1. Explain why the knee-jerk and Achilles reflexes are important in walking.
The knee-jerk and Achilles reflexes are important in walking because they help maintain stability and control in the lower limbs. These reflexes are part of the stretch reflex, which is a rapid protective response to prevent overstretching or damaging the muscles and tendons involved in walking.
To understand why these reflexes are important, it's essential to know how they work. Let's start with the knee-jerk reflex, also known as the patellar reflex. When the doctor taps the patellar tendon just below the kneecap with a reflex hammer, it causes a rapid contraction of the quadriceps muscle at the front of the thigh. This contraction extends the leg at the knee joint, causing the lower limb to straighten.
The Achilles reflex, also called the ankle jerk reflex, occurs when the Achilles tendon, located at the back of the ankle, is tapped. This reflex results in a quick contraction of the calf muscles, causing plantarflexion of the foot (pointing the toes downward).
Now, how do these reflexes aid in walking?
During the stance phase of walking (when the foot is on the ground), the knee-jerk reflex provides stability by keeping the knee joint extended. When the foot strikes the ground, the jolt caused by the impact stretches the quadriceps muscle, triggering the reflex contraction. This rapid extension of the leg helps maintain balance and prevents the knee from buckling.
Similarly, the Achilles reflex plays an important role in walking as well. As the foot is lifted off the ground during the swing phase of walking, the Achilles tendon stretches. When the foot prepares to touch the ground again, the tap on the Achilles tendon during the reflex test leads to contraction of the calf muscles. This contraction acts to resist the downward pull of gravity, ensuring a controlled and gentle landing of the foot.
In summary, the knee-jerk and Achilles reflexes contribute to the coordinated movement and stability of the lower limbs during walking. They act as protective mechanisms by counteracting forces of muscle stretch, helping to maintain balance, preventing joint collapse, and ensuring a smooth and controlled gait pattern.
The knee-jerk and Achilles reflexes play important roles in walking by providing necessary stability and coordination.
1. Knee-jerk reflex: The knee-jerk reflex, also known as the patellar reflex, is the response that occurs when the patellar tendon below the kneecap is tapped. This causes the quadriceps muscles in the front of the thigh to contract and the leg to extend.
- Importance in walking: The knee-jerk reflex helps to maintain balance and stability while walking. When the foot comes in contact with the ground during each step, sensory receptors in the sole of the foot send signals to the spinal cord, triggering the knee-jerk reflex. This reflex causes the leg to extend, helping to keep the body in an upright position. It also helps to maintain a steady rhythm and aids in energy conservation during walking.
2. Achilles reflex: The Achilles reflex, also known as the calcaneal reflex, is the response that occurs when the Achilles tendon at the back of the ankle is tapped. It causes the calf muscles to contract and the foot to flex.
- Importance in walking: The Achilles reflex is crucial for walking because it helps to regulate the movement of muscles involved in ankle joint control. During walking, the Achilles tendon stores and releases energy as the foot rolls from heel to toe. This energy plays a significant role in propelling the body forward, reducing the energy required from the muscles. The reflex contraction of the calf muscles (gastrocnemius and soleus) through the Achilles reflex ensures the coordinated movement of the foot and aids in maintaining balance and stability during walking.
In summary, the knee-jerk and Achilles reflexes are important in walking as they help maintain balance, stability, and coordinated muscle movements. The knee-jerk reflex helps keep the body upright and maintain a steady rhythm, while the Achilles reflex aids in ankle joint control and provides energy for forward propulsion.
Since this is not my major area of expertise, I searched Google under the key words "Patellar Achilles reflex walking" to get these possible sources:
http://www.waybuilder.net/sweethaven/MedTech/Neurology/Neurology01.asp?mode=1&iNum=0204
http://brain.oxfordjournals.org/cgi/content/full/126/2/495
http://www3.interscience.wiley.com/cgi-bin/summary/117886745/SUMMARY?CRETRY=1&SRETRY=0
http://books.google.com/books?id=g2eqHcnm1W4C&pg=PT691&lpg=PT691&dq=patellar+achilles+reflex+walking&source=web&ots=ujgOFwjzVY&sig=1nGnKZP0r-0XXvz0hfm4ao43KPM
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search.
I hope this helps. Thanks for asking.