7.1 Autonomic Nervous System Flashcards
What do the motor neurons in the ANS do
- Innervate smooth muscle, cardiac muscle & glands
- Make adjustments to ensure optimal support for body activities
- Operate via subconscious control
divisions of the autonomic nervous system
sympathetic and parasympathetic
comparison of neurons and actions in somatic and autonomic nerous system
- Somatic
- cell bodies in central NS
- single neuron from CNS to effector organs
- release ACh
- always stimulatroy
- Autonomic
- cell bodies in central NS
-
two neuron chain from CNS -> effector organ
- preganglionic myelinated axons releases Ach to non myelinated postganglionic
- release ACh OR NE to effector
- stimulatory or inhibitory
the ANS has ____ innervation
Dual innervation
(inputs from sympathetic and non sympathetic NS)
- almost all visceral organs served by both divisions but cause opposite effects
compare origin of fibers, length and location of ganglia in PSNS vs SNS
- Parasympathetic
- origin of fibers: craniosacral (brain & S2-4)
- Length: long pregnaglionic, short postganglionic
- location of ganglia: visceral effector organs
- Sympathetic
- origin of fibers: thoracolumbar (T1-L2)
- legnth: short preganglionic, long postganglionic
- location of ganglia: close to spinal chord (synpase close to it)
What is the role of the parasympathetic division?
- maintenance activities & conserves body energy
ex: a person who relaxes, reading, after a meal: - > Blood pressure, heart rate & respiratory rates are low
- > Gastrointestinal tract activity is high
- > Pupils are constricted & lenses are accommodated for close vision
” D division: digestion, defication and urine porduction”
what roots are involed in PSNS division outflow
Oculomotor (CN III)
Facial (CN VII)
Glossopharyngeal (CN IX)
Vagus (CN X)
what is the ganlia, lits location and effector organs for
oculomotor (CN III)
Ganglia: cilliary ganglion
ganglia location: posterior orbit
Effector organ: eye (ciliary muscle & sphincter pupillae)
*makes pupil smaller
what is the ganlia, lits location and effector organs for
facial (CN VII)
Ganglia: Pterygopalatine and submandicular ganglion
Location of ganglion: pterygopalatine fossa & infratemporal fossa
effector organ: Nasal, palatine & lacrimal glands, & Submandibular & sublingual salivary glands
what is the ganlia, lits location and effector organs for
glossopharyngeal (CN IX)
ganglia: otic ganglion
location: infratemporal fossa
effector organ: parotid salivary glands
what is the ganlia, lits location and effector organs for
Vagus nerve (CN X)
ganglia: intramural ganglion
location: in walls of target organs
effector organs: most visceral organs
what is the ganlia, its location and effector organs for
sacral parasympathetic division outflow
*S2-S4
- ganglia: intramural ganglion
location: within walls of target organs
effector organs: Distal large intestine, urinary bladder, ureters & reproductive organs
what is the role of the sympathetic divison
- Mobilizes body during activity: fight or fight
- promtoes adjustments during exercise or when threatened
- > Blood flow is shunted to skeletal muscles & heart
- > Bronchioles dilate
- > Liver releases glucose
- > pupils dilate (wide eyes)
” e division: exercise, excitment, emergency, embarassment”
where are the preganglionic neruons in the sympathetic divisons?
- in spinal chord segments T1-L2
- sympathetic neruons produce spinal chord lateral horns (extra gray horns in spinal chord)
where do preganglionic fibers of the sympathetic division pass through in spinach chord
- pass trhough white rami communicates to enter the sympathetic trunk (paravertebral ganglia)
where are the sympathetic trunk ganglia?
- hve 23 sympathic trunk ganglia in sympathetic trunk
- located in all areas of spinal chord (cervical, thoracic, lumbar, sacral and occygeal)
describe what happens when a preganglionic fiber enters the sympathetic trunk ganlion and synpases at the same level
- starts at lateral horn
- exists spinal chord form ventral root
- enters sympathetic trunk ganglion via white ramus communicans
- exists sympathetic trunk via gray ramus to effector
describe what happens when a preganglionic fiber enters the sympathetic trunk ganlion and synpases at a higher or lower level
- starts at lateral horn
- exists spinal chord at ventral root
- trhough white ramus communicans -> sympathetic trunk ganlgion up or down a few levels
*if didnt do this would only get innveration T1-L2
- exists via gray ramus communicans to effector
describe the pathway of the SNS to the head
- fibers emerge from T1- T4 (upper part) and synpase in superior cervial ganglion
- these fibers
- > innervate skin and blood vessels of head
- > stimulate dilator muscles of iris
- > inhibit nasal and salivary galnds
describe the SNS pathways to the thorax
- preganglionic fibers emerge from T1-T6 & synapse in cervical trunk ganglia
- postganglionic fibers emerge from ganglia and enter nerves C4-C8 to innervate
- > heart (via cardiac plexus) and lungs (via pulmonary plexus)
- > thyroid gland
- > skin (majority)
Describe the SNS pathway to the abdomen
- preganglionic fibers from T5-L2 travel throuhg splanchnic nerves to synapse in prevertebral (collateral) gnaglia
*contribute to plexuses
- > celiac ganglion: liver, gall bladder, stomach, spell, pancreas *proximal duodenum
- > superior mesenteric ganglia: pancreas, distal duodenum, jejunum ,ileum, ascending colon + transverse colon
- > inferior nesenteric ganglia: descending colon, sigmoid colon + upper rectum
describe the SNS pathway to the pelvis
- pathways synapse in sympathetic trunk ganglia
- sacral splanchnic nerves: inneravte genitalia and blasser
describe the SNS pathway to the adrenal medualla
*pathway is only 1 neuron
- preganglionic fibers pass directly to adrenal meduall without synpases in celiac ganglion
- upon stimualtion, adrenal emdulla secretes: norepinephrine and ***epiephrine into blood directly
*upon sympathetic activation get quick efefcts bc adrenal medially pumps direclty into blood
