Muscles Flashcards
muscles: function
- provide force for movement
skeleton: function (3)
- support the body
- protect delicate body tissues
- provide levers for muscles to act on to produce movement
what happens when a muscle contracts
- it shortens and applies force by PULLING
skeletal muscles attachment sites
- origin
- insertion
skeletal muscles attachment sites: origin
- relatively fixed structure
skeletal muscles attachment sites: insertion
- relatively mobile site
antagonistic pairs
- pairs of muscles that pull the same body part in opposite directions
flexion (2)
- to bend one part relative to another about a joint
- decreases the angle between these two parts
extension
- to straighten one part relative to another about a joint
- increases the angle between these two parts
levators
- elevate (raise) a body part
depressors
- depress (lower) a body part
adduction (2)
- to move a body part towards the midline of the body
- to elevate the lower jaw, closing the mouth
abduction (2)
- to move a body part away from the midline of the body
- to depress the lower jaw, opening the mouth
protractors (2)
- projection of a part away from its base
- movement of an appendage in the anterior direction
retractors (2)
- withdrawal of a body part: pulling it back closer to its base
- movement of an appendage in the posterior direction
classification of skeletal muscles (4)
- branchiomeric
- hypobranchial
- axial
- appendicular
trunk somites
- myotome of trunk somites develop into axial and appendicular muscles
anterior somites (2)
- grow ventrally and anteriorly to form hypobranchial muscles
- ventral to pharyngeal slits
somitomeres
- epimere mesoderm forms connected clusters in the head
- develop into branchiomeric muscles
terrestrial locomotion: propulsive stroke (2)
- foot contacts the ground
- limb moves from anterior to posterior (retraction) propelling body forward
terrestrial locomotion: recovery stroke (2)
- foot is lifted (no contact with ground)
- limb moves from posterior to anterior (protraction), back into position for another propulsive stroke
sprawled limb posture (2)
- amphibia, testidunata, lepidosauria, and crocodilia
- limbs positioned laterally
erect limb posture (2)
- mammalia, aves
- limbs are positioned directly under the body
terrestrial locomotion: sprawled limb posture (3)
- walk or run with lateral undulations of the body, using feet as pivot points
- recovery stroke requires an overarm swing for each limb
- limb movement is both anterior/posterior and dorsal/ventral