Autonomic Nervous System Flashcards
ANS primary function
primary function
-acts to maintain the internal environment within the limits compatible with life
ANS
-responsds to..
responds to both internal and external changes and makes appropriate homeostatic adjustments
ANS
- controlled by…
- coordinated with…
controlled by the hypo and through it is coordinated with the CNS, endocrine and immune systems
ANS “final common pathway” or “LMN”
-how is it different from the somatic motor system?
consists of a “two neuron chain” LMN organization
ANS “two neuron chain”
- consists of…
- how do they get their names
preganglionic neuron
-has a cell body located within the CNS
postganglionic neuron
-has a cell body located in a peripheral ganglion
where do the following synapse
- preganglionic neurons
- postganglionic neurons
pre
-post neurons
post
-ANS target tissues
what are ANS target tissues?
smooth muscle
cardiac muscle
glands
ANS major divisions
-location of each
sympathetic
-thoracolumbar
parasympathetic
-craniosacral
sympathetic nervous system is organized with…
preganglionic cell bodies
postganglionic cell bodies
SNS preganglionic cell bodies
-located in…
the intermediolateral cell column (lateral horn) of spinal cord levels T1-L2 (thoracolumbar)
SNS preganglionic cells
- axon descriptions
- neurotransmitter
short myelinated axon (type III) directed toward peripheral sympathetic chain ganglion
neurotransmitter
-Ach (nicotinic)
SNS postganglionic cell bodies
-location
paravertebral ganglion located parallel to the spinal cord along a paravertebral chain associated with the ventral roots of spinal nerves T1-L2
also located in the cervical region and as prevertebral ganglion
SNS postganglionic cells
- axon descriptions
- neurotransmitter
long unmyelinated axons (type IV) travel as components of peripheral nerves to target organs
neuro
-norepinephrine
SNS postganglionic cells
-how is norepinephrine released?
adrenal medulla receives preganglionic innervation
-activates and releases norepinephrine hormonally
PSNS preganglionic cell bodies
-location
located in nuclei associated with CN III, VII, IX, X
located in the intermediolateral cell column of spinal cord levels S2-S4 (craniosacral)
PSNS preganglionic cells
- axon description
- neurotransmitter
long myelinated axon (type III) directed toward peripheral ganglion
neuro
-ACh (nicotinic)
PSNS postganglionic cell bodies
-location
ganglion located near the target organ or within the wall of the target organ
PSNS postganglionic cell bodies
- axan description
- neurotransmitter
short unmyelinated axons (type IV)
neuro
-ACh (muscarinic)
ANS functional interactions: convergence-divergence
-explain
preganglionic axon can synapse on more than one postganglionic cell body resutling in divergence
OR
several preganglionic axons can synapse on a single postganglionic cell body resulting in convergence
which of the ANS systems displays a greater degree of divergence
-what is the resut?
SNS
accounts for mass action effect of sympathetic activity
as a “final common pathway,” the innervation of smooth muscles, cardiac muscles, and glands establishes and maintains _____ similar to _____
establishes and maintains “tone” similar to the tone noted in our somatic extrafusal muscles
smooth muscles of capillary beds are controlled by _____ “tone”
sympathetic
how is blood flow controlled in the capillary beds of the peripheral vascular system
they receive no parasympathetic innervation
an increase or decrease in sympathetic activity changing the “tone” of precapillary sphincters results in changes of flow through capillary beds