Neural Signalling

• What is the functional unit of the nervous system?

  Neuron
• What is the primary function of a neuron?

  Transmits electrical impulses
• What are the main parts of a neuron?

  • Dendrites
  • Cell body (soma)
  • Axon
  • Axon terminal
• What is the role of dendrites in a neuron?

  Receive signals from other neurons
• What does the cell body (soma) contain?

  Nucleus and organelles
• What is the function of the axon?

  Conducts impulses away from the cell body
• What is released at the axon terminal?

  Neurotransmitters
• In what direction do impulses travel in a neuron?

  Dendrites → Cell body → Axon → Axon terminal
• What is the resting potential of a neuron?

  ~ -70 mV
• Why is the inside of a neuron more negative than the outside at rest?

  Due to Na⁺/K⁺ pump and K⁺ leakage
• What does the Na⁺/K⁺ pump do?

  Transports 3 Na⁺ out and 2 K⁺ in
• What does it mean for a membrane to be polarized?

  Charge separation exists across the membrane
• What is an action potential?

  Rapid reversal of membrane potential
• What is the membrane potential during depolarization?

  From -70 mV to +40 mV
• What are the phases of action potential?

  1. Depolarization: Na⁺ influx
  2. Repolarization: K⁺ efflux
  3. Hyperpolarization: Overshoot of K⁺ efflux
  4. Resting potential restored
• How does action potential propagate along the axon?

  As a self-regenerating wave
• What is the speed of nerve impulses in myelinated neurons?

  ~100–120 m/s
• What is the myelin sheath?

  Insulating layer around axons
• What is saltatory conduction?

  Impulses jump between Nodes of Ranvier
• What are the advantages of myelination?

  Faster transmission and energy efficiency
• What is the speed of nerve impulses in non-myelinated neurons?

  ~1–2 m/s in humans
• What is a synapse?

  Junction between neurons or effectors
• What are the components of chemical synapses?

  • Presynaptic neuron: Releases neurotransmitters
  • Postsynaptic cell: Receives signal via receptors
  • Synaptic cleft: Gap between cells
• What is the role of acetylcholine?

  Muscle contraction
• How are neurotransmitters terminated in the synapse?

  By reuptake or degradation by enzymes
• What triggers the release of acetylcholine?

  Ca²⁺ influx
• What happens when an action potential arrives at the axon terminal?

  Ca²⁺ channels open
• What occurs when acetylcholine binds to postsynaptic receptors?

  Na⁺ channels open, causing muscle depolarization
• What resets the synapse after acetylcholine action?

  Acetylcholinesterase breaks down ACh
• What is a negative correlation in neural signaling?

  Animal size vs. nerve impulse speed
• What is a positive correlation in neural signaling?

  Axon diameter vs. impulse speed
• What does the correlation coefficient (r) indicate?


  Strength and direction of a relationship
• What does the coefficient of determination (R²) indicate?

  How much IV variation explains DV variation
• What are the components of the central and peripheral nervous systems?

  • CNS: Brain and spinal cord
  • PNS: Sensory and motor neurons
• What is the role of the CNS?

  Processes information and coordinates responses
• What is the role of sensory neurons in the PNS?

  Carry signals to CNS
• What is the role of motor neurons in the PNS?

  Carry signals from CNS to effectors
• What is a nerve?

  Bundle of axons in the PNS
• What are the key takeaways from neural signaling?

  • Neurons use ion gradients for signaling
  • Myelination enhances impulse propagation
  • Synapses rely on neurotransmitters
  • Correlations analyze biological relationships