Question

While walking through the woods one day, Ricardo sees a large bear. His sympathetic nervous system will most likely a. cause his heart to beat faster as he prepares to run away b. allow him to notice how smooth his can of bear spray feels against his hand c. cause a reflexive reaction in his spinal cord that lets him run away d. allow his breathing to slow as he relaxes and thinks about what to do next

Short answer

a. cause his heart to beat faster as he prepares to run away

Step-by-step solution

Choice A: Cause his heart to beat faster as he prepares to run away

The sympathetic nervous system does increase the heart rate in stressful situations as part of the "fight or flight" response. This option aligns with the known response of the sympathetic nervous system.

Choice B: Allow him to notice how smooth his can of bear spray feels against his hand

The sympathetic nervous system does not have a direct influence on the sense of touch. This option does not align with the known response of the sympathetic nervous system.

Choice C: Cause a reflexive reaction in his spinal cord that lets him run away

The spinal cord reflexes are indeed involved in the "fight or flight" response. However, this option incorrectly attributes this response to the spinal cord rather than to the sympathetic nervous system.

Choice D: Allow his breathing to slow as he relaxes and thinks about what to do next

The sympathetic nervous system does not cause relaxation or slowed breathing. The parasympathetic nervous system is responsible for the "rest and digest" response, which involves slowing breathing and calming the body. This option does not align with the known response of the sympathetic nervous system. Based on the analysis of each choice, the correct response is:

Answer

a. cause his heart to beat faster as he prepares to run away

Key concepts

Fight or Flight Response

The fight or flight response is our body's automatic reaction to perceived danger. When faced with a threatening situation, such as encountering a large bear, our brains send signals to the sympathetic nervous system.
This initiates a cascade of physiological changes designed to prepare the body to either fight the threat or flee from it. This response is part of our evolutionary survival mechanisms.

• Increased heart rate: The heart pumps faster to deliver more oxygen-rich blood to muscles, helping them perform intense physical tasks.
• Faster breathing: Breathing quickens to increase the oxygen supply in the bloodstream.
• Dilated pupils: Eyes widen to improve vision and assess the surrounding environment better.

These changes enable quick reactions, enhancing our ability to handle potentially dangerous situations effectively.

Autonomic Nervous System

The autonomic nervous system (ANS) is a crucial part of the human body responsible for regulating involuntary activities, such as breathing, heart rate, and digestion. It operates subconsciously and consists of two main branches: the sympathetic and parasympathetic nervous systems.

• Sympathetic Nervous System: Often referred to as the 'fight or flight' system, it prepares the body for dealing with stress and emergencies by increasing heart rate and energy levels.
• Parasympathetic Nervous System: Known as the 'rest and digest' system, it helps the body conserve energy and return to a state of calm by lowering heart rate and facilitating digestion.

Both systems work in harmony to maintain balance, also known as homeostasis, in our bodies by responding to various internal and external changes.

Stress Response

A stress response refers to the body's reaction to pressure or threat. This is triggered when the brain perceives any situation as stressful, be it physical danger or emotional strain.
The process begins in the brain, which signals the adrenal glands to release hormones like adrenaline and cortisol. These hormones catalyze several changes in the body to handle stress.
Some common physiological responses include:

• Increase in energy: Hormones released boost glucose levels in the bloodstream for extra energy.
• Heightened alertness: The mind becomes more focused to address the immediate threat.
• Suppression of non-essential functions: Activities like digestion slow down so that the body can direct energy to more critical functions.

In the long term, frequent activation of the stress response can affect health, highlighting the need for effective stress management strategies.