Copyright ©Mark Nelson, 2002. All rights reserved.
Chapter 3: Structure of Nervous Systems
What you need to know

(exam questions will be a drawn from this subset of material)

What's the difference between afferent and efferent fibers?   (p. 51-53)
    afferent fibers carry information toward the CNS (usually some sort of sensory input)
    efferent fibers carry information away from the CNS toward peripheral targets (often motor output signals)

What's the difference between the CNS and the PNS?  (p. 51-53)
     the central nervous system (CNS) includes the brain and central nerve cord
    the peripheral nervous system (PNS) includes the outlying nerves and ganglia

What are the autonomic and somatic components of the nervous system?  (p.51-53)
     these are divisions of the PNS;
    the autonomic system involves  involuntary control (blood pressure, heart rate, etc.)
    the somatic system involves voluntary control (external sense organs, skeletal muscle control, etc.)

How are invertebrate nervous systems organized?  (p. 54-56)
     varies widely;
    diffuse nerve nets in hydra,
    ladderlike networks in flatworms,
    prominent cerebral ganglion (brain), central nerve cord, and segmental ganglia in arthropods

What is the typical structure of  invertebrate ganglia?  (p. 55-56)
     cell bodies arranged around the outer periphery;
    central neuropil containing neurites and synapses
    connectives containing axons join the ganglia

What is the organization of the vertebrate spinal cord?  (p. 59-61)
     nerve tracts arranged around the periphery (white matter)
    central core containing cell bodies, dendrites and synapses (gray matter)

Where does sensory information enter the spinal cord?  (p. 59-61)
     through the dorsal root, from the dorsal root ganglia

Where does motor information leave the spinal cord?  (p. 59-61)
     from the ventral root;

Where are the cell bodies of the sensory neurons entering the spinal cord?  (p. 59-61)
    in the dorsal root ganglia that lie just outside the spinal cord

Where are the cell bodies of the motor neurons leaving the spinal cord?  (p. 59-61)
     in the central gray matter; specifically the ventral horn region

What is a sulcus (plural, sulci); what is a gyrus (plural gyri)?  (p. 62)
     sulcus: an infolding of brain tissue (sulci are the valleys)
    gyrus: an outfolding of brain tissue bounded by sulci (gyri are the ridges)

What are the three major outswellings that appear during early vertebrate brain development?  (p. 64)
     forebrain (prosencephalon), midbrain (mesencephalon) and hindbrain (rhombencephalon)

What are the two main parts of the fully developed forebrain?  (p.64-65)
    telencephalon and diencephalon

What are the three  main parts of the fully developed hidbrain(p. 64-65)
     cerebellum, pons, and medulla

Is brain region X part of the telencephalon, diencephalon, midbrain or hindbrain?  (p.65)
     memorize table 3-1 on p. 65

What is the general function of brain region X?  (p. 65)
     memorize table 3-1 on p. 65

What are ventricles?  (p. 66)
     internal chambers of the brain filled with cerebral spinal fluid (CSF)

What is the meninges?  (p. 66)
     the protective layer of tissue surrounding the brain; also produces CSF

What is the blood-brain barrier?  (p. 66)
     the blood-brain barrier arises from tight packing of endothelial cells lining the capillaries in the brain;
    the endothelial cells fit together so tightly that most substances cannot pass out of the bloodstream;
    protects the brain from toxins in the blood that may injure the brain;
    protects the brain from circulating hormones in the rest of the body.

Where is area X in the adult human brain?  (p.69)
     memorize Figs. 3-10 (right-hand panel), 3-13 and  3-19

What are the cranial nerves?  (p.70)
     nerves that enter the brain directly, rather than entering through the spinal cord
    some carry afferent fibers, some carry efferent fibers, and some are mixed

How many pairs of cranial nerves are there? Do I need to know the names/functions of individual nerves (p. 70)
     twelve; no

What is the corpus callosum (p. 75)
     a broad bundle of nerve fibers linking the left and right cerebral hemispheres

What are the two main divisions of the autonomic nervous system?  (p.80-81)
     sympathetic and parasympathetic

What is the general function of the sympathetic/parasympathetic division?  (p. 80-81)
     sympathetic - arousal; prepare for action; "fight or flight"
    parasympathetic - calms and relaxes