A reflex that causes reciprocal activation of the antagonist muscle is the a. crossed-extensor, b. flexor, c. tendon, d. muscle stretch.

Video transcript

Welcome back, everyone. Let's look at our next question, which reflex is commonly used as a neurological test and is elicited by stimulating cutaneous receptors in the sole of the foot. A stretch reflex b, superficial cord reflex, C crossed extensor reflex or D planter reflex. Well, if you've ever heard of planter warts, uh that could help you remember that our answer choice here would be the planter reflex choice. The planter meaning on the sole of the foot. And this reflex is, as our question says, caused by stimulating the skin, stroking the sole of the foot firmly. It causes uh the toes to flex and come closer together in a normal response. It can be used as a neurological test. Um If it has an abnormal response, the babinski response in which the big toe moves upward, this is a normal response in infants and very young Children up until about the age of two. But in individuals older than that, it's an abnormal response and that can indicate certain uh neurological disorders. So that's how it can be used as a neurological test. So let's look at our other answer. Choices. Choice. A the stretch reflex uh this is a response to a sudden stretching of a muscle which causes the activation of muscle spindles, but it's not a reflex of the sole of the foot. So not what we're looking for. Choice. B the superficial cord reflex, this is an abdominal reflex and doesn't involve the foot. So we'll cross that out and then finally to c the crossed extensor reflex. This is when you have a withdrawal reflex in one limb causing an extension reflects on the opposite limb and the other than in the standing position, these are abnormal after infancy. In the standing position, it's useful because you, it's seen most commonly in a situation where say stepping on something sharp or painful causes the withdrawal of the foot that stepped on that and the shifting of weight, the extension on the other side. So naturally shifting your weight. So you'll be able to pull your foot away from the painful sensation and stand on the other side. But aside from in a standing position, if this is seen in other limbs, uh after infancy, that's considered an abnormal sign, but it's not caused by stroking the soul of the foot. It's not cutaneous repor receptors being stimulated in the sole of the foot. So not our correct answer. So again, that reflex being used as a neurological test, elicited by stimulating cutaneous receptors in the sole of the foot. Choice d the plant or reflex. See you in the next video