2.85

2.85: describe the structure and functioning of a simple reflex arc illustrated by the withdrawal of a finger from a hot object


Key Points:
1. A synapse is the gap between different neurones - this allows the electrical impulse to jump across at faster speed and results in a faster impulse. They also function as a resistor and a junction box. Synapses are easily affected by drugs and this can either slow down or heighten peoples' reactions.
2. Reflex arcs are stimulation's caused by the body to protect one from harm or damage. An example would be something very hot.
3. STIMULUS (HEAT) -> RECEPTOR (PAIN SENSOR IN SKIN) -> COORDINATOR (CENTRAL NERVOUS SYSTEM) -> EFFECTOR (ARM MUSCLE) -> RESPONSE (REFLEX ARC)
4. In specifics, the heat causes the pain sensor in the skin to send a message along the sensory neurone to the central nervous system, in which it gets passed on to the relay neurone which then passes to the motor neurone and carries the impulse to the muscle (in this case the arm muscle), and causes a reflex.
5. Some other examples of reflexes are: Blinking with dust in your eye, Coughing when liquid or food goes down the trachea, blinking when someone claps in your face etc.