lecture summaries.docx - Lecture 1 Introduction to the...

This preview shows page 1 - 3 out of 13 pages.

Lecture 1: Introduction to the Nervous System Nervous System oResponsible for most functionsoDistributed throughout body; influences all other systems oComplex aggregation of cells oCommunication network and supportive matrix oTwo major divisions:Central nervous systems (CNS) brain & spinal cord Peripheral nervous system (PNS) rest of body oNS is a complex aggregation of cells Communication network and supportive matrix Neurons oMajor functional unit of NSoCommunication network oReceive information and transmits to others oClassified functionally a.Sensory neurons -Afferent neurons -Relay information collected from stimuli and move towardsintegration centreb.Motor neurons -Efferent neurons -Output portion of neuronal circuit; information moves awayfrom integrative enter c.Interneurons -Link neurons in CNS-Transmit impulses between other neurons to perform complex computations producing thought and behaviour oBasic neuron types: bipolar, unipolar, multipolar, pyramidal cell Glial cells (Neuroglia)oSupportive matrix oProportion increases with evolutionary complexity oMammalian brain has 10x more neuroglia than neurons oDifferent types:d.Astrocytes -Line surface of capillaries in CNS-Provide metabolic substrates-Provide biochemical support to endothelial cells that form the BBB-Remove neurotransmitters -Nervous system development e.Oligodendrocytes (CNS)-Brain + spinal column -Increase velocity of impulse propagation through the production of myelin -Equivalent to Schwann cells in PNS-Action potential jumps from node to node-Fewer protuberances than astrocytes f.Microglial cells -Aid immune response in neural tissue -**Act as phagocytes (macrophages) in CNS-Pick up pathogens, and after brain injury can pick up cellular debris Endocrine System oEndocrine glands and cells Organized into endocrine glands or isolated cells Ductless glands release hormones into capillaries Hormone released into blood widespread response (slow action)Target cells posses receptor molecules recognized by the hormone oEndocrine system controls:All systems affected by NS because the two are interconnected Water balanceMetabolism Reproduction Development Stress response Endocrine cell types:oNonneural endocrine cells oNeurosecretory cells Nervous and endocrine control oNervous system Neuronal signals are fact Signals are precisely targeted
Neuron contacts target cell oEndocrine system Release hormones; response is slow and on longer time scale (hormones may have to be synthesized before release; e.g., cortisol) Widespread response (broadcast) ** most tissues are under dual control (e.g., muscle twitch)Organization of Nervous System 1.Incoming stimulus 2.Sensory receptors 3.Afferent neuron4.Integrating center to CNS (brain, ganglia)5.Afferent neurons 6.Effector organs 7.Output Diversity of Nervous Systems – Comparative Anatomy oThroughout the entire animal kingdom, the neuron essentiallyremains unchanged o

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture