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level: Level 1 of MUSCULAR SYSTEM

Questions and Answers List

level questions: Level 1 of MUSCULAR SYSTEM

Question	Answer
What are the 3 types of Muscle?	Cardiac,Smooth,and Skeletal Muscle
This muscle is Long and cyndrical in shape its nucleus are multiple and peripherally located. Has striations and it is Voluntary.	Skeletal Muscle
This muscle is Spindle-Shaped and its nucleus is single,centrally located. There is no striations and it is involuntary.	Smooth Muscle
This muscle is branched and cylindrical in shape its nucleus is single and also centrally located. There is striations and it is involuntary.	Cardiac Muscle
Loose connective tissue seperates muscles fasciles from each other.	Permysium
Loose connective tissue surrounds each muscle fibers.	Endomysium
It is the cytoplasm of a muscle fiber. cytoplasm of muscle fiber (cell) • Has little RER or free ribosomes • Filled primarily of myofibrils • acidophilic	Sarcoplasm
Within the sacroplasm,each muscles fiber contains many bundles of proteins filaments called	Myofibrils
Myofibrils consist of 2 major kinds of proteins what are those?	Actin myofilaments and Myosin myofilaments.
It is the basic structural and fundamental unit of a skeletal muscle beacuse it it the smallest portion of a skeletal muscle capable of contacting.	Sacromeres
It is the cell membrane of the muscle fiber.	Sarcolemma
ability to shorten	Contractility
respond to stimulus	Excitability
can stretch	Extensibility
Ability of muscle to recoil	Elasticity
Skeletal muscle is surrounded by a connective tissue sheath called	Epimysium
• skeletal muscle cells • many nuclei	Muscle Fiber
proteins that make up myofibrils • Myosin II (thick filaments) • Actin (thin filaments) • + associated proteins	Myofilament
• Specialized for calcium ion sequestration • The depolarization of its membrane, which results to Ca2+ ions, is initiated at the specialized neuromuscular junction (NMJ) on the surface of the muscle cell	Sarcoplasmic reticulum
• Finger-like invaginations in the sarcolemma • Form a complex network of tubules that encircles every myofibril near the A-I band boundaries of each sarcomere • Provide uniform contraction	Transverse Tubule (T-tubule)
• Darker bands • More electron-dense • Composed mainly of thick filaments in addition to overlapping portions of thin filaments	A band
• Lighter bands • Consist of thin filaments that do not overlap with thick filaments	I band
• Narrow, less electron-dense (lighter zone) bisecting the A bands • A region consisting only of the rod-like portions of the myosin molecule with no thin filaments present	H zone
• Zwischenscheiben (Ger., between the disks) • A dark transverse line bisecting each I band	Z line or Z disk
• Thick filaments • contain two heavy chains: MYOSIN TAIL; • free ends of heavy chains + light chains: MYOSIN HEAD (binds to actin) • BODY: tails that are bundled together • CROSS-BRIDGES: arms and myosin heads • HINGES: arm-body and arm-head	Myosin
• Think filaments occupying the I bands • One end bound to α-actinin (major protein of Z disk)	Actin
• Covers the binding site (underwear)	Tropomyosin
• Responsible for the control Two minute strands pearls twisted together.	Troponin
attaches troponin complex to tropomyosin	Troponin T
Inhibits actin-myosin binding	TROPONIN I
calcium binding protein; displaces tropomyosin	Troponin C
• Largest protein in the body • Tethers myosin to Z lines (scaffolding) • Binds Z line to M line	Titin
• Attaches to plasmalemma • Stabilizes plasmalemma and prevents contraction-induced rupture	Dystrophin
Binds actin to Z lines	Actinin and CAPZ protein
Binds Z lines to plasma membrane	Desmin
• Myosin head is attaching to a new binding site • Myosin head is displaced toward the positive end of actin	Recocking
• Actin towards the negative pole	Power stroke=force
• “electricity” • stimulus that causes rapid depolarization and repolarization • causes muscle to contract	Action Potential
change in charges - inside becomes more + and outside more – - Na+ channels open	Depolarization
- Na+ channels close - change back to resting potential	Repolarization
- pumps Na+ out of cell and transports K+ into cell - restores balance	Sodium Potassium Pump
nerve cells that carry action potentials to muscle fibers	Motor neuron
where nerve cell and muscle fiber meet	Neuromuscular junction (synapse)
end of nerve cell (axon)	Presynaptic terminal
muscle fiber membrane	Postsynaptic membrane
space between presynpatic terminal and postsynaptic membrane	Synaptic Cleft
- in presynaptic terminal - store and release neurotransmitters	Synaptic Vesicles
- chemicals that stimulate or inhibit a muscle fiber - Ex. Acetylcholine	Neurotransmitter
group of muscle fibers that motor neuron stimulates	Motor unit
person dies and no ATP is available to release cross- bridges	Rigor mortis
Striations of skeletal and cardiac muscle are due to	sarcomeres (actin and myosin).
muscle contracts or doesn’t (no in between)	All or None Law
nonmovable end	Origin
movable end	Insertion
middle of the muscle	Belly
muscles that work together	Synergists
muscles that oppose each other	Antagonist
raises eyebrows (forehead)	Occipitofrontalis
allows blinking (eyes)	Orbicularis oculi
kissing muscle (mouth)	Orbicularis oris
smiling muscle (cheek)	Zygomaticus
chewing (mastication) muscle	Masseter
elevate ribs for inspiration	External intercostals
depress ribs during forced expiration	Internal intercostals
moves during quiet breathing	Diaphragm
- center of abdomen - compresses abdomen	Rectus abdominis
- sides of abdomen - compresses abdomen	External abdominal oblique
compresses abdomen	Internal abdominal oblique and Transverse Abdominis
- shoulders and upper back - extends neck and head	Trapezius
- chest - elevates ribs	Pectoralis major
between ribs - elevates ribs	Serratus anterior
- shoulder - abductor or upper limbs	Deltoid
- 3 heads - extends elbow	Triceps brachii
- “flexing muscle” - flexes elbow and shoulder	Biceps brachii
flexes elbow	Brachialis
- lower back - extends shoulder	Latissimus dorsi
4 thigh muscles	Quadriceps femoris
- front of thigh - extends knee and flexes hip	Rectus femoris
extends knee	Vastus lateralis,Vastus medialis and Vastus intermedius:
adducts thigh and flexes knee	Gracilis
- hamstring - back of thigh - flexes knee, rotates leg, extends hip	Biceps femoris, semimembranosus, semitendinosus
- front of lower leg - inverts foot	Tibialis anterior
- calf - flexes foot and leg	Gastrocnemius
- attaches to ankle - flexes foot	Soleus
What are the 4 functional groups of skeletal muscle?	Prime Movers,Antagonist,Synergists,Fixators
One of the Functional Groups of skeletal muscle that is responsible for adduction.	Prime movers
One of the Functional Groups of skeletal muscle that reverse the particular movement of prime movers. responsible for abduction.	Antagonists
One of the Functional Groups of skeletal muscle that helps the prime movers. Lending a little extra oomph and stabilizing joints against dislocation.	Synergist
Group of muscle fibers that all get their signals from the same,single motor neuron.	Motor Units
Motor neuron may synapse with & innervate,a thousand muscle fibers.	Large motor units
No matter how large or small,responds to a single action potential those fibers quickly contract and release,in what you call?	TWITCH
What are the three distict phases of twitch?	Latent Period,Period of contraction,Relaxation Period
What distict phases of twitch,when the stimulus arived,but no force is being produced.	Latent Period
What distict phases of twitch,when myosin head are binding,and pulling,and releasing,over and over,and the muscle fibers contract.	Period of Contraction
What distict phases of twitch,When the calcium gets pumped back into the sarcoplasmic reticulum,and the actin and myosin stop the binding cycle.	Relaxation Period
one muscle can produce a variation of smoooth forces. they're generally affected by both the frequency and strength with which they're stimulated.	Graded Muscle
twitches end up adding to each other as they get closer together in time,this happens when relaxation are being occur and anothenr contraction happens.	Temporal Summation
When all those little twitches blend together until they feel like one gigantic contraction.This is when you use all your force in contraction nonstop until you gets fatigue.	Tetanus