Podcast
Questions and Answers
What is a reflex defined as?
What is a reflex defined as?
Which type of reflex involves muscle spindles?
Which type of reflex involves muscle spindles?
In the reflex arc, which component comes directly after the Afferent neuron?
In the reflex arc, which component comes directly after the Afferent neuron?
What characterizes the difference between monosynaptic and polysynaptic reflexes?
What characterizes the difference between monosynaptic and polysynaptic reflexes?
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What is the primary function of reflexes in the nervous system?
What is the primary function of reflexes in the nervous system?
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Which type of reflex involves inhibition by the Golgi tendon organs?
Which type of reflex involves inhibition by the Golgi tendon organs?
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What is a key characteristic of autonomic reflexes?
What is a key characteristic of autonomic reflexes?
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Which statement is true regarding the central nervous system's role in reflexes?
Which statement is true regarding the central nervous system's role in reflexes?
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What is the primary initial step to elicit a Deep Tendon Reflex?
What is the primary initial step to elicit a Deep Tendon Reflex?
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Which reflex testing method is specifically used to enhance the excitability of reflex circuits?
Which reflex testing method is specifically used to enhance the excitability of reflex circuits?
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What signifies a grade of 1+ in the reflex activity scale?
What signifies a grade of 1+ in the reflex activity scale?
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What is typically observed in a patient with hypertonia after a cerebrovascular accident (CVA)?
What is typically observed in a patient with hypertonia after a cerebrovascular accident (CVA)?
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Which condition is characterized by flaccidity and can result from lower motor neuron injury?
Which condition is characterized by flaccidity and can result from lower motor neuron injury?
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What action should be taken if there is no visible movement or muscle contraction after the initial reflex strike?
What action should be taken if there is no visible movement or muscle contraction after the initial reflex strike?
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Which of the following reflexes is related to the nerve root C5-6?
Which of the following reflexes is related to the nerve root C5-6?
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What distinguishes rigidity from spasticity in muscle tone abnormalities?
What distinguishes rigidity from spasticity in muscle tone abnormalities?
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What is one method to assess reflexes without using the upper extremities?
What is one method to assess reflexes without using the upper extremities?
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Flashcards
Reflex
Reflex
An automatic, involuntary response to a stimulus, occurring without conscious thought. It often involves specific neural pathways that respond quickly before the brain has time to process.
Reflex Arc
Reflex Arc
A neural pathway involved in a reflex response. It includes sensory neurons, interneurons, and motor neurons, enabling very fast responses.
Somatic Reflex
Somatic Reflex
A reflex involving skeletal muscles.
Autonomic Reflex
Autonomic Reflex
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Monosynaptic Reflex
Monosynaptic Reflex
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Polysynaptic Reflex
Polysynaptic Reflex
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Muscle Spindles
Muscle Spindles
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Interneurons
Interneurons
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Deep Tendon Reflex (DTR)
Deep Tendon Reflex (DTR)
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Jendrassik Maneuver
Jendrassik Maneuver
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Biceps reflex
Biceps reflex
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Hypertonia
Hypertonia
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Hypotonia
Hypotonia
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Hyperreflexia
Hyperreflexia
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Clonus
Clonus
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Flaccidity
Flaccidity
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Study Notes
What is a Reflex?
- Reflexes are automatic, involuntary responses to a stimulus
- They occur without conscious thought
- They can involve neural pathways called reflex arcs which act on an impulse before it reaches the brain
- Reflexes can be inhibited and are contextually flexible
Types of Reflexes
- Somatic reflexes involve skeletal muscles
- Autonomic reflexes involve smooth muscles
Somatic Reflexes
- Monosynaptic reflexes involve only one synapse in the spinal cord. An example is the knee-jerk reflex. This reflex utilizes muscle spindles.
- Polysynaptic reflexes involve more than one synapse in the spinal cord, utilizing interneurons. An example is the withdrawal reflex.
Reflex Arc Summary
- Sensory to motor pathway occurs at the spinal level
- No direct cortical control
- The CNS can anticipate and inhibit reflexes
- Reflexes allow for very rapid motor responses
How to Elicit a Deep Tendon Reflex
- Take up the slack in the muscle by putting the joint in a neutral position
- Use a reflex hammer to strike the tendon with a quick, brief tap
- If the movement is not visible, palpate the muscle upon repetition
- Utilize a reinforcement maneuver bilaterally for proper comparison
- Always compare bilaterally
Jendrassik Maneuver
- Used for testing reflexes except for upper extremities (UE)
- To perform:
- Hook fingers together and resist contralateral pull as much as possible
- Elicit a reflex during the isometric pulling action
- Function:
- Acts as a distraction, potentially increasing excitability
- Helps the reflex circuitries function
- For UE reflexes, you may have the patient make a fist with the opposite extremity, count, or give the names of their family members.
Deep Tendon Reflex Testing
- Biceps (C5-6)
- Brachioradialis (C5-6)
- Triceps (C6,7,8)
- Patellar (L2,3,4)
- Achilles Tendon (S1-2)
Determining the Degree of Muscle Reflex Activity for DTR
- 0: Absent, no response (flaccidity)
- 1+ Minimal/Decreased response (hypotonia)
- 2+ Normal response
- 3+ Brisk/strong, exaggerated response (mild/moderate hypertonia)
- 4+ Sustained response, clonus (severe hypertonia)
Abnormalities of Muscle Tone
- Hypertonia: Upper motor neuron (UMN) syndrome
- Hyperreflexia or clonus
- Spasticity: Often seen in those who have had a stroke (CVA). Velocity-dependent resistance to passive stretch.
- Rigidity: Classic symptom of Parkinson's disease. Increased/uniform resistance throughout ROM (independent of velocity).
- Hypotonia: Often due to Lower motor neuron (LMN) injury.
- Flaccidity (decreased or absent muscle tone)
- Diminished (or absent) resistance to passive movement and reflexes
- Characteristic of Down Syndrome
- Commonly assessed in pediatrics
- Dystonia: Disordered tone and involuntary movements of the body. Transmission of motor impulses to/from the cerebral cortex and cerebellum.
Muscle Tone Assessment
- Observation of resting posture
- Palpation of muscle belly
- Passive and active motion testing (vary the speed of movements to check for tone)
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Description
Explore the fascinating world of reflexes, which are automatic responses to stimuli that occur without conscious thought. This quiz covers types of reflexes, including somatic and autonomic, and delves into the neural pathways involved, such as reflex arcs. Test your understanding of how reflexes function and their importance in rapid motor responses.
