P21: Autonomic Nervous System

What functions does the autonomic nervous system control?

heart rate, digestion, respiratory rate, salivation, perspiration, pupillary dilation, urination

Where is the autonomic nervous system located in the brain?

medulla oblongata

What are the subsystems of the autonomic nervous system?

parasympathetic, sympathetic

How do the subsystems of the autonomic nervous system work?

one activates physiological response and the other inhibits it

What is mimetic activity?

stimulating

What is lytic activity?

inhibition

What is another term for parasympathomimetics?

cholinergic agonists

What is another term for parasympatholytics?

cholinergic antagonists

What is another term for sympathomimetics?

adrenergic agonists

What is another term for sympatholytics?

adrenergic antagonists

What do parasympathotropic agents act on?

cholinergic receptors

Which neurotransmitter acts on cholinergic receptors?

acetylcholine

What are the classes of cholinergic receptors?

muscarinic, nicrotinic

Where are muscarinic receptors found?

smooth muscle of exocrine glands and in the lungs

What does the stimulation of muscarinic receptors cause?

hypersecretion

Where are nicotinic receptors found?

neuromuscular junctions of somatic muscles

What does the stimulation of nicotinic receptors cause?

muscular contraction

What are drugs with parasympathomimetic activity divided into?

directly acting, indirectly acting

What are directly acting parasympathomimetic drugs?

act like acetylcholine and bind to cholinergic receptors

What are examples of directly acting parasympathomimetic active substances?

pilocarpine, carbachol, arecoline, acetylcholine, metacholine

What are indirectly acting parasympathomimetic drugs?

inhibit enzyme acetylcholine esterase and inhibit degradation of acetylcholine

What are examples of indirectly acting parasympathomimetic active substances?

physostigmine, neostigmine, pyridostigmine, organophosphates

What are parasympatholytic drugs?

cholinergic blockers (competitive inhibition)

What are examples of parasympatholytic active substances?

atropine, scopolamine, homatropine, propanteline

What is atropine?

competitive antagonist for muscarinic acetylcholine receptors (anticholinergic drug)

What is atropine used as?

cycloplegic, mydriatic, resuscitation, premedication, treatment for organophosphate poisoning

What effect do parasympatholytic drugs have on the pupils?

contraction of radial muscle fibres dominated; mydriasis (dilation)

What effect do parasympathomimetic drugs have on the pupils?

contraction of circular muscle fibres dominated; miosis (constriction)

Which muscle fibres of the iris and innervated by sympathetic nervous system?

radial muscle fibres

Which muscle fibres of the iris and innervated by parasympathetic nervous system?

circular muscle fibres

How do sympathotropic agents work?

bind to adrenergic receptors

What are the neurotransmitters of adrenergic receptors?

adrenaline, noradrenaline

What are examples of sympathomimetic agents?

adrenaline, noradrenaline, dopamine, ephedrine, amphetamine

What are examples of sympatholytic agents?

ergotamine, prazosine, propranolol, bisoprolol, esmolol, methyldopa