What is the stimulus in a reflex?

What is the stimulus in a reflex?

Most reflex arcs involve only three neurons. The stimulus, such as a needle stick, stimulates the pain receptors of the skin, which initiate an impulse in a sensory neuron. This travels to the spinal cord where it passes, by means of a synapse, to a connecting neuron called the relay neuron situated in the spinal cord.

What is a flexion or withdrawal response?

The withdrawal reflex (nociceptive flexion reflex or flexor withdrawal reflex) is a spinal reflex intended to protect the body from damaging stimuli. A withdrawal reflex is mediated by a polysynaptic reflex resulting in the stimulation of many motor neurons in order to give a quick response.

What does the flexion withdrawal reflex mediate?

This automatic response is known as the withdrawal reflex defined as the automatic withdrawal of a limb from a painful stimulus. Specifically, the withdrawal reflex mediates the flexion of the limb that comes into contact with the noxious stimuli; it also inhibits the extensors of that same limb.

Is flexor reflex Intersegmental?

flexor reflex = withdrawal reflex – A type of protective polysynaptic ipsilateral segmental reflex in which a painful stimulus triggers the contraction of ipsilateral flexor muscles (and the ipsilateral extensors are inhibited) which takes the limb or structure away from source of the pain; these reflexes have a slower …

Which is the best definition of flexion reflex?

A sudden automatic withdrawal movement occurring in response to a painful stimulus and effected by the contraction of the flexor muscles of all the joints on the same side. flexion. the act of bending or the condition of being bent. see flexor reflex.

How does increasing the stimulus affect the flexor reflex?

Increasing the stimulus strength decreases the latency and increases the duration and amplitude of both components. These reflexes are enhanced in spasticity. The involuntary movements in periodic movements in sleep may be released flexor reflexes.41

How are flexor reflexes related to muscle spasms?

These observations suggest that the activity of flexor reflexes is little related to the occurrence of muscle spasms in spasticity of spinal origin. Flexor reflexes are spinal polysynaptic reflexes that can be produced by trains of electrical stimuli delivered to cutaneous or mixed nerves. 1 The normal flexor reflex consists of two EMG components.

How are the flexor reflex and the withdrawal reflexes related?

Flexor Reflex and the Withdrawal Reflexes. In the spinal or decerebrate animal, almost any type of cutaneous sensory stimulus from a limb is likely to cause the flexor muscles of the limb to contract, thereby withdrawing the limb from the stimulating object. This is called the flexor reflex.

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