SENSORY AND SOMATIC PATHWAYS (REFLEXES)

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Questions and Answers

What is the name of the receptors that prevent rupture of muscle?

Golgi tendon organs (correct)

Nociceptors

Flexor reflex afferents

Somatic afferents

What type of reflex is an example of polysynaptic spinal reflex?

Stretch reflex

Withdrawal reflex (correct)

Inverse stretch reflex

Autogenic inhibition

What is the primary function of the withdrawal reflex?

To protect against painful stimuli (correct)

To integrate sensory input

To prevent muscle rupture

To control voluntary movements

At which level of the nervous system are spinal reflexes integrated?

Spinal cord Signup and view all the answers

What type of afferents are involved in the withdrawal reflex?

Type III and IV somatic afferents Signup and view all the answers

What is the term for the integration of sensory input at multiple points in the CNS?

Sensory-motor integration Signup and view all the answers

What is the name of the reflex that prevents rupture of muscle?

Autogenic inhibition Signup and view all the answers

What level of the nervous system controls voluntary movements?

Cerebral cortex and basal ganglia Signup and view all the answers

Which of the following reflexes can be initiated by pain receptors?

Withdrawal reflex Signup and view all the answers

What is the function of proprioceptors in reflexes?

To detect changes in joint structure Signup and view all the answers

What type of reflex is the stretch reflex?

Monosynaptic reflex Signup and view all the answers

What is the role of the stretch reflex in maintaining posture?

It helps to maintain muscle tone Signup and view all the answers

Which of the following is NOT a function of the stretch reflex?

Initiating withdrawal reflex Signup and view all the answers

What is the role of the gamma motor neuron in the stretch reflex?

It is involved in the discharge of proprioceptors Signup and view all the answers

What is the inverse stretch reflex also known as?

Golgi tendon reflex Signup and view all the answers

What is the result of a strong stretch on a muscle in the Golgi tendon reflex?

Relaxation of the muscle Signup and view all the answers

What is the primary function of a reflex in the body?

To play a critical role in the coordination of body movement and protection Signup and view all the answers

What is the functional unit of the nervous system for a reflex?

Reflex arc Signup and view all the answers

Which type of reflexes are processed at the level of the spinal cord?

Some autonomic reflexes Signup and view all the answers

What is the characteristic of a reflex response?

Involuntary and rapid Signup and view all the answers

What is the classification of reflexes based on the number of synapses?

Monosynaptic vs. Polysynaptic reflexes Signup and view all the answers

What is the classification of reflexes based on the location of the integrating center?

Cortical vs. Cerebellar vs. Midbrain vs. Medullary vs. Spinal reflexes Signup and view all the answers

What is the characteristic of a polysynaptic reflex?

More than one synapse is involved Signup and view all the answers

What is the classification of reflexes based on their origin?

Inborn vs. Acquired reflexes Signup and view all the answers

Study Notes

Reflexes

A reflex is an inborn, involuntary, sudden, rapid, and stereotyped response to a stimulus, serving as a survival mechanism.
Reflexes play a critical role in coordinating body movement and protection by withdrawal.

Reflex Arc

A reflex arc is the functional unit of the nervous system for a reflex, consisting of 5 components.

Somatosensory & Motor Pathways

Reflexes involve somatosensory and motor pathways.

Classification of Reflexes

Reflexes can be classified based on the number of synapses (monosynaptic vs. polysynaptic reflexes).
Reflexes can also be classified based on the location of the integrating centre (cortical, cerebellar, midbrain, medullary, or spinal reflexes).
Physiological classification includes flexor reflexes and extensor reflexes.
Reflexes can be classified as inborn or acquired, and clinically as somatic, visceral (autonomic), or pathologic reflexes.

Spinal Somatic Reflexes and Stretch Receptors

Four common spinal reflexes involving skeletal muscle as the effector include:
- Stretch reflex
- Golgi tendon reflex
- Withdrawal (flexor) reflex
- Crossed-extensor reflex
These reflexes can be initiated by proprioceptors or pain receptors (nociceptors).

Stretch Reflex

A stretch reflex is a monosynaptic reflex that helps maintain muscle tone and posture.
It is under the influence of discharge from the gamma motor neuron.
Stretch reflex helps the motor command system in performing voluntary movements.

Golgi-Tendon Reflex or Inverse Stretch Reflex

An inverse stretch reflex is a polysynaptic reflex that relaxes the muscle in response to a strong stretch.
This reflex is also known as autogenic inhibition and prevents muscle rupture.
Receptors involved are Golgi tendon organs (GTO).

Flexor Withdrawal & Crossed Extensor Reflex

A withdrawal reflex is a protective reflex and a polysynaptic spinal reflex.
It is elicited by noxious or painful stimulation of skin, subcutaneous tissue, or muscle.
Receptors involved are nociceptors (type III and IV somatic afferents).

Sensory-Motor Integration

Sensory input can be integrated at many points in the CNS, with increasing complexity with ascent through the CNS.
The three levels of the nervous system that control movement are:
- The spinal cord, which integrates spinal reflexes and contains central pattern generators.
- The brain stem and cerebellum, which control postural reflexes and hand and eye movements.
- The cerebral cortex and basal ganglia, which are responsible for voluntary movements.

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Description

Learn about reflexes, an inborn, involuntary response to stimuli, and their role in body movement and protection. Understand the reflex arc and its importance in physiology.