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• Cell types belonging to either CNS or PNS

  • Schwann cells (aka neurolemmocytes)
  • Oligodendrocytes
  • Astrocytes
  • Satellite cells
  • Ependymal Cells
  • Microglial cells
• Neuron types


  • Afferent neurons
  • Association neurons/interneurons
  • Efferent neurons
• Nerve signals travel faster on myelinated axons versus unmyelinated axons
• An action potential (AP) is "all or nothing"
• The Central Nervous System (CNS) has limited repair capabilities if, for example, the Schwann cells are still active and the cell body is still intact
• Saltatory conduction is slower than continuous conduction
• Nissl bodies


  Similar to ribosomes because they help make proteins for neurons
• CNS


  Responsible for the brain and spinal cord
• PNS


  Houses all other nerves in the body like cranial nerves and spinal nerves
• Characteristics of a neuron

  • Excitability
  • Conductivity
  • Secretion
  • Extreme longevity
  • Amitotic
• Axon hillock


  Also called the trigger zone
• The soma must still be intact for the PNS's limited repair to damaged axons and dendrites
• Damaged PNS axons recovering

  1. Distal portion of axon disintegrates

  2. Axon is severed

  3. Regeneration tube forms

  4. Axon regenerates and myelination occurs

  5. Innervation of nerve is restored
• Ligand-gated channels


  Involved in the receptive segment and transmissive segment
• Statements about white matter

  • Myelinated axons
  • Funiculus in the spinal cord
• Action potential sequence


  1. RMP is -70mV and awaits a stimulus

  2. Summation of graded potential (GP)

  3. Threshold of -55mv is met and an influx of Na+ occurs from voltage-gated Na+ opening

  4. Voltage-gated K+ opens causing an efflux of K+ ions

  5. Drops below resting membrane potential (RMP) because of voltage-gated K+ channels are slow to close
• Cell types and their functions/descriptions

  • Ependymal cells (have cilia and responsible for making cerebrospinal fluid (CSF))
  • Astrocytes (form the Blood Brain Barrier (BBB) and wrap around blood vessels with perivascular feet)
  • Schwann cells (wrap their entire body around a single axon to form a myelin sheath; in the PNS)
  • Oligodendrocytes (myelinate multiple axons; found in the CNS)
  • Microglial cells (clean debris and dead cells; found in the CNS)
  • Astrocytes (most abundant cell in the CNS; star-shaped)
  • Satellite cells (flat cells found in posterior root ganglion around somas)
  • Cells of the PNS
  • Cells of the CNS
• Terms related to neuron function

  • Absolute refractory period
  • Relative refractory period
  • Substance P (enhances perception of pain)
  • Hyperpolarization (falls below resting membrane potential (RMP))
  • Depolarization (when inside of cell becomes more positive; sodium ions enter cell)
  • Repolarization (when inside of cell becomes more negative; potassium ions leave cell)
  • Agonist (enhances the effects of a neurotransmitter)
  • Antagonist (blocks the effects of a neurotransmitter)
  • Converging circuit (recruits many presynaptic inputs to one postsynaptic output such as salivating)
  • Diverging circuit (walking recruits one presynaptic input (wanting to walk) to many postsynaptic outputs)
  • Glioma (tumor cells in the CNS)
  • Acupuncture (a procedure to release endorphins to relieve pain sensation)
  • Another stimulus must be greater than first stimulus to trigger another AP (relative refractory period)
  • Cannot stimulate another AP (absolute refractory period)
• The 12 Cranial nerves

  • Olfactory (Sensory)
  • Optic (Sensory)
  • Oculomotor (Motor)
  • Trochlear (Motor)
  • Trigeminal (Mixed)
  • Abducens (Motor)
  • Facial (Mixed)
  • Vestibulocochlear (Sensory)
  • Glossopharyngeal (Mixed)
  • Vagus (Mixed)
  • Accessory (Motor)
  • Hypoglossal (Motor)
• Brain structures and their functions

  • Meningitis (inflammation of the meninges)
  • Falx cerebri (separates the 2 cerebral hemispheres)
  • Falx cerebelli (separates the 2 cerebellar hemispheres)
  • Decussation (a crossing-over of tufts of axon tracts)
  • Hydrocephalus (CSF blockage causing increased cranial pressure)
  • Habituation (our brain's ability to filter out background noise)
  • Diencephalon (consists of the thalamus, hypothalamus, and epithalamus)
  • Brain stem (consists of the midbrain, pons, and medulla oblongata)
  • Cerebellum (has the arbor vitae ("tree of life"); one of the first parts of the brain to be affected by alcohol)
  • Contusion (bruising of the brain)
  • Concussion (temporary loss of consciousness)
  • Laceration (tearing in the brain)
  • Fluent aphasia (can still speak, but sentences are nonsensical known as "word salad"; damage to Wernicke's area)
  • Nonfluent aphasia (unable to speak, but can still understand their own language; damage to the Broca's area)
  • Reticular Activating System (RAS) (keeps you mentally alert and arouses you from sleep)
• Lobes of the brain and their functions

  • Frontal lobe (our intelligence, personality, higher order thinking; Broca's area resides here)
  • Parietal lobe (somatosensory)
  • Occipital lobe (vision)
  • Temporal lobe (hearing and smell)
  • Insula (gustation (taste))
• Terms related to the brain and nervous system

  • Contralateral (the right cerebral hemisphere of the brain controls the left body (and vice versa))
  • Epilepsy (occurs in the form of a seizure when left and right hemisphere fail to properly communicate)
  • Transient Ischemic Attack (TIA) (temporary ministroke caused by improper blood flow; no permanent damage; usually very brief)
  • Encoding (converting short-term memory to long-term memory)
  • Hemorrhagic stroke (ruptured blood vessel(s) that can lead to internal bleeding)
  • Ischemic stroke (impaired blood flow to the brain; can be caused by a blood clot (embolism))
• The left and right hemispheres communicate with each other through the intermediate mass
• The left hemisphere of our brain governs language, speech, math, and analytics
• The meninges protect the brain and spinal cord
• Functions of cerebrospinal fluid (CSF)

  • Remove waste
  • Absorb shock
  • Give buoyancy
  • Circulate via cilia
• Arachnoid villi and Arachnoid granulation

  Where CSF is reabsorbed
• Tissue plasminogen activator


  Can decrease severe damage from blood clots if given within a few hours
• Stupor


  A moderately deep level of unconsciousness that requires a strong stimulus (such as smelling salts) to wake the person
• Limbic system


  Also called the "emotional brain"
• Hemispheric lateralization is the idea that our left and right hemispheres are functionally different
• Hypothalamus


  The pituitary gland is attached to it, while the pineal gland is found in the epithalamus, which releases melatonin
• Brain structures and their functions

  • Pneumotaxic area (part of the pons that controls breathing muscles and alters respiratory rate)
  • Apneustic area (cardiac center and blood pressure (vasomotor) center; inferior to the pons)
  • Thalamus (relays and filters sensory information; egg-shaped pair)
  • Cerebellum (uses integration and analysis to correct our planned versus actual movement)
  • Cerebrum (consists of 5 lobes)
  • Hypothalamus (regulates our homeostasis; our thirst and hunger center)
  • Medulla oblongata (cardiac center and blood pressure (vasomotor) center; inferior to the pons)
  • Homunculus (a "map" to show you how nerves are distributed throughout the body)
  • Ventricles (openings/spaces in the brain that is filled with CSF)
• Functions of the 12 cranial nerves

  • Vagus (called the "wandering" nerve; travels outside the brain and spinal cord)
  • Olfactory (sense of smell)
  • Glossopharyngeal (speech and swallowing)
  • Vestibulocochlear (hearing and equilibrium)
  • Glossopharyngeal (posterior 1/3 of the tongue)
  • Oculomotor (helps with accommodation of the eye; innervates 4 of the 6 eye muscles)
  • Abducens (innervates 1 of 6 eye muscles, the lateral rectus)
  • Accessory (helps innervate the trapezius and sternocleidomastoid muscles)
  • Optic (sense of visual stimuli)
  • Facial (helps innervate facial expressions)
  • Hypoglossal (innervates 1 or 6 eye muscles)
• Rate


  Uses integration and analysis to correct our planned versus actual movement
• Cerebrum


  • Consists of 5 lobes
• Cerebrum


  Relays and filters sensory information; egg-shaped pair
• Nervous system map


  Shows how nerves are distributed throughout the body
• Cranial nerves by function/description

  • Olfactory (Sense of smell)
  • Optic (Sense of visual stimuli)
  • Oculomotor (Helps with accommodation of the eye; innervates 4 of the 6 eye muscles)
  • Trochlear (Innervates 1 of 6 eye muscles, the superior oblique muscle)
  • Trigeminal (3 large branches; helps with mastication (chewing))
  • Abducens (Innervates 1 of 6 eye muscles, the lateral rectus)
  • Facial (Helps innervate facial expressions)
  • Vestibulocochlear (Hearing and equilibrium)
  • Glossopharyngeal (Posterior 1/3 of the tongue)
  • Vagus (Called the "wandering" nerve; travels outside the brain and spinal cord)
  • Accessory (Helps innervate the trapezius and sternocleidomastoid muscles)
  • Hypoglossal (Speech and swallowing)
• Vagus nerve


  Called the "wandering" nerve; travels outside the brain and spinal cord