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Muscle Contraction Vocab
Terms in this set (72)
Thin contractile protein involved in cross-bridge formation, comes in filamentous or globular forms
Store neurotransmitters, and following a Ca+2 driven signal, dump neurotransmitters into the synapse
The structure at the end of the axon that contains neurotransmitters and vesicles
the functional unit of the muscle fiber that includes the A-band, I-band, H-zone and the M-line
the ion responsible for depolarizing the muscle membrane by traveling through the nACh receptor, down its electrochemical gradient.
Located on the sacroplasmic reticulum and once opened, allows Ca+2 flow from the sacroplasmic reticulum into the sacroplasm
Thick filaments contractile protein involved in cross-bridge formation, has a club-like appearance with a "head"
these invaginations allow depolarization of the muscle membrane to quickly penetrate from the sacrolemma to the myofibril
Motor end plate
Large and complex terminal formation by which an axon of a motor neuron establishes synaptic contact with a skeletal muscle fiber, transmitting neural impulses to a muscle
the plasma membrane of a muscle fiber
the enzyme responsible for stopping the ACh signal. Functions by metabolizing ACh into choline, which is recycled, and acetate.
Nicotinic acetylcholine receptor
Responsible for opening a ligand-gated Na+/K+ channel in the muscle membrane when the proper ligand binds to it
A L-type calcium channel in the msucle cell membrane, activated upon depolixation, couples depolization signal to release of calcium
An electrical change which brings the relative charge of the inside of the cell more positive; necessary for transmission of electrical impulses within a cell, or from one cell to another
Modified endoplamsic reticulum, stores and releases calcium
Z and M line proteins and titin
Myofilaments are held in place by what type of stbalizing proteins?
Troponin and Tropomyosin
What proteins are repsonsible for starting and stopping muscle contraction?
various types of connective tissue
What are 5 types of tissues that are composed in skeletal muscles
This muscle fiber has a slow twitch, oxidative and aerobic (SO) and is connected with small motorneurons
This muscle fiber has a fast twitch, glycolytic (FG) and is also connected with large motorneruons
This muscle fiber has an intermediate twitch and it has both glycolytic and oxidative.
Sarin irreversibly binds to and inactivates the AChE in the synaptic cleft. This allows excess levels of ACh to reach the post synpatic (muscle) membrane. Sarin or sarin-like molecules would drastically increase Na+ levels going into the cell.
what is the mechanism of action of sarin or a sarin-like chemical?
In a healthy person, do they have autoimmune antibodies present?
striated, uninucleate, and neuron innervation is under involuntary control
- body movement
- body positions
- storage and movement of substances within the body
- Heat generation
Functions of the muscular tissue
Ability to respond to certain stimuli by producing action potentials that travel along the plasma membrane
Ability to contract forcefully when stimulated by an action potential
Ability to stretch without being damaged
Ability to return to original length after contraction or extension
sheet of dense irregular connective tissue, holds muscles with similar functions together
Encloses entire muscle; dense irregular
Surrounds groups of 10 to 100 fibers to form fascicles (fiber bundles)
Separates individual fibers; areolar
Band of dense regular connective tissue that attaches the muscle to the periosteum
a flat, broad tendon
tunnels from sarcolemma to the center of the cell
Cytoplasm in muscle; contains glycogen and myoglobin
network of channels within muscle fiber
thick and thin filaments that are contractile organelles
thick and thin filaments are arranged in compartments
generate force in contractions
connects Z disc and M line`
thick and thin filaments overlap
middle of the sarcmere
Connection between 2 neurons or neruon and a target cell
Synapse between axon terminal and muscle cell
Gap between two cells in synpase
A neurotransmitter released by a terminal axon to "deliver" action potential across the synaptic cleft
True or False: The Action potential always travels along the whole length of muscle fiber
Steps of muscle action potential initiation
1. Release of acetylcholine- nerve impulse arriving to axon terminal stimulates exocytosis of synaptic vesicles with acetylcholine
2. Activation of acetylcholine- Receptors in motor plate opens channels for Na+ to flow in
3. Production of muscle action potential- Inside of the muscle fiber becomes more positive changing membrane potential
4. Termination of impulse- Acetylcholine is rapidly broken down by an enzyme in synaptic cleft
The Contraction Cycle
1. Ca2+ is released by sarcoplasmic reticulum in reponse to action potential
2. Ca2+ binds to troponin on thin filaments tropomyosin band which changes the shape of troponin and opens the site for myosins head to attach
3. Myosin heads form a crossbridge with actin molecules
4. ATP is hydrolyzed to ADP and P to provide energy for a power stroke, which is the movement of the myosin head to the next attachment site
Sliding Filament Theory
Myosin heads attach to and "walk" along thin filament pullling it toward the M line of a sarcomere. The "walking" is powered by ATP and triggered by Ca2+ ions
a breif contraction of all muscle fibers in a motor unit in response to a single action potential
Time of lost excitability after the reception of an impulse. The impulse arriving during _______ will not cause contraction.
A normal response of a muscle to many stimuli arriving at intervals after the refactory period is over but before the fiber is relaxed
Motor Unit Recruitment
The increase of the number of motor units needed to enforce the contraction
The firmness of muscles. Even when the whole muscle is relaxed, some motor units are involuntarily contracting taking turns.
Tension of muscle is constant and the muscle changes length; involves body movements or movement of objects
the type of muscle contraction where the muscle produces tense, but does NOT change length
lengthening under pressure
tension is developed within muscle but joint angles remain constant; static contractions; significant amount of tension may be developed in muscle to maintain joint angle in relatively static or stable position
involve muscle developing tension to etiher cause or control joint movement; dynamic contractionc; are either concentric or eccentric on basis of whether shortening or lengthening occurs.
involve msucle developing tension as it shortens
involves the muscle lengthening under tension
make up visceral muscle
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