Nervous System (VCE Psych 3/4)

The Role of the Nervous System - answer-Receive information, process information, coordinate a response to information Central Nervous System (CNS) - answer-Processes information received from the body's internal and external environments and to activate appropriate responses. (Brain and Spinal Cord) Brain - answer-An intricate network of cells and neural pathways. It continuously receives, analyses and processes sensory information by controlling all bodily actions and functions. Neural Pathway - answer-One or more circuits of interconnected neurons that form a communication network Spinal Cord - answer-A long, thin bundle of nerve fibres that extend from the base of the brain to the lower back. It is encased in vertebrae. Its two major functions are to receive sensory (afferent) information from the body and send them to the brain (via the ascending tract), and to receive motor (efferent) information from the brain and send them to relevant parts of the body (via the descending tract). Ascending Tract - answer-Pathways in the spinal cord that carry sensory information up to the brain Descending Tract - answer-Pathways in the spinal cord that carry motor information from the brain to the body Sensory Information (Afferent) - answer-Information that is transmitted along sensory neurons from sensory organs to the CNS Motor Information (Efferent) - answer-Information that is transmitted along motor neurons from the CNS to organs, muscles and glands Peripheral Nervous System (PNS) - answer-The entire network of nerves located outside the CNS. It carries information to and from the CNS. (Somatic NS and Autonomic NS) Somatic Nervous System - answer-Carries sensory information to the CNS, and motor information from the CNS to skeletal muscles. (It initiates movement) Autonomic Nervous System - answer-Connects the CNS to the body's visceral muscles, internal organs and glands. (It regulates activity) (Sympathetic NS and Parasympathetic NS) Sympathetic Nervous System - answer-Responsible for increasing activity to prepare the body for action Parasympathetic Nervous System - answer-Responsible for decreasing activity to return the body to normal functioning and maintain homeostasis Conscious Responses - answer-A reaction to a stimulus that involves awareness. Unconscious Responses - answer-A reaction to a stimulus that does not involve awareness. Spinal Reflex (reflex arc) - answer-An unconscious, involuntary and automatic response to certain stimuli initiated within the spinal cord without any involvement of the brain. Neuron - answer-An individual nerve cell that is specialised to receive, process and transmit information. They communicate with each other, muscles and glands. Dendrite - answer-An extension of a neuron that detects and receives information from other neurons. Dendritic Spines - answer-Tiny protrusions off of dendrites, these provide sites with receptors where a neuron can receive information from a neighbouring neuron. Soma - answer-The cell body of a neuron, it integrates information received from the dendrites and transmits it along the axon. Axon - answer-A single tubelike extension that transmits neural information (impulses) along the neuron and to other neurons. Myelin (myelin sheath) - answer-A white, fatty substance that surrounds and insulates the axon. Glia cells - answer-Cells that support the function of neurons Nodes of Ranvier - answer-Small unmyelinated gaps along the myelin sheath Sclerosis - answer-Scarred areas along the axon from demyelination Axon Collaterals - answer-The branches of the axon Axon Terminals - answer-Found at the ends of axon collaterals Terminal Buttons (synaptic buttons) - answer-Small tips along the axon terminals that secrete neurotransmitters which carry the neural messages across the synaptic gap Synapse - answer-The site where communication occurs between adjacent neurons. Synaptic Gap - answer-The tiny space between neurons Neurotransmitter - answer-A chemical substance produced by a neuron that carries a message to other neurons or cells. Reuptake - answer-The process of excess neurotransmitter being reabsorbed by the terminal buttons of the presynaptic neuron Presynaptic Neuron - answer-The neuron which transmits the message to an adjacent neuron