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The Central Nervous System
Ch. 5 The Central Nervous System
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Objectives Understand how the nervous system is organized
Know the various cell types that are found in nervous tissue and their function Identify and understand the function of the various parts of the central nervous system Define and know what memory is Understand how a reflex arc works
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Organization and Cells
faculty.clintoncc.suny.edu
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Neurons and Glial Cells
Three functional classes of neurons Afferent sensory Interneurons Efferent motor Four types of glial cells Astrocytes Spatial orientation and support Synapse formation Thrombospondin Repair and barrier formation Nourish Degradation of neurotransmitters K+ regulation Oligodendrocytes myelination Microglia Immune protection Nerve growth factor Ependymal cells Internal lining of CNS Production of CSF Neural stem cells yachigusaryu.com
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Protection and Nourishment
Skull Meninges Dura mater Arachnoid mater Pia mater Cerebral Spinal fluid Secreted by choroid plexus Rich in Na+ Blood-brain barrier Anatomical and physiological barrier Oxygen neuroglobin Glucose csuchico.edu
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Overview of CNS Brain and spinal cord Brain organization Forebrain
Cerebrum Cerebral cortex Basal nuclei Diencephalon Thalamus Hypothalamus Cerebellum Brain stem Midebrain Pons medulla open-source-cranio.com
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Cerebrum Composed of two hemispheres divided into four lobes Frontal
Voluntary motor skills, speaking, though Parietal Somatosensory processing Temporal Auditory processing Occipital Visual processing Hemispherical specialization Left – logical and analytic Right – creative and artisitic islamicmiracles.net
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Motor and Sensory Humunculi
Use-dependent competition Modifications based on use Plasticity Ability to be functionally remodeled structural-communication.com
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Electroencephalogram (EEG)
Record of postsynaptic activity in cortical neurons EPSPs or IPSPs Uses Brain dysfunction Brain death Sleep stages
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Basal Nuclei and Diencephalon
Regulatory inhibition of motor control Divided into four regions of grey matter Caudate nucleus Putamen Globus pallidus Claustrum Associated with Parkinson’s disease Diencephalon Thalamus Relay station for sensory input Also involved in motor control Hypothalamus Integrates and regulates important homeostatic functions Body temp Thirst Adenohypophysis control
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The Limbic System Associated with learning and emotions
Controls basic behavioral patterns Reward and punishment centers Motivation – ability to direct behavior to toward specific goals Norepinephrine, dopamine, and seratonine
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Learning and Memory The acquisition of knowledge or skills as a consequence of experience or instruction The storage of acuired knowledge for later recall Memory traces Neural changes responsible for storage of knowledge
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Short-term Memory Involve temporary modifications in the function of preexisting synapses Two types Habituation Decreased responsiveness to a repetitive indifferent stimulus Ca2+ channels do not readily open Sensitization Increased responsiveness to mild stimuli following a strong stimulus Ca2+ channel open and stay open longer K+ influx prevented Long term Potentiation Modifications due to increased use, connection gets stronger the more it is used Transition to long term memory
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Long-Term Memory Involves formation of new, permanent synaptic connections Immediate early genes Play a role in memory consolidation Genes may encode for proteins that are necessary for synapse formation, production of neurotransmitters, answer not clear yet
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Memory Traces in the Brain
Hippocampus Declarative memory The “what’ memories of specific people, places, objects, facts (semantic) and events (episodic) Cerebellum Procedural memories “how to” memories involving repetitive motor skills Prefrontal cortex Working memory Memory necessary to integrate information that is relevant now
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Cerebellum Balance and coordination Three regions Vestibulocerebellum
Balance and controls eye movements Spinocerebellum Enhances muscle tone and coordinates voluntary movements Cerebrocerebellum Plans and initiates voluntary activity by providing input to cortical motor areas Procedural memory yourbrainetc.tumblr.com
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Brain Stem Link between spinal cord and high brain
Medulla, pons, midbrain 12 cranial nerves arise from brain stem Cardiac, respiratory, and digestive control centers Reticular formation (RAS) Regulates muscle reflexes involved with euilibrium and posture House the sleep center
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Spinal Cord Slender tube that extends from the brain stem and goes through vertebral column Gives rise to 31 pairs of spinal nerves Cervical, thoracic, lumbar, sacral, coccygeal Grey matter core, white matter on the periphery White matter organized into tracts Begin and end in specific brain regions and transmit specific information
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Spinal Tracts Ascending tracts Descending tracts Horns of spinal cord
Carry sensory information up Descending tracts Carry motor input down Horns of spinal cord Dorsal Synapse with sensory neurons Ventral Cell bodies of motor neurons Lateral Fibers supplying cardiac and smooth muscle, glands people.eku.edu
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Reflexes Response that occurs automatically without conscious effort
Basic reflexes Acquired reflexes Reflex arc Sensory receptor Afferent pathway Integrating center Efferent pathway Effector Please know reflexes described
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