Autonomic Nervous System Flashcards
regulates the activity of smooth muscle, cardiac muscle, and certain glands
autonomic nervous system
maintains homeostasis (depends on the continual flow of sensory afferent input, from receptors in organs, and efferent motor output to effector organs)
autonomic nervous system
structures of the ANS
autonomic sensory neurons, integrating centers in the CNS and autonomic motor neurons
operates w/o conscious control
ANS
what parts of the brain control the ANS
mainly the hypothalamus and the medulla oblangata
sensory input for somatic nervous system
from somatic senses and special senses
sensory input for ANS
mainly from interoceptors; some from somatic senses and special sense
control of motor output for somatic nervous system
VOLUNTARY control from cerebral cortex, with contributions form basal ganglia, cerebellum, brain stem, and spinal cord
control of motor output for ANS
INVOLUNTARY control from hypothalamus, limbic system, brain stem and spinal cord; limited control from cerebral cortex
motor neuron pathway for somatic nervous system
one-neuron pathway; somatic motor neurons extending from CNS synapse directly with effector
motor neuron pathway for ANS
usually two-neuron pathway; preganglionic neurons extending from CNS synapse with postganglionic neurons in autonomic ganglion, and postganglionic neurons extending from ganglion synapse with visceral effector. Alternatively, preganglionic neurons may extend from CNS to synapse with chromaffin cells of adrenal medullae
neurotransmitters and hormones of the somatic nervous system
all somatic motor neurons release only acetylcholine (ACh)
neurotransmitters and hormones of the ANS
all sympathetic and parasympathetic preganglionic neurons release ACh. Most sympathetic postganglionic neurons release NE; those to most sweat glands release ACh. All parasympathetic postganglionic neurons release ACh. Chromaffin cells of adrenal medulla release epinephrine and norepinephrine (NE)
effectors of the somatic nervous system
skeletal muscle
effectors of the ANS
smooth muscle, cardiac muscle, and glands
responses of the somatic nervous system
contraction of skeletal muscle
responses of the ANS
contraction or relaxation of smooth muscle; increased or decreased rate and force of contraction of cardiac muscle; increased or decreased secretions of glands
ANS motor pathways
1) the axon of the first neuron of the ANS extends from the CNS & synapses in a ganglion with the second neuron
2) the second neuron synapses on an effector. Preganglionic fibers release ACh and postganglionic fibers release ACh or NE
3) the efferent part of the ANS is divided into 2 principal parts: the sympathetic and the parasympathetic divisions. Organs that receive impulses from both sympathetic and parasympathetic fibers are said to have dual innervation
where are the cell bodies of sympathetic preganglionic neurons found; what division is this called
lateral gray horns of the 12 thoracic and first 2 or 3 lumbar segments; thoracolumbar division
what are the axons of the sympathetic preganglionic neurons known as
thoracolumbar outflow
where are the cell bodies of parasympathetic preganglionic neurons found
in cranial nerve nuclei (III, VII, IX, and X), brain stem, lateral gray horns of the 2nd-4th sacral segments of the cord
parasympathetic division is aka
craniosacral division
types of sympathetic ganglia
sympathetic trunk, prevertebral ganglia
where is the vertebral trunk located
vertical row on either side of the vertebral column
where is the prevertebral ganglia located
anterior to spinal column and close to large abdominal arteries
what abdominal arteries are considered prevertebral ganglia
celiac, superior mesenteric, and inferior mesenteric ganglia
where does the sympathetic preganglionic neurons synapse with postganglionic neurons
ganglia of the sympathetic trunk or prevertebral ganglia
type of parasympathetic ganglia
terminal or intramural ganglia
where are terminal ganglia located
close to or within the wall of a visceral organ
name some terminal ganglia
ciliary, pterygopalatine, submandibular, and otic ganglia
what synapses with postganglionic neurons in terminal ganglia
neurons
major autonomic plexuses
cardiac, pulmonary, celiac and hypogastric
sympathetic responses are stimulated by 4 E’s
Emergency, embarassment, exercise, and excitement
effects of sympathetic stimulation are
longer-lasting and more widespread
specific sympathetic responses
dilation of pupils, increased HR and BP, blood flow to kidneys and GI tract diminishes, blood flow to skeletal muscles, liver, heart, and adipose tissue increases
flight or flight system
sympathetic
rest or relax system
parasympathetic
effects of parasympathetic stimulation last for
short time and less widespread
parasympathetic responses
salivation, lacrimation, urination, digestion, defacation, decreased HR, decreased airway diamteter, and decreased pupil diameter
which neural path consists of two motor neurons
autonomic
sympathetic preganglionic fibers synapse in
sympathetic trunk and prevertebral ganglia
postganglionic sympathetic fibers leave the sympathetic trunk ganglia by way of the
gray rami
80% of the total craniosacral outflow is carried by
vagus nerve (x)
parasympathetic fibers associated with cranial nerve VII synapse in which terminal ganglia before continuing to their visceral effectors
submandibular and pterygopalatine
parasympathetic preganglionic neurons synapse with postganglionic neurons in
terminal ganglia
what is true concerning the sympathetic division of the ANS
most presynaptic fibers are very short
all postganglionic sympathetic fibers from the ___ ganglion go to structures in the head
superior cervical
nerve fibers of the sympathetic division originate in the
thoracic and lumbar region of the spinal cord
which autonomic ganglion is associated with the superior mesenteric artery
superior mesenteric
the cell bodies of sympathetic preganglionic neurons are located in the
spinal cord
pelvic splanchnic nerves are examples of
parasympathetic nerves
preganglionic fibers to the ciliary ganglion are associated with CN
III
the white rami contain
preganglionic sympathetic neurons
parasympathetic preganglionic fibers are ____; parasympathetic postganglionic fibers are ____
long; short
what is a drug classified as a non-specific beta blocker that reduces HR and force of contraction
propranolol
adrenergic neurons release
NE
what is true of adrenergic fibers
they are stimulated during the flight-or-flight response
the adrenergic receptors for NE and epinephrine are
alpha and beta
what is the balance between sympathetic and parasympathetic activity called
autonomic tone
what part of the NS is the main control and integrative center of the ANS
hypothalamus
what part of the autonomic reflex pathway differs from the somatic reflex pathway
motor pathway