Tommy was hiking one day and all of a sudden, a bear appeared just up the pathway. Please describe the likely physiological responses that his body undergoes in response to the bear’s sudden appearance.
The first thing that would happen is the famous adrenaline rush. It is also known as "fight or flight." When faced with dangers you frequently have only 2 options: stand your ground and fight, or take flight and run away. Either choice you will need a large amount of Energy in a short time, and Adrenaline triggers these changes:
Increased heart rate
Heightened hearing acuity
Decreased pain sensitivity
In addition to the adrenaline induced changes, he might also experience a dry mouth, increased perspiration, and goose bumps.
There might be further physiological changes, but those depend on the actions of the bear.