| A | B |
|---|
| Axon | Single, long neurite responsible for conducting impulses away from the cell body |
| Nerve Fibers | Axons and dendrites |
| Ganglia | Collection of nerve cell bodies located outside the CNS |
| Craniospinal Ganglia | Ganglia concerned with sensory reception and distribution |
| Autonomic Ganglia | Clusters of neurons found from around the base of the skull to the pelvis; they are multipolar and receive synaptic input from various areas of the nervous system |
| Axon | Name given to the longest process of the cell body. Its point of departure is known as the axon hillock |
| Dendrite | Usually has more than one; increases the receptive surface area |
| Ion | Small molecules dissolved in extra or intracellular fluid that carry either a positive or negative electrical charge |
| Interneurons | Neurons that are interposed between sensory and motor neurons |
| Cell Body | Contains cytoplasm and bounded by a plasma membrane that separates the inside of the cell from the outside |
| Mitochondria | Governs the use of sugars and oxygen |
| Mitochondria | Scattered throughout the cell body, axons and dendrites; important in the production of energy |
| Cell Body | Its cell membrane is composed of lipids and globular proteins that when stimulated allow certain molecules to pass through the plasma |
| Neurons | Excitable cells that are specialized for reception of stimuli and conduction of nerve impulses; they vary in size and shape |
| Dendrites | Responsible for receiving information and conducting it toward the cell body |
| Unipolar | Functions like an axon; spherical cell body and single process that bifurcates |
| Bipolar | Spindle shaped or elongated cell body with one process at each end of the cell |
| Multipolar | Has a number of processes arising from the cell body; one axon rest are dendrites |
| Golgi Type I | Unmyelinated neuron that has one long arm eg. pyramidal cells of the cerebral cortex |
| Golgi Type II | Has a short axon that terminates near the cell body or is entirely absent |
| Afferent | Sensory neuron |
| Efferent | Motor neuron |
| Nucleus | Stores the genes; usually centrally located in the cell body |
| Nissl Substance | Granules distributed throughout the cytoplasm; they are composed of membrane bound ribonucleoproteins that are responsible for synthesizing protein |
| Ribonucleoproteins | aka: granular endoplasmic reticulum |
| Golgi Complex | Responsible for transport of proteins and active lysosome production |
| Neurofibrils | Concerned with the rapid transport of protein molecules synthesized in the cell body that are carried through the dendrites and axons |
| Neurofibrils | Composed of neurofilaments which forms the main component of the cytoskeleton |
| Satellite Cells | Facilitates the activity of the neurons and are more numerous. In the CNS they are glial cells and in the PNS they are Schwann Cells |
| Satellite Cells | In the CNS they are called Glial Cells |
| Satellite Cells | In the PNS they are called the Schwann Cells |
| Neuroglia | Neurons of the CNS: astrocytes, oligodendroglia, microglia and ependymal |
| Astrocytes | Are electrical insulators and limit the spread of neurotransmitters |
| Oligodendroglia | Are responsible for the formation of myelin sheath of nerve fibers in the CNS |
| Microglia | The smallest neuroglia found scattered throughout the CNS; are inactive in a normal brain and spinal cord, but in disease they migrate to the site of lesion |
| Ependymal | They line the cavities of the brain and spinal cord; contributes to the formation and circulation of the CSF |
| CSF | Cerebal Spinal Fluid |
| Nerve Fiber | Name given to axon or dendrite of a nerve cell |
| Nerve Tracts | Bundles of nerve fibers found in the CNS |
| Peripheral Nerves | Bundles of nerve fibers found in the PNS |
| Myelin Sheath | Segmented, discontinuous layer that is interrupted at regular intervals by Nodes of Ranvier |
| Myelin Sheath | Increases the speed of propagation of the nerve impulse |
| Saltatory Conduction | Because the myelin between the Nodes of Ranvier prevents propagation of the AP along the axon, impulses jump from node to node |
| Saltatory Conduction | This type of conduction is faster than the continuous conduction process found in nonmyelinated nerve fibers |
| Synapse | The site where the functional interneuron communcation occurs when two neruons come into close proximity |
| Telodendria | Chief branching is at its termination; the branches can be grouped into a variety of shapes |
| Synaptic Vesicles | Small bulbs or knobs that contain the neurotransmitters |
| Presynaptic Membranes | Membranes at the terminal bulb |
| Postsynaptic Membranes | Membranes on the other side of the synaptic cleft |
| Terminal Button | Terminal axonal branches that are swollen into little button like structures, which are in contact with the cell bodies and dendrites of other neurons |
| ATP | Adenosine Triphosphate |
| Electrical Synapses | Communication between gap junctions is electrical and bi-directional |
| Depolarization | Sudden influx of Na+ altering the resting potential to less than -70mV |
| AP | Action Potential |
| Hyperpolarization | When the resting potential becomes more negative |
| Pertubation | When a mechanical or chemical event affects a neurons plasma membrane; may be excitatory or inhibitory |
| Graded Potential | As the potential in dendrites extends further away from stimulation the response becomes smaller |
| Action Potential | Occurs when there is a depolarization of 15 mV at the axon hillock; its a all-or-nothing response |
| Medulla | Part of the brainstem that regulates vital functions; contiguous with the spinal tracts; Nuclei of Origin for cranial nerves IX-XII |
| Pons | Constitutes the main mass of the middle cerebellar peduncles; Nuclei of Origin for the cranial nerves V-VIII; reticular materials |
| Midbrain | Consists of the tectum and cerebral aqueduct; the tectum contains the inferior colliculi which is important for audition |
| Tegmentum | Contains sensory fibers of the lateral lemniscus; Nuclei of Origin for cranial nerves III and IV and part of V; red nucleus |
| Cerebellum | Servomechanism for motor function; receives sensory information from the cortex and sensory systems. Important for movements relative to body position, co-ordination between muscles and rapid refined movements |
| Thalamic Nuclei | Nuclei of origin of the medial geniculate body, which is important for audition |
