- attached to bones - striated - voluntarily controlled

- located in the heart - striated - involuntarily controlled

- located in blood vessels, hollow organs - non-striated - involuntarily controlled

the ability of muscle to shorten forcefully, or contract

- the capacity of muscle to respond to a stimulus

- the ability to be stretched beyond it normal resting length and still be able to contract

the ability of the muscle to recoil to its original resting length after it has been stretched

a connective tissue sheath that surrounds skeletal muscle

- muscle group subdivisions of skeletal muscles

connective tissue covering that surrounds each fascicle

connective tissue covering that surrounds each skeletal muscle cell fiber

a single cylindrical cell, with several nuclei located at its periphery

contain several nuclei that are located at the periphery of the fiber

has many tubelike inward folds called transverse tubules, or tubules

- occur at regular intervals along the muscle fiber and extend into the center of the muscle fiber -connect the sarcolemma to the terminal cisternae to form a muscle triad

plays a major role in muscle contraction

- cytoplasm of a muscle fiber - contains many bundles of protein filaments

- bundles of protein filaments - consist of the myofilaments, actin and myosin

the basic structural and functional unit of a skeletal muscle

form a network of protein fibers that both serve as an anchor for actin myofilaments

slide past each other, causing the sarcomeres to shorten

light bands that consist only of actin - extends toward the center of the sarcomere to the ends of the myosin myofilaments

- dark staining bands - extend the length of the myosin myofilaments

made up of three components: actin, troponin, and tropomyosin

resemble bundles of tiny golf clubs

the electrical charge difference across the cell membrane of an unstimulated cell

have a resting membrane potential, but can also perform action potentials

due to the membrane having gated channels

the increase in positive charge inside the cell membrane

- a value where the depolarization changes - an action potential is triggered

a rapid change in charge across the cell membrane

cause for action potential in muscle fibers

Na+ channels close change back to resting potential

- a nerve cell stimulates muscle cells

a synapse where a the fiber of a nerve connects with a muscle fiber

refers to the cell-to-cell junction between a nerve cell and either another nerve cell

a group of muscle fibers that a motor neuron stimulates

the end of a neuron cell axon fiber

the space between the presynaptic terminal and postsynaptic membrane

the muscle fiber membrane (sarcolemma)

- a vesicle in the presynaptic terminal that stores and releases neurotransmitter chemicals

- chemicals that stimulate or inhibit postsynaptic cells

the neurotransmitter that stimulates skeletal muscles

a single contraction of a muscle fiber in response to a stimulus - three phases: latent phase, contraction phase, and relaxation phase

the time between the application of a stimulus and the beginning of contraction

the time during which the muscle contracts

the time during which the muscle relaxes

- has a blend of types, with one type dominating - humans have both types of fibers - the distribution of fibers is genetically determined

very energy-demanding cells whether at rest or during any form of exercise

a temporary state of reduced work capacity

an increase in muscle tension, but no change in length

o a change in muscle length with no change in tension

- the constant tension produced by body muscles over long periods of time - responsible for keeping the back and legs straight, the head in an upright position, and the abdomen from bulging

non-striated small, spindle-shaped muscle cells, usually with one nucleus per cell

ony striated, usebranching, with usually striated as a result of the sarcomere arrangement

specialized structures that include desmosomes and gap junctions

connects skeletal muscle to bone

broad, sheetlike tendons

- band of connective tissue that holds down the tendons at each wrist and ankle

the end of the muscle attached to the bone undergoing the greatest movement

group of muscles working together

muscle or group of muscles that oppose muscle actions