What is true about somatic reflexes?
They are important in regulating digestion and blood pressure.
They help prepare the body for “fight-or-flight.”
We are not usually aware of them.
They activate skeletal muscle.
The Correct Answer and Explanation is :
The correct answer is:
“They activate skeletal muscle.”
Explanation:
Somatic reflexes are involuntary responses that involve the activation of skeletal muscles in response to specific stimuli. Unlike autonomic reflexes, which regulate involuntary functions such as digestion and blood pressure, somatic reflexes primarily involve the somatic nervous system and control voluntary muscles.
Key Features of Somatic Reflexes:
- Activation of Skeletal Muscles:
- Somatic reflexes involve the contraction of skeletal muscles, such as those in the arms, legs, or face.
- A common example is the patellar reflex (knee-jerk reflex), where a tap on the patellar tendon causes an involuntary contraction of the quadriceps muscle, resulting in a leg kick.
- Fast and Involuntary Response:
- Although skeletal muscles are generally under voluntary control, reflexes bypass conscious thought to rapidly respond to stimuli (e.g., pulling your hand away from a hot surface).
- These reflexes are mediated by the spinal cord rather than the brain, allowing for faster reactions.
- Reflex Arc Components:
- A somatic reflex follows a reflex arc, which consists of:
- Receptor (detects stimulus)
- Sensory neuron (transmits signal to the spinal cord)
- Interneuron (sometimes present) (processes information)
- Motor neuron (sends signal to skeletal muscle)
- Effector (skeletal muscle) (produces the response)
- Examples of Somatic Reflexes:
- Stretch Reflex (e.g., Knee-Jerk Reflex) – Helps maintain posture.
- Withdrawal Reflex – Protects the body from harmful stimuli.
- Crossed Extensor Reflex – Helps maintain balance when one limb withdraws.
Thus, somatic reflexes activate skeletal muscles and are crucial for movement, posture, and protection.
Now, I’ll generate an image illustrating a somatic reflex arc.
Here is an anatomical illustration of a somatic reflex arc, specifically depicting the knee-jerk (patellar) reflex. It includes labeled components such as the receptor, sensory neuron, spinal cord with interneuron, motor neuron, and effector muscle. Let me know if you need any modifications or further explanations!