Nervous System VI: Autonomic Nervous System Flashcards
autonomic nervous system definition
- a motor system
- regulates the activity of cardiac muscle, smooth muscle, and glands
- responds to external factors to maintain homeostasis
- has components in both CNS and PNS
the ANS involves a two neuron chain containing what two neurons?
- preganglionic neuron
- postganglionic neuron
preganglionic neuron location
- cell body is located in CNS
- axon from this neuron exits CNS through a cranial or spinal nerve
which neuron in the two neuron chain synapses onto the other
-preganglionic neuron synapses on the postganglionic neuron
postganglionic neuron location
- cell body located in PNS autonomic ganglion
- axon of this neuron innervates smooth muscle, cardiac, muscle, and glands
what are the two subdivisions of the ANS?
- sympathetic
- parasympathetic
how do the two subdivisions of the ANS differ?
- location of their pre and postganglionic neurons
- neurotransmitter
- effect**
sympathetic division location
-thoracolumbar nerve fibers from thoracic and upper portions of spinal cord T1-L2
location of sympathetic division components
-gray matter of thoracic and lumbar spinal cord
sympathetic division: preganglionic neuron
- all thoracic nerve (T1-T12)
- upper lumbar nerve(L1-L2)
what does the preganglionic nerve from sympathetic division synapse with?
-postganglionic neuron with sympathetic chain ganglia (paravertebral chain ganglion)
sympathetic division: postganglionic neuron
- neuron after ganglion
- nerve cell body located in paravertebral chain ganglion or prevertebral ganglion
sympathetic division: paravertebral ganglia
-long vertical interconnected chain of ganglia that runs alongside the spinal column
sympathetic division: prevertebral ganglia
- found anterior to vertebral column
- found in abdomen and pelvis
sympathetic division autonomic neurotransmitters components
- preganglionic neuron: acetylcholine**
- postganglionic neuron: norepinephrine**
sympathetic division general effect
- fight or flight response
- (i.e. short term response, requires increased energy)
sympathetic division: adrenal medulla
-contains cell derived from opstganglionic neurons
sympathetic division: adrenal medulla location
-on the superior pole of the kidney
sympathetic division: adrenal medulla secretions
- epinephrine
- norepinephrine
parasympathetic division
-craniosacral nerve fibers come from brain and sacral portion of spinal cord
parasympathetic division location of components
- preganglionic neurons
- postganglionic neurons
parasympathetic division preganglionic neurons
- nuclei of cranial nerves located in the brain stem**
- nuclei in sacral region of spinal cord (S2-S4)
parasympathetic division preganglionic neurons nuclei cranial nerves
- oculomotor (III)**
- facial (VII)**
- glossopharyngeal (IX)**
- vagus (X)**
parasympathetic division postganglionic neurons location
- located close to organ innervated
- i.e. eye, sensory glands, thoracic cavity
parasympathetic division neurotransmitter components
- preganglionic: acetylcholine
- postganglionic: acetylcholine
parasympathetic division general effect
- resting/digesting
- active when body at rest
- long term response
each division’s effect on heart
- sympathetic: heart rate increases
- parasympathetic: heart rate decreases
each division’s effect on smooth muscle of bronchioles
- sympathetic: dilate
- parasympathetic: constrict
each division’s effect on urinary bladder
- sympathetic: relax/fill
- parasympathetic:contract/expand
each division’s effect on digestive tract
- sympathetic: decrease
- parasympathetic: increase
each division’s effect on sweat galnds
- sympathetic: increase
- parasympathetic: no effect
each division’s effect on arrector pili
- sympathetic: hair stands
- parasympathetic: neutral
each division’s effect on eye
- sympathetic: dilate
- parasympathetic: constrict
vasoconstriction
-constriction of blood vessels
difference between somatic and autonomic motor: movements
- sensory: conscious and voluntary
- autonomic: not under conscious control (involuntary)
difference between somatic and autonomic motor: # of neurons
- sensory: single neuron to effects(motor unit)
- autonomic: two neuron chain (pre & postganglionic)
difference between somatic and autonomic motor: myelination
- sensory: thick/heavy myelinated
- autonomic: pre=myelinated & post=unmyelinated
difference between somatic and autonomic motor: conduction rates
- sensory: rapid conduction of impulse innervates skeletal muscle
- autonomic: slow conduction of an impulse smooth muscle, cardiac and glands
difference between somatic and autonomic motor: stimulation differences
- sensory: always stimulatory
- autonomic: may be stimulatory or inhibitory
