Chapter 11 Regulation, Tools A B Regualtion Control and Coordination of all life functions Nervous System Receptors, Neurons, and Effectors Receptors Specialized structure, Sensitive to change in in and external enviorment Neurons Basic unit of cell structure in the nervous system Effectors Muscle or gland in which nuerons are attached to Impulse Electro-chemical message Stimulus Change in ex and internal enviorment which causes impluse Receptors Structure specialized to detect stimuli Dendrites Generate impluse towards cytons Cytons Cell body that contains the nucleus of the neuron Axon Sends inpluse away from cyton and towards terminal brances Terminal Branches The end of axon that secretes neurontramitters Synapse Gap between terminal branches of 1 neruon adn dendrites another neuron Neurotransmitters Chemicals secreted by terminal branches that aid in the transmission of an impulse across the synapse Sensory Neurons carry impulses from the receptors toward the spinal cord and brain Interneuron relay impulses from one neuron to another Motor neuron carry impulses from brain and spinal cord toward the effectors Hydra l Contains no brain or control center, so impulses travel in all directions across a nerve net