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Skeletal and Muscular Systems

Published on Nov 18, 2015

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PRESENTATION OUTLINE

Skeletal and Muscular Systems

Photo by postbear

Objectives

  • Explain how bones grow and develop
  • Distinguish types of joints and how they move
  • Describe the three types of human muscle tissue
  • Explain how skeletal muscles move bones

Bones are hard because they store minerals as mineral salts. When levels in the blood are low, bones release them, restoring homeostasis.

Photo by Theen ...

Bones

  • Living tissue
  • Have blood supply
  • Constantly making new bone
Photo by perpetualplum

As a fetus, the skeleton is made of cartilage. It is changed to bone through ossification.

Photo by Urijamjari

Ossification begins at the center and continues toward bone ends. At birth, several areas of cartilage remain.

A thin layer of cartilage reduces friction at joints.

Joints

  • Immovable, ie skull
  • Partly movable, ie ribs
  • Movable joints, aka synovial joints

Movable Joints

  • Bones connected by ligament
  • Space between filled with synovial fluid
  • Ball-and-socket, eg shoulder
  • Hinge, eg knee
  • Pivot, eg elbow

Muscles

Not the bivalve kind.

Muscle Cells

  • AKA muscle fiber
  • Long, thin
  • Can contract
  • Three types

Smooth Muscle

  • Contractions involuntary
  • Helps organs carry out functions
  • Eg, lines stomach and intestines

Skeletal Muscle

  • Contractions volutary
  • Most common muscle type
  • Muscle that is attached to bone
  • Over 600 in the human body
  • Wrapped in connective tissue for support

Skeletal Muscle

  • Attached to skeleton by tendons
  • Can only contract
  • Can increase in size, strength, and efficiency
  • Will atrophy if not used

Cardiac Muscle

  • Contractions involutary
  • Found only in heart walls
  • Contains many mitochondria
  • Arranged in bundles, so striated