L3: OCULAR AUTONOMIC INNERVATION

Question 1

what is the autonomic nervous system (ANS)?

Answer 1

The part of the nervous system responsible for control of the bodily
functions not consciously directed

such as breathing, the heartbeat, and digestive processes

Question 2

why is the ANS important?

Answer 2

In emergencies that cause stress and require us to “fight” or take
“flight” (run away) and in non-emergencies that allow us to “rest” and “digest”

Question 3

what is the pupil action during parasympathetic and sympathetic stimulation?

Answer 3

sympathetic: Pupil Dilation
parasympathetic: Pupil Constriction

Question 4

what is a neurotransmitter? what are the 2 main neutotransmitters released in the ANS?

Answer 4

Neurotransmitters chemically conduct nerve impulses from neuron to neuron, or neuron to effector

Ach: Acetylcholine
NA: noradrenaline / NE: Norepinephrine, also known as

Question 5

what are the 2 nerve fibres in the parasympathetic nervous system? and what NTs do they release?

Answer 5

Preganglionic nerve fibres: Releases Ach, activates nicotinic (N) receptors

Postganglionic nerve fibres: Releases Ach, activates muscarinic (M) receptors

Neurons that release ACh are called cholinergic.
Cholinergic, C for constrict

Question 6

what are the 2 nerve fibres that release in the sympathetic nervous system? and what NTs do they release?

Answer 6

Preganglionic nerve fibres: Releases Ach, activates nicotinic
(N) receptors

Postganglionic nerve fibres: Releases NA, activates either α (alpha) or
β(beta) receptors.

Neurons that release NA/NE are called adrenergic.
aDrenergic, D for dilate

Question 7

go practice the sympathetic and parasympathetic diagrams

Answer 7

ok

Question 8

Classification of 2 drugs affecting the sympathetic pathway?

Answer 8

Adrenergic Agonists (sympathomimetic) ON DRUGS, mimics action of sympathetic pathway
◦ eg: phenylephrine (Mydriatic)

Adrenergic Antagonists (sympatholytic) OFF DRUGS, kills action of sympathetic pathway
◦ eg: thymoramine (Miotic)

Question 9

Classification of 2 drugs affecting the parasympathetic pathway?

Answer 9

Cholinergic Agonists (parasympathomimetic), ON DRUGS, mimics action of parasympathetic pathway
◦ eg: pilocarpine (Miotic)

Cholinergic Antagonists (parasympatholytic)
◦ eg: tropicamide (Mydriatic)

Question 10

what are the 5 targets in the sympathetic pathway? what are their respective actions and receptors?

Answer 10

-dilator–Mydriasis–a1
-Superior Tarsal Muscle at eyelids–elevate eyelids–a1
-Increase aqueous humor formation–ciliary body–b2
-Inhibit Aqueous humor formation–ciliary body–a2
- Relax ciliary muscle–allow focusing for distance vision–b2

Question 11

what is neurotransmitters, receptors and enzymes released to stop action of NTs in the parasympathetic and sympathetic pathways?

Answer 11

parasympathetic: ACh–>muscarinic/nicotinic–> Acetylcholinesterase
(AchE)

sympathetic: Noradrenaline (NA)–> a/b–> COMT:catechol-O-methyl transferase or MAO: monoamine oxidase