Transcript Muscles and Movement 2015

MUSCLES AND MOVEMENT
Bozeman muscles
Endoskeleton vs Exoskeleton
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Exoskeleton
 Found
on the outside of the animal
 Composed of chitin
 Attachment of muscles is on the inside
 Allows organisms to lift/jump huge amounts in
proportion to their body
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Endoskeleton
 Found
on the inside of the body
 Composed of bone
 Attachment of the muscles in on the outside
Definitions
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Bones
Support and partially protect body parts
 Atriculate with other bones at the joints
 Provide anchorage for the muscles
 Consists of the
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Axial skeleton – skull and vertebral column
Appendicular skeleton – limb girdles and limbs
Ligaments
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Hold the bones together
Form protective capsules around moveable joints
Strong but elastic fibers
Definitions cont.
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Muscle
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Cause movement by contraction
Three types
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Tendons
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Skeletal which moves the skeleton
Smooth which is involuntary and lines the gut and veins
Cardiac which makes the heart beat
Attach muscle to the bone
Cords of dense connective tissue
Nerves
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Bundles of nerve fibers of individual nerves
Connect the central nervous system with the peripheral nervous system
Stimulate the muscles to contract
Co-ordinates movement
Antagonistic Pairs
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Work in pairs to move the bone
Each muscle can accomplish the opposite effect
 Bicep
raises the forearm
 Tricep lowers the forearm
The elbow joint
Parts of the Elbow Joint
Joint Part
Function
Cartilage
Reduces friction and absorbs impact
Synovial fluid
Lubricates joint to reduce friction
Joint capsule
Encloses the synovial capsule and unites
the bones
Tendons
Attach muscles to bone
Ligaments
Connect bone to bone
Bicep muscle
Contracts to bend arm
Tricep muscle
Contacts to extend arm
Humerus
Acts as a lever that allows anchorage of
the muscles
Radius
Acts as a lever for the bicep
Ulna
Acts as a lever for the tricep
Elbow movement
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Humerus, radius and ulna
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Biceps muscle
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Contains and protects the joint
Limits its motions
Synovial fluid
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Holds bones in the correct position in the joint
Capsule
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Anchored to the shoulder blade and attached to the ulna
Contraction extends the lower arm and stretches the biceps
Ligaments
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Anchored to the shoulder blade and attached to the radius
Contraction flexes the lower arm and stretches the triceps
Triceps muscle
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Bones of the skeleton
Function as a system of levers
Lubricates the joints
Nourishes the cartilage and removes debris
Cartilage
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Firm flexible material
Slippery to reduce friction
Striated (Skeletal) muscles
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Contains multiple nuclei
Specialized for contraction
Store glycogen
Has myoglobin stores (oxygen
released during heavy use)
• Lots of mitochondria
structure of the sarcomere
The muscle contraction
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When the muscle contracts
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The myofibril is simulated to contract by the arrival of the action
potential of a nerve
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Each charged blubous head (containing an ADP + P) reacts with the
binding site on the actin molecule beside it
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P is shed at this time releasing energy
ADP is released creating a rowing movement
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Triggers the release of calcium ions from the sarcoplasmic reticulum
Triggers the removal of the blocking molecule exposing binding sites
Pushes the actin filament along
Power stroke shortens the myofibril causing a contraction
A fresh ATP binds to the bulbous head
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The charged head detaches from the bulbous end
The muscle is once again charged
Video of contraction
Analyze a micrograph of muscle
Troponin and
Tropomyosin
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Tropomyosin
 Blocks
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the binding sites on the actin
Troponin
 Attached
to the tropomyosin
 Has binding sites for calcium
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When calcium binds to the troponin it causes the
tropomyosin to uncover the binding sites on the actin
which allows contraction
Release of calcium is based on nervous system
activity
Crash Course Muscles