Bio 102 notes- Ch 40,41,42

Bio 102 notes- Ch 40,41,42 - Neural Signaling Chapter 40...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Neural Signaling Chapter 40 Learning Objective 1 Describe the processes involved in neural signaling: reception, transmission, integration, and action by effectors Response to Stimulus (Fig 40-1) KEY CONCEPTS Neural signaling involves reception, transmission, integration, and action by effectors Now known that neurogenesis occurs regularly in at least several regions of the adult mammalian brain Learning Objective 2 What is the structure of a typical neuron? Give the function of each of its parts Neurons Specialized to receive stimuli transmit electrical and chemical signals Via nerve impulses or action potentials Cell body contains nucleus and organelles Largest part of the neuron Integrates incoming signals Axons A single long axon extends from neuron cell body forms branches (axon collaterals) Axons 1 Transmits signals Away from the cell body to another neuron, muscle or gland At end forms into terminal branches which end in synaptic terminals Release neurotransmitters Junction between synaptic terminal and another neuron (or effector) is a synapse Axon Structure 1 Schwann cells Surround the axons of many neurons in PNS These glial cells form the myelin sheath Myelin sheath surrounds and insulates many axons Composed of myelin – white fatty substance deposited in the plasma membranes
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Axon Structure 2 In the CNS sheath is formed by other glial cells Nodes of Ranvier gaps in sheath between successive Schwann cells Axon is not insulated with myelin at these points When 2um or more in diameter – myelinated Less than 2um - demyelinated Neuron Structure Fig 40-2 Nerves and Ganglia in the PNS, CNS Nerve several hundred axons wrapped in connective tissue in PNS Tracts/Pathways Bundles of axons within the CNS Nerve Structure Fig 40-3 Learning Objective 3 Name the main types of glial cells Describe the functions of each Glial Cells Support and nourish neurons Make up the neuroglia Are important in neural communication Carry out major regulatory functions 90% of the cells in the human CNS Four main types: astrocytes, microglia, oligodendrocytes and ependymal cells, table 40-1 Glial Cell Types 1 Astrocytes Star shaped physically support neurons, and provide nutrient regulate extracellular fluid in CNS (by taking up excess potassium ions and maintaining normal neuron excitability) communicate with one another (and with neurons) via chemical signals induce and stabilize synapses in the brain Astrocytes 2 In response to astrocytes, endothelial cells in the brain form tight junctions preventing substances in the blood from penetrating brain tissue Called the blood –brain barrier Guide neurons to appropriate locations in the body Induce synapse formation and strengthen their activity Can function as stem cells in brain and spinal cord New neurons, astrocytes, other glial cells
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 10/08/2010 for the course BIO 380 taught by Professor Martin during the Spring '10 term at Rutgers.

Page1 / 26

Bio 102 notes- Ch 40,41,42 - Neural Signaling Chapter 40...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online