UNIT 5 NERVOUS SYSTEM SUMMARY NOTES RESPONSE TO STIMULI STIMULUS a detectable change in the internal or external environment of an organism that – produces a response RESPONSE something that aids survival which includes movement, secretion from glands and – behaviours such as stalking, prey, communication and reproducing RECEPTORS cells or organisms that detect stimuli. They transfer the energy of a stimulus into a – form that can be processed by the organism and leads to a response EFFECTOR the cells, tissues, organs and organ systems that bring about a response – COORDINATOR interneurons connecting the sensory and motor systems. They connect – information from each receptor with its appropriate effector. Taxis A simple response that’s direction is determined by the direction of the stimulus – An organism can respond directly to a change in the environment by moving its body either: Toward the stimulus (positive taxis) Away from the stimulus (negative taxis) Kinesis A response which results in an increase of random movements (instead of the direct – movement towards a stimulus) which ultimately brings the organism back into favourable conditions. Tropism a growth movement of part of a plant in response to a directional stimulus – Nervous Control The nervous system has two main divisions: The central nervous system (CNS) brain and spinal cord – The peripheral nervous system (PNS) Made up of pairs of nerves that originate either from – the brain or the spinal cord
UNIT 5 NERVOUS SYSTEM SUMMARY NOTES RESPONSE TO STIMULI STIMULUS – a detectable change in the internal or external environment of an organism that produces a response RESPONSE – something that aids survival which includes movement, secretion from glands and behaviours such as stalking, prey, communication and reproducing RECEPTORS – cells or organisms that detect stimuli. They transfer the energy of a stimulus into a form that can be processed by the organism and leads to a response EFFECTOR – the cells, tissues, organs and organ systems that bring about a response COORDINATOR – interneurons connecting the sensory and motor systems. They connect information from each receptor with its appropriate effector. Taxis – A simple response that’s direction is determined by the direction of the stimulus An organism can respond directly to a change in the environment by moving its body either: Toward the stimulus (positive taxis) Away from the stimulus (negative taxis) Kinesis – A response which results in an increase of random movements (instead of the direct movement towards a stimulus) which ultimately brings the organism back into favourable conditions. Tropism – a growth movement of part of a plant in response to a directional stimulus Nervous Control The nervous system has two main divisions: The central nervous system (CNS) – brain and spinal cord The peripheral nervous system (PNS) – Made up of pairs of nerves that originate either from the brain or the spinal cord
unit_5_nervous_system_summary_notes.docx