Autonomic Nervous System Overview

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Questions and Answers

What is the primary function of the sympathetic nervous system?

Prepares the body for 'fight or flight' responses (correct)

Facilitates voluntary muscle movement

Regulates digestive processes

Promotes energy conservation

Which neurotransmitter is primarily associated with the parasympathetic nervous system?

Acetylcholine (correct)

Dopamine

Glycogen

Norepinephrine

What characteristic differentiates the fibers of the sympathetic nervous system from those of the parasympathetic nervous system?

Sympathetic fibers exit from thoracic and lumbar regions (correct)

Parasympathetic fibers exit only from the lumbar region

Sympathetic fibers exit in the cervical region

Parasympathetic fibers exit from the thoracic region

Which of the following functions is NOT generally associated with the activation of the sympathetic nervous system?

Increased salivation Signup and view all the answers

During a stress response, which of the following actions would most likely occur?

Increased heart rate and blood pressure Signup and view all the answers

Which function is primarily associated with the Sympathetic Nervous System (SNS)?

Mobilizing energy stores Signup and view all the answers

How does the Autonomic Nervous System (ANS) primarily differ from the Somatic Nervous System (SNS)?

ANS is responsible for involuntary actions while SNS is responsible for voluntary actions Signup and view all the answers

What is the primary role of the hypothalamus in regulating the Autonomic Nervous System?

Processing information and triggering short-term and long-term responses Signup and view all the answers

Which of the following neurotransmitters is most likely released by postganglionic neurons of the Sympathetic Nervous System?

Norepinephrine Signup and view all the answers

What response is primarily triggered by the Parasympathetic Nervous System (PNS)?

Conservation of energy stores Signup and view all the answers

What anatomical structure primarily integrates reflexes associated with the Autonomic Nervous System?

Spinal cord Signup and view all the answers

Which statement best summarizes the relationship between the SNS and PNS?

They innervate the same organs and have opposite effects. Signup and view all the answers

Which organ’s function is NOT primarily regulated by the Autonomic Nervous System?

Skeletal muscles Signup and view all the answers

Which division of the autonomic nervous system is responsible for the 'rest and digest' functions?

Parasympathetic Nervous System Signup and view all the answers

What type of receptors are stimulated by acetylcholine at postganglionic synapses in the parasympathetic nervous system?

Cholinergic receptors Signup and view all the answers

Which of the following best describes the sympathetic nervous system's primary functions?

Facilitates stress response and physical activity Signup and view all the answers

What neurotransmitter is primarily associated with adrenergic fibers?

Norepinephrine Signup and view all the answers

Which receptor type is involved in the stimulation of smooth muscle contraction via acetylcholine in the autonomic nervous system?

Muscarinic receptors Signup and view all the answers

What is the primary role of α1 adrenergic receptors within the sympathetic nervous system?

Cause vasoconstriction Signup and view all the answers

Which of the following describes the adrenergic receptors associated with the heart?

β1 receptors increase heart rate Signup and view all the answers

Identify the primary neurotransmitter released by the postganglionic neurons of the sympathetic nervous system.

Norepinephrine Signup and view all the answers

What distinguishes the fiber length in the parasympathetic nervous system compared to the sympathetic nervous system?

Parasympathetic has longer preganglionic fibers. Signup and view all the answers

Which cranial nerve is primarily responsible for the constriction of the pupil?

Oculomotor nerve (CN III) Signup and view all the answers

Where are the ganglia of the sympathetic nervous system typically located in relation to the effector organs?

Far from the effector organs Signup and view all the answers

What is the primary output from the Vagus nerve (CN X) in terms of the parasympathetic nervous system?

It innervates the lungs and digestive tract. Signup and view all the answers

What effect does an EpiPen have on the body during anaphylactic shock?

It stimulates the sympathetic nervous system leading to increased heart rate and blood pressure. Signup and view all the answers

The sacral outflow of the parasympathetic nervous system originates from which part of the spinal cord?

Ventral horn of S2-S4 Signup and view all the answers

Which of the following is NOT true regarding the branching of the sympathetic nervous system?

It provides selective innervation to individual organs. Signup and view all the answers

Study Notes

Autonomic Nervous System - Lecture Notes

The autonomic nervous system (ANS) is a part of the peripheral nervous system.
It's responsible for involuntary functions.
It is comprised of two main divisions:
- Sympathetic Nervous System (SNS)
- Parasympathetic Nervous System (PNS)

Sympathetic Nervous System (SNS)

Origin: Thoracic and lumbar regions of the spinal cord.
Fiber Length: Short preganglionic fibers, long postganglionic fibers.
Ganglia/Synapse: Ganglia are close to the spinal cord.
Branching: Extensive branching.
Neurotransmitter: Primarily norepinephrine but sometimes acetylcholine (e.g., sweat glands).
Function: Mobilizes the body's resources during stressful situations or physical activity, often referred to as the "fight or flight" response.

Parasympathetic Nervous System (PNS)

Origin: Craniosacral (cranial nerves and sacral spinal cord segments).
Fiber Length: Long preganglionic fibers, short postganglionic fibers.
Ganglia/Synapse: Ganglia are located near or within the target organ.
Branching: Minimal branching.
Neurotransmitter: Primarily acetylcholine.
Function: Conserves and restores energy, often referred to as the "rest and digest" response.

Cholinergic and Adrenergic Fibers

Cholinergic fibers: Release acetylcholine (ACh).
- All preganglionic neurons in both the sympathetic and parasympathetic systems are cholinergic.
- Most postganglionic parasympathetic neurons are cholinergic.
- There are two types of cholinergic receptors: Nicotinic and Muscarinic
Adrenergic fibers: Release norepinephrine (NE).
- Most postganglionic sympathetic neurons are adrenergic.
- There are multiple types of adrenergic receptors (α1, α2, β1, and β2).

Receptors

Muscarinic receptors: G protein-coupled receptors, found in effector cells stimulated by postganglionic synapses.
Nicotinic receptors: Ligand-gated cation channels, found in synapses between pre- and postganglionic fibers.

Adrenergic Receptors

α1: Vasoconstriction, relaxation of GI smooth muscle, sweat gland secretion, and dilation of pupils.
α2: Vasoconstriction, decreased secretion from salivary glands.
β₁: Increase heart rate and contractility, renin release.
β₂: Glycogenolysis, gluconeogenesis, smooth muscle relaxation, increased insulin release.