KIN 1223 Unit 5 Lecture 1 Nervous System Functions 1 Collecting information a Receptors monitor inside and outside 2 Evaluating Decision making Integrate sensory input a b Make decisions 3 Triggers Response a Activating muscles glands Peripheral Nervous System Cranial nerves arise from brain Spinal nerves arise from cord Afferent sensory and efferent motor functions Cranial Nerves CN 1 Olfactory 2 Optic 3 Oculomotor 4 Trochlear 5 Trigeminal 6 Abducens 7 Facial Smell Sensory Vision Sensory Eye movements eyelid opening pupillary focusing Motor Eye movements Motor Touch Temp pain from face Sensory Mastication Motor Lateral eye movement Motor Taste Sensory Facial expression secretion of tears saliva mucus Motor 8 Vestibulocochlea Hearing equilibrium Sensory 9 Glossopharyngea r l 10 Vagus 11 Accessory 12 Hypoglossal Taste touch pressure pain temp from tongue and outer ear BP respiration Sensory Taste hunger fullness GI discomfort Sensory Salivation swallowing gagging Motor Swallowing speech deceleration of heart bronchoconstrictio n GI secretion motility Motor Swallowing head neck shoulder movements Motor Tongue movements of speech food manipulation swallowing Motor Spinal Nerves 31 pairs 1st cervical between condyle atlas 8th between C7 T1 Arise from pairs of roots o Rootlets come together Roots combine Spinal Nerves and exit vertebral column through intervertebral foramen Dorsal root sensory receptors to cord afferent fibers Cell bodies from dorsal root ganglion enlargement of dorsal root containing neuron cell bodies in PNS Ventral root motor cord to skeletal muscles efferent fibers Give rise to Peripheral nerves carry afferent efferent visceral efferent fibers Spinal nerves in cervical lumbar sacral regions form plexuses networks of converging and diverging nerve fibers Thoracic region o Do not enter plexuses except T1 T2 T12 o Form single nerves to muscles of chest and abdomen Sensory portions o All spinal nerves o Organized into Dermatomes cutaneous region of sensation supplied by specific spinal nerve The bite 1 Nocireceptors 2 Graded potential 3 Cell body of the sensory neuron 4 Action potential to the brain which issues an order 5 Action potential to ventral horns of cervical sections of the spinal cord C4 C8 which control the arm muscles to appropriate peripheral nerves o Sensory input from visceral sensory neurons via afferent divisions of PNS Autonomic Nervous System ANS Efferent System Involuntary part of PNS Innervates o Smooth muscle of blood vessels o Abdominal and thoracic visceral organs o Many glands o Cardiac muscle of heart Maintains homeostasis w o conscious control Anatomically and physiologically 2 divisions o Both contain 2 neuron chains ganglion between Preganglionic neuron in cord or brain Sends myelinated axon out of CNS part of CN or SN to autonomic ganglion Postganglionic neuron muscle gland Sends fibers to effector organ e g smooth muscle cardiac 1 Sympathetic or Thoracolumbar a Ventral roots All Thoracic and L1 3 b Cell body lateral horn of cord c Chain ganglia along vertebral column also in 3 cervical ganglia superior to chain d Preganglionic fibers short Postganglionic fibers long e NT at the effector Norepinephrine widespread in the body Fight or Flight Arousal 2 Parasympathetic or Craniosacral a CN 3 7 9 10 and ventral roots of S2 4 b Cell body brain stem sacral cord c Chain ganglia in effector organ wall d Preganglionic fibers long Postganglionic fibers short e NT at the effector Ach single response generally antagonistic Rest and repair Organ System Eye Sweat Glands Heart Rate Respiration Digestive Tract Digestive Secretion salivary gastric Sympathetic Dilated More Sweating Increased Rapid deep Inhibits Decrease Parasympathetic Constricted None Decreased Slow Excites Increase Autonomic Somatic Comparison ANS Sympathetic 2 neurons CNS to effector Preganglionic lightly myelinated Post unmyelinated NT at preganglionic synapse ACh NT at effector Noreepinephrine ANS Parasympathetic 2 neurons CNS to effector Preganglionic lightly myelinated Post unmyelinated NT at both synapses ACh NT effect in ANS depends on receptors on target organ may inhibit or excite Somatic NS 1 neuron CNS to effector Fibers Myelinated NT at effector synapse ACh Signals travel faster fewer synapses fibers highly myelinated Central Nervous System Spinal Cord Brain Spinal Cord Gray matter Contains cell bodies in H shape varies along length of cord o Lateral Horn Only in thoracic region Has preganglionic neurons of sympathetic division o Dorsal Horn o Ventral Horn Contains cell bodies of association neurons Synapse with sensory fibers from dorsal root ganglia Contains cell bodies of motor neurons organized by region innervated Medial part of ventral horn Proximal Limb Lateral part of ventral horn Distal Limb Dorsal Flexors Ventral Extensors Larger in plexus regions correspond to cervical lumbar enlargements White matter Contains myelinated fibers ascending sensory descending motor o Funiculus or Column divided into 3 regions Anterior Lateral Posterior Carry information Cord Brain Brain Cord Cord Cord Fasciculi close to gray matter between cord levels Tracts named carry specific information Name o Motor descending or sensory ascending o Where in CNS to and from Passes through many structures o Synapses occur opportunity to spread information o Can make decisions o Actions transmitted to effectors Lateral Spinothalamic o Fiber Tracts Fasciculus Gracilis Fasciculus Cuneatus Ascending Descending Spinocerebellar Dorsal Reticulospinal Rubrospinal Cord Thalamus Upper Extremity Thalamus Lower Extremity Thalamus Cord Cerebellum Reticular formation of pons medulla Cord Red Nucleus Skeletal Muscle Sensory pain temperature deep pressure touch Sensory proprioception touch light pressure Sensory From muscle spindle stretch reflex Motor Extensor motor neurons tone Motor Flexor motor neurons tone Lateral Ventral Corticospinal Cerebral cortex motor region Each spinal level for muscles Motor Skilled movements Lateral Ventral Corticospinal cont d Largest most important In Medulla o Lateral CS decussate or Cross Over Pyramids Pyramidal motor tracts o Connect motor cortex with muscles on opposite side of body Both synapse o With association neurons o Or directly with motor neurons List of some structures tracts pass through Medulla Pyramids Reticular formation Pons Crus cerebri Inferior cerebellar peduncle Midbrain Red Nucleus Cerebral cortex Thalamus Internal capsule Sensory cortex Cerebellum