Transcript Musculoskeletal System

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
Types of Joints
• 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
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=VsBJ4o
Uff10&safe=active
http://www.youtube.com/watch?v=YyfytTqbgUE&safe=active
Types of Muscles
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=active
http://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)