Chapter 30 ANS Flashcards
What are splanchnic nerves?
Nerves that arise from within the sympathetic
thoracic trunk
What are characteristics of the sympathetic nervous system?
- Thoracolumbar system
- Ganglia are near the spinal cord
- Short pre-ganglionic fibers and long post-ganglionic fibers
- Unit action/activates many organs at one time
What are characteristics of the parasympathetic nervous system?
- CN III, CN VII, CN IX, CN X & sacral spinal cord segments: S2, S3, & S4
- Craniosacral system
- Ganglia are near/within the wall of the innervated organ
- Long pre-ganglionic fibers & short post-ganglionic fibers
- stimulates ONLY one organ at a time
What is a pre-ganglionic neuron?
Neurons that connect the CNS to the ganglia of the ANS
What is a post-ganglionic neuron?
A neuron that has its cell body in the autonomic ganglion and carries the impulse from the ganglion to the effector
What are the origins for the sympathetic nervous system?
Lateral horns of T1-L2 segments of spinal cord
What are the origins for the parasympathetic nervous system?
Brainstem nuclei & S2-S4 segments of spinal cord
What are the main effectors for the somatic nervous system?
Skeletal muscle
What are the main effectors for the autonomic nervous system?
- Smooth muscle
- Cardiac muscle
- Endocrine glands
- Exocrine glands
How many nerves does the somatic nervous system contain?
11 nerves
How many nerves does the autonomic nervous system contain?
4 nerves
What is the function of the parasympathetic nervous system?
Rest and digest; relaxes the body after periods of stress and danger
What is the function of the sympathetic nervous system?
Fight or flight
How many neurons does the motor pathway of the somatic system involve?
1 motor neuron
How many neurons does the motor pathway of the autonomic system involve?
2 neurons
