뒤로Anatomy & Physiology: Muscles, Nervous System, and Muscle Contraction
04:47
이 집합의 용어 (74)
Skeletal muscle - attached to bones; Cardiac muscle - heart walls; Smooth muscle - walls of hollow organs.
Voluntary, striated, multinucleated, and attached to bones for movement.
Movement, posture maintenance, joint stabilization, and heat generation.
Epimysium surrounds entire muscle; Perimysium surrounds fascicles; Endomysium surrounds individual muscle fibers.
Muscle is the whole organ; fascicle is a bundle of muscle fibers; muscle fiber is a single muscle cell.
The plasma membrane of a muscle fiber that conducts action potentials.
A protein in muscle fibers that stores oxygen for use during muscle contraction.
Long, cylindrical organelles in muscle fibers composed of sarcomeres; responsible for contraction.
The functional contractile unit of a myofibril, defined by Z discs.
Invaginations of the sarcolemma that transmit action potentials deep into the muscle fiber.
Specialized smooth ER that stores and releases calcium ions for muscle contraction.
Enlarged areas of the sarcoplasmic reticulum adjacent to T tubules that release calcium.
The sarcoplasmic reticulum stores calcium ions.
Thin filaments are mainly actin; thick filaments are mainly myosin.
Blocks myosin-binding sites on actin when muscle is relaxed.
Regulates tropomyosin position by binding calcium, allowing contraction.
Thin filaments slide past thick filaments, shortening sarcomeres and contracting muscle.
Synapse where a motor neuron communicates with a muscle fiber to trigger contraction.
Acetylcholine triggers muscle action potential; acetylcholinesterase breaks it down to stop signal.
Continuous muscle stimulation occurs, causing prolonged contraction or spasm.
Acetylcholine release → sarcolemma depolarization → action potential propagation along membrane.
Action potential triggers calcium release from SR, initiating contraction.
To stop contraction and allow muscle relaxation.
ATP powers calcium pumps in the sarcoplasmic reticulum membrane.
Myosin binds actin, power stroke pulls thin filament, ATP binds myosin to release, ATP hydrolysis resets myosin.
Calcium binds troponin, moving tropomyosin to expose myosin-binding sites on actin.
ATP detaches myosin from actin and re-cocks myosin head for next cycle.
ATP depletion prevents myosin detachment from actin, causing muscle stiffness.
A motor neuron and all the muscle fibers it innervates.
Increase muscle contraction force by adding twitches before relaxation.
Increasing number of active motor units to control contraction force.
Small, slow units recruited first; large, fast units recruited last.
No; recruitment depends on force needed to prevent fatigue and allow fine control.
Continuous, passive partial contraction of muscles for posture and readiness.
Muscle changes length while tension remains constant.
Muscle shortens while generating force.
Muscle lengthens while generating force.
Muscle generates force without changing length.
Creatine phosphate, anaerobic glycolysis, and aerobic respiration.
Aerobic respiration requires oxygen; creatine phosphate and anaerobic glycolysis do not.
Anaerobic glycolysis produces lactic acid.
Aerobic respiration produces CO2.
Creatine phosphate: 1 ATP, seconds; anaerobic glycolysis: 2 ATP, ~1 min; aerobic respiration: ~36 ATP, hours.
Creatine phosphate: short bursts; anaerobic glycolysis: moderate activity; aerobic respiration: endurance.
Oxygen replenishment, lactic acid removal, ATP and creatine phosphate restoration.
Extra oxygen used after exercise to restore muscle homeostasis.
Number of motor units recruited, muscle fiber size, frequency of stimulation, and muscle length at contraction.
Muscle fiber type, load, and recruitment.
Slow oxidative: slow, fatigue-resistant; fast oxidative: fast, moderate fatigue; fast glycolytic: fast, fatigable.
Smooth muscle lacks striations and is involuntary; skeletal muscle is striated and voluntary.
Origin: fixed attachment; insertion: movable attachment; action: movement produced by muscle.
Agonist: muscle causing primary movement; antagonist: muscle opposing the movement.
Synergists assist agonists; fixators stabilize origin of agonist.
Control and communication system regulating body functions and responses.
CNS: brain and spinal cord, integration; PNS: nerves, sensory input and motor output.
CNS: astrocytes, oligodendrocytes, microglia, ependymal cells; PNS: Schwann cells, satellite cells.
Excitability, conductivity, secretion, longevity, and amitotic nature.
Fatty sheath around axons that increases conduction speed.
Multipolar, bipolar, unipolar; multipolar mainly in CNS.
Sensory (afferent), motor (efferent), and interneurons.
Leakage, ligand-gated, voltage-gated, mechanically gated channels.
Approximately -70 mV; inside negative relative to outside; high K+ inside, high Na+ outside.
Depolarization: membrane potential becomes less negative; hyperpolarization: more negative than RMP.
Graded potentials vary in size and decay; action potentials are all-or-none and propagate without decay.
Action potentials occur fully or not at all once threshold is reached.
To maintain ion gradients essential for resting potential and action potentials.
By frequency of action potentials and number of neurons activated.
Absolute: no new AP possible; relative: AP possible with stronger stimulus.
Continuous: AP travels along unmyelinated axon; saltatory: AP jumps between nodes in myelinated axon.
EPSPs depolarize membrane, promoting AP; IPSPs hyperpolarize, inhibiting AP.
Temporal: multiple signals from one neuron; spatial: signals from multiple neurons combined.
Type of receptor and ion channel it activates on postsynaptic cell.
Norepinephrine: alertness and mood; acetylcholine: muscle activation; endorphins: pain relief.
Network of interconnected neurons processing specific information.