The autonomic nervous system (ANS) Flashcards
What is the main role of the Autonomic Nervous System (ANS)?
The ANS controls the organs of the body and operates autonomously, meaning we have little voluntary control over its actions.
What are the two major divisions of the Autonomic Nervous System (ANS)?
Sympathetic Nervous System
Parasympathetic Nervous System
How do the sympathetic and parasympathetic nervous systems work in relation to each other?
They act in opposition to each other, balancing body functions. The sympathetic system prepares the body for action, while the parasympathetic system helps the body relax and recuperate.
What is the main function of the Sympathetic Nervous System?
The Sympathetic Nervous System prepares the body for immediate action, activating the fight-or-flight response. It increases heart rate, raises blood pressure, dilates pupils, and more.
Where do sympathetic nerves originate, and how do they innervate organs?
Sympathetic nerves exit from the middle parts of the spinal cord, travel a short distance, and innervate the sympathetic ganglia, which are found in two chains along the spinal column. From there, axons spread to the organs.
What is the role of the Parasympathetic Nervous System?
The Parasympathetic Nervous System helps the body relax, recover, and prepare for future action, also called the rest-and-digest response.
Where do parasympathetic nerves originate, and how do they travel?
Parasympathetic nerves originate in the brainstem and sacral spinal cord and typically travel longer distances before reaching parasympathetic ganglia, which are located near the organs.
How do the sympathetic and parasympathetic systems differ in terms of neurotransmitters?
The sympathetic system uses norepinephrine, while the parasympathetic system uses acetylcholine to influence organs.
How does the balance between the sympathetic and parasympathetic systems affect the body?
The balance determines the state of the internal organs:
Parasympathetic predominance slows heart rate, lowers blood pressure, and activates digestion.
Sympathetic predominance increases heart rate, raises blood pressure, and inhibits digestion.
Why is the balance between the sympathetic and parasympathetic systems important?
This balance ensures the body is prepared for the current circumstances, whether it requires relaxation and recovery or a heightened state for action.
