1 Flashcards
What is the Autonomic Nervous System (ANS)?
The autonomic nervous system is a set of pathways to and from the central nervous system (CNS) that innervates and regulates smooth muscle, cardiac muscle, and glands.
What role does the ANS play in the body?
The autonomic nervous system plays a major role in homeostasis but also controls non-homeostatic organs such as the reproductive system.
How does the output of the ANS differ from the somatic nervous system?
Autonomic nervous system output to visceral organs is continuous (tonic), while the somatic nervous system output to skeletal muscle is phasic and undergoes periods of repose.
How does ANS activity respond to demands?
Autonomic nervous system activity changes in anticipation of demands placed on us.
How is ANS output coordinated with somatic activity?
Autonomic nervous system output is coordinated with somatic activity to provide supportive visceral function, such as blood flow.
What is a notable characteristic of the ANS?
One of the most striking characteristics of the autonomic nervous system is the rapidity and intensity with which it can change visceral functions.
How quickly can the ANS increase heart rate?
The autonomic nervous system can increase the heart rate to twice normal within 3 to 5 seconds.
What are the three divisions of the ANS?
The autonomic nervous system has three divisions: sympathetic, parasympathetic, and enteric.
What is the nature of the sympathetic nervous system?
The sympathetic nervous system has an intense ramification (1:20), is very diffuse, and has generalized action; it is catabolic in nature.
What is the nature of the parasympathetic nervous system?
The parasympathetic nervous system has a limited ramification (1:1), discrete discharge, affects specific effector systems individually, and is anabolic in nature.
Where are the synapses between neurons made in the ANS?
Synapses between neurons are made in the autonomic ganglia.
Where are the parasympathetic ganglia located?
Parasympathetic ganglia are located in or near the effector organs.
Where are the sympathetic ganglia located?
Sympathetic ganglia are located in the para-vertebral chain.
Where do pre-ganglionic neurons originate in the sympathetic nervous system?
Pre-ganglionic neurons of the sympathetic nervous system originate in spinal cord segments T1-L3, or the thoraco-lumbar region.
What are the characteristics of sympathetic pre-ganglionic neurons?
Sympathetic pre-ganglionic neurons are short and myelinated.
