Neuroscience: Flexion and Crossed Extensor Reflex

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Questions and Answers

What type of reflex is the flexion reflex classified as?

Monosynaptic reflex

Visceral reflex

Autonomic reflex

Polysynaptic reflex (correct)

What is the primary role of the crossed extensor reflex?

To increase pain perception

To enhance the flexion reflex

To create a postural adjustment (correct)

To activate voluntary muscle contractions

Which of the following best describes the pathway involved in a polysynaptic reflex?

Only sensory and motor neurons are involved.

It consists of a single synapse.

It relies on divergent pathways in the spinal cord. (correct)

It does not involve the spinal cord.

Which type of reflex involves involuntary responses to painful stimuli?

Somatic reflexes Signup and view all the answers

What activates nociceptors in the reflex pathway?

Painful stimuli Signup and view all the answers

What type of reflex is involved when the foot is pulled away from a painful stimulus?

Withdrawal (Flexion) reflex Signup and view all the answers

Which reflex helps maintain body stability when weight shifts away from a painful stimulus?

Crossed extensor reflex Signup and view all the answers

What is the main role of nociceptors in the reflex actions described?

To transduce pain sensations Signup and view all the answers

In the context of CNS integration, which pathway is activated by collateral signals following a painful stimulus?

Ascending pathways for sensation Signup and view all the answers

How do flexors and extensors respond during the crossed extensor reflex?

Flexors are contracted, extensors are inhibited Signup and view all the answers

What is the primary function of nociceptors during a painful stimulus?

To transmit pain signals to the brain Signup and view all the answers

What type of reflex involves a direct route from sensory neuron to spinal motor neuron?

Monosynaptic reflex Signup and view all the answers

The withdrawal reflex is primarily an example of which type of reflex?

Polysynaptic reflex Signup and view all the answers

Which part of the nervous system is primarily involved in processing autonomic reflexes?

Spinal cord Signup and view all the answers

How does the central nervous system (CNS) integrate responses to a painful stimulus?

By activating pain pathways while adjusting posture Signup and view all the answers

What emotional response can be associated with the experience of pain?

Fear Signup and view all the answers

What happens during the flexion reflex in response to a painful stimulus?

Flexor muscles contract to withdraw the limb from harm Signup and view all the answers

What role do primary sensory neurons play in reflex actions?

They enter the spinal cord and diverge to multiple pathways Signup and view all the answers

Study Notes

Reflex Responses to Painful Stimuli

Flexion reflexes are polysynaptic reflexes that occur in response to painful stimuli, leading to immediate withdrawal from the source of pain.
Nociceptors are sensory receptors that activate upon the detection of painful stimuli, initiating the reflex arc.

Mechanism of Flexion Reflex

Upon activation of nociceptors, the sensory neuron sends signals to the spinal cord.
The primary sensory neuron enters the spinal cord and diverges, activating:
- Ascending pathways for the perception of pain.
- Pathways for postural adjustments to maintain balance.

Crossed Extensor Reflex

The flexion reflex in one limb causes opposing limb extension through the crossed extensor reflex, which aids in maintaining body posture and balance.
When the reflex is triggered:
- The flexors of the affected limb contract to move away from the painful stimulus.
- Extensors of the opposite limb inhibit their contraction, allowing the extension necessary for weight support.

Functional Importance

The flexion reflex serves as a protective mechanism, allowing rapid withdrawal from harmful stimuli.
The crossed extensor reflex is critical for maintaining stability and balance during withdrawal, ensuring the body can reposition effectively after a painful experience.

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Description

This quiz covers the flexion reflex and the crossed extensor reflex as presented in neuroscience. It focuses on the neurological pathways involved, particularly the role of the spinal cord and ascending pathways to the brain. Test your understanding of these critical reflexes and their physiological processes.