Autonomic nervous system

Question 1

What is the main function of the autonomic nervous system?

Answer 1

Controls involuntary visceral activity to maintain homeostasis or respond to stress

Question 2

What components form the autonomic nervous system?

Answer 2

General visceral efferent nerves
General visceral afferent nerves
Components of CNS that regulate visceral activity by receiving or sending signals to GVE & GVA systems

Question 3

What are the 2 branches of of the General Vsceral Efferent nervous system?

Answer 3

Sympathetic: fight or flight (thoracolumbar)

Parasympathetic: Rest and Digest (Craniosacral)

Question 4

Do any autonomic nerves come off the cervical region?

Answer 4

No

Question 5

There are 2 neuronal components that form both the divisions of the General Visceral Efferent System, what are they?

Answer 5

A preganglionic component

A post ganglionic component

Question 6

What are pre ganglionic & post ganglionic components?

Answer 6

Pre-ganglionic: Axon exits spinal cord and synapses on post-ganglionic cell body

Post-ganglionic: Pre-ganglionic component synapses on cell body, and post-ganglionic axon innervates Effector muscle

Question 7

How do the pre- and post-ganglionic components differ between Para- and Sympa- systems?

Answer 7

Sympathetic: Equal sized pre- and post-ganglionic portions. Post-ganglionic cell body located outside the organ wall

Parasympathetic: Long pre-ganglionic aspect, post-ganglionic cell body & axon is located in the organ wall

Question 8

The sympathetic pathway always starts the same, describe the signal flow

Answer 8

Lateral grey horn -> Ventral root -> spinal nerve -> ramus communicans -> Sympathetic trunk

Question 9

Describe sympathetic signal flow for the body wall & limbs

Answer 9

Lateral grey horn -> Ventral root -> spinal nerve -> ramus communicans -> sympathetic trunk -> ganglion sympathetic trunk ganglia -> post (other sympathetic trunk rami -> other spinal nerves) or continue down ventral branch of spinal nerve after sympathetic trunk ganglion

Question 10

Do all spinal nerves have a GVE and GVA branch?

Answer 10

Yes, both the dorsal branch and ventral branch of a spinal nerve are mixed

Question 11

What is the communicating branch of the sympathetic nervous system?

Answer 11

Ramus communicans

Branches off the spinal nerve

Question 12

What are paravertebral ganglion?

Answer 12

Sympathetic trunk ganglion

Question 13

Describe the sympathetic pathway for the head

Answer 13

Lateral grey horn -> ventral root -> spinal nerve -> ramus communicans -> sympathetic trunk -> Ansa subclavia -> vagosympathetic trunk -> ganglion cranical cervical ganglion -> post internal & external carotid nerve plexus

Question 14

Describe the sympathetic pathway for the neck

Answer 14

Lateral grey horn -> ventral root -> spinal nerve -> ramus communicans -> sympathetic trunk -> ganglion cervicothoracic ganglion -> post vertebral nerve -> rami communicates to cervical spinal nerves -> dorsal/ventral branches of cervical spinal nerves

Question 15

Describe the sympathetic pathway for the thorax

Answer 15

Lateral grey horn -> ventral root -> spinal nerve -> ramus communicans -> sympathetic trunk -> ansa subclavia -> ganglion cervicothoracic ganglion or middle cervical ganglion -> post branches from ansa subclavia or courses with vagus nerve

Question 16

Describe the sympathetic pathway for the abdominal cavity

Answer 16

Lateral grey horn -> ventral root -> spinal nerve -> ramus communicans -> sympathetic trunk -> major, minor, lumbar splanchnic nerves -> ganglion celiacomesenteric ganglion & plexus -> nerve plexus on abdominal muscles

Question 17

Describe the sympathetic pathway for the pelvic cavity

Answer 17

Lateral grey horn -> ventral root -> spinal nerve -> ramus communicans -> sympathetic trunk -> lumbar splanchnic nerves -> ganglion caudal mesenteric ganglion -> post hypogastric nerves -> pelvic plexus -> branches that follow blood vessels to pelvic viscera

Question 18

What is the last sympathetic ganglion?

Answer 18

Caudal mesenteric ganglion

Question 19

What is the only nerve that comes fro the caudal mesenteric ganglion?

Answer 19

Left & Right hypogastric nerves

Question 20

The parasympathetic system is composed of which nerves?

Answer 20

Cranial nerves III, VII, IX, X (vagus), sacral spinal cord

Question 21

What parasympathetic nerves innervate the head?

Answer 21

Cranial nerves III, VII, and IX

Question 22

What parasympathetic nerves innervate the thoracic and abdominal viscera?

Answer 22

Cranial nerve X (vagus)

Question 23

What parasympathetic nerves innervate the pelvic viscera?

Answer 23

Sacral spinal cord

Question 24

Describe the pathway of the vagus nerve to the thorax/cervical region

Answer 24

Parasympathetic Nucleus of vagus nerve -> vagus nerve -> vagosympathetic trunk -> vagus nerve -> vagal branches to heart, lungs, recurrent laryngeal nerves -> ganglion terminal ganglia within organs -> post axon in organ wall

Question 25

Describe the pathway of the vagus nerve to the abdominal region

Answer 25

Parasympathetic Nucleus of the vagus nerve -> vagus nerve -> vagosympathetic trunk -> vagus nerve -> dorsal & ventral vagal branches -> dorsal & ventral vagal trunks -> dorsal vagal trunk joins celiacomesenteric plexus, ventral vagal trunk goes directly to stomach & liver -> ganglion terminal ganglia within organ -> post axon in organ wall

Question 26

Does the dorsal vaga trunk synpase on the celiacomesenteric nerve plexus?

Answer 26

No, it joins the celiacomesenteric plexus via the celiac branch

Question 27

What are the 2 branches of the celiacomesenteric plexus and what organs do they innervate

Answer 27

Celiac plexus: stomach, spleen, liver, gallbladder, pancreas

Cranial mesenteric plexus: small intestines, cecum, ascending & transverse colon

Question 28

What is the pathway of the sacral spinal cord to the pelvis viscera?

Answer 28

Intermediate gray matter of S1 - S3 -> ventral root -> spinal nerve -> ventral branch -> lumbosacral plexus -> pelvic nerve -> pelvis plexus -> ganglion pelvic ganglia in pelvic plexus -> post branches from pelvic plexus to pelvic viscera

Question 29

Why can nerves pass through a plexus without synapsing?

Answer 29

Nerves will wait to synapse until the last possible ganglion within the pathway

Question 30

What segments do parasympathetic nerves originate in?

Answer 30

Brainstem (cranial nerves III, VII, IX, X) and Sacral spinal segments S2, S3, S4

Question 31

What spinal cord segments do sympathetic nerves originate in?

Answer 31

T1 to L2 (Thoracolumbar)

Question 32

What is the cutaneous area?

Answer 32

Entire area of the skin that is innervated by a nerve

Question 33

What is the autonomous zone?

Answer 33

Area of skin that is innervated solely by a specific nerve with no overlap from adjacent nerves

Question 34

There are 4 nerve* and vessel branches in the fore paw, what are they?

Answer 34

Superficial dorsal common digital, superficial palmar common digital

Deep dorsal metacarpal (vessels only, no nerves)
Deep palmar metacarpal

Question 35

What cervical nerve becomes the phrenic nerve?

Answer 35

Deep branch of C5

Question 36

What are the 2 branchs of C2?

Answer 36

Great auricular nerve, transverse cervical nerve

Question 37

What is the endothoracic fascia?

Answer 37

Fascia of the thorax that supports all serosal layers and gives strength to thoracic ligaments