Stretch Reflex: Patellar Reflex Pathway

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What is the main function of the stretch reflex?

To excite sensory fibers of muscle spindles

To activate alpha motor neurons of antagonist muscles

To cause muscle relaxation

To prevent muscle tearing from over-stretching (correct)

What does hyporeflexia indicate about the reflex response?

Damage to the upper motor neuron

Damage to the lower motor neuron (correct)

Enhanced stretch reflex

Normal functioning of the CNS

In the stretch reflex, what do abnormal reactions suggest?

Damage to the central nervous system (CNS) (correct)

Lack of sensory fiber excitation

Damage to the peripheral nervous system (PNS)

Inhibition of alpha motor neurons

In hyporeflexia, a disruption in which fibers can lead to a weak reflex response?

Both afferent and efferent fibers Signup and view all the answers

What happens when sensory fibers activate interneurons in the stretch reflex?

Inhibition of alpha motor neurons of antagonist muscles Signup and view all the answers

What is a characteristic of the stretch (patellar) reflex?

It activates sensory fibers that excite alpha motor neurons indirectly Signup and view all the answers

What is the significance of hyperreflexia in the context of the upper motor neuron?

Enhanced stretch reflex Signup and view all the answers

Which spinal segment does the biceps reflex correspond to?

C5-C6 Signup and view all the answers

How does the stretch reflex respond to over-stretching?

By causing muscle contraction to oppose over-stretching Signup and view all the answers

What can cause hyporeflexia in the stretch reflex loop?

Nerve or root compression Signup and view all the answers

What is the neural pathway for the biceps reflex?

Activation of interneurons that excite alpha motor neurons directly Signup and view all the answers

Why does hyperreflexia occur according to the text?

CNS lesions affecting motor pathways Signup and view all the answers

What is the role of the stretch reflex in muscle contraction?

Inhibits alpha motor neurons of the stretched muscles Signup and view all the answers

What does abnormality in the stretch reflex reaction suggest?

Damage to the central or peripheral nervous system Signup and view all the answers

How does the stretch reflex help in smoothing muscle contractions?

Dampens (stabilizes) the signals for smooth contraction Signup and view all the answers

What is the function of the Golgi tendon reflex?

Relieves excess tension on tendons Signup and view all the answers

What happens when a muscle contracts and creates tension on its tendon?

Triggers Golgi tendon organs Signup and view all the answers

Why might a sectioned muscle spindle sensory nerve lead to jerky muscle contractions?

Disrupts the ability to dampen signals for smooth contraction Signup and view all the answers

Which type of neurons directly innervate skeletal muscle fibers?

Alpha Motor neurons Signup and view all the answers

What is the main function of Gamma Motor neurons?

Excite intrafusal muscle fibers Signup and view all the answers

Where are muscle spindles primarily located?

Throughout the muscle belly (intrafusal fibers) Signup and view all the answers

What do Golgi Tendon Organs primarily sense?

Muscle tension Signup and view all the answers

Which receptors provide proprioceptive sensation by sensing the state of muscles?

Muscle Spindles Signup and view all the answers

What is the main role of Interneurons in the spinal cord?

Integrate sensory and motor information Signup and view all the answers

What is the role of Golgi tendon sensory fibers (Ib) in transmitting impulses to the spinal cord?

Inhibit alpha motor neurons causing muscle relaxation Signup and view all the answers

What happens when a painful stimulus initiates the withdrawal reflex?

Flexor muscle contracts and extensor muscle relaxes Signup and view all the answers

Which type of reflex is initiated by a painful stimulus causing automatic withdrawal of the threatened body part?

Withdrawal reflex Signup and view all the answers

In the Withdrawal and Crossed Extensor Reflex, what happens in the opposite limb to the one experiencing the painful stimulus?

Flexor reflex causing limb extension Signup and view all the answers

What is the purpose of the series of reflexes involving Withdrawal & Crossed Extensor reflexes?

To push body away from the stimulus and shift weight to the opposite limb Signup and view all the answers

How do sensory neurons synapse with excitatory interneurons affect antagonist muscles?

Cause contraction Signup and view all the answers