Test 2 Parasympathetic Nervous System

Question 1

“fight or flight”

Answer 1

sympathetic nervous system

Question 2

“rest and digest”

Answer 2

parasympathetic nervous system

Question 3

Parasympathomimetic

Answer 3

Drug that stimulates the parasympathetic nervous system

Question 4

Parasympatholytic

Answer 4

Drug that blocks the parasympathetic nervous system

Question 5

Where does the parasympathetic nervous system originate?

Answer 5

In the central nervous system at the craniosacral region of the spinal cord

Cranial nerves: 3, 7, 9, 10

Sacral spinal segments: S2 - S4

Question 6

Parasympathetic preganglionic neurons are __________

and postganglionic neurons are __________

Answer 6

Preganglionic are LONG

Postganglionic are SHORT

in the parasympathetic nervous system

Question 7

The predominate neurotransmitter at the terminal synapses of

parasympathetic neurons

Answer 7

Acetylcholine (cholinergic)

Question 8

The two major cholinergic (acetylcholine) receptors of the

parasympathetic nervous system

are

Answer 8

Muscarinic Recceptors

Nicotinic Receptors

Question 9

This receptor of the parasympathetic nervous system

is present at all ganglionic and somatic synapses

Answer 9

Nicotinic receptors

Question 10

This receptor of the parasympathetic nervous system

is found on only the target tissues of the parasympathetic nervous system

Answer 10

Muscarinic receptors

Question 11

The 3 EXCITATORY

Muscarinic Receptors of the parasympathetic nervous system

Answer 11

M1

M3

M5

Question 12

Receptor of the parasympathetic nervous system

that is

Excitatory

Neural (CNS stimulation, gastric acid secretion, increased GI motility)

Answer 12

M1

Question 13

Receptor of the parasympathetic nervous system

that is

Excitatory

Glandular (secretions, smooth muscle contraction, vasodilation)

Answer 13

M3

Question 14

Receptor of the parasympathetic nervous system

that is

Excitatory

Salivary glands, iris

Answer 14

M5

Question 15

The receptor of the parasympathetic nervous system

that is

Inhibitory

Cardiac (and neural inhibition)

Answer 15

M2

Question 16

The receptor of the parasympathetic nervous system

that is

Inhibitory

CNS/Smooth muscle

Answer 16

M4

Question 17

When **acetylcholine **is released at the ganglia

Answer 17

It stimulates the post-synaptic neuron to carry on the action potential

Question 18

When **acetylcholine **is released at the neuromuscular junction

Answer 18

It stimulates muscle contraction

Question 19

When acetylcholine is released at the CNS, it can cause

Answer 19

convulsions

Question 20

When acetylcholine is released at a parasympathetic terminal synapse with the

target organ, it will facilitate ____________ signs

Answer 20

Muscarinic signs

Diarrhea

Urination (smooth muscle contraction)

Miosis

Bradycardia (slowing of heart)

Bronchoconstriction

Emesis (increased GI motility)

Lacrimation

Salivations (increases secretions)

Question 21

Drugs that cause the same response as acetylcholine

that interact directly with post-synaptic receptors

Answer 21

Muscarinic agonists

will cause muscarinic signs

Diarrhea, Urination, Miosis,

Bradycardia, Bronchoconstriction, Emesis,

Lacrimation, Salivation

Question 22

What are the direct acting

parasympathomimetics?

Answer 22

Bethanechol

Pilocarpine

• will cause muscarinic signs*
• DUMBBELS*

Question 23

What are the indirect-acting

parasympathomimetics

that are reversible?

Answer 23

Neostigmine

Pyridostigmine

Edrophonium

Physostigmine

Demarcarium

• These impair the function of acetylcholinesterase, so acetylcholine cannot be*
• bound or broken down. These will have muscarinic effects*

Question 24

Oral medication

Tx of urinary disorders

(associated with spinal injury) (lower motor neuron bladder dysfunction)

Muscarinic agonist

M3 selectivity (excitatory-glandular: secretion, smooth muscle cont. vasodilation)

Stimulates detrusor muscle contraction

Answer 24

Bethanechol

only used if urethra is patent (no obstruction)

Question 25

Ophthalmic medication Used to *stimulate miosis *to **decrease intraocular pressure** or to *localize the cause of **anisocoria***

Answer 25

**Pilocarpine** *should not be used if anterior uveitis or lens luxation*

Question 26

Impairs the function of acetylcholinesterase Approved in cattle, horses, pigs, and sheep Injection med ARCI Class 3 Tx of rumen atony Used to stimulate intestinal motility in horses Can be used to reverse competitive NMBs

Answer 26

**Neostigmine**

Question 27

Longer duration than Neostigmine Impairs the function of acetylcholinesterase Used to Tx **myasthenia gravis in small animals**

Answer 27

**Pyridostigmine**

Question 28

Very short acting anticholinesterase Used in the Dx of *myasthenia gravis* Used to differentiate between *myasthenic crisis *and *cholinergic crisis* Requires a "crash cart" with atropine on hand when testing

Answer 28

**Edrophonium**

Question 29

Topical ophthalmic drug Used to **induce miosis** that will last **12 hours** Used systemically to Tx Ivermectin toxicity in dogs Used to Dx narcolepsy in dogs and horses *Unlike other cholinesterase inhibitors, it WILL cross the BBB*

Answer 29

**Physostigmine** *Should not be used if anterior uveitis or lens luxation*

Question 30

An anticholinesterase drug A topical ophthalmic drug Used to **induce miosis** in the **management of glaucoma**

Answer 30

**Demarcarium**

Question 31

Toxicity that induces Muscarinic signs --\> Nicotinic Excitement (muscle tremors, CNS excitement)--\> Nicotinic blockade

Answer 31

**Carbamate Insecticide Toxicity** *involves a very high dose, WILL cross the BBB*

Question 32

Echothiophate Iodide and Organophosphate Insecticides are both

Answer 32

**Irreversible INDIRECT acting *parasympathomimetics***

Question 33

Topical ophthalmic drug Not used clinically very often Can undergo "aging" Induced **miosis** that will last **12 hours**, decreases intraocular pressure

Answer 33

**Echothiophate iodide** *do not use if anterior uveitis or lens luxation*

Question 34

What is the antidote to organophosphate toxicity

Answer 34

**2-PAM/ Pralidoxime** *can also be treated with atropine*

Question 35

These drugs act as **muscarinic antagonists** preventing the action of acetylcholine at PSNS target tissues

Answer 35

**Direct Acting ParasympathoLYTICS**

Question 36

A non-specific muscarinic antagonist Injectable or Ophthalmic An alkaloid originally extracted from the belladonna plant Its major actions are **antimuscarinic** Most often used to Tx **bradycardias** Can be used to Tx OP and Carbamate toxicity

Answer 36

**Atropine** * Do not use if glaucoma because will increase intraocular pressure* * Do not use if pre-existing tachycardia* * Can cause cycloplegia (blurred vision), panic in horses* * Severe hypersalivation in cats using ophthalmic formula (very bitter)* * Rabbits metabolize Atropine VERY quickly, can't use in rabbits*

Question 37

A muscarinic antagonist Injectable form It is a **quaternary ammonium compound **so it does NOT cross the BBB Preferred over Atropine in Rabbits

Answer 37

**Glycopyrrolate**

Question 38

What is the difference between Atropine and Glycopyrrolate

Answer 38

Atropine crosses the BBB, Glycopyrrolate does not Glycopyrrolate has a *slower onset *and *longer duration* than Atropine Tachyarrhythmias are seen *less frequently *with Glycopyrrolate Glycopyrrolate is preferred in use in Rabbits (because they metabolize Atropine very fast)

Question 39

A direct muscarinic antagonist Known as a **urinary antispasmodic** Used for urinary incontinence due to *detrusor hyperreflexia (overactive bladder)* It will relax the detrusor muscle Not often used in vet med

Answer 39

**Oxybutynin **and **Propantheline**

Question 40

A muscarinic antagonist Topical ophthalmic used as a **mydriatic** to dilate pupils Can cause cycloplegia More rapid onset and shorter duration than ophthalmic atropine Mostly used to facilitate **ophthalmic retinal exams**

Answer 40

**Tropicamide** *Should not use in glaucoma, will increase the IOP*