Nervous System Overview Quiz

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Questions and Answers

What is the primary function of the sympathetic nervous system?

  • To increase alertness and metabolic activities for emergencies (correct)
  • To control voluntary muscle movements
  • To regulate digestion and energy conservation
  • To manage body temperature during rest

Which statement accurately describes the parasympathetic nervous system?

  • It governs sensory receptors in the skeletal muscles.
  • It primarily functions to prepare the body for immediate physical activity.
  • Its activities conserve and restore body energy. (correct)
  • It increases heart rate and respiration rates.

How does the autonomic tone function in relation to the autonomic nervous system?

  • It reflects the balance between sympathetic and parasympathetic activity. (correct)
  • It indicates an imbalance in sympathetic control.
  • It is the sum of all heart rate variations.
  • It is caused solely by sympathetic activity.

What is the main role of the enteric nervous system?

<p>To regulate chemical changes and movements in the GI tract. (D)</p> Signup and view all the answers

Which of the following statements is true regarding the peripheral nervous system?

<p>It connects the brain and spinal cord to the limbs and organs. (C)</p> Signup and view all the answers

Which ganglion is primarily responsible for supplying the small and large intestines?

<p>Superior mesenteric ganglion (B)</p> Signup and view all the answers

What structure do the postganglionic neurons from the ciliary ganglion supply?

<p>Smooth muscle of the eye (D)</p> Signup and view all the answers

Which plexus is known as the largest autonomic plexus and surrounds the celiac trunk?

<p>Celiac (solar) plexus (A)</p> Signup and view all the answers

Which type of neuron typically connects with only 4 to 5 postsynaptic neurons?

<p>Parasympathetic preganglionic neurons (A)</p> Signup and view all the answers

What is the primary function of adrenal medullae in the sympathetic division?

<p>Release of hormones into the blood (B)</p> Signup and view all the answers

Which of the following is NOT a major collateral ganglion?

<p>Pterygopalatine ganglion (A)</p> Signup and view all the answers

Which preganglionic axons primarily carry craniosacral outflow?

<p>Vagus nerve (B)</p> Signup and view all the answers

What anatomical structure do sympathetic postganglionic neurons enter to merge with spinal nerves?

<p>Grey ramus (B)</p> Signup and view all the answers

Which ganglion supplies the parotid salivary glands?

<p>Otic ganglion (B)</p> Signup and view all the answers

How many ways can sympathetic preganglionic neurons connect with postganglionic neurons?

<p>Four (B)</p> Signup and view all the answers

Which syndrome is characterized by the loss of sympathetic innervation leading to droopy eye and constricted pupils?

<p>Horner's syndrome (C)</p> Signup and view all the answers

Which ganglion supplies the smooth muscle of the eye?

<p>Ciliary ganglion (A)</p> Signup and view all the answers

What effect do the sympathetic ganglia generally have on the body when activated?

<p>Divergent responses across multiple organs (B)</p> Signup and view all the answers

Which of the following options describes the preganglionic axons in the sacral parasympathetic outflow?

<p>They travel with the spinal nerves and branch off. (D)</p> Signup and view all the answers

What is the primary focus of the sympathetic division during stress?

<p>Vigorous physical activity and rapid ATP production (A)</p> Signup and view all the answers

Which statement accurately describes the autonomic ganglion?

<p>It connects the preganglionic and postganglionic neurons in the autonomic nervous system. (C)</p> Signup and view all the answers

What effect does a high sympathetic tone have on blood vessels in the skeletal muscles?

<p>Dilates blood vessels to increase blood flow. (A)</p> Signup and view all the answers

Which neurotransmitters are primarily released by autonomic motor neurons?

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

What physiological response is associated with parasympathetic activation?

<p>Increased digestion (B)</p> Signup and view all the answers

Which cranial nerve is NOT associated with the parasympathetic division?

<p>Optic nerve (Cranial Nerve II) (D)</p> Signup and view all the answers

What type of neuron pathway is characteristic of the somatic nervous system?

<p>One neuron pathway (B)</p> Signup and view all the answers

During a fight or flight response, which of the following occurs?

<p>Dilation of pupils (C)</p> Signup and view all the answers

Which structure primarily does NOT receive sympathetic innervation?

<p>Skeletal muscle (D)</p> Signup and view all the answers

Where do the cell bodies of preganglionic neurons for the sympathetic division reside?

<p>Lateral horns of gray matter in T1 to L2 (C)</p> Signup and view all the answers

Which of the following does NOT occur during the rest and digest state?

<p>Increased heart rate (A)</p> Signup and view all the answers

Which of the following blood vessels constricts during a sympathetic response?

<p>Blood vessels to the gut (A)</p> Signup and view all the answers

What role does the adrenal medulla play in the sympathetic nervous system?

<p>It releases hormones like norepinephrine and epinephrine. (A)</p> Signup and view all the answers

Which type of fibers are typically used by postganglionic neurons in the autonomic nervous system?

<p>Type C fibers (B)</p> Signup and view all the answers

How does the sympathetic division affect the kidneys?

<p>Decreases blood flow to the kidneys (D)</p> Signup and view all the answers

Flashcards

CNS

Central Nervous System; the brain and spinal cord

PNS

Peripheral Nervous System; nerves extending from the CNS

ANS

Autonomic Nervous System, involuntary actions.

Sympathetic Nervous System

"Fight or Flight" response; increase alertness and energy.

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Autonomic Tone

Balance of Sympathetic and Parasympathetic activity; regulates bodily functions.

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Parasympathetic Nervous System

The part of the autonomic nervous system that promotes "rest and digest", supporting energy conservation.

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Autonomic Nervous System

The part of your peripheral nervous system controlling involuntary functions like heart rate and digestion.

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Fight or Flight

The physiological response triggered by the sympathetic nervous system, preparing the body for action in stressful situations.

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Preganglionic Neuron

The first neuron in an autonomic pathway, its cell body is in the CNS.

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Postganglionic Neuron

The second neuron in an autonomic pathway, located in the PNS and synapsing with the effector.

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Autonomic Ganglion

A cluster of nerve cell bodies where pre- and postganglionic neurons synapse in the autonomic nervous system.

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Sympathetic Trunk Ganglia

A row of ganglia near the spinal cord, part of the sympathetic nervous system.

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Paravertebral Ganglia

A structure part of the sympathetic trunk ganglia, located alongside the spinal column.

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Prevertebral Ganglia

Ganglia located in front of the vertebral column in the sympathetic nervous system.

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Terminal Ganglia

Ganglia of the parasympathetic system, located near the target organ.

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Somatic Nervous System

Part of the peripheral nervous system responsible for voluntary movement and sensory perception.

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Hypothalamus

Brain region that controls the autonomic nervous system, acting as its central control.

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Adrenal Medulla

Part of the adrenal gland, releases epinephrine and norepinephrine in response to SNS stimulation.

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Collateral Ganglia

Collections of neurons outside the sympathetic trunk, located anterior to the vertebral column, whose postganglionic axons innervate organs below the diaphragm.

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Celiac Ganglion

A major collateral ganglion that innervates organs in the upper abdomen.

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Superior Mesenteric Ganglion

A collateral ganglion innervating the small and large intestines.

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Inferior Mesenteric Ganglion

A ganglion that innervates the large intestine.

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Splanchnic Nerves

Nerves that carry sympathetic preganglionic axons to prevertebral ganglia.

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Divergence (Sympathetic)

One preganglionic neuron synapsing with many postganglionic neurons, resulting in widespread responses.

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Ciliary Ganglion

Cranial parasympathetic ganglion affecting smooth muscles of the eye.

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Otic Ganglion

Parasympathetic ganglion supplying the parotid salivary gland.

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Pterygopalatine Ganglion

Ganglion supplying nasal mucosa, palate, pharynx, and lacrimal glands.

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Submandibular Ganglion

Parasympathetic ganglion innervating submandibular and sublingual glands.

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Autonomic Plexuses

Tangled networks of autonomic axons, and sensory neurons in thorax, abdomen, and pelvis.

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Celiac (Solar) Plexus

The largest autonomic plexus surrounding the celiac trunk, innervating abdominal organs.

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Horner's Syndrome

Sympathetic outflow problem causing ptosis, miosis, anhydrosis, and enophthalmos.

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Parasympathetic Outflow

Cranial and sacral divisions of the autonomic nervous system.

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Study Notes

Central Nervous System (CNS)

  • Composed of the brain and spinal cord

Peripheral Nervous System (PNS)

  • Includes the somatic, autonomic, and enteric nervous systems

Somatic Nervous System (SNS)

  • Controls voluntary movements
  • Contains sensory receptors and motor neurons connecting to skeletal muscles

Autonomic Nervous System (ANS)

  • Controls involuntary functions
  • Contains sensory neurons from internal organs (viscera) and motor neurons to smooth muscle, cardiac muscle, and glands
  • Two subdivisions: sympathetic and parasympathetic

Sympathetic Nervous System

  • "Fight or flight" response
  • Increases alertness and metabolic activity to prepare for emergencies
  • Impacts various physiological processes like heart rate, blood pressure, and blood sugar levels to support physical activity

Parasympathetic Nervous System

  • "Rest and digest" response
  • Conserves and restores energy during rest
  • Targets the GI tract and respiratory system for digestive functions

Enteric Nervous System (ENS)

  • Involuntary system
  • Regulates activity within the gastrointestinal tract
  • Contains sensory neurons responding to chemical changes and stretching in the GI tract
  • Contains motor neurons to GI smooth muscle

Autonomic Tone

  • Balance between sympathetic and parasympathetic activity
  • Maintained by the hypothalamus
  • Certain organs (like sweat glands, blood vessels) receive only sympathetic innervation, exhibiting a range in response by increasing or decreasing the sympathetic tone

Sympathetic Responses (fight-or-flight)

  • Dominates during stress

  • Favors functions like energy production and reduces non-essential functions

  • Emotional stress can activate the sympathetic division

  • Pupil dilation

  • Increased heart rate, contraction force, and blood pressure

  • Bronchodilation (widening of airways)

  • Vasodilation to skeletal muscles

  • Vasodilation to heart

  • Vasoconstriction to GI tract

  • Vasoconstriction to kidneys

  • Vasodilation to liver (blood sugar)

  • Vasodilation to adipose tissue (fat)

Parasympathetic Responses (rest-and-digest)

  • Supports conservation and restoration of energy

  • Slows down body activity for rest and recovery

  • Decreased heart rate and force of contraction

  • Bronchoconstriction (narrowing of airways)

  • Pupil constriction

  • Increased salivation and lacrimation (tears)

  • Increased urination, digestion, and defecation

Comparison: Somatic vs. Autonomic Nervous Systems

Feature Somatic Nervous System Autonomic Nervous System
Sensory Input From receptors for somatic senses (touch, temperature, pain, body position) From internal receptors (viscera, blood vessels)
Consciousness Consciously perceived Generally not consciously perceived
Motor Output Voluntary; from the cerebral cortex Involuntary; from the hypothalamus
Neuron Pathway One neuron Two neurons (preganglionic and postganglionic)
Neurotransmitter Acetylcholine only Acetylcholine or norepinephrine
Effectors Skeletal muscle Smooth muscle, cardiac muscle, and glands
Response Skeletal muscle contractions Contraction/relaxation of smooth muscle; Increased/decreased heart rate/secretion

Anatomy of Autonomic Motor Pathways

  • Preganglionic neuron: First neuron; cell body in CNS, travels to ganglion; "B" type fiber
  • Postganglionic neuron: Second neuron; cell body in ganglion, innervates effector; "C" type fiber
  • Autonomic ganglion: Location where preganglionic and postganglionic neurons synapse

Sympathetic Division

  • Preganglionic neurons: Cell bodies in the lateral horns of spinal cord (T1-L2/L3)
  • Ganglia: Paravertebral (sympathetic trunk) and prevertebral ganglia
  • Connections: Axons can synapse in the first reached ganglion, ascend/descend to other ganglia, synapse in prevertebral ganglia (e.g., splanchnic nerves), or synapse with chromaffin cells in adrenal medulla (hormone release). This divergence explains widespread effects of sympathetic responses

Parasympathetic Division

  • Preganglionic neurons: Cell bodies in nuclei of brainstem (cranial nerves 3, 7, 9, 10) and lateral gray matter of S2-S4
  • Ganglia: Terminal ganglia, located near or within the visceral effector
  • Connections: Synapse with usually 4-5 postganglionic neurons, leading to localized effects

Autonomic Plexuses

  • Networks of sympathetic and parasympathetic neurons, sensory neurons, and ganglia, in thorax, abdomen, and pelvis
  • Examples: Cardiac, pulmonary, celiac, superior mesenteric, inferior mesenteric, hypogastric, renal plexuses

Connections: Sympathetic postganglionic neurons to visceral effectors

  • Spinal nerves: via grey rami communicantes to skin, blood vessels, arrector pili
  • Cephalic periarterial nerves: to head and face; involving sweat glands, smooth muscle, lacrimal glands etc...
  • Sympathetic nerves: to thoracic organs (heart, lungs)

Sympathetic Nerves to Adrenal Medulla

  • Preganglionic fibers synapse with chromaffin cells
  • Chromaffin cells release epinephrine and norepinephrine into bloodstream

Horner's Syndrome

  • Loss of sympathetic innervation (e.g., trauma or disease) causes drooping eyelid (ptosis), constricted pupils (miosis), lack of sweating (anhidrosis) and sometimes posterior displacement of eyeball (enophthalmos).

Structure of the Parasympathetic Division

  • Cranial Parasympathetic outflow from nuclei in brain stem along cranial nerves, especially the vagus nerve
  • Sacral Parasympathetic outflow: from S2-S4 spinal nerves
  • Ganglia (Cranial): Ciliary, Pterygopalatine, Submandibular, Otic
  • Ganglia (Sacral): terminal ganglia near/in the visceral effector ( e.g., colon, bladder, reproductive organs)

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