Autonomic Nervous System (ANS)

Question 1

What does ANS stand for?

Answer 1

Autonomic nervous system

Question 2

1) What main pathway makes up the ANS?
2) What other neurons can be included sometimes under ANS?

Answer 2

1) Visceral Efferent pathway (VE)
2) GVA - general visceral afferent

Question 3

True or False:

The VE pathway is one of two pathways that utilize 2 neurons.

Answer 3

False

VE is the only pathway to utilize 2 neurons, all the others only use a single neuron.

Question 4

Are the VE neurons multipolar or unipolar?

Answer 4

multipolar because the cell body receives the synapse and is excited and then transmits it

Question 5

Describe the two neurons of the VE pathway.

Answer 5

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

Question 6

What neurotransmitter does each neuron release?

Answer 6

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

Question 7

Answer 7

Question 8

Answer 8

Question 9

1) Name the ANS division that controls “fight or flight”?
2) Name the ANS division that restores and maintans routine visceral operations

Answer 9

1) Sympathetic
2) Parasympathetic

Question 10

1) Where is the sympathetic distributed in the body?
2) Where does the preganglion originate?

Answer 10

1) whole body
2) thoracolumbar spinal cord

Question 11

1) Where is the parasympathetic located in the body?
2) Where does the preganglion originate?

Answer 11

1) viscera in body cavities; in head
2) sacral spinal cord and brainstem

Question 12

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

Answer 12

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

Question 13

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

Answer 13

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

Question 14

What is the relationship between penis and gut and bladder sphincters in sympathetic?

Answer 14

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)

Question 15

True or False:

The gut and bladder wall, and gut and bladder sphincters are always opposing actions.

Answer 15

True

Question 16

Which part of the VE pathway do we mostly see?

Answer 16

preganglion because postganglion neurons are in terminal ganglia located within submucosal and myenteric nerve plexuses within muscle or glands

Question 17

Name the three parts of the parasympathetic pathway.

Answer 17

1) Cranial nerves III, VII and IX
2) Cranial nerve X (vagus nerve)
3) Sacral spinal cord

Question 18

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?

Answer 18

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)

Question 19

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?

Answer 19

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

Question 20

Name the six regions of the sympathetic pathway

Answer 20

1) Head
2) Neck
3) Body Wall and Limbs and tail
4) Thoracic Viscera
5) Abdominal viscera
6) Pelvic Viscera

Question 21

Head region:

1) Preganglion path:
2) Synapse:
3) Postganglion path:

Answer 21

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

Question 22

What does plexus mean in this context (ANS)?

Answer 22

plexuses = visceral nerves running on vessels –> named for whatever vessel they run on

Question 23

Neck:

1) Preganglion path:
2) synapse:
3) postganglion path:

Answer 23

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

Question 24

body wall, limbs and tail:

1) preganglion path:
2) synapse:
3) postganglion path:

Answer 24

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

Question 25

Thoracic viscera:

1) Preganglion path:
2) synapse:
3) postganglion path:

Answer 25

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)

Question 26

What is the relationship between spinal neves adn ramus communicans?

Answer 26

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

Question 27

abdominal viscera:

1) preganglion path:
2) synapse:
3) postganglion path:

Answer 27

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

Question 28

Pelvic viscera:

1) preganglion path:
2) synapse:
3) postganglion path:

Answer 28

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)

Question 29

Label the numbered structures

Answer 29

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)

Question 30

Label the numbered structures

Answer 30

1) ventral root
2) spinal nerve
3) lumbosacral plexus
4) pelvic nerve
5) pelvic plexus and ganglia

Question 31

What is this region of the sympathetic pathway?

Answer 31

head region

Question 32

What region of the sympathetic pathway is shown in the picture?

Answer 32

neck region

Question 33

What region of the sympathetic pathway is show here?

Answer 33

body wall and limbs and tail

Question 34

What region of the sympathetic pathways is shown here?

Answer 34

thoracic viscera

Question 35

What region of the sympathetic pathway is shown here?

Answer 35

abdominal viscera

Question 36

What is the region of the sympathetic pathway shown here?

Answer 36

pelvic viscera