12_LectureOutline

12_LectureOutline - An Introduction to the Nervous System...

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Unformatted text preview: An Introduction to the Nervous System The Nervous System * Includes all neural tissue in the body Neural Tissue Contains two kinds of cells * Neurons : cells that send and receive signals * Neuroglia (glial cells): cells that support and protect neurons Organs of the Nervous System * Brain and spinal cord * Sensory receptors of sense organs (eyes, ears, etc.) * Nerves connect nervous system with other systems Divisions of the Nervous System Anatomical Divisions of the Nervous System Central nervous system (CNS) * Peripheral nervous system (PNS) * The Central Nervous System (CNS) Consists of the spinal cord and brain * Contains neural tissue, connective tissues, and blood vessels * Functions of the CNS * Are to process and coordinate: sensory data: from inside and outside body *motor commands: control activities of peripheral organs (e.g., skeletal muscles) *higher functions of brain: intelligence, memory, learning, emotion * The Peripheral Nervous System (PNS) Includes all neural tissue outside the CNS * Functions of the PNS Deliver sensory information to the CNS *Carry motor commands to peripheral tissues and systems * Nerves (also called peripheral nerves) *Bundles of axons with connective tissues and blood vessels *Carry sensory information and motor commands in PNS: * cranial nerves connect to brain * spinal nerves attach to spinal cord Divisions of the Nervous System * Functional Divisions of the PNS * Afferent division *Carries sensory information *From PNS sensory receptors to CNS * Efferent division *Carries motor commands * From CNS to PNS muscles and glands *Receptors and effectors of afferent division * Receptors : *detect changes or respond to stimuli *neurons and specialized cells *complex sensory organs (e.g., eyes, ears) * Effectors : *respond to efferent signals *cells and organs * The efferent division * Somatic nervous system (SNS): controls skeletal muscle contractions: voluntary and involuntary (reflexes) muscle contractions * Autonomic nervous system (ANS): controls subconscious actions: contractions of smooth muscle and cardiac muscle and glandular secretions * sympathetic division : has a stimulating effect * parasympathetic division : has a relaxing effect Neurons The basic functional units of the nervous system The Structure of Neurons * The multipolar neuron Common in the CNS: * cell body (soma) *short, branched dendrites *long, single axon * Major Organelles of the Cell Body *Large nucleus and nucleolus * Perikaryon ( cytoplasm) *Mitochondria (produce energy) *RER and ribosomes (produce neurotransmitters) *Cytoskeleton * Neurofilaments and neurotubules : in place of microfilaments and microtubules * Neurofibrils : bundles of neurofilaments that provide support for dendrites and axon * Nissl bodies Dense areas of RER and ribosomes *Make neural tissue appear gray ( gray matter ) * Dendrites Highly branched * Dendritic spines: many fine processes *receive information from other neurons...
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This note was uploaded on 12/29/2011 for the course BIOLOGY 24011 taught by Professor Pan during the Fall '11 term at HCCS.

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12_LectureOutline - An Introduction to the Nervous System...

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