Final answer:
The autonomic nervous system consists of the sympathetic and parasympathetic branches, with the former triggering the fight-or-flight response and the latter supporting rest and digest functions. Target organs like the heart and muscles change their activity levels during the fight-or-flight response to prepare the body for potential danger.
Step-by-step explanation:
Autonomic Nervous System Functions and Fight-or-Flight Response
The autonomic nervous system regulates the body's internal organs without conscious effort and consists of two main branches: the sympathetic and parasympathetic nervous systems. The sympathetic nervous system triggers the fight-or-flight response during perceived threats, increasing heart rate, breathing rate, and blood flow to skeletal muscles, while decreasing blood flow to the digestive system. Conversely, the parasympathetic nervous system supports rest and digest functions, such as slowing the heart rate and promoting digestion.
Changes in Target Organs During Fight-or-Flight
During the fight-or-flight response, various target organs undergo significant changes. The heart rate increases to pump more blood to muscles and vital organs. The digestive system's activity is reduced to prioritize functions that aid in responding to danger, like muscle readiness. Additionally, there may be increased sweat gland secretion to help regulate body temperature during intense physical activity.