Fundamentals of Anatomy and Physiology

The Nervous System: The Brain, Cranial Nerves, Autonomic Nervous System, and the Special Senses 277

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Study Guide activities for Chapter 11

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Laboratory

Exercise:

The Nervous System

Materials needed: A model of a human brain, a

sheep or cow eye for dissection, a model of the

external and internal ear, a dissecting pan, and a

dissecting kit

1. Obtain a model of a preserved human brain
   showing a frontal and cross section. These are
   available from a biologic supply com-pany
   and will be provided by your instruc-tor.
   Identify the various parts of the brain,
   referring to Figure 11-1 in your text. In ad-
   dition, identify the four ventricles of the brain.


2. Obtain a sheep or cow eye from your in-
   structor. Make a transverse cut through the
   eye with your scalpel. Refer to Figure 11- 10
   in your text. Identify the three layers of the
   eye: the hard white outer sclera, the black

choroid in the middle, and the innermost

retina. Locate the biconvex lens. Anterior to

the lens is the aqueous humor and posterior to

the lens is the vitreous humor. Note the dark

delicate iris surrounding the opening into the

lens, the pupil. If you look care-fully at the

rear half of the eye, you will see a shiny

greenish blue material. This is the ta-petum.

There is no tapetum in a human eye, but in a

cow or sheep eye this area reflects light,

causing the animal’s eye to glow in the dark

when light is shined on it.^

3. Obtain an anatomic model of the ear from
   your instructor. Identify the auricle and ex-
   ternal auditory meatus of the outer ear, the
   middle ear, and the structures of the inner ear.
   Refer to Figure 11-12 in your text.