Muscular System Flashcards
Muscle Fibers?
Muscle cell, arranged parallel to each other.
Fascia?
Holds muscles together, forms groups, deep fascia.
Epimysium?
Connective tissue around entire muscle.
Perimysium?
Surrounds bundles of muscle fibers or fascicles.
Fasicles?
Bundles of muscle fibers.
Endomysium?
Wraps each individual muscle fibers.
Tendons?
Attach muscle to bone.
Sarcolemma?
Plasma membrane around muscle fiber.
T Tubules? “transverse tubules”
Connect the muscle fibers, continuous with sarcolemma.
Sarcoplasmic Reticulum?
Membranous network similar to ER, stores Ca++ for contraction.
Myoglobin?
Pigment similar to Hb for oxygen carrying.
Myofibrils?
Protein filaments running length of fibers, but not continuous.
Thin Filament?
Contains actin, troponin & tropomyosin.
Thick Filament?
Contains myosin.
Sarcomeres?
Basic functional unit of skeletal muscle (striated).
Z Discs?
Zigzag of dense material separating sarcomeres.
Myosin?
Golf club shaped protein, form crossbridge.
Actin?
Helix shape, anchored to Z disc, has myosin-binding sites.
Tropomyosin & Troponin?
Both cover myosin binding sites on relaxed muscle.
Sliding Filaments?
Filament length does not change even though the fibers change and slide past each other.
Action Potential?
Electrical signal/ stimulus.
Motor Neuron?
Neuron delivering stimulus to muscle.
Motor Unit?
Single motor neuron & all of the fibers it stimulates, size of motor unit varies with the precision of movement.
Motor Endplate?
The region of sarcolemma that connects to the nerve.
Synaptic Cleft?
Space between axon end of nerve & motor endplate.
First step of excitement of skeletal muscle (at the neuromuscular junction)?
Release AcH: diffuse across synaptic cleft.
Second step of excitement of skeletal muscle (at the neuromuscular junction)?
Activation of AcH: binds to motor endplates & opens Na+ ion channels
Third step of excitement of skeletal muscle (at the neuromuscular junction)?
Generates action potential: flow of Na+ generates action potential along sarcolemma.
Fourth step of excitement of skeletal muscle (at the neuromuscular junction)?
Breakdown AcH: Ach esterase breaks down Ach in synaptic cleft.
Creatine Phosphate?
Short term, not useful for endurance, extra supply of phosphate when ATP supply is depleted to ADP.
Anaerobic Glycolysis/Metabolism?
After about 15secs, creatine phosphate is depleted, process to breaking down glucose to pyruvate for more ATP, last 30-40secs (short term) (fee ATP)
Aerobic Respiration/Metabolism?
In presence of oxygen (aerobic), pyruvate broken down further for more ATP, uses Krebs cycle & electron transport chain (in mitochondria), ( long term) (high amount of ATP)
Muscle Fatigue?
Inability to contract forcefully after prolonged activity. depletion of Ca++, Creatine phosphate, glycogen, Ach.
Recovery?
Need to increase oxygen after exercise for increased tissue repairs, heart still working harder and increase in body reactions= body still need more oxygen.
Skelatal Muscle Fibers?
Slow oxidative fiber, fast oxidative fiber, fast glycolytic fibers
Slow Oxidative Fibers?
Red fibers, high in myoglobin, small diameter, slow pace contraction, fatigue resistant, many mitochondria, (endurance training)
Fast Oxidative Fibers?
Dark red, some myoglobin, medium diameter fibers, moderate strength, some glycogen, some mitochondria, moderate fatigue, (makes mod. ATP, moderate resistance, intermediate size)
Fast Glycolytic Fibers?
White fibers, low in myoglobin, large diameter fibers, powerful, high strength, high in glycogen, low in mitochondria, fatigue rapidly, (strength training)
