Coordination in animals br Nervous Coordination br Elements of Nervous system br 1. Neurons br 2. Receptors br They detect changes in the environment of the animal br Classification of Receptors br a) Chemoreceptor br b) Mechanoreceptor br c) Photoreceptor br d) Thermoreceptor br e) Nociceptor br 3. Effectors br Coordination and Control br Chapter No.