Chapter 28 - Introduction A The nervous system is basic to the functioning of any animal 1 In order to survive and reproduce an animal must respond

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Chapter 28 Lecture Outline Introduction Can an Injured Spinal Cord Be Fixed? A. The nervous system is basic to the functioning of any animal. 1. In order to survive and reproduce, an animal must respond appropriately to environmental stimuli, both internal and external. 2. The nervous system coordinates immediate responses to stimuli with long-term responses from the endocrine system (Chapter 26). B. The spinal cord acts as a conduit for information flow between the brain and the rest of the body. But what happens if the spinal cord is injured? 1. Minor injuries to the spinal cord can be healed; however, severe injuries can be devastating physically, monetarily, and emotionally to the victim and the victim’s family. 2. Previously, patients suffering a severe injury to the spinal cord were often left paralyzed and without hope for a cure. 3. Recently, with the advances in growth factors, cell transplantation, and stem cell research, the possibility of a cure has become closer to a reality (Module 11.12). C. Structure, function, and evolution of the nervous system are reviewed in this chapter. Emphasis will be placed on the vertebrate nervous system and on the human brain. I. Nervous System Structure and Function Module 28.1 Nervous systems receive sensory input, interpret it, and send out appropriate commands. A. The nervous systems of animals are the most complex data processing systems on Earth. The human brain contains approximately 100 billion neurons. A neuron is the functional unit of the nervous system containing a cell body; a nucleus; organelles; and long, thin neuron fibers that convey signals. B. The two main divisions of nervous systems are the central nervous system (CNS) and the peripheral nervous system (PNS). The CNS consists of the brain and (in vertebrates) spinal cord. The PNS carries information from sensory receptors to the CNS and from the CNS to effector cells. A nerve (part of the PNS) is a bundle of neuron fibers wrapped in connective tissue that carries information into and out of the CNS. The PNS also has clusters of neuron cell bodies called ganglia. NOTE: Clusters of nerve cell bodies within the CNS are called nuclei. C. The nervous system is organized with three interconnecting functions (Figure 28.1A): 1. Sensory input is triggered by stimulation of receptors and involves the conduction of signals from the receptors to integration centers. 2. Integration is the interpretation of these signals and the formulation of responses by the processing centers. 3. Motor output is the conduction of signals from the processing center to effector cells  (muscles or glands) that respond to the stimuli.
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D. PNS nerves that convey information from sensory receptors to the CNS are called sensory  neurons. PNS nerves that convey information from the CNS to effector cells are called motor  neurons. Nerves that convey information from one region of the CNS to another are called interneurons  (Figure 28.1B). E.
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This note was uploaded on 03/10/2011 for the course BIOL 10 taught by Professor Kite during the Spring '11 term at Laney College.

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Chapter 28 - Introduction A The nervous system is basic to the functioning of any animal 1 In order to survive and reproduce an animal must respond

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