Understanding the Body's Emergency Response System

The question asks how the body prepares for an emergency. The correct answer is the sympathetic nervous system.

Step 1: Understanding the Autonomic Nervous System

The autonomic nervous system controls involuntary bodily functions and is divided into two main parts:

• The Sympathetic Nervous System
• The Parasympathetic Nervous System

These two systems often have opposing effects.

Step 2: Role of the Sympathetic Nervous System

The sympathetic nervous system is responsible for the "fight or flight" response. It is activated in stressful or emergency situations. Its job is to prepare the body to either confront a threat or run away from it.

When activated, it causes several physiological changes:

• Increases heart rate and blood pressure
• Dilates airways to increase oxygen intake
• Stimulates the release of glucose for energy
• Diverts blood flow away from digestion and towards muscles

This entire process is coordinated by the sympathetic nerves and the hormone adrenaline (epinephrine).

Step 3: Why the Other Options Are Incorrect

• Skeleton and muscles: While these are the physical structures that carry out the movement (e.g., fighting or fleeing), they do not coordinate the body's preparation. They are the effectors, not the control system.
• Parasympathetic nervous system: This system is responsible for "rest and digest" activities. It conserves energy and calms the body down. Its effects are the opposite of an emergency response (e.g., it slows the heart rate).
• Muscles and glands: Again, these are the organs that respond to commands. Muscles contract, and glands (like adrenal glands) secrete hormones. However, the command to activate them comes from the nervous system, specifically the sympathetic division.

Final Answer

The body is prepared for an emergency through the sympathetic nervous system.

Related Topics & Formulae

Key Concept: Homeostasis

Homeostasis is the maintenance of a stable internal environment. The sympathetic and parasympathetic nervous systems work together to maintain homeostasis by adjusting the body's physiology to internal and external demands.

Key Neurotransmitters & Hormones

The sympathetic nervous system uses norepinephrine at synapses between nerves and effectors. It also signals the adrenal medulla to release epinephrine (adrenaline) and norepinephrine into the bloodstream. The general effect can be summarized by the physiological changes listed in Step 2.

Comparison of Autonomic Divisions