Autonomic Nervous System and Hormones

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the typical structure of the autonomic nervous system?

Two-neuron structure (correct)

Four-neuron structure

One-neuron structure

Three-neuron structure

Where is the cell body of the preganglionic neuron located in the sympathetic nervous system?

Thoracic and lumbar spinal cord (correct)

Sacral spinal cord

Brainstem

Autonomic ganglion

What is the neurotransmitter released by sympathetic neurons?

Norepinephrine (correct)

Acetylcholine

Prostaglandins

Histamine

What is the neurotransmitter released by cholinergic neurons?

Acetylcholine Signup and view all the answers

Where are the preganglionic neurons of the parasympathetic nervous system located?

Brainstem and sacral spinal cord Signup and view all the answers

Which part of the spinal cord has the most spinal nerves?

Thoracic Signup and view all the answers

What is the primary mechanism by which beta-adrenergic blocking agents reduce cardiac output?

Block cardiac beta-1 receptors leading to lower HR and lower CO Signup and view all the answers

Which of the following is a 2nd generation beta blocker?

Metoprolol Signup and view all the answers

What is the effect of beta-adrenergic blocking agents on the SA node and ectopic pacemakers?

Decrease in automaticity Signup and view all the answers

Which of the following is a clinical use of beta-adrenergic blocking agents?

Treatment of migraine Signup and view all the answers

What is the effect of beta-adrenergic blocking agents on the refractory period of the AV node?

Increase in refractory period Signup and view all the answers

What is the mechanism by which beta-adrenergic blocking agents reduce renin secretion?

Block renal beta-1 receptors Signup and view all the answers

Which of the following beta blockers is a hybrid, having both alpha and beta blocking properties?

Labetalol Signup and view all the answers

Which receptor subtype is responsible for the vasoconstriction effect of norepinephrine?

Alpha 1 Signup and view all the answers

What is the primary mechanism of action of indirect-acting adrenergic agonists?

Inhibiting the reuptake of norepinephrine Signup and view all the answers

What is the effect of dopamine on the renal vascular bed?

Vasodilation Signup and view all the answers

What is the primary use of fenoldopam?

Rapid vasodilation for severe hypertension in hospitalized patients Signup and view all the answers

What is the mechanisms of action of guanethidine?

Depleting norepinephrine from nerve endings Signup and view all the answers

Which of the following is a mixed alpha and beta receptor agonist?

Epinephrine Signup and view all the answers

What is the primary therapeutic use of dobutamine?

Treatment of congestive heart failure Signup and view all the answers

What is the effect of alpha 2 receptors on dilator muscle?

Relaxation Signup and view all the answers

Where is endogenous epinephrine produced?

Medulla of the adrenal gland Signup and view all the answers

What is the effect of epinephrine on uveal scleral outflow?

Increase Signup and view all the answers

What is the use of 1% epinephrine in the treatment of POAG?

Hypotensive effect Signup and view all the answers

What is the diagnosis where epinephrine is used?

Horner's syndrome Signup and view all the answers

What is the side effect of epinephrine in aphakic patients?

Maculopathy Signup and view all the answers

What is the characteristic of phenylephrine?

Alpha 1 agonist Signup and view all the answers

What is the duration of action of 2.5% and 10% phenylephrine?

45-60 minutes Signup and view all the answers

What is the primary mode of action of Brimonidine tartrate in reducing intraocular pressure?

Decreases aqueous humor production Signup and view all the answers

What is the main advantage of Betaxolol over other beta blockers in glaucoma treatment?

It is a beta-1 selective blocker Signup and view all the answers

What is the primary action of Dapiprazole on the eye?

It reversibly blocks alpha 1 receptors on the dilator muscle Signup and view all the answers

Why is Cocaine not commonly used in ophthalmic practice?

It is not commercially available in ophthalmic solution Signup and view all the answers

What is the primary mechanism of action of Aproclonidine in reducing intraocular pressure?

It decreases aqueous humor production Signup and view all the answers

What is the primary indication for Combigan?

Treatment of glaucoma Signup and view all the answers

What is the main side effect of Lumify that is unique to this medication?

Blanching Signup and view all the answers

Why is Carteolol considered a safer option for some patients?

It increases the ratio of high density lipids to total cholesterol Signup and view all the answers

Study Notes

Regulation of Biological Process

Hormones: regulate various physiological processes
Neurotransmitters: transmit signals between neurons
Histamine: involved in allergic responses
Prostaglandins: involved in inflammation and smooth muscle contraction

Organization of the Nervous System

Afferent (sensory) neurons -> PNS -> Efferent (motor) neurons -> Autonomic Nervous System (ANS) or Somatic Nervous System
Thoracic region has the most spinal nerves
ANS: regulates involuntary actions (e.g., heart rate, digestion)
- Subdivisions: Sympathetic, Parasympathetic, and Enteric systems

Autonomic Nervous System (ANS)

Sympathetic system:
- Preganglionic neuron in thoracic and lumbar spinal cord
- Produces widespread physiological activity
- Uses norepinephrine as neurotransmitter
Parasympathetic system:
- Preganglionic neuron in brainstem and sacral spinal cord
- Produces response on an organ basis
- Uses acetylcholine as neurotransmitter

Neurotransmission

3 stages: Preganglionic synapse, Postganglionic synapse, Metabolites excreted in urine

Classification of Beta-Adrenergic Blocking Agents

Non-selective (1st gen)
Cardioselective (beta-1 selective, 2nd gen)
Hybrid antihypertensive drugs (3rd gen)

Clinical Uses of Beta-Blockers

Hypertension
Angina pectoris
Glaucoma
Migraine
Thyrotoxicosis
Arrhythmia prophylaxis

Adrenergic Agonists

Direct action: drug directly activates receptor
Indirect action: drug enhances release of norepinephrine
Mixed action: drug acts both directly and indirectly
Examples:
- Tyramine (indirect action)
- Cocaine (indirect action)
- Amphetamines (indirect action)
- Pseudoephedrine (direct action)
- Ephedrine (direct action)

Adrenergic Antagonists

Decrease sympathetic tone of blood vessels
Results in decrease in total peripheral resistance (TPR)
Examples:
- Phenoxybenzamine (non-competitive antagonist)
- Phentolamine (competitive reversible antagonist)

Alpha Adrenergic Receptors

Alpha 1:
- Works through phospholipase C pathway
- Increases intracellular Ca++ in smooth muscle cells
- Contraction of smooth muscle
Alpha 2:
- Works through adenylate cyclase pathway
- Decreases release of neurotransmitters and hormones

Beta Adrenergic Receptors

Beta 1:
- Works through stimulation of adenylate cyclase pathway
- Increases cardiac muscle contraction
Beta 2:
- Works through stimulation of adenylate cyclase pathway
- Relaxation of smooth muscle
Beta 3:
- Works through stimulation of adenylate cyclase pathway
- Lipolysis in adipose tissue

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Test your knowledge of the autonomic nervous system, including its structure and function, as well as the role of hormones and neurotransmitters like histamine and prostaglandins. Learn about the organization of the nervous system and the different types of neurons involved.