Question

Trace the path that a nerve signal would take after you felt something sharp with your finger. Then trace the signal to remove your hand from the sharp object.

Answer 1

A nerve signal from feeling something sharp with your finger follows a reflex arc that involves sensory receptors, action potentials, interneurons in the spinal cord, and motor neurons that lead to muscle contraction to withdraw the hand.

Step-by-step explanation:

When you feel something sharp with your finger, a series of events involving sensory neurons and reflex arcs occur. The path taken by a nerve signal after such a sensation involves several key steps:

1. A sensor receptor in your skin detects the sharp stimulus. This receptor, sensitive to pain or mechanical changes, generates a graded potential.
2. If the stimulus is strong enough to hit the threshold, it triggers an action potential in the neuron.
3. The action potential propagates along the sensory neuron towards the spinal cord.
4. In the spinal cord, the signal is transferred to an interneuron, which then relays it to a motor neuron.
5. This motor neuron sends the signal to the appropriate muscles in the hand, prompting them to contract and pull away from the sharp object.

This entire process forms a reflex arc, which allows for a rapid response, often without the need for direct involvement of the brain. This quick reaction time is crucial for protecting the body from harm.