Anatomy & Physiology: The Unity of Form and Function, 7th Edition

Published by McGraw-Hill Education
ISBN 10: 0073403717
ISBN 13: 978-0-07340-371-7

Chapter 14 - Section 14.5 - Figure 14.22 - The Primary Motor Cortex (Precentral Gyrus) - Page 538: 1

Answer

Fig 14.22 Regions with numerous small muscles Somatopy --point by point correlation of body areas with areas on the cerebral cortex leads to a representation known as the homunculus. The amount of CNS tissue representing a body area is related not to the size of the area, but to the amount of innervation of the organ/tissue. Thus the trunk of the body is represented by a smaller area of homunculus than those that represent hands, and fingers.

Work Step by Step

Note to editor; Fig 14.14 was mysteriously removed by the website. The answer in Fig 14.15 space is for Fig.14.14. The following is the answer for Fig.14.15 Dendrites These are ascending dendrites from cortical cells in the neocortex. The neocortex has both pyramidal cells and stellate cells. Stellate cells are spherical in shape and have dendrites that go in all directions. Pyramidal cells are conical in shape . Each pyramidal cell has basal dendrites and an axon, In addition a tall dendrite extends upward from the apex of a pyramidal cell towards the surface of the cerebral cortex (brain)..
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