Transcript Muscles and Skeletal Systems

Musculo-Skeletal system
• http://kidshealth.org/PageManager.jsp?lic=1&
article_set=59302&cat_id=20607
• Skeletal system
• http://www.youtube.com/watch?v=UGTenIDJ
BwU
Evolution of the System
• Muscles evolved 500-800 million yrs. ago
• Actin muscle protein structure
resembles mreB structure in bacteria
– mreB is used to maintain shape of the
bacterial cell
• Myosin resembles Muk and SMC in
bacteria
– Muk condenses DNA after DNA replication
• 500 million yrs. ago, striated and smooth
muscle diverged
Types of Skeletons
• Hydrostatic Skeleton
– Fluid-filled body cavity
– Found in Porifera, Nematoda, and most
other invertebrate phyla
• Exoskeleton
– Hard segments cover muscles
– Found in Arthropoda
• Endoskeleton
– Internal, contains bones and cartilage
– Found in Chordata
Types of Bones
• Long Bones
– Work as levers
• Short Bones
– Cube-shaped
– In wrists and ankles
• Flat Bones
– Protect organs
– Broad, have muscles attached
• Irregular Bones
Divisions of Human Skeleton
• Axial Skeleton
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• Appendicular Skeleton
Skull
Sternum
Ribs
Vertebral Column
– Shoulder Girdle
– Pelvic Girdle
– Extremities
Types of Muscle
• Skeletal Muscle
– Voluntary movement
– Example: Biceps
• Smooth Muscle
– Involuntary contraction
– Used in digestion
• Cardiac Muscle
– Located in the heart
– Pumps blood through the body
http://faculty.etsu.edu/forsman/Histologyof
muscleforweb.htm
Interdependence
• Skeletal muscle is directly
controlled by the nervous system
– Motor neurons are attached to
muscle at neuromuscular junctions
• B cells for the immune system are
produced in bone marrow
• Eyes use muscles to move
• Digestion and Excretion use
smooth muscles to transport the
food
Diseases and Disorders
• Duchenne Muscular Dystrophy
– Afflicts skeletal muscle
– Person cannot create dystrophin
– Muscle cells break down
– X-linked genetic disorder
• Cardiomyopathy
– Afflicts cardiac muscle
– Lower chambers of the heart weaken first
• Osteosarcoma
– Type of cancer
– Mostly develops in bones near the knee
Bone Cells
• Osteoblasts
– Create bone
– 10 microns diameter
– Derived from mesenchymal stem cell
• Osteoclasts
– Absorb bone
– 20-100 microns diameter
– Derived from macrophages
• Osteocytes
– Osteoblasts encased in bone matrix
Bone: Connective Tissue
Example of Skeletal Muscle
-Connects muscle to bone
-Connect bones
Myofibrils
• A fiber bundle contains hundreds of myofibrils that
run the length of the fiber
• Each myofibril is a linear array of sarcomeres
• Each sarcomere is capped on ends by a transverse
tubule (t-tubule) that is an extension of
sarcolemmal membrane
• Surfaces of sarcomeres are covered by SR
Muscle Contraction
Muscle Contraction in Action
http://www.sci.sdsu.edu/movies/actin_myosin.html
http://www.dnatube.com/video/1306/Muscle-contraction
Works Cited
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http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookMUSSK
EL.html
http://kidshealth.org/teen/diseases_conditions
http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&p
ubmedid=17158703#id358647
http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&p
ubmedid=10677457
http://www.sci.sdsu.edu/movies/actin_myosin.html
http://www.mnsu.edu/emuseum/biology/humananatomy/skeletal/ske
letalsystem.html
http://www.engin.umich.edu/class/bme456/bonephys/bonephys.htm
Garrett and Gershom. Biochemistry.