The SKELETAL SYSTEM

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The SKELETAL SYSTEM
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What is the skeleton?

• made up of bones
• -300 at birth ? 206 by adulthood
• -why?

-some fuse over time (ex. Plates in the skull and
lower parts of the vertebral column)

• The main functions of the skeletal system are

Structural support -support for muscles and skin
Protection -protects the sensitive/delicate parts of body (brain, heart, lungs,etc)
Growth centre for cells -red blood cells and platelets
Reservoir for minerals -stores calcium and phosphorus
Movement -contracting muscles pull on bones for movement
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Structure of the Skeleton

• the human skeleton is divided into 2 main
  sections the AXIAL and APPENDICULAR

• AXIAL
• from axis ? centreline

• comprised of the vertebral column (spine), the
  spinal column and skull

• the core of the body
• protects the most important parts of the body
  heart, lungs, spinal cord, brain, etc

• most muscles will originate from parts of the
  axial skeleton

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• APPENDICULAR
• think of appendage

• includes the moveable limbs and the supporting
  structures (girdles)

shoulder pelvis

• plays a key role in allowing movement

There are 5 types of bones you need to be
familiar with. . .
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• Using page 11 in your text, label each on of
  these bones, and provide a short description

Short bones -commonly found in wrists
Long bone -found in arms and legs
Irregular bones - odd-looking bones not
otherwise classified
Flat bones -flat and thin -protect vital organs
Sesamoid bones -small, flat and wrapped in
tendons -glide over body surfaces
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The Anatomy of a Bone

• Bones may look like they are dead, but in fact
  are very much alive, growing and changing all the
  time.
• Before we talk about how bones grow and change,
  we first need to understand the various parts of
  a bone.
• Using figure 2.3 on page 12 in your text, label
  the picture below, and using the information on
  page 12, complete the structure function chart.

Articular cartilage Periosteum Cancellous
bone Medullary cavity Compact bone
Epiphyseal plate
Epiphysis Diaphysis (shaft) Epiphysis (head)
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Structure Function
Articular cartilage
Cancellous bone
Epiphyseal plate
Medullary cavity
Periosteum
Compact bone
Epiphysis
Diaphysis
-covers/protects ends of bones allows smooth
movement of joints no blood/nerve
endings -spongy, marrow-filled will strengthen
with resistance training -cartilage at each end
of bone (growth plate) allows longitudinal bone
growth -inside shaft contains red and yellow
marrow production of red blood cells -outer
connective tissuecovers length of bone connects
bone to bone or muscle -most dense bone
structural integrity happiest -ends of bone
compact articulates with another bone -thickest
part of bone shaft