Skeletal unit bone introduction notes

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Skeletal unitbone introduction notes

• MMHS Anatomy and Physiology

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Skeleton design

• Human Skeleton has 206 Bones.
• Humans have endoskeletons (internal)
• Arthropods have exoskeletons (external)
• Humans must rely on nervous system and sensory
  organs for protection
• oncoming car
• hot stove

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Skeletal divisions

• 2 Main Divisions of the Skeleton
• Axial skeleton (bodys central frame)
• Appendicular skeleton (bodys lateral frame)
• Axial (forms the midline of the body)
• Includes the following parts
• ?cranium, rib cage, vertebral column,
  sacrum, coccyx
• Appendicular (think appendages)
• Includes the following parts
• ? pectoral girdle (shoulder), pelvic girdle
  (hips), arms to hands, legs to feet.

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Axial vs appendicular skeleton
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Function of skeleton

• Protection of vital internal organs
• Skull protects brain.
• Rib cage protects heart and lungs
• Pelvis protects reproductive organs.
• Support provides framework for tissues to hang
  on.
• Movement muscles attached via tendons.
• Storage of minerals like calcium (Ca) and
  phosphorous (P)
• Production of Erythrocytes (RBCs) from red
  marrow.

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Bone classification by shape
Bone Shape Location in Body
1. Long Bones Femur, humerus, tibia, fibula
2. Short Bones Carpals and tarsal
3. Flat Bones Clavicle, ribs, cranial plates, scapula
4. Irregular Bones Vertebrae
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Bone classification
a. long b. irregular c. flat d.
irregular e. short
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Bone Anatomy

• Epiphysis ends of bone (covered in hyaline
  cart)
• Epiphyses form RBCs
• Diaphysis narrow shaft of bone
• Periosteum layer of connective tissue outside
  of bone.
• Contains blood vessels and nerves.
• Medullary Cavity Hollow center of the bone.
• Contains major blood vessels and marrow.

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Anatomy of bone
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Compact bone

• Calcified matrix ( Canaliculi ) contain
  lacunae which hold osteocytes.
• Osteocytes are connected to each other by
  canaliculi.
• Receive nutrients
• Get rid of wastes
• Blood vessels and nerves that travel the length
  of the bone do so through Haversian Canals.

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Cancellous spongy bone

• Trabeculae (interconnecting rods of bone) create
  the spongy appearance.
• Located in epiphyses of bones (close to joints)
• Joints bear greater amounts of stress from many
  directions.
• Cancellous bone channels stress into direction of
  compact bone ( more strength)

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Cancellous bone
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Gender differences in skeletons

• Male skeletons tend to be heavier to bear greater
  muscle attachment.
• Coxa bones (hips) are narrower and more upright
• Female skeletons have fewer markings on the
  skeleton
• Female skeletons are better designed for
  childbirth.
• Enlarged pelvic outlet / inlet
• Less curvature of the sacrum and coccyx.
• Broader Iliac bones stick out more laterally
  but not as high as in males.

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Male vsfemale