Question

Autonomic or somatic reflex that involved stimulation of skeletal muscle

Answer 1

Reflex arcs have five essential components:

1.        The receptor at the end of a sensory neuron reacts to a stimulus.

2.       The sensory neuron conducts nerve impulses along an afferent pathway towards the CNS.

3.        The integration center consists of one or more synapses in the CNS.

4.        A motor neuron conducts a nerve impulse along an efferent pathway from the integration center to an effector.

5.        An effector responds to the efferent impulses by contracting (if the effector is a muscle fiber) or secreting a product (if the  

           effector is a gland).

Reflexes can be categorized as either autonomic or somatic. Autonomic reflexes are not subject to conscious control, are mediated by the autonomic division of the nervous system, and usually involve the activation of smooth muscle, cardiac muscle, and glands. Somatic reflexes involve stimulation of skeletal muscles by the somatic division of the nervous system.
Most reflexes are polysynaptic (involving more than two neurons) and involve the activity of interneurons (or association neurons) in the integration center. Some reflexes; however, are monosynaptic ("one synapse") and only involve two neurons, one sensory and one motor. Since there is some delay in neural transmission at the synapses, the more synapses that are encountered in a reflex pathway, the more time that is required to effect the reflex.

The knee jerk reflex is called a monosynaptic reflex. This means that there is only 1 synapse in the neural circuit needed to complete the reflex. It only takes about 50 milliseconds of time between the tap and the start of the leg kick...that is fast. The tap below the knee causes the thigh muscle to stretch. Information is sent to the spinal cord. After one synapse in the ventral horn of the spinal cord, the information is sent back out to the muscle...and there you have the reflex.

Answer 2

Skeletal muscles are innervated by somatic nervous system, their response is controlled by somatic reflex.