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Anatomy & Physiology: Muscle and Nervous System Review

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Termini in questo insieme (53)

  • Types of muscle tissue
    Skeletal: voluntary, striated, attached to bones; Cardiac: involuntary, striated, heart muscle with intercalated discs; Smooth: involuntary, non-striated, found in walls of organs.
  • Intercalated discs
    Specialized connections between cardiac muscle cells that allow synchronized contraction by facilitating electrical and mechanical coupling.
  • Five common properties of muscle tissue
    Contractility, Excitability, Conductivity, Distensibility, and Elasticity.
  • Sarcoplasm
    The cytoplasm of a muscle cell containing glycogen and myoglobin for energy and oxygen storage.
  • Sarcolemma
    The plasma membrane of a muscle fiber that conducts electrical impulses.
  • Myofibrils
    Long, cylindrical organelles composed of myofilaments responsible for muscle contraction.
  • Sarcoplasmic reticulum
    Specialized smooth ER in muscle cells that stores and releases calcium ions.
  • Transverse (T) tubules
    Invaginations of the sarcolemma that transmit action potentials into the muscle fiber.
  • Triad in muscle cells
    A structure formed by a T tubule flanked by two terminal cisternae of the sarcoplasmic reticulum.
  • Contractile proteins in muscle
    Myosin (thick filament) and actin (thin filament) generate force during contraction.
  • Regulatory proteins in muscle
    Tropomyosin and troponin control the interaction between actin and myosin.
  • Structural proteins in muscle
    Proteins like titin and nebulin maintain the alignment and elasticity of myofilaments.
  • Sarcomere regions and structures
    I band: thin filaments only; A band: thick and thin filaments overlap; H zone: thick filaments only; M line: center of thick filaments; Z disc: boundary of sarcomere.
  • Sliding filament mechanism
    During contraction, thin filaments slide past thick filaments, shortening the sarcomere without changing filament length.
  • Changes in sarcomere during contraction
    H zone shortens, Z discs move closer, A band length remains constant.
  • Resting membrane potential
    The electrical gradient across the membrane of a resting cell, typically around -70 mV, due to ion distribution.
  • Difference between leak and gated ion channels
    Leak channels are always open; gated channels open or close in response to stimuli.
  • Difference between ligand-gated and voltage-gated ion channels
    Ligand-gated channels open when a chemical binds; voltage-gated channels open in response to changes in membrane potential.
  • Sodium-potassium pump function
    Moves 3 Na+ ions out and 2 K+ ions into the cell using ATP to maintain resting potential.
  • Action potential stages
    Depolarization: Na+ influx makes inside positive; Repolarization: K+ efflux restores negative inside.
  • Neuromuscular junction components
    Synaptic vesicles store acetylcholine; acetylcholine is the neurotransmitter; synaptic cleft is the gap between neuron and muscle.
  • Acetylcholine fate after release
    Binds to receptors on muscle fiber; broken down by acetylcholinesterase in the synaptic cleft.
  • Excitation phase of muscle contraction
    Acetylcholine binding opens Na+ and K+ channels, causing ion influx that depolarizes the muscle fiber.
  • Excitation-contraction coupling
    Depolarization opens calcium channels in sarcoplasmic reticulum; calcium is released into cytosol to initiate contraction.
  • Crossbridge cycle steps
    Myosin head cocks using ATP; power stroke pulls actin; ATP binding causes myosin-actin detachment.
  • Muscle relaxation events
    Actin active sites covered by tropomyosin; acetylcholine broken down; calcium pumped back into sarcoplasmic reticulum.
  • Difference between unfused and fused tetanus
    Unfused: partial relaxation between stimuli; fused: no relaxation, sustained maximal contraction.
  • Three methods of ATP synthesis in muscle
    Creatine phosphate (fast, short), anaerobic glycolysis (moderate, short), aerobic respiration (slow, long duration).
  • Motor unit
    A motor neuron and all the muscle fibers it innervates.
  • Isotonic concentric contraction
    Muscle shortens while generating force.
  • Isometric contraction
    Muscle generates force without changing length.
  • Muscle fatigue causes
    Depletion of ATP, accumulation of lactic acid, ionic imbalances, and impaired calcium handling.
  • Functions of smooth muscle
    Controls involuntary movements in organs, regulates blood flow, and moves substances through hollow organs.
  • Dense bodies in smooth muscle
    Anchor points for actin filaments, analogous to Z discs in skeletal muscle.
  • Single-unit vs multi-unit smooth muscle
    Single-unit contracts as a unit via gap junctions; multi-unit contracts independently, controlled by nerves.
  • Central vs peripheral nervous system structures
    CNS: brain and spinal cord; PNS: all nerves outside CNS.
  • Three tasks of the nervous system
    Sensory: detect stimuli; Integrative: process information; Motor: respond via effectors.
  • Afferent vs efferent divisions of PNS
    Afferent: sensory input to CNS; Efferent: motor output from CNS to muscles/glands.
  • Somatic vs visceral sensory divisions
    Somatic: senses you consciously perceive; Visceral: senses internal organ status, usually unconscious.
  • Somatic vs visceral motor divisions
    Somatic: voluntary control of skeletal muscles; Visceral (autonomic): involuntary control of smooth muscle, cardiac muscle, glands.
  • Neuron characteristics
    Excitable, amitotic, long-lived cells that transmit electrical signals.
  • Neuron parts and functions
    Cell body: contains nucleus; Dendrites: receive signals; Axon: conducts impulses; Axon terminals: release neurotransmitters.
  • Retrograde vs anterograde axonal transport
    Retrograde: moves materials toward cell body; Anterograde: moves materials away from cell body.
  • Functional regions of a neuron
    Receptive: dendrites and cell body; Conducting: axon; Secretory: axon terminals.
  • Structural classifications of neurons
    Multipolar (many dendrites), bipolar (one dendrite), unipolar (single process).
  • Neuroglia in CNS vs PNS
    CNS: astrocytes, oligodendrocytes, microglia, ependymal cells; PNS: Schwann cells (neurolemmocytes), satellite cells.
  • Myelin formation in CNS vs PNS
    Oligodendrocytes myelinate multiple axons in CNS; Schwann cells myelinate single axons in PNS.
  • Phases of membrane potential changes
    Depolarization: Na+ influx; Repolarization: K+ efflux; Hyperpolarization: membrane potential more negative than resting.
  • All-or-None principle
    An action potential either occurs fully or not at all once threshold is reached.
  • Continuous vs saltatory conduction
    Continuous: action potential travels along unmyelinated axon; Saltatory: jumps between nodes of Ranvier on myelinated axon.
  • Chemical vs electrical synapses
    Chemical use neurotransmitters and synaptic cleft; electrical use gap junctions for direct ion flow.
  • EPSPs vs IPSPs
    EPSPs depolarize postsynaptic membrane (excitatory); IPSPs hyperpolarize it (inhibitory).
  • Neurotransmitter functions
    Acetylcholine: excitatory at neuromuscular junction; Norepinephrine: excitatory/inhibitory; Glycine: inhibitory; others vary.