401 exam 3 autonomics

Does the parasympathetic system constrict or dilate the pupil?

Constrict

Does the sympathetic system constrict or dilate the pupil?

Dilate

Where do the parasympathetic fibers originate from?

Brain stem and sacral spinal cord

Where do the sympathetic fibers originate from?

Thoracic and lumbar spinal cord

What happens to NE when a2 is stimulated? What is the physiologic affect?

NE production is inhibited, BP decrease

Where are alpha 1 receptors found

Blood vessels

Where are alpha 2 receptors found

Pre-ganglionically and in the CNS

What is the physiologic effect of alpha 1 receptor activation

Vasoconstriction

What is the physiologic effect of alpha 2 receptor activation

Decrease in sympathetic flow from CNS

• EPI

• NE

• D

Where are beta 1 receptors found

Heart and kidney

What is the physiologic effect of beta-1 receptor activation

Increase HR

Increase force of contraction

Stimulates renin production

• Increase fluid retention

  • Increase BP

Where are beta 2 receptors found

Smooth muscles of blood vessels and bronchi

What is the physiologic effect of beta 2 receptor activation

Vasodilation

Bronchodilation

Breakdown of glycogen → glucose

Is NE or EPI more potent at alpha 1?

Equal

Is NE or EPI more potent at alpha 2?

NE

Is NE or EPI more potent at beta 1?

EPI

NE has decent activity

Is NE or EPI more potent at beta 2?

EPI

NE has very little activity

• Won’t dilate bronchioles on it’s own

How does an alpha-selective agonist impact HR and BP

• Increases BP

• HR unaffected

How does a non-selective sympathomimetic impact HR and BP

• Increases BP

• Increases HR

How does a beta-selective agonist impact HR and BP

• No significant impact on BP

• Increase HR

What adrenergic receptor causes dilation in the arterioles?

Beta 2

What adrenergic receptor causes constriction in the arterioles?

Alpha 1

How do alpha 1 receptors impact stomach and intestinal motility/tone

Decrease

How do alpha 1 receptor impact urinary/gastric/intestinal sphincters

Cause contraction

What receptor is responsible for renin secretion in the kidneys

Beta 1

What is the mechanism of action for direct acting parasympathomimetics (muscarinic receptor agonists)

Stimulate muscarinic receptors at neuro-effector junction w little or no nicotinic receptor stimulation

What are the direct acting parasympathomimetics (muscarinic receptor agonists)

Methacholine

Pilocarpine

What does: “My Pet Dog Always Played” stand for?

Methacholine

Pilocarpine

Direct acting parasympathomimetics

What is the mechanism of action for indirect-acting parasympathomimetics?

Prolong duration of action by inhibiting acetylcholinesterase

What are the indirect-acting parasympathomimetics?

Physostigmine

Neostigmine

Pyridostigmine

END IN -STIGMINE

What does: “Parasites near” stand for?

Physostigmine

Neostigmine

How can toxic reactions to muscarinic agonists be treated?

Atropine

EPI

What is the mechanism of action for muscarinic receptor antagonists?

Competitive blocking of M receptors with little blockade of the effects of acetylcholinesterase at nicotinic receptor sites.

How do muscarinic receptor antagonists impact the heart?

Raise HR by blocking vagal nerve effects

How do muscarinic receptor antagonists impact blood vessels

They do not affect vascular smooth muscle contractility

• There is NO parasympathetic control of the vascular system

How do muscarinic receptor antagonists impact the respiratory tract?

Induce bronchodilation

Inhibit secretions of the nose/pharynx/bronchi

• Dry out the mucous membranes of respiratory tract

How do muscarinic receptor antagonist impact the GI tract?

Inhibit motility and secretions

Inhibit gastric acid secretion

How do muscarinic receptor antagonist impact the urinary tract?

Decrease contractions of ureter and bladder

How do muscarinic receptor antagonist impact the sweat glands?

Inhibit sweating (despite sweating being under sympathetic control)

How do muscarinic receptor antagonist impact the CNS?

Low doses = dry mouth

Mild doses = Cardiac acceleration

Moderate doses = Bladder control issues

High doses = severe CNS impact (coma, delirium, excitement)

What are the muscarinic receptor antagonists

Homatropine hydrobromide

Tropicamide

Scopolamine

Atropine

Terodine tartrate

Fesoterodine fumarate

What does: “My red apple helps Tom see all the flowers” mean?

Muscarinic receptor antagonists

Homatropine hydrobromide

Tropicamide

Scopolamine

Atropine

Terodine tartrate

Fesoterodine fumarate

What are the adverse side effects of muscarinic receptor antagonists?

Dry mouth

Urinary retention

Anhidrosis (inhibition of acid secretion in the stomach)

Tachycardia

Constipation

What is the mechanism of action for sympathomimetic agents?

Direct stimulation of adrenergic receptors

Effects of EPI on cardiac

Increase HR through B2 stimulation

Effects of EPI on respiratory

Bronchodilation through B2 stimulation

Why is NE not useful as a bronchodilator?

Weak activator of B2

Non-selective beta agonists

Isoproterenol

Beta 2 selective agonists

Albuterol

Salmeterol

What does: “Sally always itches” stand for?

Salmeterol, albuterol, isoproterenol

What are the alpha 1 selective agonists?

Oxymetazoline, phenylephrine

What does: “one snake always outsmarts people” stand for?

(alpha)1 selective agonists

Oxymetazoline

Phenylephrine

What are the alpha 2 selective agonists?

Clonidine

Dexmedetomidine

What does: “All tiny snakes can dance” stand for?

Alpha 2 selective (agonists)

Clonidine

Dexmedetomidine 

Non-specific alpha adrenoreceptor blockers

Phenoxybenzamine

Phentolamine

What does: “Silly Newt! Always admiring big purple people” stand for?

Sympatholytic non-specific alpha adrenoreceptor blockers

Phenoxybenzamine

Phentolamine

What are the alpha 1 selective blockers?

Prazosin

Doxazosin

Temulosin

What does: MNEMONIC FOR A1 SELCETIVE BLOCKERS stand for?

What are the non-selective beta blockers?

Propanolol

Timolol

Pindolol

Labetalol

Carvedilol

What does: “MNEMONIC FOR NON SELECTIVE B BLOCKERS” stand for?

What are the beta 1 selective blockers?

Metoprolol

Atenolol

Esmolol

Nebivolol

What does: “MNEMONIC FOR B1 SELECTIVE BLOCKERS” stand for?

Adverse effects of alpha 1 selective blockers

• First-dose phenomenon

  • Postural hypotension + syncope 60-90 min after first dose

• Water retention

Adverse effects of beta blockers

• Life threatening arrythmia (in patients w AV conduction defects)

• Discontinuation of long-term B1 blockers can exacerbate angina → increase risk of sudden heart attack

• B2 blockade can worsen bronchoconstriction in asthmatics