1. Central nervous system (CNS)Peripheral nervous system (PNS) Motor (efferent) divisionSensory (afferent) division Somatic nervous system Autonomic nervous system (ANS) Sympathetic division Parasympathetic division

2. . 1 2 3 Receptor level (sensory reception and transmission to CNS) Circuit level (processing in ascending pathways) Spinal cord Cerebellum Reticular formation Pons Muscle spindle Joint kinesthetic receptor Free nerve endings (pain, cold, warmth) Medulla Perceptual level (processing in cortical sensory centers) Motor cortex Somatosensory cortex Thalamus

3. Fascicle Perineurium EndoneuriumNerve fibers Blood vessels

4. . Blood vessels Fascicle Epineurium Perineurium Endoneurium Axon Myelin sheath

5. Frontal lobe Temporal lobe Infundibulum Facial nerve (VII) Vestibulo- cochlear nerve (VIII) Glossopharyngeal nerve (IX) Vagus nerve (X) Accessory nerve (XI) Hypoglossal nerve (XII) Filaments of olfactory nerve (I) Olfactory bulb Olfactory tract Optic chiasma Optic nerve (II) Optic tract Oculomotor nerve (III) Trochlear nerve (IV) Trigeminal nerve (V) Abducens nerve (VI) Cerebellum Medulla oblongata

6. *PS = parasympathetic Cranial nerves I – VI I II III IV V VI Olfactory Optic Oculomotor Trochlear Trigeminal Abducens Yes (smell) Yes (vision) No Yes (general sensation) No Yes No Yes No Cranial nerves VII – XII Sensory function Motor function PS* fibers Sensory function Motor function PS* fibers VII VIII IX X XI XII Facial Vestibulocochlear Glossopharyngeal Vagus Accessory Hypoglossal Yes (taste) Yes (hearing and balance) Yes (taste) No Yes Some Yes No Yes No

7. Receptor Sensory neuron Integration center Motor neuron Effector Spinal cord (in cross section) Interneuron Stimulus Skin 1 2 3 4 5

8. The patellar (knee-jerk) reflex – a specific example of a stretch reflex Muscle spindle Quadriceps (extensors) Hamstrings (flexors) Patella Patellar ligament Spinal cord (L 2 – L 4 ) 3a 2 1 3b 1 Tapping the patellar ligament excites muscle spindles in the quadriceps muscle. 2 3a The motor neurons (red) send activating impulses to the quadriceps causing it to contract, extending the knee. Afferent impulses (blue) travel to the spinal cord, where synapses occur with motor neurons and interneurons. 3b The interneurons (green) make inhibitory synapses with ventral horn neurons (purple) that prevent the antagonist muscles (hamstrings) from resisting the contraction of the quadriceps. Excitatory synapse Inhibitory synapse – +