17 November 2014
Does Age affect Reaction Time?
When a person sees a health care provider and the doctor hits the person’s knee with a rubber mallet, the person’s leg kicks up on its own. This happens because when the doctor hits your kneecap, the tendon under it gets stretched, which in turn will send a signal to an awaiting motor neuron so it can command the muscle to contract. Let’s take for example the reflex arc. A reflex is the involuntary movement of the body in response to a stimulus such as pain. The nerve impulses move so quickly that the person being affect doesn’t think about it, he just does it. Skin has a lot of sensory receptors, and when they are stimulated, the impulses are carried to the central nervous system. There the neuron may form a synapse with other interneuron or it may pass it on to other interneurons. What happens will depends on the particular body part stimulated and the stimulus. The interneuron then passes the impulse to a motor neuron, and then it goes to the muscle. Then at the same time, the interneurons may send impulses to the brain. But the action of the muscle happens before the person is aware of it happening, therefore reflexive arcs are involuntary. The part of the body that is responsible for reflex arcs are called the effector. The effector may either be glands or muscles, but it depends on the reflex arc. For example the muscles in the eyelids are effector muscles when something gets in them and sweat glands are effectors in the reflex arc when someone is in a hot room. There could be many motor neurons and sensory neurons in one reflex arc, but no matter how many neurons are involved, the central nervous system and the brain are the main components of the reflex arc.
Our brain is involved by remodeling and modifying reflex actions. For example when you fall down, your reflexes will have automatically told your arms to be reach out so you can break your fall and keep...
Cited: "A Quick Look at Reflexes." - Online Medical Encyclopedia. N.p., n.d. Web. 15 Nov. 2014
Infoplease. Infoplease, n.d. Web. 15 Nov. 2014.
Please join StudyMode to read the full document