Anatomy & Physiology: Unit 2 Concept 3

Insertion

where the muscle is attached to a moveable bone

Origin

the anchor

where muscle is attached to an immoveable bone

Muscular System Various Functions

maintain posture, stabilize joints, and generate heat

Generating Heat

ATP is an exothermic reaction which means that contractions give off heat

Anaerobic Respiration

occurs if oxygen becomes limited

builds up lactic acid

Prime Movers

Agonists / Main Actors

muscles most responsible for producing a certain movement 

primary source of power for the action

Biceps Brachii

prime mover during forearm flexion 

Antagonists

brakes

muscles that do the reverse of a certain movement 

usually stretched or relaxed when prime mover is active 

can regulate prime movers by adding resistance

located on the opposite of a joint from the prime mover

Triceps Brachii

antagonist in a bicep curl

Synergists

personal assistant

muscles that help the prime mover, such as stabilizing across a joint or adding “oomph”

Fixators

synergists muscles that immobilize the origin bone to increase the prime movers effectiveness

Brachialis and Brachioradialis

synergists in the bicep curl 

Cardiac Tissue

striated muscle of the heart that contract involuntarily to pump blood throughout the body

Smooth

non striated muscles in the walls of visceral organs that contract involuntarily to propel objects/substances down internal passageways

Skeletal

striated muscles generally attached to bones that contract involuntarily to produce movement

Every Muscle Is…

its own organ, composed mainly of skeletal muscle tissue, but also blood vessels, nerves, and connective tissue

Myofibrils

organelle that makes up most of muscle cells 

Myofilaments

actin and myosin

run the length of each myofibril 

Sacromeres

contractile unit of the muscle

where myofibrils are located

Muscle Fibers

made up of myofibrils

aka muscle cells

Muscle Fibers Contain

many mitochondrias, nuclei, a specialized ER (sarcoplasmic reticulum), cytoplasm (sacroplasm), and cell membrane (sacrolemma)

Fascicles

muscle fibers bundled together

Muslce Organ

fascicles bundled together with connective tissue, nerves, and blood

Epimysium

wraps around the entire outside of the muscle

Perimysium

surrounds each fascicle

Endomysium

surrounds each muscle fiber