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muscle fibers are grouped together in fascicles that are surrounded by a layer of connective tissue
the fascicles are bundled together and surrounded by another layer of connective tissue, which also fills the spaces between the fascicles
several layers of fibrous connective tissue called the ___ which surrounds the entire muscle, then cover the ____
the portion that forms the connective tissue layer of the serous membranes covering organs in various body cavities and lining those cavities
when the motor neuron is ___, the impulse is carried to all of the muscle fibers attached to its branches
all the muscle fibers attached to the motor neuron and the motor neuron itself constitute a
the basic energy source for muscle contraction comes from ___ supplied by the mitochondria
the cross bridges of myosin contain the enzyme ___ that causes ATP to decompose into ____ and phosphate, thereby releasing energy
high energy phosphate bonds
creatine phosphate contains ____ and is 4-6 times more abundant in the muscle fibers than ATP
create phosphate cannot directly supply energy to the muscle fiber, it acts as a ___ of energy for the ADP
mitochondria, ATP synthesis
in the __, the enzyme creatine phosphokinase creates creatine phosphate to be used for ___
when the hemoglobin reaches the muscle, the oxygen is transferred to the __ in hte muscle fiber
is similar to hemoglobin in its oxygen capacity, and reduces the muscles need for continuous blood supply during contraction
the amount of oxygen needed by the liver to convert the lactic acid back into glucose, plus the amount needed by the muscles to resynthesize ATp and create phosphate and return them to their original concentrations
a muscle fiber remains unresponsive until a certain amount of stimulus is applied. the minimal strength required is __
all or none response
when a muscle fiber contracts, it always contracts to the fullest extent possible. because of a muscle fiber cannot contract partially, the phenomenon is ___
a muscle fiber that has been inactive can be subjected to a series of stimuli, such that it undergoes a series of twitches with complete relaxation in between. the strength of each successive contraction increases, reaching a maximum
reponse to nerve impulses originating repeatedly from the spinal cord, and traveling to small numbers of muscle fibers within a muscle
shortening occurs; muscle ends pull closer together and the object is moved. the muscle contracts with force greater than resistance and shortens
consists of alternating contractions and relaxations of the longitudinal and circular muscle fibers. it functions to force the contents of a tube along its length
smooth and skeletal muscles
contractions involve the reactions of actin and myosin, are triggered by membrane impulses and the release of calcium ions, and use energy from ATP molecules
Several hormones that cause either contractions or alter the amount of response to the neurotransmitters
can maintain a forceful contraction for a longer period of time with a given amount of ATP.
fibers can change length without changes in tautness. as the hollow organs become filled, the muscles can stretch without internal pressure changing.
works in a network. When one portion of the
network is stimulated, the impulse travels to the other fibers in the network. It then contracts as a unit. It is self-exciting and rhythmic, and the entire network responds in an all-or-none manner.
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