Musculoskeletal System. Why is locomotion essential to most organisms? Motile vs. Sessile –Get...
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Transcript of Musculoskeletal System. Why is locomotion essential to most organisms? Motile vs. Sessile –Get...
Musculoskeletal System
• Why is locomotion essential to most organisms?
• Motile vs. Sessile
– Get food– Move away from harmful things and predators– Seek shelter– Seek out mates
Skeletons
• Humans and other vertebrates have endoskeletons– Made of bone and
cartilage– Can grow along with
animal
• Insects and animals like crabs and lobsters have exoskeletons– Made of chitin– Jointed and flexible– Muscles attached from inside– Must be shed periodically for organism to grow larger
Bone• Hard inflexible tissue
• Made of living bone cells called osteocytes
• Haversian Canals– inner cavities containing blood vessels and nerves
Broken Bones
– If bone is broken, osteocytes become active and produce new bone
Bone
• Function:– Site of attachment of skeletal
muscles– Levers that make body parts move
when muscles contract– Protect delicate structures like
brain and spinal cord– Storage site for important minerals
like calcium– Place where red blood cells and
some white blood cells produced
• Types of Bones:– Compact bone– Spongy bone
• Marrow: – Tissue found in long bones
– make RBC, platelets, some types of WBC
Joints
• Point where bones meet
• Immovable– Bones tightly fitted together
• Ex: skull
• Movable– Hinge Joint
• Ex: elbow and knee
– Pivot Joint• Ex: base of skull
– Ball and Socket Joint• Ex: Hip, shoulder
– Saddle Joint• Allow Ex: wrists
Types of Joints
Cartilage
• Found between joints
• Found in nose and earlobe
Cartilage
• Provides support and flexibility
• Allows bones to bend more easily
• Cushions bones against impact or pressure
• Makes up most of an embryo’s skeleton
Ligaments
• Tough elastic fibers
• Hold bone to bone at the joints
• http://www.youtube.com/watch?v=VsBJ4oUff10&safe=active
Types of Muscles
http://www.youtube.com/watch?v=YyfytTqbgUE&safe=active
Types of Muscles
• Skeletal Muscle (striated)– Voluntary movement,
locomotion – Bundles of muscle fibers– Appear striped or “straited”
under microscope
• Human locomotion is made possible by voluntary contractions of striated muscle.
• Muscles operate in pairs:– Flexors: bend limb– Extensors: extend limb
• Muscle Contraction– Muscle fibers contain contractile proteins– Require ATP (many mitochondria in muscle)
Types of Muscles
• Smooth Muscle (nonstriated)– Involuntary– Controlled by autonomic
nervous system– Found in:
• walls of digestive organs blood vessels, bladder
Types of Muscles
• Cardiac Muscle– Found in heart– Involuntary– Cells contract
together as a unit
Tendons
• Inelastic connective tissue
• Attaches muscle to bone
Disorders of Muscular/Skeletal System
• Tendonitis– Inflammation of connective tissue called
tendons that connect muscles to joints
• Arthritis– Inflammation of the
joints– Deterioration of cartilage
• Osteoporosis: – loss of bone due to calcium deficiencies
Locomotion in Animals• Protists
– Pseudopods (amoeba)– Cilia (paramecium) and flagella (euglena)
• Hydra– Tends to be sessile but can glide along base,
do somersault or use tentacles to pull itself
• Earthworm– Uses muscles to burrow into soil– Has tiny bristles on each segment (setae) that
hook onto earth to help it move
http://www.youtube.com/watch?v=bFpblBf1dfE&safe=activehttp://www.youtube.com/watch?v=0Texxu3p7I8&safe=active
• Grasshopper– Exoskeleton made of chitin divided into
plates that have flexible joints– Muscles attached from the inside– Can walk jump, fly (3 pairs of legs and wings)