Functions of Skeletal Muscle

produce skeletal movement, maintain posture and body position, support soft tissues, regulate entering and exiting of material, body temp

muscle contractions pull on tendons and move the bones of the skeleton; the effects range from simple motions, such as extending the arm

contraction of specific muscles also maintains body posture - for example, holding the head in position when reading a book

the abdominal wall and the floor of the pelvic cavity consist of layers of skeletal muscles

encircle the openings, or orifices, of the digestive and urinary tracts; provide voluntarycontrol over swallowing, defecation, etc

muscle contractions require energy, and whenever energy is used in the body, some of it is converted to heat

openings

skeletal muscles, smooth muscles, and cardiac muscles

attached to the bones of the skeleton; called striated (striped with bands of light and dark bands); called voluntary

cells that are small and spindle-shaped (tapered at the ends); one centrally located nucleus; nonstriated - no bands; not attached to bones

found only in the heart; cells are striated, branched and involuntary; contraction on one cell, signals all neighboring cells to contract

a subset of smooth muscles; circular muscles found in the esophagus, stomach, small intestine, anus, urethra and mouth; open and close

the ability to shorten or contract the muscle cell and tissue; only muscular tissue has this ability; allows the body to move various parts

the ability to respond to stimuli by producing electric signals called action potentials (impulses)

electric signals; impulses

the ability to stretch the tissue

the ability to return to the original length or position after being stretched or contracted

contractability, excitability or irritability, extensibility, and elasticity

the least movable attachment during contraction because it is attached as an anchoring point to pull towards

this attachment is the movable end pulling (never pushing) the attached structures toward the anchoring point

the larger muscle tissue section in between the origin and insertion attachments

the muscle that contracts to allow a movement to happen

the muscle that relaxes to allow a movement to happen

a muscle that helps create a movement (a weaker, but assisting muscle) or it is used to stabilize a joint so that movement can occur

myoneural stimulation and muscle contraction

a nerve cell impulse stimulates the muscle cells it is attached to through the neuromuscular junction

the neuron releases a chemical, a neurotransmitter, called acetylcholine; this chemical moves across the gap

contraction is dependent upon this basic source of energy from glucose (simple form of sugar) stored in the body

a chemical released by a neuron; moves across the gap between the neuron (nerve cell) and the muscle cell; stimulates the muscle cell

when the sarcolemma is back at its original electric charge again; the point at which the muscle cell can be stimulated to contract again