Autonomic Nervous System

Question 1

what are the functions of parasympathetic system

Answer 1

day to day control of viscera

ex. breathing at rest, digestion, elimination of wastes

Question 2

what are the functions of the sympathetic nervous system

Answer 2

active when the animal is stressed (fight or flight)

ex. increases in heart rate, respiration, blood flow to active muscles

Question 3

what are the main control centres of the CNS

Answer 3

hypothalamus and midbrain

Question 4

what are the functions of the hypothalamus and the midbrain

Answer 4

direct control of sympathetic & parasympathetic divisions

cerebral cortex can influence but not command the control centres (emotional status causes blushing)

Question 5

where do the fibres of the CNS run

Answer 5

descending fibres to the brain stem and spinal cord

Question 6

where is the outflow of parasympathetic innervation of the PNS

Answer 6

brain stem & sacral cord level

Question 7

where is the sympathetic outflow of the PNS

Answer 7

thoracolumbar cord level

Question 8

what is the two-neuron system in the PNS

Answer 8

1. pre-synaptic fibre
2. post-synaptic fibre

Question 9

what are the neurotransmitters in the parasympathetic fibres

Answer 9

Ach

at pre and post

Question 10

what are the neurotransmitters at the pre and post synaptic fibres in the sympathetic nervous system

Answer 10

pre = ach

post = ach or NE

Question 11

where are the neural cell bodies located for sensory cell bodies, motor striated muscle, motorneuron cell bodies

Answer 11

dorsal horn for sensory cell bodies

ventral horn for motor striated muscle

intermediated/lateral horn for motorneuron cell bodies of ANS in thoracolumbar and sacral cord

Question 12

how do parasympathetic fibres innervate viscera

Answer 12

cranial nerves from brain to head via CN III, VIII, IX

to cervical, thoracic and abdominal viscera via CN X and vagosympathetic trunk

segmental spinal nerves from sacral spinal cord S1, S2, S3 to pelvic viscera

Question 13

what are the features of pre and post synaptic fibres and where do they synapse

Answer 13

pre-synaptic fibres: long

synapse: close to organ

post-synaptic fibres: short

Question 14

how do sympathetic fibres innervate all viscera

Answer 14

thoracolumbar outflow from CNS –> C8/T1 to L4/5

thoracic cavity –> sympathetic chain of nerves and paravertebral ganglia

abdominal and pelvic cavitites –> fusion of fibres to form prevertebral ganglia –> celiac, cranial, and caudal mesenteric

head –> supplied by spinal nerves from C8-T7 via vagosympathetic trunk

Question 15

what are the features of the pre and post synaptic fibres and where they synapse in the sympathetic system

Answer 15

pre-synaptic: short

synapse: remote from organ

post-synaptic: long

Question 16

what is the white Rami communicans

Answer 16

carries presynaptic sympathetic fibres to the sympathetic trunk in spinal segments T1-L2

Question 17

what is the grey rami communicantes

Answer 17

carries post-synaptic sympathetic fibres from the sympathetic trunk to all spinal nerves

Question 18

where do the pre-ganglionic fibres from T1-5 (to T7) run in the sympathetic supply to the head and neck and where do they synapse

Answer 18

run cranially in vagosympathetic trunk

synapse: cranial cervical ganglion (located deep to tympmanic bulla)

Question 19

where do the post-synaptic fibres of the sympathetic supply to head and neck run

Answer 19

some follow arteries of the head region (carotid artery)

some follow CN IX-XII, vagal nerve branches to larynx and pharynx

Question 20

what are the functions of the post-synaptic fibres from the sympathetic

Answer 20

innervation of smooth muscle (vascular, ocular, orbital, erector pilae, glands (sweat, salivary, nasal))

Question 21

what supplies the thorax in the sympathetic nervous system

Answer 21

sympathetic trun

vagus and sympathetic trunk company at chest entrance near middle cervical ganglion at first rib

fibres slpit to pass around the subclavian artery forming the ansa subclavia

large cervicothoracic ganglion followed by a regular chain of ganglia throughout thorax

Question 22

what is the sympathetic supply to abdomen and pelvis

Answer 22

lumbar trunk steadily becomes more erratic –> branches of the sympathetic trunk

supply pre and post synaptic fibres to the abdominal and pelvic regions

Question 23

whare the specific parasympathetic supplies to the body

Answer 23

1. craniosacral system
2. cranial origin: CN III, VII, IX, X
3. sacral origin: S1-3 spinal cord segments

Question 24

what is the nucleus of origin of the oculomotor nerve (CN III)

Answer 24

edinger-westphal (paras. nucleus of CN III) (midbrain)

Question 25

what is the ganglion of the oculomotor nerve

Answer 25

ciliary (close to eye)

Question 26

what is the target organs of the oculomotor nerve

Answer 26

ciliary muscles (regulate lens curvature) muscles of iris (pupil constriction)

Question 27

what is the nucleus of origin of facial nerve (CN VII)

Answer 27

rostral salivatory (paras. nucleus of CN VII) (brainstem)

Question 28

what are the ganglions of the facial nerve

Answer 28

1. pterygopalatine (sphenopalatine) 2. sublingual and mandibular

Question 29

what are the target organs of the pterygopalatine (sphenopalatine)

Answer 29

lacrimal, nasal & palatine glands (secretion, vasodilation)

Question 30

what are the target organ of the sublingual and mandibular

Answer 30

sublingual and mandibular glands (secretion, vasodilation)

Question 31

what is the nucleus of origin of the glossopharyngeal nerve (CN IX)

Answer 31

caudal salivary (paras. nucleus of CN IX) (brainstem)

Question 32

what is the ganglion of glossopharyngeal nerve

Answer 32

otic

Question 33

what is the target organ of the glossopharyngeal nerve

Answer 33

parotid and orbital salivary glands (secretion, vasodilation)

Question 34

what are the nucleus of origin of the vagus nerve

Answer 34

dorsal efferent nucleus of CN X (paras. nucleus of CN X) (brainstem)

Question 35

what is the ganglion of the vagus nerve

Answer 35

terminal (intramural)

Question 36

what are the target organs of the vagus nerve

Answer 36

parasympathetic supply to neck, thorax, abdomen (majority of body viscera --\> cervical, thoracic, abdominal)

Question 37

what is the response of the vagus nerve

Answer 37

heart rate peristalsis sweating larynx opening many

Question 38

where does the CN X travel down the neck

Answer 38

CN X travels down the neck in the vagosympathetic trunk

Question 39

where are the cell bodies in the parasympathetic supply to the pelvic viscera

Answer 39

lateral horn of S1-3 spinal cord segments

Question 40

what are the presynaptic and post synaptic fibres of the parasympathetic supply to the pelvic viscera

Answer 40

axons travel in pelvic nerves (located lateral wall of rectum) synapse at terminal ganglion (near the bladder, rectum and sexual organs) distribution to pelvic viscera, lower intestinal cavity and repro organs

Question 41

what is the function of the sympathetic innervation of the eye

Answer 41

supplies smooth muscle of the orbit and the iris dilators protrusion of eyeball third eyelid retraction dilation of pupils widening of the palpebral fissure

Question 42

how does the sympathetic nervous system innervate the eye

Answer 42

first order neuron goes down to spinal segments T1-T3 second order neuron (in vagosympathetic trunk) third order neuron innervates the eye

Question 43

what are the signs of Horner's syndrome

Answer 43

1. pupillary constriction (miosis) 2. prolapse of third eyelid 3. narrowing of the palpebral fissure 4. enophthalmos

Question 44

what are the causes of Horner's syndrome

Answer 44

herniation (neck) or middle ear infection (otitis) --\> close to tympanic bulla brachial plexus lesion in spinal cord

Question 45

what is the parasympathetic innervation of the eye

Answer 45

CN III is part of the pupillary light reflex 1. retina --\> optic nerve 2. optic tract 3. pretectal nucleus 4. CN III parasympathetic nucleus 5. ciliary ganglion 6. eyeball (smooth muscle constrictor)

Question 46

what does the oculomotor nerve innervate

Answer 46

primarily the smooth muscle constrictor of the pupil

Question 47

what is the function of the oculomotor nerve

Answer 47

pupil constriction (miosis)

Question 48

what are the signs of oculomotor nerve dysfunction

Answer 48

pupil dilation (mydriasis) unresponsive to light

Question 49

a dog has anisocoria (right pupil smaller than left) how will you determine which is the abnormal eye

Answer 49

put in the dark should get dilation

Question 50

left eye constricts when shine a light in eye right eye already constricted

Answer 50

sympathetic can't dilate pupil in right eye

Question 51

how does brain herniation lead to miosis

Answer 51

often miosis intially --\> as midbrain swells --\> compression of CN --\> non-functioning parasympathetic nucleus of III --\> mydriasis progression from miotic to mydriatic pupils indiactes increasingly severe brain pathology

Question 52

what is the sympathetic innervation of the urinary tract and its function

Answer 52

hypogastric nerve (L1-4 in dogs, L2-5 cats) relaxes the detrusor muscle in the bladder contraction of the smooth muscle of the bladder neck/internal urethral sphincter

Question 53

what is the parasympathetic innervation to the bladder and its function

Answer 53

predominant in voiding phase pelvic nerve (S1-3) contraction of detrusor muscle of bladder wall supplies urogenital organs, rectum, descending colon

Question 54

what is the somatic innvervation of the bladder

Answer 54

pudendal nerve (S1-3) contraction of the striated sphincter muscles for urinary retention innervates anal sphincter (perineal reflex)

Question 55

what is grass sickness

Answer 55

impaired activity of the gut due to ANS damage cause still unknown

Question 56

what are the 3 main presentations of grass sickness

Answer 56

1. acute: severe and sudden onset with 100% mortality within 48hrs 2. sub-acute: milder clinical signs but most usually die within 7 days 3. chronic: slower onset presenting with rapid weight loss, some will survive

Question 57

what are the clinical signs of AGS and SAGS grass sickness

Answer 57

depression ileus tachycardia salivation gastric reflux fasciculations ptosis sweating dysphagia colic impaction

Question 58

what are the clinical signs of CGS

Answer 58

rapid and severe weight loss rhinitis sicca ptosis tachycardia fasciculation patchy sweating inappetance dysphagia

Question 59

what are thought to be the causes of grass sickness

Answer 59

clostridium botulinum type C most cases between April and July grazing increases risk factors, pasture disturbance, feed change, grazing previously affected pasture

Question 60

what is feline dysautonomia

Answer 60

widespread dysfunction of the ANS all breeds and ages susceptible but commonly seen in younger cats

Question 61

what are the clinical signs of feline dysautonomia

Answer 61

depression anorexia bilateral pupil dilation non-responsive to light third eyelid protrusion and ptosis decreased tear and saliva production megaesophagus bradycardia fecal and urinary incontinence

Question 62

what does definitive diagnosis of feline dysautonomia

Answer 62

histopathology radiographs, schirmer tear test and pharmacological testing

Question 63

how is feline dysautonomia treated

Answer 63

purely supportive

Question 64

where do the recurrent laryngeal nerves arise from and what do they supply

Answer 64

vagus at the middle cervical ganglion and run back up the neck supply the trachea and cervical esophagus

Question 65

Answer 65