Reflex actions
A Automatic and rapid response to a stimulus. is an automatic and rapid response to a Something that sets off a reaction in the nervous system, for example, light, heat, sound, gravity, smell, taste, or temperature. These changes in the environment are detected by receptors in an organism. The plural is stimuli. - we do not have to think about a response. Reflex actions minimise damage to the body from potentially harmful conditions, such as touching something hot.
Different types of Nerve cells. They carry an electrical message or impulse when stimulated. work together in a reflex action. A reflex action follows this general sequence:
The nerve pathway followed by a reflex action is called a The pathway of information from a sensory neuron through an inter neuron to a motor neuron..
A simple reflex action happens if we accidentally touch something hot. We rapidly move our hand away. This is called the pain withdrawal reflex.
The diagram shows the reflex arc involved.
- The Organ, tissue or cell that detects a stimulus. in the skin detects a stimulus - the change in temperature.
- The The nerve cell that transmits electrical impulses from receptors in the sense organs to the CNS. sends nerve impulses to the spinal cord.
- The The nerve cell that transmits electrical impulses from sensory neurones to motor neurones., which is located in the spinal cord, carries the nerve impulses from sensory neurones to The nerve cell that carries electrical impulses from the CNS to effectors such as muscles or glands..
- The motor neurone sends nerve impulses to the The organ, tissue or cell that produces a response..
- The effector - the biceps muscle in the arm - contracts so that the hand is moved away.