Question

What are the importance of sensory and motor neurons in reflex action

Answer 1

ɪɴ ᴀ ʀᴇғʟᴇx ᴀʀᴄ, ᴀɴ ᴀᴄᴛɪᴏɴ ᴘᴏᴛᴇɴᴛɪᴀʟ ɴᴇᴠᴇʀ ᴛʀᴀᴠᴇʟs ᴛᴏ ᴛʜᴇ ʙʀᴀɪɴ ғᴏʀ ᴘʀᴏᴄᴇssɪɴɢ ᴀɴᴅ sᴏ ʀᴇsᴜʟᴛs ɪɴ ᴀ ᴍᴜᴄʜ ǫᴜɪᴄᴋᴇʀ ʀᴇᴀᴄᴛɪᴏɴ. ᴡʜᴇɴ ᴀ sᴛɪᴍᴜʟᴜs (ᴀ) ɪs ᴇɴᴄᴏᴜɴᴛᴇʀᴇᴅ, ᴛʜᴇ sɪɢɴᴀʟ ғʀᴏᴍ ᴛʜᴀᴛ sᴛɪᴍᴜʟᴜs ᴡɪʟʟ ᴛʀᴀᴠᴇʟ ᴜᴘ ᴛʜᴇ sᴇɴsᴏʀʏ ɴᴇᴜʀᴏɴ (ʙ, ɪɴ ɢʀᴇᴇɴ) ᴛᴏ ᴛʜᴇ sᴘɪɴᴀʟ ᴄᴏʟᴜᴍɴ (ᴄ). ᴛʜᴇʀᴇ, ɪᴛ ᴡɪʟʟ ʟɪᴋᴇʟʏ ᴘᴀss ᴛʜʀᴏᴜɢʜ ᴀ sʜᴏʀᴛ ɪɴᴛᴇʀɴᴇᴜʀᴏɴ (ᴅ, ɪɴ ᴘᴜʀᴘʟᴇ) ʙᴇғᴏʀᴇ ᴄᴏɴᴛɪɴᴜɪɴɢ ᴅᴏᴡɴ ᴀ ᴍᴏᴛᴏʀ ɴᴇᴜʀᴏɴ (ᴇ, ɪɴ ʙʟᴜᴇ) ᴛᴏ ᴛʜᴇ ᴏʀɪɢɪɴ ᴏғ ᴛʜᴇ sɪɢɴᴀʟ. ᴛʜᴇɴ, ᴀ ᴄᴏɴᴛʀᴀᴄᴛɪᴏɴ ᴏғ ᴛʜᴇ ᴍᴜsᴄʟᴇs (ғ, ɪɴ ʀᴇᴅ) ɪs ᴛʀɪɢɢᴇʀᴇᴅ, ᴍᴏᴠɪɴɢ ᴛʜᴇ ʙᴏɴᴇ (ɢ).

ᴀ ʀᴇғʟᴇx ᴀʀᴄ ɪs ᴀ ɴᴇᴜʀᴀʟ ᴘᴀᴛʜᴡᴀʏ ᴛʜᴀᴛ ᴄᴏɴᴛʀᴏʟs ᴀ ʀᴇғʟᴇx. ɪɴ ᴠᴇʀᴛᴇʙʀᴀᴛᴇs, ᴍᴏsᴛ sᴇɴsᴏʀʏ ɴᴇᴜʀᴏɴsᴅᴏ ɴᴏᴛ ᴘᴀss ᴅɪʀᴇᴄᴛʟʏ ɪɴᴛᴏ ᴛʜᴇ ʙʀᴀɪɴ, ʙᴜᴛ sʏɴᴀᴘsᴇ ɪɴ ᴛʜᴇ sᴘɪɴᴀʟ ᴄᴏʀᴅ. ᴛʜɪs ᴀʟʟᴏᴡs ғᴏʀ ғᴀsᴛᴇʀ ʀᴇғʟᴇx ᴀᴄᴛɪᴏɴs ᴛᴏ ᴏᴄᴄᴜʀ ʙʏ ᴀᴄᴛɪᴠᴀᴛɪɴɢ sᴘɪɴᴀʟ ᴍᴏᴛᴏʀ ɴᴇᴜʀᴏɴs ᴡɪᴛʜᴏᴜᴛ ᴛʜᴇ ᴅᴇʟᴀʏ ᴏғ ʀᴏᴜᴛɪɴɢ sɪɢɴᴀʟs ᴛʜʀᴏᴜɢʜ ᴛʜᴇ ʙʀᴀɪɴ. ʜᴏᴡᴇᴠᴇʀ, ᴛʜᴇ ʙʀᴀɪɴ ᴡɪʟʟ ʀᴇᴄᴇɪᴠᴇ ᴛʜᴇ sᴇɴsᴏʀʏ ɪɴᴘᴜᴛ ᴡʜɪʟᴇ ᴛʜᴇ ʀᴇғʟᴇx ɪs ʙᴇɪɴɢ ᴄᴀʀʀɪᴇᴅ ᴏᴜᴛ ᴀɴᴅ ᴛʜᴇ ᴀɴᴀʟʏsɪs ᴏғ ᴛʜᴇ sɪɢɴᴀʟ ᴛᴀᴋᴇs ᴘʟᴀᴄᴇ ᴀғᴛᴇʀ ᴛʜᴇ ʀᴇғʟᴇx ᴀᴄᴛɪᴏɴ.

Answer 2

Hey friend here is your answer.....


Answer :


Reflex action does not involve conscious thought . Rather , it is an automatic response to a stimulus requiring swift action . For example, you instantly blink when a strong like this flashed in your eyes some other examples are


❀ Withdrawing one's hand instantly when it touches a hot object accidentally .

❀ Protecting once held with one's hands, or bending it down or sideways to save it from and object rushing towards it .

❀ Adjusting one's posture to avoid falling .

❀ Coughing , sneezing , yawning and hiccuping .


Reflexes do not involve the brain directly . It is the spinal cord, with the help of the peripheral nervous system, which effects such instant responses . The mechanism of action is different from that involved in involuntary activities controlled by the autonomic nervous system . In the case of reflex action, a message from the sensory cells, or receptors that have been stimulated is sent via sensory neurons, which sinapse on motor neurons situated in the spinal cord . The motor neurons send messages directly to the effector organ . This route of transmission of impulses (messages) is called a reflex arc .

As most reflex actions are meant to protect us from danger, they require a shorter route of transmission .

A doctor tests the condition of the muscles of a leg by testing the knee-jeŕk reflex . The doctor taps on a tendon just below the knee with hammer . This tap stretches a group of muscles in the front of the thigh called the quadriceps femoris . This stimulus activate stretch receptors within the muscles, which send an impulse to the spinal cord via a sensory neuron . The axon of this sensory neuron has two branches . One of the branches synapses on a motor neuron , which carries an impulse back to the quadriceps femoris , triggering their contraction . The other branch synapses on an interneuron , a connecting neuron which synapses on another motor neuron that carries an impulse to the hamstring muscles at the back of the thigh . The hamstring muscles relax in response to this impulse. The knee jeŕks upwards due to the simultaneous contraction of the quadriceps femoris and relaxation of the hamstring muscles .



Hope it helps you.......