The Human Skeleton

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The Human Skeleton
Unless otherwise noted, all pictures are from
http//www.sirinet.net/jgjohnso/skeletonorg.html
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• Functions
• Support the body
• Protect internal organs
• Movement
• Store minerals
• Site for blood cell formation
• Two divisions
• Axialcentral axis
• Appendiculararms, legs, pelvis, shoulder areas

http//www.personal.psu.edu/faculty/g/x/gxs22/NewH
ouse.html
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• Bones are living tissue. They are a solid
  network of living cells and protein fibers that
  are surrounded by deposits of calcium salts.

Parts Periosteum, compact bone, spongy bone,
and bone marrow
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Ossification

• The process of bone formation is called
  ossification.
• Osteobone
• Osteoblastsmake bone
• Osteocytesmaintain cellular activities of bone
• Osteoclastsbreak down bone

http//www.ithaca.edu/faculty/lahr/HistPath/HP_jpe
gs/Spec_CT_jpegs/bone/bone_cart_s11high.jpg
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What about when you break a bone?
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Jointsplace where one bone attaches to another
bone

• Three main types
• Immovable
• Slightly movable
• Freely movable
• What do you think the four types of freely
  moveable joints are?
• Where are they found?

http//www.thehumanbody.ecsd.net/bones.htm
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Muscular System

• More than 40 percent of the average persons mass
  is muscle.
• Functions
• Movement
• Blood pressure regulation
• Move food
• Any other movement

http//www.images-eye.com/graphics/artwork/sketche
s/muscles.jpg
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• Skeletal muscle cells
• are usually attached to bones
• Voluntary actions
• Have striations
• Are large
• Have many nuclei
• Are often called muscle fibers.

http//www.biology.eku.edu/RITCHISO/tendon.jpg
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Who has more skeletal muscle cells?
http//www.creatina.com.br/muscles.jpg
http//www.sc.edu/library/spcoll/nathist/darwin/da
rwinyoung.jpg
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• Smooth muscles
• Are usually not under voluntary control
• Are spindle-shaped
• Are not striated
• Have only one nucleus
• Are found in hollow structures (digestive tract,
  blood vessels)
• Can mainly function without nervous stimulation.

http//www.udel.edu/Biology/Wags/histopage/modelsp
age/smooth_muscle_fiber.GIF
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• Cardiac muscle
• Is found only in the heart
• Have intercalated discs
• Shares features with both of the other muscle
  types
• Striated like skeletal (but smaller)
• One or two nuclei

http//learninglab.co.uk/headstart/images/four41.g
if
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Comparing the Three Types of Muscle Tissue
http//www.bergen.org/ACADEMY/Bio/AnP/AnP1/AnP1Tri
3/FIGS/MUSCLE/muscle.html
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Muscle Contraction
http//www.sirinet.net/jgjohnso/amuscle.html
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• Striations are from two types of filaments
  Actin and Myosin
• Muscles contract when the thin filaments in a
  muscle fiber slide past the thick filaments.

http//www.sirinet.net/jgjohnso/amuscle.html
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• Muscle contractions need to be in a controlled
  fashion.
• Neuromuscular junctions are the contact points
  between nerves and muscles.
• One motor neuron can junction with many muscle
  fibers.
• Muscle fiber contractions are all-or-none.

http//www.dmacc.cc.ia.us/instructors/neuromus.htm
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• Muscles can only contract and relax.
• They can only pull in one direction.
• Tendons are attached so muscles pull on bones and
  make them work like levers.
• Most muscles work in opposing pairslike the
  biceps and triceps.
• Controlled movement requires contraction by both
  muscles.

http//www.howe.k12.ok.us/jimaskew/bio/hinge2.gif
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• Muscle tonelimited stimulation that causes a
  tightening of some muscles.
• It keeps your back straight and your head upright
  when relaxing.

http//posters.westbalkanonline.com/speedlist/LP07
5820Eminem20sitting.jpg