Biol172_Chapter48_handout

Biol172_Chapter48_handout - 1 Ch 48 Nervous Systems Ch 48...

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Unformatted text preview: 1 Ch 48 Nervous Systems Ch 48 Nervous Systems Note : this PowerPoint lecture handout is issued only at the request of several students. It is not the sole basis for exam questions and duplicate the figures that can be found in the text. To prepare for exams and to review the lecture material it is recommended that you a) read the relevant book chapter , and b) the written lecture notes, which contain all written comments seen on the slides in class, in addition to supplementary material and review questions. Command and Control Center Command and Control Center The human brain Contains an estimated 100 billion nerve cells, or neurons ( ~10 11 ) Each neuron communicates with thousands of other neurons via chemical synapses (~10 15 synapses) Command and Control Center Command and Control Center Distinct neurological functions are localized in defined areas of the brain Motor control centers Language Sensory functions: hearing, vision, smell, touch Balance, gait Emotions Analysis by high-tech methods Brain trauma Stroke, injury, surgery Functional magnetic resonance imaging Functional magnetic resonance imaging Functional magnetic resonance imaging Functional magnetic resonance imaging Technology that can reconstruct a three- dimensional map of brain activity 2 The results of brain imaging and other research methods reveal that groups of neurons function in specialized circuits dedicated to different tasks Neuron Structure Neuron Structure Dendrites Cel body Nucleus Nucleus Axon hil ock Axon Signal direction Synapse Myelin sheath Synaptic terminals Presynaptic cell Postsynaptic cell Neuron Structure Neuron Structure Most neurons have dendrites Highly branched extensions that receive signals from other neurons The axon is typically a much longer extension The axon is typically a much longer extension transmits signals to other cells at synapses may be covered with a myelin sheath Neurons have a wide variety of shapes That reflect their input and output interactions Axon Dendrites Cel body (a) Sensory neuron (b) Interneurons (c) Motor neuron Supporting Cells (Glia) Supporting Cells (Glia) Glia are supporting cells That are essential for the structural integrity of the nervous system and for the normal functioning of neurons 3 Astrocytes provide structural support for neurons and regulate the extracellular concentrations of ions and neurotransmitters Astrocytes provide structural support for neurons and regulate the extracellular concentrations of ions and neurotransmitters 50 m Oligodendrocytes (in the central nervous system (CNS) Schwann cells (in the peripheral nervous system (PNS) Glia forms the myelin sheaths around the axons of many vertebrate neurons Glia forms the myelin sheaths around the axons of many vertebrate neurons system (PNS) Myelin sheath Nodes of Ranvier Schwann cel Schwann cel Nucleus of Schwann cel Axon Layers of myelin Node of Ranvier...
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Biol172_Chapter48_handout - 1 Ch 48 Nervous Systems Ch 48...

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