Autonomic Nervous System Overview

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Questions and Answers

What is the primary function of the sympathetic division of the autonomic nervous system?

Controlling voluntary muscle movements

Enabling fight-or-flight responses during stress (correct)

Regulating normal bodily functions during rest

Promoting digestion and energy conservation

Which of the following receptors is activated first in the autonomic nervous system pathway?

Muscarinic

Beta-adrenergic

Adrenergic

Nicotinic (correct)

Which of the following statements is true regarding dual-innervation in the autonomic nervous system?

Some organs require both divisions for complete functional response. (correct)

Only the sympathetic division is involved in dual-innervation.

Dual-innervation results in both divisions exciting and inhibiting organs simultaneously.

Both divisions act independently without influence on one another.

How do adrenergic receptors primarily respond to norepinephrine compared to epinephrine?

They tend to be more sensitive to norepinephrine than epinephrine. Signup and view all the answers

Which brain structures are NOT directly involved in autonomic control?

Cerebral Cortex Signup and view all the answers

What is the primary function of the parasympathetic nervous system?

Facilitating rest-and-digest activities Signup and view all the answers

Which of the following statements accurately describes the vagus nerve?

It conducts both sensory and motor signals related to visceral organs. Signup and view all the answers

What is a consequence of overstimulation of the vagus nerve?

Vasovagal syncope leading to fainting Signup and view all the answers

What is required for activation of the cholinergic receptors at the neuromuscular junction?

Two acetylcholine molecules Signup and view all the answers

Which statement about exogenous toxins affecting acetylcholine is true?

Atropine can be used to treat muscarine poisoning. Signup and view all the answers

What type of receptors does the parasympathetic division primarily use?

Muscarinic receptors Signup and view all the answers

Which area of the spine does the sympathetic nervous system primarily emerge from?

Thoracolumbar region Signup and view all the answers

What secondary response does sympathetic activation of the adrenal medulla trigger?

Fight-or-flight response Signup and view all the answers

What is the primary function of chromaffin cells in the sympathetic nervous system?

Act as axon-less post-ganglionic neurons Signup and view all the answers

Which of the following is NOT considered an 'E' situation in the context of sympathetic activation?

Education Signup and view all the answers

How does cocaine affect norepinephrine levels in the body?

Blocks its reuptake Signup and view all the answers

What effect does xylazine have when acting on beta1-adrenergic receptors?

Vasoconstriction of local blood vessels Signup and view all the answers

What is the primary consequence of xylazine-induced skin ulceration?

Hypoperfusion and necrosis Signup and view all the answers

What is the primary effect of botulinum toxin at the neuromuscular junction?

It prevents the release of acetylcholine. Signup and view all the answers

What type of paralysis is caused by botulinum toxin?

Flaccid paralysis Signup and view all the answers

Which of the following best describes curare's action at the neuromuscular junction?

It competes with ACh for receptor sites. Signup and view all the answers

Which statement is true regarding the various toxins affecting the neuromuscular junction?

Different toxins affect different stages of ACh function. Signup and view all the answers

How does AChE (acetylcholinesterase) function at the neuromuscular junction?

It breaks down acetylcholine. Signup and view all the answers

What role does muscarine play in regard to ACh?

It mimics ACh at muscarinic receptors. Signup and view all the answers

What is the action of nightshade or atropine on ACh receptors?

It blocks muscarinic receptors. Signup and view all the answers

In the context of the neuromuscular junction, which process follows the binding of ACh to its receptor?

AChE breaks down ACh. Signup and view all the answers

Study Notes

Parasympathetic System

Parasympathetic system is responsible for "rest-and-digest" activities.
Its nerves originate from the cranial and sacral regions of the spinal cord.
Key functions include salivation, lacrimation, urination, and defecation (SLUD).
Ganglia typically lie near or within target tissues.
The vagus nerve is a major component responsible for 75% of parasympathetic activity.

Sympathetic System

Responsible for "fight-or-flight" responses.
Nerves originate from the thoracolumbar region of the spinal cord.
Key features include chain ganglia, collateral ganglia, and the adrenal medullae.
The sympathetic chain ganglia function as the first synapse, located close to the spinal cord.

Adrenal Medulla

The adrenal medulla is a neurosecretory gland responsible for releasing hormones like epinephrine (adrenaline) and norepinephrine (noradrenaline).
Chromaffin cells in the adrenal medulla are modified post-ganglionic neurons that lack axons.
Sympathetic activation of the adrenal medulla triggers the fight-or-flight response.

Autonomic Receptors

Parasympathetic neurons primarily use acetylcholine (ACh) as their neurotransmitter.
Sympathetic neurons use ACh at the first synapse and norepinephrine (noradrenaline) at the second synapse.
Sympathetic receptors show greater sensitivity to norepinephrine than epinephrine.
Acetylcholine receptors can be categorized as nicotinic or muscarinic.
Nicotinic are found at the first synapse (ganglia) in both sympathetic and parasympathetic divisions, while muscarinic receptors are located at the second synapse (target tissues) in the parasympathetic system.