AQA GCSE Biology - The Nervous System

AQA GCSE Biology - The Nervous System What does the nervous system enable humans to do? React to (their) surroundings (and) coordinate their behaviour What is the central nervous system? Brain and spinal chord What do your brain and spinal chord make up? C(entral )N(ervous )S(ystem) What are stimuli? Changes in the environment What are receptors? Cells detecting stimuli What is a nerve impulse? (An) electrical message Where does a nerve impulse travel? (Along a) neurone What is a neurone? (A) nerve cell Why are neurones very long? So as impulses can travel quickly (to different places in the body) Why do neurones have branched ends? (To) allow connections with many other branches Why do neurones have an insulating sheath? (To) maintain the (nerve) impulse What is a nerve? A bundle of neurones connected to the CNS Where does the sensory neurone run? Receptor to CNS Where is the relay neurone? (The) CNS Where does the motor neurone run? CNS to effector What can the effector be? (A) muscle or gland What is a synapse? (A) junction between nerve cells What happens to the chemicals released by one end of the synapse? (They) diffuse across the gap What happens when the chemical has travelled across the synapse? (A) new nerve impulse (is) started in the next neurone What are receptors in the skin sensitive to? Pressure and temperature changes What do reflex actions protect the body from? Harm Without synapses, what is the order of neurones in a reflex action? S