Locomotion, Part I

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Locomotion, Part I

• Lecture 3

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Skeletons and Muscles

• Three types of skeletons in animal kingdom
• Hydrostatic as muscles contract, fluid in
  cavity is displaced causing change in body shape

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1. Hydrostatic Skeleton
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2. Exoskeleton
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3. Endoskeleton
Outside is flexible
Bone is living unlike chitin. It can grow,
repair and remodel
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Vertebrate Skeletons

• Divided into two divisions
• Axial those bones associated with skull, rib
  cage and vertebral column

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1. Axial Skeleton
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2. Appendicular Skeleton

• Those bones associated with the extremities
  including shoulder and hip bones

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Human Skeleton

• Total of bones 206
• Axial 80
• Appendicular 126
• Upper extremity 60
• Lower extremity 60
• Shoulder and hip total 6 bones

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Composition of bone

• Bone is a living organ
• Comprised of CT fibers -- collagen
• Comprised of bone salts hydroxyapatite
• Hydroxyapatite (Ca2)10(PO-4)6(OH)2
• Comprised of bone cells osteocytes
• Two types of osteocytes
• Osteoblasts lay down bone (build)
• Osteoclasts solubilize bone (deconstruct)

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Movement of the Skeleton

• Movement (motion) occurs when skeletal muscle
  shortens
• Muscles are attached to 2 separate bones
• These two bones share a movable joint.
• Next topic.how do muscles shorten?

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Movement
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Structure of Skeletal Muscle
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Structure of Skeletal Muscle

• Muscle comprised of many fascicles

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Structure of Skeletal Muscle

• Fascicle a bundle of muscle fibers (cells)

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Structure of Skeletal Muscle

• Muscle fiber cell contain bundles called
  myofibrils

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Structure of Skeletal Muscle

• Myofibrils comprised of myofilaments
• 2 types
• Thin
• filaments
• 2. Thick
• filaments