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50 terms

Muscular Tissue

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Three types of muscular tissue
skeletal, cardiac, smooth
Skeletal Muscle
striated, works mainly in a voluntary manner
Cardiac Muscle
found only in the walls of the heart, striated, involuntary
Smooth Muscle
located in the walls of hollow internal structures, lacks striations, involuntary
Functions of muscular tissue
producing body movements, stabalizing body positions, moving substances with the body, generating heat
properties of muscular tissue
excitability, contractility, extensibility, elasticity
Excitability
ability to respond to stimuli
contractility
ability to contract forcefully when stimulated
extensibility
ability to stretch without being damaged
elasticity
ability to return to an original length
fascia
dense sheet or broad band of irregular CT that surrounds muscles
epimysium
the outer most layer, separates muscle fibers into bundles called fascicles
perimysium
surrounds numerous bundles of fascicles
endomysium
separates individual muscle fiber from one another
tendon
cord that attach muscle to a bone
aponeuosis
broad, flattened tendon (attach the muscle to the structures that they move)
hypertrophy
the way muscle growth occurs
satellite cells
retain the capacity to regenerate damaged muscle fibers
sacolemma
the plasma membrane of a muscle cell
transverse tubules
tunnel in from the plasma membrane, muscle action potential travel through them
sarcopolasm
the cytoplasm of a muscle fiber
myoglobin
releases oxygen when itis needed for ATP production
myofibrils
thread like structures whcih have a contractile function
Sarcoplasmic Reticulum
membraneous sacs which encircles each myofibril and stores the calcium ions
sarcomeres
basic functional unit of a myofibril
z-discs
separate one sarcomere from the next
A band
darker middlepart of sarcomere, thick and thin filaments overlap one another
I band
lighter, contains thin filaments but no thick filaments
H zone
center of each A band which contains thick but no thin filaments
M line
supporting proteins that hold the thick filaments together in the H zone
Regulatory Proteins
switch the contraction process on and off
Contractile proteins
generate force during contraction
myosin
thick filaments that functions as a motor protein which can achieve motion
actin
thin filaments that provide a site where a myosin head can attach
structural proteins
align the thick and thin filaments properly
titin
stabilize the position of myosin
dystrophin
links thin filaments t the sarcolemma
synapse
where communication occurs between a somatic motor neuron and a muscle fiber
synaptic cleft
gap that separates the two cells
neurotransmitter
chemical released by the initial cell communicating with the second cell
synaptic vesicles
sacs suspended within the synaptic end bulb containing molecules of the neurotransmitter acetylcholine
motor end plate
the region of the muscle cell membrane opposite the synaptic end bults, contain Ach receptors
Botulinum toxin
blolcks release of Ach from synaptic vesicles
Creatine Phosphate
excess ATP is used to synthesize creatin phosphate and transfer a phosphate group to ADP
Anaerobic Respiration
series of ATP producing reactions that do not require oxygen
Aerobic Respiration
pyruvic acid is completely oxidized generating ATP, carbon dioxide, water, and heat
The 4 periods of contraction
latent period, contraction period, relaxation period, refractory period
Isotonic contraction
the tension developed remains constant while the muscle changes its length
isometric contraction
the tension generated is not enough for the object to be moved and the muscle does not change its length
Aging of muscle
brings a progressive loss of skeletal muscle mass, decrease in maximal strength, slowing of muscle reflexes, and loss of flexibility