The Central Nervous System Ch. 5 The Central Nervous System

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

Organization and Cells faculty.clintoncc.suny.edu

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

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

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

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

Motor and Sensory Humunculi Use-dependent competition Modifications based on use Plasticity Ability to be functionally remodeled structural-communication.com

Electroencephalogram (EEG) Record of postsynaptic activity in cortical neurons EPSPs or IPSPs Uses Brain dysfunction Brain death Sleep stages

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

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

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

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

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

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

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

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

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

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

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