Anatomy Ch. 10, Muscular Tissue

hrdcorhrvivor's version from 2017-03-13 04:50

Section 1

Question Answer
characteristics of skeletal musclestriated, voluntary, multinucleate
characteristics of cardiac musclestriated, involuntary (autorhythimic), cells are bifurcated
characteristics of smooth musclenonstriated, involuntary (usually autorhythimic), walls of hollow organs
4 functions of muscular tissue1. produce body movements 2. stabilize body positions 3. move substances within the body 4. generate heat
4 properties of muscular tissue1. excitability (respond to stimuli) 2. contractility (ability to contract when stimulated) 3. extensibility (stretch w out damage) 4. elasticity (return to original shape after stretch)
what components make up a tendon?epimysium, outer layer surrounds entire muscle. perimysium, middle layer surrounds fascicles. endomysium, inner most layer surrounds individual muscle cells.
somatic motor neuronsstimulate skeletal muscle
axon terminalsbranches many times, each branch innervates a single muscle fiber/cell
organization of skeletal muscle muscle, fascicle, myofiber, myofibril, sarcomere, myofilaments
sarcolemmaplasma membrane of muscle cell
transverse (T) tubulesinvagination of PM, APs travel through these to deep muscle fibers
sarcoplasmcytoplasm of muscle cell, abundant mitochondria, glycogen & myglobin
myofibrilsthread like organelles, have contractile function
sarcoplasmic reticulummuscle ER, stores Ca2+ ions, terminal cisternae: ends of SR form triads with T tubule
filamentsstructures within myofibrils, thin actin & thick myosin
sarcomeresfunctional unit of muscle
z discboundaries of sarcomeres
a bandactin and myosin overlap (middle sides)
I bandactin only, z discs pass through center of it
H zonemyosin only (very center)
M linemiddle of sarcomere

Section 2

Question Answer
contractile proteins generalgenerate force during contraction
regulatory proteins generalturn the contraction process off and on
structural proteins generalalign thick and thin filaments, provide elasticity and extensibility, link myofibrils to sarcolemma
contractile proteins containactin, thin filaments that contain binding site for myosin. myosin, thick filament that converts ATP to motion and attaches to actin
regulatory proteins containtroponin, binds to Ca2+. tropomyosin, blocks myosin binding site on actin and removed when Ca2+ binds to troponin
structural proteins containtitin, stabilizes myosin accounts for most elasticity and extensibility of muscle. nebulin, anchor thin filaments to z discs. dystropin, connects actin to sarcolemma leads to muscle atrophy if problems
sliding filament mechanismmyosin attaches to, pulls actin towards m line, sarcomere shortens, entire muscle shortens
neuromuscular junction NMJsite where axon of motor neuron synapses with skeletal muscle fiber (axon terminal)
synapseregion of communication
synaptic cleftgap between neuron and muscle cell
how does acetylcholine work with NMJ?NT that is released in the NMJ that causes a muscle contraction, binds to receptors on the motor end plate
contraction cycle1. cocking: myosin hydrolyzes ATP 2. crossbridge formation: myosin binds to actin 3. powerstroke: ADP and free phosphate leaves, myosin bends pulling actin 4. release: new ATP binds and myosin releases actin
regulation of contractionCa2+ binds to troponin causes a conformational change, change in tropomyosin's shape moves troponin, myosin binding sites now exposed on actin
excitation contraction couplingsteps that connect excitation of a muscle to its contraction
calcium's role in muscle contraction and relaxation1. calcium is released from SR when stimulated by APs 2. calcium binds to troponin moving tropomyosin 3. muscle cell pumps calcium back into SR 4. drop in calcium leads to muscle relaxation
myasthenia gravisimmune system attacks ACh receptors on motor end plate, symp: muscle fatigue & weakness, facial muscles. treat: anticholinesterase drugs to reduce breakdown of ACh
botoxform of botulism toxin, blocks the release of ACh, used for wrinkle reduction, excessive sweating
cardiac muscle tissue factsintercalated discs: allow APs to spread, autorhythmic, contractions last longer than SkelMus, same actin and myosin as skelmusc, aerobic more mitochondria than skelmusc
smooth muscle tissue factsinvoluntary, found in: BV walls, walls of hollow organs, ariways to lungs, arrector pili muscles, muscles that adjust pupil and lens
microscopic anatomy of SMthin and thick filaments not in sarcomeres, dense bodies: funx in same manner as z discs, during contrax filaments pull on these
development of musclederived from mesoderm, somites: segments of mesoderm, differentiate into 3 regions w the myotome forming skelmusc. cardiac mucle and SM derived from mesodermal cells

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