Chapter 15 - Autonomic Nervous System Flashcards
What is the peripheral nervous divided into?
- Somatic nervous system
- Autonomic nervous system
- Enteric nervous system
What does the somatic nervous system include?
Sensory neurons
Motor neurons
What is the sensory input for the somatic nervous system?
What is the sensory input for the autonomic nervous system?
Somatic: somatic senses (tactile, thermal, pain, proprioceptive sensations) and special senses
(sight, hearing, taste, smell, equilibrium)
Autonomic: Interoceptors, some somatic senses & special senses
What happens when a somatic motor neuron stimulates a muscle?
It contracts
- the effect is always excitation
What kind of movements are produced by the somatic motor neurons?
What kind of movements are produced by the autonomic motor neurons?
Somatic: Reflexive and voluntary
Autonomic: Involuntary
What is the main input to the ANS?
Autonomic (visceral) sensory neurons
What are interoceptors?
Sensory receptors located in blood vessels, visceral organs, muscles and the nervous system (that monitors the INTERNAL environment)
What makes interoceptors different than regular sensory receptors?
They are usually not consciously perceived
What are the effectors of autonomic motor neurons?
What are the effectors of somatic motor neurons?
Autonomic: Regulate visceral activities by increasing (exciting) or decreasing (inhibiting) ongoing activities in their effector tissues (cardiac muscle, smooth muscle, glands)
Somatic: Skeletal muscles
What makes tissues innervated by the ANS different from skeletal muscles?
- will function to some extent if their nerve supply is damaged (heart will still beat after removed for transplantation)
- cannot be consciously altered
How are somatic and autonomic neural pathways different?
Somatic: one neuron pathway (extend from CNS synapse directly with effector)
Autonomic: usually two neuron pathway (preganglionic neurons extend from CNS, synapse with postganglionic neurons in autonomic ganglion. Postganglionic neurons synapse with effector)
What is an autonomic ganglion?
Collection of neuronal cell bodies in the PNS
What is a preganglionic neuron?
The first neuron;
- has it’s cell body in the CNS
- myelinated
What is the postganglionic neuron?
The second neuron;
- lies outside the CNS, inside the PNS
- unmyelinated
- axon extends from ganglion to the effector
What are the two division of the autonomic nervous system?
- Sympathetic
2. Parasympathetic
What is dual innervation?
Organs that receive input from both sympathetic and parasympathic neurons
What is the sympathetic division often called?
Fight-or-flight response
- excitiory
What is the parasympathetic division often called?
Rest-and-digest division
- inhibitory
What does the sympathetic division of the ANS do to the body?
Results in increased alertness and metabolic activities in order to prepare the body for an emergency situation
What does the parasympathetic division of the ANS do to the body?
Conserves and restores body energy during times of rest or digesting a meal
What is the thoracolumbar division?
Part of sympathetic division
- preganglionic neurons have cell bodies in 12 thoracic segments and first 2/3 lumbar segments
What is the thoracolumbar outflow?
Axons of the sympathetic preganglionic neurons
What is the craniosacral division?
Part of parasympathetic dividion
- preganglionic neurons have cell bodies in 4 cranial nerves (III, VII, IX, X) and in the 2nd-4th sacral segments
What is the craniosacral outflow?
Axons of the parasympathetic preganglionic neurons
What are the two major groups of autonomic ganglia?
- Sympathetic ganglia
2. Parasympathetic ganglia
What are sympathetic ganglia?
Sites of synapses between sympathetic preganglionic and postganglionic neurons
What are the two major types of sympathetic ganglia?
- Sympathetic trunk ganglia
2. Prevertebral ganglia
What are sympathetic trunk ganglia?
Postganglionic axon primarily innervate organs above the diaphragm, near the spinal cord
- head, neck, shoulders, heart
- extend from base of skull to coccyx
- preganglionic axons are short
- postganglionic axons are long
What are prevertebral ganglia?
Postganglionic axons primarily innervate organs below the diaphragm