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Unformatted text preview: BioNB222 Spring 2008 Cornell University Andrew H. Bass Lecture 15-17. Building Blocks of the Nervous System: Parts 1 & 2 Reading Assignment: Purves, Chapter 1 (Abbreviation below: P) Lecture Outline GOAL: To outline the functional organization of the nervous system. The nervous system integrates the activities of multiple organ systems to allow animals (including humans) to meet environmental challenges, to survive and to reproduce. This demands a system that can detect environmental stimuli via sensory receptors, interpret this information, and produce a coordinated motor response. How does this occur? A. TWO NERVOUS SYSTEMS: The nervous system of all vertebrates (fish, amphibians, reptiles, birds and mammals) is divided into the Central Nervous System or CNS and the Peripheral Nervous System or PNS ( P - Fig. 1.10 ). B. CENTRAL NERVOUS SYSTEM (CNS) includes the brain and the spinal cord ( P - Figs. A20, A21, pp. 840-841 ). 1. Brain - The brain has 3 major divisions: a. forebrain : includes your cerebral hemispheres and diencephalon; integrates a wide range of information about environmental stimuli (both externally and internally generated) and formulates commands that orchestrate the performance of complex behaviors. b. midbrain: includes important centers for integrating visual and auditory (sound) information with hindbrain pattern generators (see below). c. hindbrain (medulla and cerebellum): includes pattern generators that coordinate the activities of your musculoskeletal system that lead to the performance of complex body movements ranging from walking to writing and speaking. 2. Spinal cord mainly coordinates the activities of your trunk and limbs during locomotion and many different visceral organ systems that maintain homeostasis (e.g., respiratory, cardiovascular and digestive functions). BioNB222 Spring 2008 Cornell University Andrew H. Bass C. PERIPHERAL NERVOUS SYSTEM OR PNS: The PNS connects the CNS to other organ systems including sensory receptors that detect environmental stimuli, the musculoskeletal system that functions in posture and movement, and visceral organs essential to respiration, cardiovascular function and reproduction. The PNS includes: 1. Nerves - bundles of axons that travel the same route outside of the CNS. Nerves allow localized populations of neurons in the CNS that share a common function to communicate with other organ systems. a. Spinal Nerves: Also referred to as segmental nerves because there is one pair (left and right) per body segment of your trunk (cervical, thoracic, lumbar, sacral). In humans, there are 31 pairs of spinal nerves that relay information between the trunk and limbs and the spinal cord ( P Figs. 1.10, A2-p. 817 )....
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- Spring '08