Motor reflex arc. Reflex arc: characteristics, types and functions 2022-12-29

Motor reflex arc Rating: 4,5/10 1456 reviews

A motor reflex arc is a neural pathway that controls a reflexive action, such as the reflexive withdrawal of a hand from a hot stove. It is a simple, automatic response to a stimulus that does not require conscious thought. The reflex arc involves several components, including a sensory neuron, an interneuron, and a motor neuron.

The sensory neuron is responsible for detecting the stimulus and transmitting a nerve impulse to the spinal cord. For example, when the hand touches a hot stove, sensory receptors in the skin send a signal to the sensory neuron. This neuron then carries the signal through its axon, a long, thin extension of the cell body, to the spinal cord.

The interneuron, also called an integrating neuron, is located within the spinal cord and receives the signal from the sensory neuron. It processes the information and decides whether or not to initiate the reflexive response. If the interneuron determines that the stimulus is harmful, it sends a signal to the motor neuron.

The motor neuron receives the signal from the interneuron and sends it to the appropriate muscles, causing them to contract. In the example of the hand withdrawing from a hot stove, the motor neuron sends a signal to the muscles in the arm, causing the hand to quickly pull away from the stove.

The motor reflex arc allows the body to respond quickly to stimuli without waiting for the brain to process the information and initiate a response. This is important in situations where quick action is necessary to avoid harm. However, reflexive responses can also be inappropriate, such as when a person experiences a reflexive gag response to the sight or smell of certain foods.

In conclusion, the motor reflex arc is a neural pathway that controls reflexive actions in response to stimuli. It involves the interaction of sensory neurons, interneurons, and motor neurons to initiate a quick and automatic response. This reflex arc is an important part of the body's defense mechanism, but it can also cause inappropriate responses in certain situations.

What is a reflex arc example?

motor reflex arc

In contrast to this, a phasic stretch reflex consists of a synchronous motor neuron discharge caused by the brief stimulation of muscle spindles or their afferent nerve pathways. Breathing is an automatic and rhythmic act produced by networks of neurons in the hindbrain the pons and medulla. Where are reflex arcs located? Postpartum depression, also called postnatal depression, is a type of mood disorder associated with childbirth. The motor neurons then send a signal to your muscle to contract, raising your arm so you don't drop your coffee. Interaction between the afferent inflow to the spinal cord and the descending influence of supraspinal pathways may take place at inter-neurons or propriospinal neurons.

Next

What is the order of a reflex arc?

motor reflex arc

It helps organisms to quickly adapt to an adverse circumstance that could have the potential to cause bodily harm or even death. What is reflex action in simple words? How does that play into this knee jerk reflex? This impairs the function of the inflammasome and overall decreases transcription of proinflammatory cytokines. A tonic stretch reflex is one in which a stimulus produces a prolonged asynchronous discharge of motor neurons causing sustained muscle contraction for the maintenance or alteration of posture. Sensory neuron also sends signals to the brain regarding the contraction of muscle. Reflex arcs act on an impulse before that impulse reaches the brain.

Next

What are the 5 components of a reflex arc?

motor reflex arc

What are the 4 steps of a reflex action? On examination, associated saddle anesthesia with absence of the bulbocavernosus and superficial anal reflexes are common. The reflex arc is a special type of neural circuit that begins with a sensory neuron at a receptor e. These pathways operate in concert under conditions of free head movement, but in an experimental setup they are stimulated separately by giving yaw, pitch, roll or linear acceleration. They are the structures in charge of executing the automatic and involuntary response that comes from the nerve centers of the spinal cord. The action is performed by the components of the peripheral nervous system. Identify the brachioradialis tendon at the wrist. Golgi Tendon Reflex Another example of reflex action and the reflex arc is the Golgi tendon reflex.


Next

Reflex Arc

motor reflex arc

On examination, the bulbocavernosus and superficial anal reflexes are variably absent, decreased, or present. What is the correct order of a reflex arc? Reflex action is a sudden and involuntary response to stimuli. The brain regulates respiratory rate. Other receptors respond to pain or to chemical stimuli, like smells or tastes. This is because the interneuron of this reflex communicates with two efferent neurons, one for each eye. Peripheral vagal nerve stimulation by proinflammatory mediators results in an increase in efferent vagal nerve signals that lead to a downregulation of TNF-α and other proinflammatory cytokines.

Next

Reflex Arc: Definition, Components & Functions

motor reflex arc

Different stretch reflexes are performed during the normal medical examination of a person such as knee jerk, etc. Most reflex arcs have five main components: receptors, sensory neurons, interneurons, motor neurons and muscles. Somatic reflexes involve specialized sensory receptors called proprioceptors that monitor the position of our limbs in space, body movement, and the amount of strain on our musculoskeletal system. A reflex action follows this general sequence and does not involve the conscious part of the brain, which makes it much quicker. Clinically, patients present with detrusor contraction during bladder filling leading to detrusor overactivity, characterized by urinary frequency, urgency, urge incontinence, and inability to initiate micturition voluntarily.


Next

Reflex Arc: Components, Importance & Examples

motor reflex arc

This classification system does not often reflect clinical practice and deviations from these descriptions often exist. First, let's understand what is occurring during the knee jerk reflex and apply it to the reflex arc we covered before. Effector: This is the muscle or gland that is carrying out the response of the reflex. These five parts work as a relay team to take information up from the sensor to the spinal cord or brain and back down to the muscles. Which specific component of the reflex arc is confined to the CNS quizlet? The components of the reflex arc are. What is not a reflex action? VOR relay neurons are either excitatory or inhibitory in their synaptic action, and induce either contraction or relaxation of the extraocular muscles via excitation or inhibition of motoneurons. It's like one big game of telephone! Which of the following lists the parts of a reflex arc quizlet? They receive information from the sensory neuron, process this information within a few milliseconds, and decide about the response.

Next

What are the 5 steps of a reflex arc? [Facts!]

motor reflex arc

These fibers have pointed ends that are connected via glycocalyx to extrafusal muscle fibers. . FIGURE 7-1 A reflex arc contains five fundamental components: 1, a receptor; 2, a sensory neuron; 3, one or more synapses in the CNS; 4, a motor neuron; and 5, a target organ, usually a muscle. Many people know that if you shine a light into your eye, your pupil will constrict, or get smaller. Certain stimuli require some instantaneous response by the effector organ.

Next

12.10A: Components of a Reflex Arc

motor reflex arc

Ans- There are two kinds: autonomic reflex arcs which affect the internal organs and somatic reflex arcs affecting muscles. This allows for faster reflex actions to occur by activating spinal motor neurons without the delay of routing signals through the brain. The integrating nerve centers fulfill the function of connect sensory neurons with motor neurons, thus allowing the transmission of information from one party to another and the consequent automatic response. Each subdivision has structural and functional characteristics that distinguish it from the others. The interneuron then relays that signal to the next neuron, a motor neuron. Monosynaptic refers to the presence of a single chemical synapse. Carries impulses towards CNS.

Next