Autonomic Nervous System (ANS) Flashcards
What does ANS stand for?
Autonomic nervous system
1) What main pathway makes up the ANS?
2) What other neurons can be included sometimes under ANS?
1) Visceral Efferent pathway (VE)
2) GVA - general visceral afferent
True or False:
The VE pathway is one of two pathways that utilize 2 neurons.
False
VE is the only pathway to utilize 2 neurons, all the others only use a single neuron.
Are the VE neurons multipolar or unipolar?
multipolar because the cell body receives the synapse and is excited and then transmits it
Describe the two neurons of the VE pathway.
1) Preganglion neuron - cell body located in CNS –> axon synapses in an autonomic ganglion
2) Postganglion neuron - cell body in an autonomic ganglion –> axon innervates smooth muscle, cardiac muscle and glands
What neurotransmitter does each neuron release?
1) preganglion neuron always releases acetylcholine at its synaptic terminals
2) postganglion neuron releases acetylcholine or norepinephrine as its transmitter chemical to excite target cells
1) Name the ANS division that controls “fight or flight”?
2) Name the ANS division that restores and maintans routine visceral operations
1) Sympathetic
2) Parasympathetic
1) Where is the sympathetic distributed in the body?
2) Where does the preganglion originate?
1) whole body
2) thoracolumbar spinal cord
1) Where is the parasympathetic located in the body?
2) Where does the preganglion originate?
1) viscera in body cavities; in head
2) sacral spinal cord and brainstem
Name the action that the sympathetic has on this structure:
1) iris
2) heart
3) bronchi
4) gut and bladder wall
5) gut and bladder sphincters
6) cutaneous vessels
7) muscle vessels
8) sweat glands
9) penis
10) liver
1) dilate
2) increase rate and force of contraction
3) dilate (increase air in lungs)
4) inhibit motility
5) contract
6) constrict
7) dilate
8) secrete
9) semen ejaculation
10) glucose release
Name the action the parasympathetic has on these structures
1) iris
2) heart
3) bronchi
4) gut and bladder wall
5) gut and bladder sphincter
6) cutaneous vessels
7) muscle vessels
8) sweat glands
9) penis
10) GI
1) constrict
2) decrease rate
3) constrict
4) excite contraction
5) relax
6) doesn’t innervate
7) doesn’t innervate
8) doesn’t innervate
9) penis erection
10) secretion in stomach and pancreas
What is the relationship between penis and gut and bladder sphincters in sympathetic?
they have opposite actions - bladder sphincter constricts while penis ejaculates because penis can’t urinate while it’s ejaculating (urine is very acidic, don’t want to combine urine and seminal fluid)
True or False:
The gut and bladder wall, and gut and bladder sphincters are always opposing actions.
True
Which part of the VE pathway do we mostly see?
preganglion because postganglion neurons are in terminal ganglia located within submucosal and myenteric nerve plexuses within muscle or glands
Name the three parts of the parasympathetic pathway.
1) Cranial nerves III, VII and IX
2) Cranial nerve X (vagus nerve)
3) Sacral spinal cord
1) What does the vagus nerve innervate?
2) Where is the preganglion located?
3) Where does the synapse occur?
4) Where is the postganglion pathway located?
1) innervates thoracic and abdominal viscera
2) the vagus nerve branches travel to organs being innervated
3) occurs within the organs, in microscopic terminal (in plexuses)
4) axons course in submucosal or myenteric plexuses to reach innervation targets (smooth, cardiac muscle or gland cells)
1) What does the sacral spinal cord innervate?
2) Where is the preganglion located?
3) Where does the synapse occur?
4) Where is postganglion located?
1) innervates pelvic viscera (digestion, urinary bladder, genitalia)
2) from sacral cord to pelvic plexus (ventral root –>spinal nerve –>ventral branch –>lumbosacral plexus –>pelvic nerve)
3) occurs in a pelvic ganglion within the pelvic plexus (or in organ innervated)
4) branches from pelvic plexus run directly to pelvic viscera
Name the six regions of the sympathetic pathway
1) Head
2) Neck
3) Body Wall and Limbs and tail
4) Thoracic Viscera
5) Abdominal viscera
6) Pelvic Viscera
Head region:
1) Preganglion path:
2) Synapse:
3) Postganglion path:
1) ventral root –> spinal nerve –> ramus communicans –> sympathetic trunk –> ansa subclavia –> cervical sympathetic trunk
2) cranial cervical ganglion
3) nerve plexuses –> run on external and internal carotid arteries and their branches to reach target structures
What does plexus mean in this context (ANS)?
plexuses = visceral nerves running on vessels –> named for whatever vessel they run on
Neck:
1) Preganglion path:
2) synapse:
3) postganglion path:
1) ventral root –> spinal nerve –> ramus communicans –> sympathetic trunk
2) cervicothoracic ganglion
3) vertebral nerve –> rami communicantes –> cervical spinal nerve –> dorsal or ventral branches to muscles and skin
body wall, limbs and tail:
1) preganglion path:
2) synapse:
3) postganglion path:
1) ventral root –> spinal nerve –> ramus communicans –> sympathetic trunk
2) sympathetic trunk ganglia
3) rami communicantes –> spinal nerve –> dorsal or ventral branches to muscles and skin
Thoracic viscera:
1) Preganglion path:
2) synapse:
3) postganglion path:
1) ventral root –> spinal nerve –> ramus communicans –> sympathetic tunk
2) cervicothoracic adn middle cervical ganglia
3) cardiosympathetic nerve branch from ansa subclavia (also, branches that run with vagus nerve)
What is the relationship between spinal neves adn ramus communicans?
every spinal nerve has a ramus communicans –> only in thoracolumbar region ramus communicans has pre and postganglions
everywhere else ramus communicans has only postganglion going up to dorsal and ventral branches
abdominal viscera:
1) preganglion path:
2) synapse:
3) postganglion path:
1) ventral root –> spinal nerve –> ramus communicans –> sympathetic trunk –> splanchnic nerve
2) prevertebral ganglia (left/right celiac, cranial mesenteric, caudal mesenteric , renal, and gonadal ganglia) located in nerve plexuses along the aorta
3) nerve plexuses on abdominal arteries supplying particular organs
Pelvic viscera:
1) preganglion path:
2) synapse:
3) postganglion path:
1) ventral root –> spinal nerve –> ramus communicans –> sympathetic trunk –> lumbar splanchnic nerve –> caudal mesenteric plexus
2) caudal mesenteric ganglion
3) hypogastric nerve –> pelvic plexus –> branches directly to pelvic viscera (left/right)
Label the numbered structures
1) Sympathetic (thoracolumbar)
2) cranial cervical ganglion
3) middle cervical ganglion
4) cervicothoracic ganglion
5) sympathetic trunk ganglion
6) left celiac ganglion
7) cranial mesenteric ganglion
8) caudal mesenteric ganglion
9) cranial nerve X
10) Parasympathetic (craniosacral)
Label the numbered structures
1) ventral root
2) spinal nerve
3) lumbosacral plexus
4) pelvic nerve
5) pelvic plexus and ganglia
What is this region of the sympathetic pathway?
head region
What region of the sympathetic pathway is shown in the picture?
neck region
What region of the sympathetic pathway is show here?
body wall and limbs and tail
What region of the sympathetic pathways is shown here?
thoracic viscera
What region of the sympathetic pathway is shown here?
abdominal viscera
What is the region of the sympathetic pathway shown here?
pelvic viscera
