PSIO 5th Edition Lecture 28 Outline of Last Lecture Brain Structure and Function Outline of Current Lecture I Brain Structure and Functions II II Neurons and Neurolgia III Synaptic Transmission IV Cerebrum V Cerebellum VI Diencephalon VII Brainstem VIII Limbic system Current Lecture Objectives 1 Describe the major parts on a typical nerve cell and define its major functions resting potential action potential and synaptic transmission 2 Describe the location and function of the Diencephalon thalamus hypothalamus epithalamus Cerebellum Brain Stem pons medulla and midbrain 3 Briefly describe the limbic system Neuronal Tissue Two types of cells A Nerve Cells Neurons involved in the generation and interpretation of Electrical Signals B Glial Cells Neuroglia Support neuronal cell activity Dendrites collect the information inputs Cell Body process the information Axon propagate information to output site Synapses transmit information to other parts of the nervous system Resting Membrane Potential Baseline electrical condition of ALL cells There is a relatively steady voltage across the nerve cell membrane Transient changes in this voltage are interpreted as signals within the nervous system Neuronal Action Potential The action potential is a transient change in the membrane voltage than can propagate along an axon How is an electrical signal AP transmitted from one excitable cell to another Synaptic Transmission when an action potential propagates to the end of the axon a chemical transmitter is released This causes an excitatory or inhibitory postsynaptic event EPSP or IPSP in the next neuron Terminology Nucleus is a cluster of neuronal cell bodies in the CNS Ganglion is a cluster of neuronal cell bodies in the PNS Tract is a bundle of axons in the CNS Nerve is a bundle of axons in the PNS Sensory Motor Processing 1 2 3 4 Cerebrum Diencephalon Cerebellum Brain Stem Diencephalon Thalamus Relay station for sensory and motor information Crude interpretation of touch temperature pain pressure Forms walls of 3rd ventricle Organized into 7 groups of nuclei Diencephalon Hypothalamus Located inferior to the thalamus Contains 12 nuclei in 4 major regions Mammillary Tuberal Supraoptic Preoptic Functions Controls and integrated the activity of the autonomic nervous system and pituitary gland controls HOMEOSTASIS Hypothalamus is the link between the nervous and endocrine system Regulates Body temperature eating and drinking behavior and other biological drives Main control center for visceral functions Receives information from cerebrum and from brain stem and spinal cord Regulates emotions pleasure pain aggression Regulates diurnal rhythms with help from pineal gland melatonin Diencephalon Epithalamus Located superior and posterior to thalamus 1 Pineal Gland melatonin contributes to setting the biological clock 2 Habenular Nuclei emotional responses to odors Cerebellum receives input from proprioceptors in muscles and tendons about movement sends signals to motor cortex to improve and coordinate movements receives input from visual and equilibrium receptors and sends input to motor cortex to aid in regulation of posture and balance Brain Stem Pons bridge between the medulla oblongata cerebellum and higher brain centers in the cerebral cortex Pontine nuclei gray matter centers connecting the cerebral cortex and cerebellum coordinate voluntary motor output Contains two areas for respiratory control 1 Apneustic Area controls depth of breathing 2 Pneumotaxic Area controls rate of breathing Medulla Oblongata Connects the brain to the spinal cord Involves all nerve tracts that ascend sensory to or descend motor from the brain axons cross over from one side to the other of the brain stem Contains the cardiovascular center control of the heart rate and force blood pressure Control of respiratory rhythmicity Control of vegetative functions swallowing coughing sneezing vomiting Midbrain mesencephalon Located between the pons and the diencephalon Contains nuclei and tracts Superior Colliculi reflexes for certain visual activities and movements of head and trunk in response to visual stimuli Inferior colliculli part of the auditory pathway and startle reflex Midbrain contains several other nuclei including the dark pigmented substantia nigra Neurons that release dopamine extending from the substantia nigra help control subconscious muscle activities The red nucleus helps control voluntary movements of the limbs The Limbic System Encircling the upper part of the brain stem and the corpus callosum is a ring of structures on the inner border of the cerebrum and floor of the diencephalon that constitutes the limbic system Functional System composed of parts of the cerebral cortex diencephalon and midbrain Sometimes called the emotional brain because is plays a huge role in promoting emotions and memory
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