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Nervous System Basics - Anatomy & Physiology

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  • What are the two main parts of the Central Nervous System (CNS)?

    Brain and spinal cord

  • What does the Peripheral Nervous System (PNS) consist of?

    All nerves outside the CNS that carry information to and from the CNS

  • What is the function of the afferent division of the nervous system?

    It carries sensory information to the CNS

  • What is the function of the efferent division of the nervous system?

    It carries motor commands from the CNS

  • What are the two main cell types in the nervous system?

    Neurons (send signals) and Neuroglia (support and protect neurons)

  • Name the four types of neuroglia in the CNS.

    Ependymal cells, Astrocytes, Oligodendrocytes, Microglia

  • What is the role of ependymal cells?

    They make and circulate cerebrospinal fluid (CSF)

  • What are the key functions of astrocytes?

    Maintain blood-brain barrier, repair tissue, guide neuron development

  • Which CNS glial cells produce myelin?

    Oligodendrocytes produce myelin in the CNS

  • What is the function of microglia?

    Act as immune cells performing phagocytosis in the CNS

  • Name the two types of neuroglia in the PNS.

    Satellite cells and Schwann cells

  • What is the role of Schwann cells?

    Make myelin in the PNS; one Schwann cell myelinates one axon segment

  • List the four structural types of neurons.

    Multipolar, Bipolar, Unipolar, Anaxonic

  • Which neuron type is most common structurally?

    Multipolar neurons

  • What are the three functional types of neurons?

    Sensory (afferent), Motor (efferent), Interneurons

  • What is the main function of interneurons?

    Connect neurons; they make up 99% of neurons

  • What are the main parts of a neuron?

    Dendrites (receive signals), Cell body (soma), Axon (sends signals), Axon terminals (release neurotransmitters)

  • Define a synapse.

    Junction where a presynaptic cell sends a signal to a postsynaptic cell across the synaptic cleft

  • What are the three types of membrane potentials?

    Resting potential, Graded potential (small, local), Action potential (all or none)

  • What causes the resting membrane potential to be negative inside the cell?

    Ion movement, mainly Na+ and K+, creates a negative charge inside

  • List the steps of an action potential.

    Depolarization (Na+ enters), Repolarization (K+ leaves), Hyperpolarization (overshoot), Return to resting potential

  • Explain the all-or-none rule of action potentials.

    If the threshold is reached, a full action potential fires; if not, no action potential occurs

  • What are the two refractory periods during an action potential?

    Absolute refractory (no new AP possible) and Relative refractory (stronger stimulus needed)

  • Compare continuous and saltatory conduction.

    Continuous conduction is slow; saltatory conduction jumps node to node and is much faster

  • Which cells make myelin in the CNS and PNS?

    Oligodendrocytes in CNS; Schwann cells in PNS

  • What are the main functions of myelin?

    Speeds up conduction and reduces energy use