Answer :
The responsible reaction for your friend's fear of spiders is her sympathetic nervous system. Here's why:
1. The sympathetic nervous system is known as the "fight or flight" response system in the body. When a person encounters a perceived threat or stressor (like seeing a spider in this case), the sympathetic nervous system is activated.
2. Activation of the sympathetic nervous system leads to various physiological responses, such as increased heart rate (which causes her heart to start pounding) and rapid breathing (which results in her feeling short of breath).
3. These responses are part of the body's adaptive mechanism to prepare for a perceived danger or threat. In the case of your friend's fear of spiders, her body's sympathetic nervous system is triggering these reactions to help her respond to what her brain perceives as a threat.
By understanding how the sympathetic nervous system functions in response to fear or stress, you can better grasp why your friend experiences these physical symptoms when she encounters a spider.