5.1 Nerves

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Cards (73)

  • Nervous system
    The system that coordinates the body's activities and responses to internal and external stimuli
  • Components of the nervous system
    • Central Nervous System (CNS)
    • Peripheral Nervous System (PNS)
  • Central Nervous System (CNS)
    The brain and spinal cord
  • Peripheral Nervous System (PNS)
    • Afferent division (inputs)
    • Efferent division (outputs)
    • Somatic
    • Autonomic
    • Enteric (inputs and outputs from the gut)
  • Neurons
    • Specialised cells that are long-lived, have a high metabolic rate, and cannot divide (missing centrioles)
  • Structure of a neuron
    • Cell body
    • Dendrites
    • Axons
    • Telodendria
    • Axon terminals
  • Types of neuroglia
    • Maintain the Blood brain barrier
    • Repair damaged neural tissue
    • Provide 3D framework
    • Guide neuron development
    • Provide myelin sheath (insulation)
    • Regulate environment
  • Resting membrane potential
    Difference of ionic composition of ECF versus cytosol, maintained by the active Na+/K+ pump and differing membrane permeability
  • Altering the membrane potential
    Activation leads to changes in the membrane, giving rise to a local or graded potential
  • Excitation potential

    Depolarisation leads to action potentials, which have several phases and are all the same size
  • Synapse
    Connections between neurons, found at the end of the axon, where neurotransmitters are released into the synaptic cleft to activate the post-synaptic cell
  • Types of neurotransmitters
    • Cholinergic (Acetyl Choline)
    • Biogenic amines (Nor-epinephrene, Dopamine, Serotonin)
    • Amino acids (GABA)
    • Neuropeptides (Opioids)
    • Dissolved gases (Nitric oxide, Carbon monoxide)
  • Nervous system cells
    neurons and nervous tissue supporting cells are neuroglia
  • Central nervous system function

    It is responsible for integrating, processing, and coordinating sensory data and motor commands. 
  • peripheral nervous system function
    The PNS delivers sensory information to the CNS and carries motor commands to peripheral tissues and systems, except those of the enteric nervous system
  • Somatic nervous system

    Controls skeletal muscle contractions. Voluntary contractions are under conscious control. 
  • autonomic nervous system

    visceral motor system, automatically regulates smooth muscle, cardiac muscle, glandular secretions, and adipose tissue at the sub-conscious level
  • Two subdivisions of ANS
    The ANS includes a parasympathetic division and a sympathetic division, which commonly have antagonistic (opposite) effects.
  • Enteric nervous system
    The enteric nervous system is an extensive network of neurons and nerve networks in the walls of the digestive tract. 
  • Functional characteristics of neuron
    • Neurons lack centrioles and therefore typical CNS neurons cannot divide. 
    • Cell body, dendrite, axon and telodendria 
  • Cell body 
    • Has a large nucleus with nucleolus and cytoplasm called perikaryon.   
    • Neurofibrils extend into dendrite and axon to provide support. 
  • Perikaryon
    Cytoskeleton of perikaryon contain neurofilament and neurotubules. Contain organelles that provide energy and synthesize organic matieral like neurotransmitters.
  • Dendrites
    • Dendrite have dendritic spines that participate in synapses. 
    • They represent 80-90% of neuron total surface area
  • Axon
    Axon propagates electrical impulse (action potential).
  • Axoplasm
    Contain neurofibrils, neurotubules, small vesicles, lysosomes, mitochondria and various enzymes.