NROB60H3 Chapter Notes - Chapter 7: Median Plane, Sagittal Plane, Coronal Plane
11 Jun 2018
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Chapter 7- The Structure of the Nervous System
• Gross Organization of the Mammalian Nervous System
o CNS and PNS
• Anatomical References
o Anterior/rostral- front
o Posterior/caudal-behind
o Dorsal- back
o Ventral- belly
o Bilateral symmetry- if both halves of the body are mirror images
o Midline- the invisible line down the center of the body
o Medial- structures close to the midline
o Lateral- structures further away from the midline
o Ipsilateral-structures on the same side
o Contralateral- structures on opposite sides
• Anatomical planes of section
o Midsagittal plane-splits the brain to 2 equal halves
o Sagittal plane- sections that are parallel to the midsagittal plane
o Horizontal plane- parallel to the ground
o Coronal plane- perpendicular to the ground
• The Central Nervous System
o Consists of the parts of the nervous system that are encased in bone; brain and spinal cord
o Three parts of the brain that are common to all mammals consist of cerebrum, cerebellum, and
the brain stem
o The Cerebrum
▪ The most rostral and largest of the brain
▪ This part is split down the middle (deep sagittal fissure) into two cerebral hemispheres
▪ The right side of the brain receives the sensations and controls the movement for the
left side and vice versa
o The Cerebellum
▪ Contains as many neurons as the both the hemispheres combined
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▪ Primarily movement control and has a lot of connections with the cerebrum and the
spinal cord
▪ Ipsilateral control (left side of the cerebellum contains left side of movement)
o The Brainstem
▪ complex nexus of fibers and cells that relay information from the cerebrum to the spinal
cord
▪ vital functions are regulated here (e.g. breathing, consciousness, body temp.)
o The Spinal Cord
▪ Encased in the bony vertebral column
▪ Carries information about the skin, muscles, a joints of the body (a cut in this area could
lead to paralysis and the feeling of anesthesia)
▪ Spinal cord communicates with the body through spinal nerves (part of the PNS)
▪ Spinal nerves leave the spinal cord through small notches between the vertebral column
▪ The spinal nerves attach to the spinal cord by two roots; dorsal (contains axons that
bring info into the SC) and ventral roots (contains axons that carry info away from the
SC)
• The Peripheral Nervous System
o All parts other than the brain and the spinal cord
o The Somatic PNS
▪ The spinal nerves that supply the skin, joints, and muscles of voluntary control are part
of the somatic PNS
▪ Somatic motor axons derive from motor neurons of the ventral spinal cord
▪ Cell bodies of the motor neurons lie within the CNS but the axons lie within the PNS
▪ The spinal nerves that supply the information about the skin, joints and the muscles are
a part of the spinal sensory axons
▪ The cell bodies of the neurons that lie outside of the SC are called the dorsal root ganglia
o The Visceral PNS/ Autonomic NS
▪ This consists of the neurons that supply to the internal organs, blood vessels and glands
▪ The visceral sensory axon brings information about the visceral function to the CNS (e.g.
oxygen content)
▪ Visceral motor fibers command the contraction/relaxation of muscles, secretory
function of glands
o Afferent and Efferent Axons
▪ Afferent- transporting information toward
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