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muscle tissue


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Cells in muscle tissues are called muscle fibers due to their ____shape.
Muscle tissues are ____ , meaning they can shorten and thicken.
The three types of muscle tissue are
skeletal, smooth, and cardiac.
Skeletal muscle tissue forms muscles that usually attach to ___and that are controlled by ____
conscious effort
Skeletal muscle tissue is under conscious control and is therefore called ____
Striations of skeletal muscle tissue are alternating light and dark cross-markings
Skeletal muscle tissue functions to
move body parts and in swallowing and breathing
Smooth muscle tissue is called smooth because it lacks .
Smooth muscle tissue is located in
walls of most hollow internal organs
Smooth muscle is ____because it cannot be consciously controlled.
muscle tissue is located only in the heart
a specialized intercellular junction located only in cardiac muscle tissue
An intercalated disc is
cardiac muscle is not striated?
cardiac muscle is involuntary?
Functions of skeletal muscle
Produce skeletal movement

Maintain posture and body position

Guard entrances and exits

Maintain body temperature

Active pulling force
Force that opposes movement-usually a passive force
Three types of muscle tissues

Each skeletal muscle is a what?
A single muscle fiber
Three layers of connective tissue

dense layer of collagen fibers

epimysium seperates the muscle from surrounding tissues and organs

divide the skeletal muscle into a series of compartments, each containing a bundle of muscle fibers called fascicles
surround individual skeletal muscle cells (fibers) and interconncects adjacent muscle fibers
The endomysium connective tissues has three layers
capillary networks that supply blood to muscle fibers

satellite cells, embryonic stem cells that function and repair of damaged muscle tissue

nerve fibers that control the muscle

the mysium delivers
blood vessels and nerves to the muscle fibers
structural layers of a muscle
muscle fibers or cells

consist of groups of fasicles
groups of muscle fibers
muscle fibers of cells
made up of miyofibrils
made up of miyofialments
smallest unit of a muscle
epimysium and perimysium
contain blood vessels and nerves that supply the muscle fibers
our bodies need what to prouduce ATP
oxygen sugar and water
cell membrane of a muscle fiber
the sarcolemma surrounds the
Transverse Tubules (T tubules)
narrow tubes that are continuious with the sarcolema and extend into the sarcoplasm at right angles to the cell surface

electrical impulses conducted by the sarcolemma travel along the T tubles

corresponds to the cytoplasm of other cells
transmembrane potential
uneven distribution of charges between the inside and the outside of the sarcolemma
action potential
nervous impulse or electrical signal
branches of the transverse tubles encircle cylindrical structures and long as the entire cell
actin,what kind of filament
thin filament
myosin, what kind of filament
thick filament
2 terminal cisternae plus T tubules
a muscle contraction begins
when stored calcium ions are released into the sarcoplasm
sarcoplasmic recticulum
forms a tubular network around each individual myofibril
terminal cisterne
on either side of a T tublule, the tublules of the sarcoplasmic reticulum (SR) enlarge, fuse and form expanded chambers
terminal cisternae
sarcoplasmic reticulum butts up against the T tubules
myofibrils and sarcomeres
miyofibrils are bundles of thin and thick filaments (miyofilaments) These miyofilaments are organized into repeating functional units called sarcomeres
Sarcomere (contains)
Sarcomeres are the smallest functional units of the muscle fiber. Interactions between the thick and thin filaments of sarcomeres are responsible for muscle contraction.
A sarcomere contains 1) thick filaments, 2) thin filaments, 3) proteins that stabilize the positions of the thick and thin filaments, and 4) proteins that regulate the interactions between thick and thin filaments.
I band (what kind of filament)
thin filament...extends from A band to A band of next sacromere
myosin (filament)
thick filament
myosin head interacts with thin filaments during contraction

neuromuscular joint
communication between nervous system and skeletal muscle fiber
Acetylcholine or ACh
neurotransmitter, chemical released by a neuron to change permeability of the sarcolemma and trigger contraction of the muscle fiber.
synaptic cleft
narrow space, seperates the synaptic terminal of the neuron from the opposing sarcolemmal surface
motor end plate
contains membrane receptors that bind ACh
When a neuron stimulates a muscle fiber
arrival of the action potential

*Release of ACh

*ACh binding to the motor end plate

*Appearance of an action potential in the sarcolemma

*Return to initial state

Contraction cycle
*Exposure of active site

*Formation of crossbridges


*Detachment of crossbridges

*Reactivation of myosin

Rigor Mortis
calcium levels increase But ATP supply does not. Cross brdiges (heads of myosin are bound to actin) are attached due to calcium effect, but myosin head dont detach. No ATP to spilt. So the contractin is never allowed to relax. The heads pivot and the actin and myosin are locked. There is no energy avaiable to break the connection between actin and myosin
Tension determined by
*frequency of stimulation

*the number of fibers stimulated

single contration is a
twitch has three phrases
*latent period- begins at stimulation and last about 2 msec

*contraction phase-tension rises to a peak

*relaxation phase-continues for about another 25msec

wave summation
addition of one twitch to another
incomplete tetanus
stimulation continues and muscle cell is never allowed to completely relax which results in small, breif relaxation processes.
complete tetanus
obtained by increasing the stimulation rate until the relaxation phase is eliminated
complete tetanus produces a
Incomplete tetanus provides
jerky movement
soon as the bottom of the relaxtion phase is reached, the stimulus occurs again and so the contraction starts again.
muscle tone
resting tension in a skeletel muscle
motor unit
consist of muscle fibers that are controlled by a single neuron
isotonic contractions
tension remains constant and the muscle lengthens
isometric contractions
peak tension is produced but there is no change in the lenghth of the muscle
what colors are fast fibers
what color are slow fibers
fast fibers
contract fast after stimualtion. most common fibers in the body
slow fibers
slow to contract and fatigue.smaller
muscle hypertrophy
muscle is built up....the muscle fibers increase in size
muscle atrpohy
muscle immobility. Size and power of the muscle decreases and tone is reduced

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