Chapter 14) The ANS Flashcards
1
Q
Autonmic Nervous System
A
- ANS is made of nuerons that
- Innervate smooth muscle, cardiac muscle, and glands
- Make automatic adjustments to ensure optimol support for body activities
- ANS brings blood where it is needed by adjusting heart rate, blood pressure, digestive processes, etc…
- Also called Involuntary Nervous System or General Visceral Motor System
2
Q
Somatic vs Autonomic system (diffrences)
A
- Effectors
- Somatic) effector innervates skeletal muscle
- Autonomic) effector innervates cardiac muscle, smooth muscle and glands
- Effrent Pathways and Ganglia
- SNS) cell body is in CNS, axon extends to muscle via nerve
- Somatic Motor Division does not have ganglia
- ANS) Effrent pathway occurs in two steps
- Preganglionic nueron) Cell body in CNS, thin, Lightly Myelinated
- Postganglionic nueron) Cell body is in autonomic ganglion outside CNS. Thin xaons that are nonmyelinated, extends to effector organ
- SNS) cell body is in CNS, axon extends to muscle via nerve
- Nuerotransmitter Effects
- SNS) Release acetycholine (ACh) at synapses
- ANS)
- Preganglionic fibers release ACh
- Postganglionic fibers release norepinepherine by sympathetic fibers, and ACh next to Parasympathetic Fibers
- Effect is either stimulitory or inhibitory
3
Q
Overlap of Somatic and Autonomic Function
A
- Higher Brain Centers regulate and coordiante both somatic and autonomic motor activties
- Most cranial and spinal nerves will contain both somatic and autonomic fibers
- Changes will usually invilve both skeletal muscles and visceral organs
- EX) when muscles are working hard ANS will speed up heart rate and open airways to allow more oxygen intake.
4
Q
Parasympathetic Division
A
- Rest and Digest) Digestion, Diuresis, Defication
- ex) person relaxing after a long meal
- Blood Pressure, Heart Rate, and Resprityory
- Gastrointestional tract activity is high
- Pupils Constrict to help with close up vision
- ex) person relaxing after a long meal
- Releases ACh which causes an ihibiotry effect
5
Q
Sympathetic Division
A
- Flight or Flight) Excercise, Excitment, Emergeny, and Embarassment
- Increased heart rate, dry mouth, cold sweaty skin, dilated pupils
- During Vigerous Physical Activity
- Shunts Blood to skeletal muscles and heart
- Dilates Bronchioles
- Causes liver to release glucose
6
Q
Diffrences in Sympathetic and Parasympathetic Divisions
A
- Sites of Origin
- Parasympetic) Brain and Sacral spinal Chord (Craniosacral)
- Sympathetic) Thoracic and Lumbar Regions of Spinal Chord (thoracolumbar)
- Relative Lenths of Fibers
- Parasympathtic) Long preganglionic and short postganglionic fibers
- Gangli is located near or in visceral organs
- Sympathetic) Short preganglionic and Long postganglionic fibers
- Ganglia are near spinal chord
- Parasympathtic) Long preganglionic and short postganglionic fibers
7
Q
Craniosacral Division
A
- Cranniosacral division = Parasympathetic division
- Preganglionic Fibers) From CNS to target organs
- Posganglionic) Terminal Ganglia that are close/within target organs synapse with effectors
- Cranial Part (cell bodies located in brain stem)
- Preganglionic fibers run from
- Oculomotor Nerves (III)
- Control smooth muscle of the eye.
- Cell bodies located in Ciliary ganglia within eye orbitals
- Facial Nerves (VII)
- Stimulate large glands in head
- Nasal/ Lacrimal Glands synapse in Pterygopalatine Ganlia
- Submandubular and Sublungual silivary glands synapse in Submandibular gangli
- Glossopharyngeal nerves (IX)
- Stimulate partoid silvary glands
- Fibers Synapse in Otic Ganglia
- Vagus Nerces (X) Account for 90% of all parasypathetic fibers in the body
- Serves all thoracic and Abdominal visvera
- Cardiac Plexus) Heart Rate
- Pulmonary Plexus) Lungs and Bronchi
- Esophageal Plexus) Organs of Digestion
- Sacral Part of Parasympatetic Division
- Orginates in nuerons S2-S4
- Serves pelvic organs and distal half of large intestine
- Branch to form Pelvic Splanchnic nerves which pass through inferior hypogastric (pelvis) plexis
- Fibers synapse in intramural ganglia
8
Q
Thoracolumbar Division
A
- Symoathetic is more complex and innervates more organs than parasympathetic
- Sweat glands, Arrector Pili (hair) and smooth muscle of arterties and veins are only innervated by sympatetic division
- Preganglionic Nuerons are in chord segments T1-L2
- come from the lateral horn of the spinal chord
- Fibers pass through white rami communicates to Sympatetic (trunk) ganglia
9
Q
Anatomical Differences Between ANS Divisions
A
- Sympathetic Trunks Exted from Neck and Pelvis but Sumpathetic Fibers only come from thoracic and lumber segments
- Parevertebrall Ganglia
- 3 cervical
- 11 thoracic
- 4 lumbar
- 4 sacral
- 1 coccygeal
10
Q
Location of Preganglionic Fiber on Trunk Ganglion
A
- Synapse at the Same Level)
- synapse is in the same trunk ganglion
- Synapse at a higher/lower level)
- Preganglionic axon ascends/descends sympathetic trunk to synapse to another trunk ganglion
- Synapse in a distant Collateral Ganglion
- Preganglionic axon passes through the trunk ganglion and emerges from the sympatic trunk without synapsing
- Only found in abdomen and Pelvis
- Synpathetic Ganglia are close to spinal chord with long postganglionic fibers (opposite in parasympathetic fibers).
11
Q
Sympathetic Pathways with Synapses in Trunk Ganglia
A
- Postganglionic Sypathetic axonx enter ventral rami via gray rami communicantes
- Grey Rami Communicantes) nonmyelinated postganglionic fibers
- White Rami Communicantes) myelinated preganglionic fibers
- Pahways to the Head
- Fibers emerge from T1-T4 and synapse in superior cervical ganglion
- Innervate skin and blood vessels of the head, Stimulate dilator muscles of the iris, Inhibit nasal and salivary glands (the reason
your mouth goes dry when you are scared), Innervate smooth muscle of upper eyelid, Branch to the heart
- Pathways to Thorax
- Preganglionic fibers emerge from T1-T6 and synapse in cervical trunk ganglia
- Postganglia run from cervical ganlia and enter nerves C4-C8
- Innervate heart (cardiac plexus) and lungs and esophagus
12
Q
Pathways With Synapeses in Collateral Ganglia
A
- Most fibers from T5-L2 synapse in collateral ganglia located outside of the trunk. These form several splanchnic nerves.
- Thoracic splanchic nerves
- Lumbar Splanchnic nerves
- Sacral Splanchnic nerves
- These Splanchnic nerves interweve forming Abdominal Aortic Plexuses which contain several important ganglia
- Celiac, Superior and Inferior Mesenteric Ganglia
- Postganglonic fibers from these ganglia then travel to abdomen and Pelvis
- Pathways to abdomen
- From T5-L2 > Through Thoricic splanchic nerves > Celiac and Superior Medentric Ganglia> Postganglionic Fibers (stomach, promixal large intestine, liver, spllen and kidneys).
- Pathways to Pelvis
- T10-L2>Lumbar/sacral splanchnic nerves > Lumbar/Sacral Ganglia> Postganglionic (Distal Large Intestine, Urinary bladder, Reproductive organs).
- Some pathways skip the lumbar/ sacral splanchnic nerves and go straight to ganglia
13
Q
Synapeses in Adrenal Medulla
A
- Pass direcilty through the celiac ganglion to adrenal medulla without synapsing.
- Will stimulate medullary celles to release norerinerpine and epineprine
- Also known as noraderenaline and adrenaline
- Adrenal Medulla can be considered a Ganglion and its horomone cells are the “postganglionic nuerons”
14
Q
Visceral Sensory Nuerons
A
- Send info about chemical changes, stretch, temprature, and irritation
- All receptors are free nerve endings scattered throuought viscera
- Cell bodies
- Dorsal root ganglia (sensory)
- Cranial Nerves
15
Q
Visceral Reflexes
A
- Receptor is in Viscera
- Afferent fibers (Visceral Sensory Nueron)
- Integration center
- can be preganglionic nueron
- Dorsal Horn internueron
- or within walls of GI tract
- Motor nueron (two nueron chain)
- Preganglionic nueron>postganglionic nueron
- Visceral Effector
