteons formed and spongy bone is created

17
  • Medullary cavity
  • Diaphysis
  • Metaphysis
  • Periosteum
  • Red marrow
  • Epiphyseal line
  • Spongy bone
  • Articular cartilage

18
Bone Growth and Remodeling
  • Bones increase in length
  • growth of ____________________________
  • ________________line is left behind when
    cartilage gone
  • Bones increase in width appositional growth
  • Bones remodeled throughout life
  • ______________ architecture of bone determined
    by mechanical stresses
  • action of osteoblasts and osteoclasts
  • greater density and mass of bone in athletes/
    manual worker is adaptation to stress

19
Dwarfism
  • ___________________
  • long bones stop growing in childhood
  • ______________________
  • spontaneous mutation during DNA replication
  • failure of ____________ ____________________
  • ____________________
  • lack of growth hormone
  • normal proportions with short stature

20
Mineral Deposition
  • ______________ is crystallization process
  • osteoblasts produce collagen fibers
  • minerals cover fibers and harden matrix
  • ions (__________________________) are deposited
    along the fibers
  • Abnormal calcification (______________)
  • may occur in lungs, brain, eyes, muscles, tendons
    or arteries (arteriosclerosis)

21
Mineral Resorption from Bone
  • Bone dissolved (osteoclasts) and minerals
    released into blood
  • Dental braces reposition teeth and remodel bone
  • create more pressure on one side of the tooth
  • stimulates osteoclasts to remove bone
  • decreased pressure stimulates osteoblasts

22
Calcium and Phosphate
  • Phosphate is component of ____________
    ____________________________________
  • 750 g in adult skeleton
  • plasma concentration is 4.0 mg/dL
  • 2 plasma forms HPO4 -2 and H2PO4-
  • Calcium needed in ___________________
    ______________________ and exocytosis
  • 1100g in adult skeleton
  • plasma concentration is 10 mg/dL

23
Ion Imbalances
  • Changes in phosphate levels _____________
  • Changes in calcium can be serious
  • __________________ - deficiency of blood calcium
  • excitability of nervous system
  • muscle spasms, tremors or tetany 6 mg/dL
  • laryngospasm and suffocation 4 mg/dL
  • with less calcium, sodium channels open more
    easily, sodium enters cell and excites neuron
  • __________________ - excess of blood calcium
  • makes sodium channels less likely to open,
    depresses nervous system
  • ______________________________________, cardiac
    arrest 12 mg/dL
  • Calcium phosphate homeostasis ? calcitriol,
    calcitonin and PTH hormone regulation

24
Hormonal Control of Calcium Balance
  • Calcitriol, PTH and calcitonin maintain normal
    blood calcium concentration.

25
__________ (Activated Vitamin D)
  • Produced by
  • ___________________________ convert steroid to
    cholecalciferol - D3
  • liver converts it to calcidiol
  • kidney converts that to ______________ (vitamin
    D)
  • Calcitriol ________________ blood calcium
    concentration
  • increases _____________________ and absorption
    from the skeleton
  • increases ______________________
  • promotes urinary reabsorption
  • Abnormal softness (________) in children and
    (______________) in adults with low vitamin D

26
Calcitonin
  • Secreted (_____________) when calcium
    concentration too high
  • Functions
  • ____________________ activity
  • increases the number/ activity of
    ___________________
  • Important in children, little effect in adults
  • osteoclasts more active in children
  • deficiency does not cause disease in adults
  • ________________________________

27
Parathyroid Hormone
  • Glands on posterior surface of ____________
  • Released with __________
  • Function ______ calcium blood level
  • increases in _____________ ____________________
  • _______________________ resorption by the kidneys
  • promotes __________________ synthesis in the
    kidneys
  • ________________________ ________________________
    ________________________

28
Other Factors Affecting Bone
  • ______________________ ______________________
  • Growth rapid at puberty
  • hormones stimulate ______________________,
    chondrocytes and matrix deposition in growth
    plate
  • girls grow faster than boys and reach full height
    earlier (estrogen stronger effect)
  • males grow for a longer time and taller
  • ______________________ ______________________
  • teenage use of anabolic steroids premature
    closure of growth plate and short adult stature

29
  • Spongy bone
  • Osteon
  • Volkmans canal
  • Periosteum
  • Osteocyte
  • Lamella
  • Canaliculi

30
Fractures
  • _________________________ caused by trauma
  • car accident, fall, athletics
  • ____________________ bone weakened by disease
  • bone cancer or osteoporosis
  • Fractures classified by structural
    characteristics
  • break in the skin (_______________________)
  • multiple pieces

31
Types of Bone Fractures
32
Healing of Fractures
  • Normally 8 - 12 weeks (__________________)
  • Stages of healing
  • __________________ - clot forms, osteogenic cells
    form granulation tissue
  • __________ - fibroblasts produce fibers and
    fibrocartilage
  • _________ - osteoblasts produce a bony collar in
    6 weeks
  • ____________ - spongy bone replaced by compact
    bone in 3 to 4 months

33
Treatment
  • ________________________
  • fragments align with manipulation/ casted
  • Open reduction
  • __________________________________________
  • Traction long-term confinement in bed
  • Electrical stimulation used on fractures
  • if 2 months necessary for healing
  • ____________________ prevention and correction
    of injuries and disorders of the bones, joints
    and muscles

34
_______________
  • Bones loses mass (__________________)
    ?______________
  • risk of fracture of hip, wrist and vertebral
    column
  • complications (pneumonia and blood clotting)
  • Postmenopausal white women at greatest risk
  • by age 70, average loss is _______ of bone mass
  • black women rarely suffer symptoms

35
Osteoporosis
  • _____________ maintains density in both sexes
    (inhibits resorption)
  • ________________ produce estrogen in men
  • rapid loss after ____________, if body fat too
    low or with disuse during immobilizaton
  • Treatment
  • HRT slows bone resorption, but increases risk
    breast cancer, stroke and heart disease
  • PTH slows bone loss if given daily injection
  • Forteo increases density by 10 in 1 year
  • may promote bone cancer
  • _____________________________ ____________________
    _________ __________________________________

36
  • Spiral
  • Comminuted
  • Potts
  • Colles
  • Greenstick
  • Open (compound) displaced

37
  • Reduces osteoclast activity
  • Dwarfism
  • Vitamin D
  • Excitable nervous system
  • Increases blood calcium
  • Pathological decrease in bone mass
  • PTH
  • Osteoporosis
  • Calcitonin
  • Hypocalcemia
  • Achondroplasia
  • Calcitriol
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