muscle action
aka: muscle effect
agonist
aka: prime mover
antagonist
opposes the prime mover
prevents excessive movement
sometimes relaxes to give prime mover control over movement
antagonistic pair
muscles that act on opposite sides of a joint
antigravity muscles
prevent us from falling over
direct attachment
little separation between muscle and bone
muscle and bone connected by collagen fibers
endomysium
thin sleeve of loose CT around each fiber (muscle cell)
allows room for capillaries and nerve fibers
provides chemical environment for fiber and nerve
epimysium
fibrous sheath surrounding entire muscle
outer surface integrates with fascia
inner surface creates projections that form perimysium
extrinsic muscle
muscles isolated from the region on which they act
fascia
sheet of CT surrounding entire muscle
separates neighboring muscles or muscle groups from each other and from the subcutaneous tissue
continuous with tendon which is continuous with periosteum
fixator
muscle that prevents movement of bone
gives prime mover something to pull against
fleshy attachment
aka: direct attachment
glycemic control
skeletal muscles absorb, store, and use glucose which helps regulate blood sugar levels
reduced muscle mass due to old age, obesity, or disuse associated with type 2 diabetes
indirect attachment
tendons connect muscle to bone
collagen fibers of the endomysium, perimysium, and epimysium continue into the tendon and from there into periosteum
insertion
bony attachment at mobile end of muscle
intrinsic muscle
muscles entirely contained within the region on which they act (both the origin & insertion are here)
muscle
Greek for “little mouse”
3 kinds: skeletal, cardiac, smooth
purpose: to convert the chemical energy of ATP into the mechanical energy of motion
muscle compartments
groupings of muscles, nerves, and blood vessels in your arms and legs
muscular system
refers to the skeletal muscles
myology
the study of skeletal muscles/muscular system
origin
bony attachment at stationary end of muscle
perimysium
thicker layer of CT around bundles of fibers (fascicles)
carries nerves, blood vessels, and stretch receptors
prime mover
muscle that produces most of the force during a movement
sphincters
internal muscular rings that control the movement of food, blood, and other materials within the body
synergist
muscle that aids the prime mover
may contribute additional force, modify the direction of movement, or stabilize the joint
tendon
a fibrous connective tissue that attaches muscle to bone
belly
thicker, middle region of muscle between origin and insertion → site of contraction