Skeletal and Muscular System

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Skeletal and Muscular System

• By
• Kim Beach, Melody Bernhardt, Priscilla Lee, and
  Shannon Vickers

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Skeletal System

• Determines shape or body
• Protects organs
• Works with muscles to create movement
• Over 200 bones in body
• Made of bones, ligaments, and tendons

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Bone Composition

• Consists of calcium, phosphorus, carbonate
  crystals, and collagen fibers.
• Layer of compact bone surrounds layer of spongy
  bone, except at the marrow cavity
• At joints, a layer of cartilage covers the end of
  the bone to prevent friction.
• Bone marrow fills bone cavities
• Red marrow produces red blood cells
• Yellow bone marrow stores fats and produces white
  blood cells

• Tendons attach a muscle to a bone and transmit a
  mechanical force of muscle contraction to the
  other part
• They are much like ligaments, and are composed of
  dense fibrous connective tissue with high
  collagen content

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Bone Growth

• Endochondral ossification- process of converting
  cartilage in embryonic skeletons to bone
• Cells begin depositing minerals and spongy bone
  forms
• Osteoclasts remove the material from the center
  of the bone
• Perichondrium forms around cartilage and begins
  forming compact bone
• Blood vessels form and grow into the perchondrium
  transporting stem cells into the interior

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Muscular System

• Allows movement
• Over 600 individual muscles
• 3 types skeletal, cardiac, and smooth
• Voluntary and involuntary muscles

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Cardiac Muscle

• Involuntary (non-controllable)
• Makes up brain, wall of the heart, mydocardium
• This muscle is striated and contracts through the
  sliding filament method
• Contains branching fibers
• Attached together instead of bone

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Skeletal Muscle

• Makes up 40 of an adults body weight
• Striated
• Composed of long muscle fibers each fiber is a
  cell with several nuclei
• Nervous system controls the contraction of the
  muscle
• Voluntary muscle
• Tendons attach muscle to bone

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Smooth Muscle

• Makes up most of our internal organs
• Controlled by the nervous system and hormones
• Involuntary muscles
• Muscles fibers tightly intertwined

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Extensor and Flexor

• Extensor muscles increase the angle of a joint
  (straightening the elbow, or the triceps).
• It is usually bent backwards, except at the knee.
• Flexor muscles decreases the angle of the joint
  (bends the elbow, or biceps).
• It is usually directed forwards, except at the
  knee.

To see the flexor and extensor at work click on
http//www.innerbody.com/anim/arm.html
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Muscle Contraction

• Neuromuscular junctions are the point where a
  motor neuron attaches to a muscle.
• When the nerve impulse reaches the junction the
  acetycholine is release from the axon of the
  nerve cell.
• Electrical changes are produced in the muscle
  cell when the Ach binds to the receptors of the
  surface of the cell and changes to Na ions. This
  is called depolarization.
• During repolarization the muscle cannot be
  stimulated. This is the refractory period and
  once started the action spreads throughout the
  entire muscle cell.
• This is the all or none response.

To See Muscle Contraction Go to
http//bio.winona.msus.edu/berg/ANIMTNS/muscle.htm

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Joints

• Immovable joints have tightly interlocked edges
  like sutures in the skull
• Partly movable joints allow some movement have
  cartilage between bones
• Synovial joints allow greatest amount of movement
  and ends of bones covered with a connective
  tissue filled with synovial fluid
• Synovial joints have an outer surface that
  strengthens joints and hold bones in place
• Some joints also have tendons-which link muscle
  to bone

Gliding Joint
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Moveable Joints

• Ball and Socket Joint a ball shaped end of one
  bone fits inside the cup shaped end of another.
  (shoulder or hip)
• Pivot Joint the end of one bone rotates inside
  ring formed by another. (forearm)
• Saddle Joint enables a bone to move backwards to
  forwards and side to side.
• Hinge Joint hinge can only move in one direction
  like a door hinge. (elbow or knee)

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Health

• Osteoporosis, or porous bone, is characterized by
  low bone mass and structural deterioration of
  bone tissue. This leads to bone fragility and an
  increased susceptibility to fractures of the hip,
  spine, and wrist. There is no known cure at this
  time, but there are many options of medications
  that you can take.
• Pagets disease results in enlarged and deformed
  bones it is a chronic disorder. The excessive
  breakdown and formation of bone tissue that
  occurs can cause bone weakening and pain,
  arthritis, deformities, and fractures. Treatments
  can lessen symptoms but not cure the disease.
• Duchenne Muscular Dystrophy (DMD) is
  characterized by muscular enlargement and by a
  rapid progression of muscle degeneration.
  Treatments on mice are promising, and may lead to
  effective therapies.
• Myotonic Dystrophy is when the muscles contract
  but have decreasing power to relax. Due to this,
  the muscle become weak, and waste away, and it
  can cause mental deficiency, hair loss and
  cataracts.
• Artificial limbs help to restore a normal way of
  life to people who have had their limbs
  amputated. Joints, like the knee and hip, can
  be replaced also so that the person can return to
  an active life. In the future, technology may be
  able to recover senses in the artificial limbs.

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Bibliography

• http//library.thinkquest.org/11965/html/cyber-ana
  tomy_musboth.html
• http//www.osteo.org/
• http//library.thinkquest.org/10348/find/content/m
  uscular.html
• http//www.enchantedlearning.com/subjects/anatomy/
  skeleton/skelprintout.shtml
• http//www.ecsu.ctstateu.edu/depts/edu/textbooks/s
  keleton/html
• The Ultimate Visual Science Dictionary. Dorian
  Kindersly (company)
• The Random House Book of 1001 Questions and
  Answers About the Human Body. Trevor Day