neurology 1

• What is the function of the cell body (soma) in a neuron?


  Contains the nucleus for protein production
• What do dendrites do in a neuron?


  Receive information from other neurons
• What is the role of the axon hillock?

  It generates action potentials based on signals
• What does the axon do in a neuron?

  Transmits the electrical signal to target cells
• What is the presynaptic terminal also known as?

  Bouton or knob
• How is the resting membrane potential (RMP) generated?

  By selective K+ permeability
• What does the GTM principle stand for?

  Gradients, Transport, Membrane Potential
• What do Na+/K+ pumps create?

  Ion concentration gradients
• What is the effect of leak K+ channels on RMP?

  Allow K+ to flow out, creating negative charge
• What is the approximate value of resting membrane potential?

  ~ -70mV
• What does the Nernst Equation determine?

  Equilibrium potential for ions
• What happens during depolarization of an action potential?

  Voltage-gated Na+ channels open, Na+ rushes in
• What is the peak voltage reached during depolarization?

  +40mV
• What occurs during repolarization?

  Na+ channels close, K+ channels open
• What is hyperpolarization in the action potential mechanism?

  K+ exits excessively, making cell more negative
• What is the mnemonic for the stages of action potential?

  D-R-H (Depolarize, Repolarize, Hyperpolarize)
• What is the absolute refractory period?

  Na+ channels are inactivated; no new AP possible
• What is the relative refractory period?

  AP can happen only with a stronger stimulus
• How does self-propagation of action potentials occur?

  Local depolarization spreads, opening more Na+ channels
• What does it mean that action potentials are all-or-none?

  A stronger stimulus increases frequency, not size
• What are two ways to speed up action potentials?

  Increase axon diameter and myelination
• How does myelination affect conduction velocity?

  Increases membrane resistance and decreases capacitance
• What is saltatory conduction?

  AP jumps between Nodes of Ranvier
• What is the speed of saltatory conduction?

  120 m/s
• What is the impact of demyelination diseases like Multiple Sclerosis?

  They cause conduction failure
• What are the key takeaways regarding neuron function?

  • RMP maintained by K+ leak channels (~ -70mV)
  • AP involves Na+ in (depolarization), K+ out (repolarization & hyperpolarization)
  • Threshold potential is the minimum voltage to trigger an AP
  • Refractory periods limit firing rate & prevent backflow
  • Myelination & saltatory conduction increase speed of APs
  • Larger axons & myelination lead to faster conduction
• What are the key mnemonics related to neuron function?

  • GTM: Gradients, Transport, Membrane Potential (RMP mechanism)
  • D-R-H: Depolarize, Repolarize, Hyperpolarize (AP stages)
  • "Myelin Makes Messages Move!" (importance of myelination)
• What do afferent pathways carry towards the CNS?

  Sensory signals
• What do efferent pathways carry away from the CNS?

  Motor signals
• What are the subdivisions of the nervous system?

  • Somatic Nervous System (SNS)
  • Autonomic Nervous System (ANS)
• What is the function of the Somatic Nervous System (SNS)?

  Transmits signals to skeletal muscles
• What does the Autonomic Nervous System (ANS) regulate?

  Internal organs and glands
• What is the origin of the Parasympathetic system?

  Craniosacral
• What is the primary function of the Sympathetic system?

  Prepares the body for activity
• What is dual innervation in the ANS?

  Organs receive both sympathetic and parasympathetic inputs
• What effect does the sympathetic system have on the pupil?

  Dilates the pupil
• What effect does the sympathetic system have on the heart?

  Increases rate and force
• How does the sympathetic system affect the GI tract?

  Reduces activity
• What are the effects of the Fight or Flight response?

  Increases:

  • Heart rate
  • Blood sugar
  • Blood flow to skeletal muscles
  • Bronchodilation

  
  

  Decreases:

  • Digestion
• What neurotransmitter is associated with the sympathetic system?

  Noradrenaline