Crossed-extensor Reflex (Nursing)

00:01 So the next reflex that we’ll discuss is the crossed-extensor reflex.

00:05 This reflex is actually a response to the withdrawal reflex and helps to maintain balance when you withdraw.

00:14 So in this reflex, we start with withdrawal.

00:18 First we step on a tack which is going to stimulate the sensory receptors in the foot.

00:24 This is going to propagate a nerve impulse from the sensory neuron to the spinal cord.

00:33 Just as we discussed before in the withdrawal reflex you're going to have an intersegmental integration of this signal where we're going to synapse with interneurons and multiple parts including descending interneurons, ascending interneurons and the interneurons of the spinal cord segment that receives the sensory signal.

00:58 From there, the interneurons is going to synapse with the motor neurons and this is going to cause us to contract the muscles and withdraw away from the pain stimulus.

01:11 So in this part, the withdrawal reflex has taken place.

01:16 But if you've ever all of a sudden lifted your foot up out of nowhere, your body is going to be off-balanced.

01:24 So the next things that happens is a contralateral reflex occurs in the opposite leg.

01:33 In this part, motor neurons are actually excited in the opposite leg and this causes you to contract and extend the opposite leg so that you can maintain your balance.