coordination and response

• any change in the internal or external environment is called a stimulus
• receptors detect stimuli and effectors produce a response
• receptors communicate with effectors via the nervous system
• the central nervous system coordinates information
• three main types of neurons- sensory neurons, relay neurons and motor neurons.
• when receptors detect a stimulus, they send electrical impulses along the sensory neuron to the central nervous system.
• The central nervous system sends electrical impulses to an effector along a motor neutron.
• synapses connect neutrons
• the nerve signal is transferred by chemicals called neurotransmitters which diffuse across the gap
• reflexes help prevent injury
• the reflex arc goes through the central nervous system
• stimulus-> receptor->sensory neuron->CNS->motor neuron->effector->response
• the central nervous system consists of the brain and spinal cord