NERVOUS SYSTEM STRUCTURE

NEURON pg. 148 figure 8-1 Nerve cell; specially constructed to carry out it’s function Transmitting a message from one cell to the next Extensions from the neuron are: Dendrite – may have several Axon – only one per cell Myelin sheath (neurilemma) Covering over the axon which speeds up the nerve impulse as it travels along the axon

BRAIN pg. 153 figure 8-5 and 155 figure 8-7 Weighs 3 lbs. Coverings Meninges – membranous coverings Cerebral cortex – outer cortex; gray matter Highest center of reasoning and intellect Ventricles 4 lined cavities filled with CSF Cerebrum a. Convolutions and sulci b. Lobes i. Frontal ii. Parietal iii. Occipital iv. Temporal

Brain continued pg. 156 figure 8-8, 158 figure 8-10, and 160 figure 8-11 Cerebellum Located behind the pons and below the cerebrum Diencephalon – located b/t the cerebrum and midbrain a. Thalamus b. Hypothalamus Brain stem – provides the pathway for the ascending and descending tracts a. Midbrain b. Pons c. Medulla oblongata

SPINAL CORD pg. 161 figure 8-12 Continues down from the brain Begins at the foramen magnum of the occipital bone and continues to the second lumbar vertebra White and soft and lies within the _________ Made up of 31 segments Then pair of spinal nerves Protected by 3 layers of meninges CSF fluid circulates over the cord

NERVES chap 9 tables 9-1 9-2 and figures 9-3 and 9-4 Cranial nerves 12 pairs beginning in the brain Mainly deal with functions of the head and neck Except vagus nerve (X) – responsible for ___ (pg. 175) Designated by name and number Name can give a clue to function Spinal nerves 31 pairs originating at the spinal cord Exit through openings in the vertebrae Named according to region and level they exit Largest is the sciatic nerve