Autonomic Ganglia and ANS Organization

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson
Download our mobile app to listen on the go
Get App

Questions and Answers

What is the role of calcium ions (Ca2+) in the release of acetylcholine (ACh)?

  • They trigger the release of ACh from the presynaptic terminal. (correct)
  • They block the action of ACh at nicotinic receptors.
  • They regulate the activity of choline esterase.
  • They help in the synthesis of acetylcholine.

Where are nicotinic receptors found in the autonomic nervous system?

  • Only at the neuromuscular junction.
  • In the central nervous system exclusively.
  • In both the sympathetic and parasympathetic ganglia. (correct)
  • Only in the sympathetic nervous system.

What substance produces effects similar to the stimulation of central cholinergic fibers?

  • Acetylcholine.
  • Norepinephrine.
  • Serotonin.
  • Nicotine. (correct)

What enzyme hydrolyzes acetylcholine into acetate and choline?

<p>Choline esterase. (B)</p> Signup and view all the answers

What is the primary function of nicotinic receptors?

<p>To produce excitation upon activation. (C)</p> Signup and view all the answers

What effect does hexamethonium have on nicotinic receptors?

<p>It blocks them in the autonomic ganglia. (B)</p> Signup and view all the answers

What is the result of ACh binding to its receptors in the postganglionic neuron?

<p>A change in the permeability of the membrane to ions. (A)</p> Signup and view all the answers

Which of the following is NOT a characteristic of nicotinic receptors?

<p>They produce inhibition upon activation. (C)</p> Signup and view all the answers

What is the function of the collateral ganglia in the autonomic nervous system?

<p>Serve as relay stations for preganglionic sympathetic fibers to abdominal and pelvic organs (B)</p> Signup and view all the answers

What characteristic of sympathetic responses is primarily due to divergence of preganglionic fibers?

<p>Widespread distribution of nerve impulses affecting many body regions (C)</p> Signup and view all the answers

How many postganglionic neurons does a single sympathetic preganglionic fiber typically activate?

<p>20 or more (A)</p> Signup and view all the answers

Where are terminal ganglia primarily located?

<p>Near or on the surface of the innervated organs (A)</p> Signup and view all the answers

What is the primary neurotransmitter released at all preganglionic endings in the autonomic nervous system?

<p>Acetylcholine (C)</p> Signup and view all the answers

In contrast to sympathetic ganglia, the activation pattern of parasympathetic ganglia results in which kind of response?

<p>Localized effects targeting individual effectors (A)</p> Signup and view all the answers

What role do autonomic ganglia play in the nervous system?

<p>Function as relay stations for preganglionic fibers from the CNS (D)</p> Signup and view all the answers

What is the primary method of synaptic transmission between preganglionic and postganglionic neurons in autonomic ganglia?

<p>Chemically mediated via neurotransmitters (D)</p> Signup and view all the answers

What is the primary function of the autonomic ganglia?

<p>To serve as relay points for synapses between preganglionic and postganglionic neurons (B)</p> Signup and view all the answers

Where do sympathetic preganglionic neurons originate?

<p>CNS locations including spinal cord segments T1-L3 (D)</p> Signup and view all the answers

How do postganglionic neurons in autonomic ganglia function?

<p>They have their cell bodies in autonomic ganglia and terminate on effector organs. (C)</p> Signup and view all the answers

What differentiates the location of parasympathetic ganglia from sympathetic ganglia?

<p>Parasympathetic ganglia are located in or near the effector organs, whereas sympathetic ganglia are found in the paravertebral chain. (B)</p> Signup and view all the answers

What neurotransmitters are primarily secreted by the chromaffin cells in the adrenal medulla?

<p>Epinephrine (80%) and norepinephrine (20%) (D)</p> Signup and view all the answers

Which statement accurately describes the structure of paravertebral ganglia?

<p>They form two lateral chains on each side of the vertebral column. (D)</p> Signup and view all the answers

How are autonomic ganglia classified based on their sites?

<p>Based on paravertebral and prevertebral positions (D)</p> Signup and view all the answers

What is the relationship between preganglionic and postganglionic neurons in the autonomic nervous system?

<p>Preganglionic neurons synapse onto postganglionic neurons in the autonomic ganglia. (D)</p> Signup and view all the answers

Flashcards

Autonomic Ganglion

An aggregation of cell bodies of neurons located outside the central nervous system (CNS).

Parasympathetic Ganglion

A cluster of nerve cell bodies located in or near the organs they innervate. They transmit signals from the CNS to target organs in the parasympathetic nervous system.

Paravertebral Ganglia

A chain of interconnected ganglia along both sides of the vertebral column. They relay signals from the CNS to target organs in the sympathetic nervous system.

Preganglionic Neuron

Nerve cells that originate in the CNS and send signals to autonomic ganglia.

Signup and view all the flashcards

Postganglionic Neuron

Nerve cells that originate in autonomic ganglia and send signals to target organs.

Signup and view all the flashcards

Adrenal Medulla

A specialized sympathetic ganglion that directly secretes hormones, epinephrine and norepinephrine, into the bloodstream.

Signup and view all the flashcards

Thoracolumbar Region

The region of the spinal cord where preganglionic neurons of the sympathetic nervous system originate.

Signup and view all the flashcards

Craniosacral Region

The region of the spinal cord and brain where preganglionic neurons of the parasympathetic nervous system originate.

Signup and view all the flashcards

Collateral ganglia

Ganglia located between the sympathetic chain and the target organ, responsible for relaying preganglionic sympathetic fibers to abdominal organs and the pelvis.

Signup and view all the flashcards

Terminal ganglia

Ganglia found near or on the surface of organs innervated by the parasympathetic nervous system, where preganglionic parasympathetic fibers are relayed.

Signup and view all the flashcards

Synaptic transmission in autonomic ganglia

The point where a preganglionic neuron releases neurotransmitters (acetylcholine) to activate a postganglionic neuron.

Signup and view all the flashcards

Neurotransmitter at preganglionic endings

Acetylcholine is the neurotransmitter released at all preganglionic synapses, both sympathetic and parasympathetic.

Signup and view all the flashcards

Divergence in the sympathetic system

A single preganglionic fiber can activate many postganglionic neurons, causing widespread effects.

Signup and view all the flashcards

Convergence in the parasympathetic system

Each preganglionic fiber activates only a few postganglionic neurons, leading to localized effects.

Signup and view all the flashcards

Generalized vs. localized effects

Sympathetic responses often affect the whole body due to divergence, while parasympathetic responses are localized to specific organs.

Signup and view all the flashcards

Relay function of autonomic ganglia

Autonomic ganglia serve as relay stations for preganglionic fibers coming from the central nervous system.

Signup and view all the flashcards

Cholinergic Neuron

A type of nerve cell that releases acetylcholine (ACh) at its terminal.

Signup and view all the flashcards

Nicotinic Receptor

The type of receptor found on postganglionic neurons in autonomic ganglia, which responds to acetylcholine (ACh) and nicotine.

Signup and view all the flashcards

Neurotransmitter

A chemical substance released by a neuron to transmit signals to another neuron or a target organ.

Signup and view all the flashcards

Acetylcholine Hydrolysis

The process of breaking down acetylcholine into inactive components.

Signup and view all the flashcards

Choline Esterase

An enzyme that breaks down acetylcholine, preventing its prolonged action on the postsynaptic neuron.

Signup and view all the flashcards

Acetylcholine Release

The release of acetylcholine from the presynaptic terminal, triggering a signal in the postsynaptic neuron.

Signup and view all the flashcards

Synaptic Cleft

The gap between the presynaptic and postsynaptic neurons where neurotransmitters are released.

Signup and view all the flashcards

Study Notes

Autonomic Ganglia

  • Autonomic ganglia are clusters of neuron cell bodies outside the central nervous system (CNS).
  • Two main types: sympathetic and parasympathetic ganglia.
  • Sympathetic ganglia are part of the sympathetic division of the autonomic nervous system (ANS).
  • Parasympathetic ganglia are part of the parasympathetic division of the ANS.

Organization of the ANS

  • Preganglionic neurons have cell bodies in the CNS and synapse in autonomic ganglia.
    • Sympathetic preganglionic neurons originate in the spinal cord segments T1-L3 (thoraco-lumbar region).
    • Parasympathetic preganglionic neurons originate in cranial nerve nuclei and spinal cord segments S2-S4 (cranio-sacral region).
  • Synapses occur in autonomic ganglia.
    • Parasympathetic ganglia are located near or within the effector organs.
    • Sympathetic ganglia are located in the paravertebral chain.
  • Postganglionic neurons emerge from autonomic ganglia and connect to effector organs (e.g. heart, blood vessels, and sweat glands).

Types of Autonomic Ganglia

  • Paravertebral (lateral) ganglia form chains alongside the spinal column.
  • Collateral ganglia located between the sympathetic chain and target organs, relaying signals to abdominal viscera and pelvis.
  • Terminal ganglia are positioned near or on the target organs. They receive signals from parasympathetic preganglionic neurons.

Functions of Autonomic Ganglia

  • Act as relay centers for preganglionic axons, with a preganglionic axon synapsing with multiple postganglionic neurons.
  • This divergences spreads nerve impulses throughout the body for sympathetic responses, and localizes parasympathetic responses to a specific effector organ.

Synaptic Transmission

  • Synaptic transmission between neurons in autonomic ganglia uses acetylcholine (ACh) to relay signals, and is a chemical process. Cholinergic neurons secrete ACh.
  • ACh triggers depolarization in the postganglionic neuron. Calcium influx triggers vesicle fusion and release of ACh into the synaptic cleft.
  • ACh binds to nicotinic receptors, and triggers postsynaptic membrane depolarization to create an action potential.
  • Enzymes (e.g. Acetylcholinesterase) rapidly break down ACh.

Adrenal Medulla

  • A specialized sympathetic ganglion where preganglionic fibers directly synapse on chromaffin cells.
  • Chromaffin cells secrete epinephrine (adrenaline) and norepinephrine (noradrenaline) into the bloodstream.

Studying That Suits You

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

Quiz Team

Related Documents

L34 Types & Function of ANS Ganglia PDF

More Like This

Use Quizgecko on...
Browser
Open
Browser
Browser