The Brain and Cranial Nerves Laboratory Exercise 29

Transcription

1 The Brain and Cranial Nerves Laboratory Exercise 29 Background The brain, the largest and most complex part of the nervous system, contains nerve centers associated with sensory functions and is responsible for sensations and perceptions. It issues motor commands to skeletal muscles and carries on higher mental activities. It also functions to coordinate muscular movements, and it contains centers and nerve pathways necessary for the regulation of internal organs. Twelve pairs of cranial nerves arise from the ventral surface of the brain and are designated by number and name. Although most of these nerves conduct both sensory and motor impulses, some contain only sensory fibers associated with special sense organs. Others are primarily composed of motor fibers and are involved with the activities of muscles and glands. Materials Needed Textbook Dissectible model of the human brain Anatomic charts of the human brain Purpose of the Exercise Review the structural and functional characteristics of the human brain and cranial nerves. Procedure 1. Label figures 29.1, 29.2, and Observe the dissectible model of the brain and locate the following features: cerebrum, cerebral hemispheres, corpus callosum, convolutions (gyri), sulci (central and lateral), fissures (longitudinal and transverse), lobes (frontal, parietal, temporal, occipital, and insula), cerebral cortex, basal ganglia, ventricles (lateral, third, fourth, choroid plexuses, cerebral aqueduct), diencephalon (thalamus, hypothalamus, optic chiasma, mammillary bodies, pineal gland), cerebellum, and brainstem (midbrain, pons, medulla oblongata). 3. Label figure Observe the brain model and locate as many cranial nerves as possible. 5. Complete Parts A, B, and C of the laboratory report. 1

2 Figure 29.1 Label the sagittal section of the brain. Figure 29.2 Label the lobes of the cerebrum. 2

3 Figure 29.3 Label the functional areas of the cerebrum. Figure 29.4 Provide the names of the cranial nerves in this inferior view. 3

4 Part A Match the terms in column B with the descriptions in column A. Place the letter of your choice in the space provided. Column A 1. Structure formed by the crossing over of the optic nerves 2. Part of diencephalon that forms lower walls and floor of third ventricle 3. Cone-shaped structure attached to upper posterior portion of diencephalon 4. Connects cerebral hemispheres 5. Ridge on surface of cerebrum 6. Separates frontal and parietal lobes 7. Part of brainstem between diencephalon and pons 8. Rounded bulge on underside of brainstem 9. Part of brainstem continuous with the spinal cord. 10. A layer of dura mater that separates cerebellar hemispheres Column B a. Central sulcus b. Cerebral cortex c. Convolution (gyrus) d. Corpus callosum e. Falx cerebelli f. Hypothalamus g. Insula h. Medulla oblongata i. Midbrain j. Optic chiasma k. Pineal gland l. Pons m. Tentorium cerebelli 11. A layer of dura mater that separates occipital lobe from cerebellum 12. Cerebral lobe located deep within lateral sulcus 13. Thin layer of gray matter on surface of cerebrum 4

5 Part B Complete the following table: Structure Location Major Functions Broca s area Cardiac center Cerebellar peduncles Cerebral peduncles Porpora quadrigemina Frontal eye fields Hypothalamus Limbic system Respiratory center Reticular formation Thalamus Vasomotor center 5

6 Part C Indicate which cranial nerve(s) is (are) most closely associated with each of the following functions: 1. Sense of hearing 2. Sense of taste 3. Sense of sight 4. Sense of smell 5. Sense of equilibrium 6. Conducting sensory impulses from upper teeth 7. Conducting sensory impulses from the lower teeth 8. Raising eyelids 9. Focusing lenses of eyes 10. Adjusting amount of light entering eye 11. Moving eyes 12. Stimulating salivary secretions 13. Movement of trapezius and sternocleidomastoid muscles 14. Muscular movements associated with speech 15. Muscular movements associated with swallowing 6