Describe the structure of Reflex Arc.
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reflex arc is a neural pathway that controls a reflex. In vertebrates, most sensory neuronsdo not pass directly into the brain, but synapse in the spinal cord. This allows for faster reflex actions to occur by activating spinal motor neurons without the delay of routing signals through the brain. However, the brain will receive the sensory input while the reflex is being carried out and the analysis of the signal takes place after the reflex action.
There are two types: autonomic reflex arc (affecting inner organs) and somatic reflex arc (affecting muscles). However, autonomic reflexes sometimes involve the spinal cord and some somatic reflexes are mediated more by the brain than the spinal cord.
During a somatic reflex, nerve signals travel along the following pathway:
Somatic receptors in the skin, muscles and tendons
Afferent nerve fibers carry signals from the somatic receptors to the posterior horn of the spinal cord or to the brainstem
An integrating center, the point at which the neurons that compose the gray matter of the spinal cord or brainstem synapse
Efferent nerve fibers carry motor nerve signals from the anterior horn to the muscles
Effector muscle innervated by the efferent nerve fiber carries out the response.
A reflex arc, then, is the pathway followed by nerves which (a.) carry sensory information from the receptor to the spinal cord, and then (b) carry the response generated by the spinal cord to effector organ(s) during a reflex action.
In a reflex arc, an action potential never travels to the brain for processing and so results in a much quicker reaction. When a stimulus (A) is encountered, the signal from that stimulus will travel up the sensory neuron (B, in green) to the spinal column (C). There, it will likely pass through a short interneuron (D, in purple) before continuing down a motor neuron (E, in blue) to the origin of the signal. Then, a contraction of the muscles (F, in red) is triggered, moving the bone (G).
There are two types: autonomic reflex arc (affecting inner organs) and somatic reflex arc (affecting muscles). However, autonomic reflexes sometimes involve the spinal cord and some somatic reflexes are mediated more by the brain than the spinal cord.
During a somatic reflex, nerve signals travel along the following pathway:
Somatic receptors in the skin, muscles and tendons
Afferent nerve fibers carry signals from the somatic receptors to the posterior horn of the spinal cord or to the brainstem
An integrating center, the point at which the neurons that compose the gray matter of the spinal cord or brainstem synapse
Efferent nerve fibers carry motor nerve signals from the anterior horn to the muscles
Effector muscle innervated by the efferent nerve fiber carries out the response.
A reflex arc, then, is the pathway followed by nerves which (a.) carry sensory information from the receptor to the spinal cord, and then (b) carry the response generated by the spinal cord to effector organ(s) during a reflex action.
In a reflex arc, an action potential never travels to the brain for processing and so results in a much quicker reaction. When a stimulus (A) is encountered, the signal from that stimulus will travel up the sensory neuron (B, in green) to the spinal column (C). There, it will likely pass through a short interneuron (D, in purple) before continuing down a motor neuron (E, in blue) to the origin of the signal. Then, a contraction of the muscles (F, in red) is triggered, moving the bone (G).
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The reflex arc is defined as the pathway through which reflex of the organism travel on the body of the organism. It travels from the stimulus to sensory neuron to motor neuron to reflex muscle movement of the body.
Reflexive arcs contain basically two neurons- a sensory and a motor neuron. These neurons are considered monosynaptic. Examples of monosynaptic reflex arcs in humans include the patellar reflex and the Achilles reflex which occurrs in the human.
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