Autonomic Nervous System 2.3A

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Questions and Answers

Which effect is directly associated with the sympathetic nervous system (SNS)?

Decreased heart rate

Pupillary constriction

Increased saliva production

Bronchodilation (correct)

What is the primary role of the parasympathetic nervous system (PSNS) concerning digestion?

Inhibits digestive activity

Diverts blood away from the digestive organs

Increases digestive activity (correct)

Promotes urinary function

Which of the following responses is NOT typically triggered by the SNS?

Pupillary dilation

Sweat gland excretion

Increased heart rate

Slower breath rate (correct)

How does the PSNS affect the eyes compared to the SNS?

Pupillary constriction in response to arousal Signup and view all the answers

Which bodily function is increased by the PSNS during arousal?

Saliva production Signup and view all the answers

What is the pathway of the presynaptic neurons in the sympathetic system?

They can follow the splanchnic nerves to the adrenal glands. Signup and view all the answers

How does the brain interpret pain signals from visceral organs?

It cannot distinguish the source of pain between visceral and somatic fibers. Signup and view all the answers

What is one consequence of the overlapping pathways of visceral and somatic sensory fibers?

Referred pain can occur from abdominal organs. Signup and view all the answers

Which of the following best describes visceral afferent neurons?

They are involved in relaying sensory information from peripheral organs to the central nervous system. Signup and view all the answers

What role does the vagus nerve play in relation to pain perception?

It is crucial for interpreting pain signals from thoracic and abdominal organs. Signup and view all the answers

Which segment of the spinal cord is likely involved in viscerosomatic convergence?

Thoracic segments, notably T5. Signup and view all the answers

Where do presynaptic sympathetic neurons primarily synapse?

Directly in the adrenal glands. Signup and view all the answers

What can result from the confusion of pain signals between visceral and somatic pathways?

False localization of pain. Signup and view all the answers

What primary function does the sympathetic nervous system (SNS) serve?

Prepares the body for stressful situations Signup and view all the answers

Which of the following accurately describes the parasympathetic nervous system (PSNS)?

Promotes 'rest and digest' functions Signup and view all the answers

What type of control does the autonomic nervous system provide?

Involuntary control of smooth muscle and glands Signup and view all the answers

Where does the parasympathetic nervous system primarily originate in the body?

Cranial and sacral regions Signup and view all the answers

What is the effect of increased sympathetic nervous system activity on heart rate?

Increases heart rate Signup and view all the answers

Which statement about visceral afferents is true?

They provide sensory input from the organs Signup and view all the answers

How does the structure of the sympathetic nervous system differ from that of the parasympathetic nervous system?

It primarily involves the sympathetic trunk Signup and view all the answers

Which system is NOT part of the autonomic nervous system?

Somatic nervous system Signup and view all the answers

What is the primary function of the parotid gland?

To produce and secrete saliva Signup and view all the answers

Which cranial nerve is associated with the chemoreceptors that sense blood pressure changes?

Cranial Nerve IX Signup and view all the answers

What does the name 'vagus' signify in reference to Cranial Nerve X?

Wanderer Signup and view all the answers

What type of innervation does the vagus nerve primarily provide?

Parasympathetic innervation Signup and view all the answers

Which organ systems does the vagus nerve particularly innervate?

Thoracic and upper abdominal organs Signup and view all the answers

What does it mean that the parasympathetic system is craniosacral?

Its components arise from the brain and sacral region. Signup and view all the answers

Which cranial nerve is the most widespread in the body?

Cranial Nerve X Signup and view all the answers

What is one way to utilize the vagus nerve's parasympathetic dominance effectively?

Promoting relaxation and digestion Signup and view all the answers

Which of the following statements is true regarding the sympathetic and parasympathetic systems?

The parasympathetic system is craniosacral, while the sympathetic system has a thoracolumbar origin. Signup and view all the answers

How does the parotid gland contribute to digestion?

By producing and releasing saliva Signup and view all the answers

What is a primary function of the parasympathetic nervous system?

To promote rest and digest activities. Signup and view all the answers

Which nerves are associated with the parasympathetic system?

Pelvic nerves S2-S4 and cranial nerves. Signup and view all the answers

Which statement accurately reflects the characteristics of the autonomic pathways?

Both the sympathetic and parasympathetic systems contribute to the autonomic pathways. Signup and view all the answers

Which region does the parasympathetic nervous system primarily originate from?

Cranial and sacral regions. Signup and view all the answers

What role does the pelvic nerves S2-S4 play in the parasympathetic nervous system?

They are involved in the physiological regulation of pelvic organs. Signup and view all the answers

How does the structure of the parasympathetic nervous system compare to the sympathetic nervous system?

It has longer pre-ganglionic fibers compared to the sympathetic system. Signup and view all the answers

What effect does mindful breathing have on the autonomic nervous system?

Activates the parasympathetic system Signup and view all the answers

Which cranial nerve is primarily responsible for pupillary constriction?

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

Which glands are stimulated by the facial nerve (CN VII)?

Lacrimal gland and salivary glands Signup and view all the answers

What role does the vagus nerve play in digestion?

Regulates digestive tract motility Signup and view all the answers

Which nerve primarily contributes to the parasympathetic functions of the digestive system?

Vagus nerve (CN X) Signup and view all the answers

What is the primary role of the sympathetic nervous system (SNS) during stressful situations?

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

Which statement best describes the autonomic nervous system's control over bodily functions?

It regulates involuntary functions of internal organs. Signup and view all the answers

Where does the parasympathetic nervous system's innervation originate?

From the cranial and sacral spinal nerves Signup and view all the answers

How do the pathways of the sympathetic and parasympathetic nervous systems mainly differ?

Sympathetic pathways travel through the sympathetic trunk, while parasympathetic is craniosacral. Signup and view all the answers

Which of the following terms is associated with the parasympathetic nervous system's function?

Rest and digest Signup and view all the answers

What type of motor output is associated with the autonomic nervous system?

Involuntary control of organs and glands Signup and view all the answers

How does increased activity in the sympathetic nervous system affect the body?

Increases heart rate and contraction force Signup and view all the answers

What characterizes the autonomic nervous system's visceral afferents?

They carry sensory information from organs. Signup and view all the answers

What is the primary function of the lacrimal glands?

To excrete tears in the eyes Signup and view all the answers

Which cranial nerve is responsible for providing sensory information from the carotid sinus?

CN IX (Glossopharyngeal Nerve) Signup and view all the answers

What is one of the roles of mucosal glands in the body?

To lubricate the nasal and oral cavities Signup and view all the answers

Which glands are primarily responsible for saliva production?

Sublingual and submandibular glands Signup and view all the answers

What type of innervation does the glossopharyngeal nerve provide to the parotid gland?

Parasympathetic innervation Signup and view all the answers

Which of the following is a function of the glossopharyngeal nerve?

General and special sensory to the posterior 1/3 of the tongue Signup and view all the answers

Which statement best describes capillary chemoreceptors?

They sense changes in blood pressure and composition. Signup and view all the answers

In what way do glands such as the submandibular and sublingual contribute to the digestive process?

By excreting saliva to aid in the digestion of food Signup and view all the answers

What is the function of gray rami communicantes in the sympathetic nervous system?

They connect preganglionic and postganglionic neurons. Signup and view all the answers

Which pathway is primarily formed by presynaptic neurons exiting the sympathetic trunk without synapsing?

Splanchnic nerves Signup and view all the answers

Where do sympathetic neurons typically synapse when they ascend or descend to different levels?

In the sympathetic trunk Signup and view all the answers

What is a characteristic feature of the sympathetic nervous system pathway from T1 to L2?

There are no white rami communicantes in areas outside T1 to L2. Signup and view all the answers

What type of ganglia do splanchnic nerves synapse with after exiting the sympathetic trunk?

Prevertebral ganglia Signup and view all the answers

What is the primary role of postsynaptic neurons in the sympathetic pathway?

To transmit signals to target organs. Signup and view all the answers

What is the significance of the sympathetic trunk in the organization of sympathetic pathways?

It serves as a site for preganglionic neuron synapses. Signup and view all the answers

Why are there no sympathetic pathways originating above T1 or below L2?

There are no sympathetic ganglia present in these areas. Signup and view all the answers

From which spinal cord levels do sympathetic neurons primarily arise?

T1 – L2 Signup and view all the answers

What is the role of white rami communicantes in the sympathetic nervous system?

They convey myelinated presynaptic neurons into the sympathetic trunk. Signup and view all the answers

Which statement accurately describes the function of the sympathetic trunk?

It permits both ascending and descending of sympathetic signals throughout the periphery. Signup and view all the answers

Which type of neurons create gray rami communicantes?

Unmyelinated postsynaptic neurons Signup and view all the answers

Where do all sympathetic fibers enter the sympathetic trunk?

Between T1 and L2 spinal levels Signup and view all the answers

What happens to signals below L2 regarding the sympathetic trunk?

Signals can leave but cannot join the sympathetic trunk. Signup and view all the answers

Which structure is responsible for conveying sympathetic output from the spinal cord?

Lateral horn Signup and view all the answers

What type of signals are associated with the sympathetic nervous system?

Fight or flight signals Signup and view all the answers

Which of the following describes a characteristic of presynaptic neurons in the sympathetic system?

They enter the sympathetic trunk via white rami communicantes. Signup and view all the answers

Which area of the body does the sympathetic trunk connect to?

The entire body through paravertebral ganglia Signup and view all the answers

Study Notes

Autonomic Nervous System (ANS)

Part of the peripheral nervous system (PNS)
Controls visceral (organ) function involuntarily

Divisions of the ANS

Parasympathetic Nervous System (PSNS): "Rest and digest" or "Feed and breed"
Sympathetic Nervous System (SNS): "Fight, flight, or fright"

Somatic vs. Autonomic

Somatic
- General sensory
- Musculoskeletal movements and reflexes (motor)
Autonomic
- Visceral afferents (sensory input from organs)
- Visceral efferents (motor output to organs)
  - Smooth muscle
  - Cardiac muscle
  - Glands

Impacts of Autonomic System

SNS:
- Increased heart rate
- Increased contraction force
- Decreased saliva and tear production/excretion
- Bronchodilation, faster breath rate
- Pupillary dilation
- Sweat gland excretion and hair erection
- Decreased digestive activity, blood diverted to periphery
- Orgasm/ejaculation
- Decreased urinary function
PSNS:
- Decreased heart rate
- Decreased contraction force
- Increased saliva and tear production/excretion
- Bronchoconstriction, slower breath rate
- Pupillary constriction
- Increased digestive activity
- Arousal/erection
- Increased urinary function

Sympathetic Pathways

Presynaptic neurons travel through the sympathetic trunk and can even follow splanchnic nerves to synapse directly within the adrenal glands.

Referred Pain

The brain cannot differentiate between visceral sensory input and somatic sensory input.
This can cause visceral pain to be perceived as coming from the periphery (skin).

Parasympathetic System

Craniosacral, meaning its components arise from the brain and sacral region.

Vagus Nerve (CN X)

The most widespread cranial nerve
It provides the majority of parasympathetic innervation to the body.
Its name means "wanderer" because of its extensive connections.

Autonomic Nervous System

Part of the Peripheral Nervous System (PNS)
Controls internal organs (viscera) involuntarily
Composed of two branches: Sympathetic and Parasympathetic nervous systems
Sympathetic nervous system: "Fight, flight, or fright"
Parasympathetic nervous system: "Rest and digest," "Feed and breed"

Somatic vs. Autonomic Nervous System

Somatic: Controls voluntary movements and reflexes of the musculoskeletal system, utilizes general sensory input
Autonomic: Controls involuntary actions of the viscera, utilizes visceral afferents (sensory input from organs) and visceral efferents (motor output to organs)

Sympathetic Trunk

All sympathetic fibers run through the sympathetic trunk, located on both sides of the vertebral column
Sympathetic neurons originate from the lateral horn of the spinal cord between T1 and L2
White rami communicantes are myelinated pre-synaptic fibers that enter the sympathetic trunk
Gray rami communicantes are unmyelinated post-synaptic fibers that exit the sympathetic trunk to reach target organs
Paravertebral ganglia are located alongside the sympathetic trunk and are the primary sites for sympathetic neuron synapses
Signals can only leave the sympathetic trunk at or below T1 and L2 levels

Sympathetic Pathways

Presynaptic neuron: Neuron originating from the lateral horn, travels through white rami communicantes
Postsynaptic neuron: Neuron that synapses with the presynaptic neuron in the sympathetic trunk or paravertebral ganglia, travels through gray rami communicantes
Sympathetic neurons can synapse and exit the sympathetic trunk at the same level they originated or ascend/ descend to synapse and exit at different levels
Splanchnic nerves: presynaptic neurons exit the sympathetic trunk without synapsing and synapse at more distal prevertebral ganglia in the abdomen
Prevertebral ganglia include: celiac ganglion, superior mesenteric ganglion, inferior mesenteric ganglion

Parasympathetic System

Craniosacral outflow: Involves cranial nerves and sacral spinal nerves
Cranial nerves involved: Oculomotor (CN III), Facial (CN VII), Glossopharyngeal (CN IX), Vagus (CN X)
Oculomotor nerve (CN III): Responsible for pupillary constriction
Facial nerve (CN VII): Stimulates tear production (lacrimal gland), saliva production (sublingual and submandibular glands), and mucus production (nasal and oral cavities)
Glossopharyngeal nerve (CN IX): Stimulates saliva production by the parotid gland
Vagus nerve (CN X): Supplies parasympathetic innervation to most thoracic and abdominal organs

Breathing and the Autonomic Nervous System

Mindful breathing can activate the somatic system (phrenic nerve) which stimulates the parasympathetic system (vagus nerve)
The phrenic nerve controls the diaphragm, the primary muscle of respiration
Sympathetic activity can lead to chronic stress and negative health outcomes
Parasympathetic activity can counter the effects of stress.

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Description

Test your knowledge of the Autonomic Nervous System (ANS) and its divisions, including the sympathetic and parasympathetic nervous systems. Learn about the differences between somatic and autonomic functions, as well as the impacts of the ANS on various bodily functions. This quiz will help reinforce your understanding of this essential aspect of the peripheral nervous system.