Questions and Answers
What type of action do the parasympathetic and sympathetic nervous systems exhibit?
Which of the following best describes the origin of the parasympathetic nervous system?
How do the ganglia of the sympathetic nervous system differ in location compared to those of the parasympathetic nervous system?
Which chemical transmitter is released by neurons of the sympathetic nervous system?
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What is the primary function of the sympathetic nervous system during stressful situations?
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Which of the following accurately describes the length of fibers in the parasympathetic nervous system?
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How many total sympathetic ganglia are there in the body?
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What is the primary function of the sensory nervous system?
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In which area are collateral or prevertebral ganglia primarily located?
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Which subdivision of the motor nervous system is responsible for voluntary muscle control?
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What type of nerve fibers are involved in the autonomic nervous system?
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What does the grey matter in the spinal cord primarily contain?
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Which of the following accurately describes the function of the central nervous system?
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How many pairs of spinal nerves are part of the peripheral nervous system?
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What is contained within the central canal of the spinal cord?
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Which is NOT a part of the autonomic nervous system?
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What type of anti-cholinesterase inhibits the destruction of acetylcholine and is relevant in war gas poisoning?
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Which of the following enzymes is responsible for converting tyrosine into DOPA?
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What process initiates catecholamine release into synapses?
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Which statement correctly describes the reuptake process of catecholamines?
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Which type of drug is atropine classified as?
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What is the final product of nor-adrenaline conversion in the presence of N-methyltransferase?
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Which of the following fibers release catecholamines?
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What is a common effect of parasympatholytic drugs?
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What effect does the vagus nerve have on the heart rate?
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Which function is NOT associated with the sacral division of the autonomic nervous system?
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What is the role of the medulla oblongata in the autonomic nervous system?
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Which of the following is a function of the autonomic nervous system that leads to secretion?
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What is controlled by the higher centers of the autonomic nervous system?
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Which area of the autonomic nervous system is responsible for gall bladder contraction?
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What kind of reflexes are managed by lower centers in the autonomic nervous system?
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Which function is NOT facilitated by the higher centers of the autonomic nervous system?
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What is the primary function of the oculomotor nerve?
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Which of the following cranial nerves is involved in the secretion of saliva from the parotid gland?
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What is the origin of the facial nerve?
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The glossopharyngeal nerve relays through which ganglion to innervate the parotid gland?
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What type of saliva secretion is primarily produced by the glossopharyngeal nerve?
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Which cranial nerve is responsible for the contraction of the ciliary muscle?
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What is the function of the vagus nerve in relation to glandular secretions?
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What is the role of the greater superficial petrosal nerve?
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Study Notes
Overview of the Nervous System
- The nervous system (NS) regulates all body functions via sensory and motor signals.
- Sensory signals travel from organs to the central nervous system (CNS) via afferent nerves.
- Motor signals travel from the CNS to organs through efferent nerves.
Functional Classification
- Sensory Nervous System: Transmits sensory signals from organs to the CNS using afferent nerve fibers.
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Motor Nervous System: Delivers motor signals from the CNS to muscles and glands via efferent nerve fibers, divided into:
- Somatic Motor Nervous System: Controls voluntary functions and skeletal muscle.
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Autonomic Nervous System: Manages involuntary functions, controlling cardiac and smooth muscles and glands, split into:
- Sympathetic Nervous System: Uses adrenergic fibers.
- Parasympathetic Nervous System: Uses cholinergic fibers.
Anatomical Classification
- Central Nervous System (CNS): Comprises the brain and spinal cord.
- Peripheral Nervous System (PNS): Includes 12 cranial nerves (sensory, motor, mixed) and 31 pairs of mixed spinal nerves.
Spinal Cord Structure
- Central Canal: Contains cerebrospinal fluid.
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Grey Matter: Involves anterior, lateral, and posterior horns with neuronal soma.
- Lateral horn is present only in sympathetic nerves (T1-L2).
- White Matter: Composed of nerve fibers with a myelin sheath, appearing white.
Characteristics of Autonomic Nervous Systems
- Antagonistic Actions: Parasympathetic promotes energy storage; sympathetic promotes energy consumption.
- Reciprocal Actions: One system's activation inhibits the other, except in specific situations (e.g., sexual activity).
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Distribution:
- Parasympathetic NS has limited distribution (7 nerves), acting in isolation.
- Sympathetic NS has widespread distribution (15 nerves), acting as a cohesive unit.
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Ganglia Location:
- Parasympathetic ganglia are distant from the CNS, with long preganglionic and short postganglionic fibers.
- Sympathetic ganglia are close to the CNS, leading to short preganglionic and long postganglionic fibers.
- Origin: Parasympathetic is craniosacral; sympathetic is thoracolumbar.
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Function:
- Parasympathetic maintains homeostasis at rest.
- Sympathetic maintains homeostasis during stress (fight or flight).
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Neurotransmitters:
- Parasympathetic uses acetylcholine.
- Sympathetic releases catecholamines (epinephrine and norepinephrine).
Autonomic Ganglia
- Definition: Collections of postganglionic neuronal cell bodies outside the CNS, versus nuclei inside the CNS.
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Types of Sympathetic Ganglia:
- Lateral or Paravertebral Ganglia: 26 in total, forming a sympathetic chain.
- Collateral (Prevertebral) Ganglia: Located mid-way between the spinal cord and organs, unpaired.
Cranial Division of the Autonomic Nervous System
- Oculomotor Nerve (III): Controls pupil constriction and lens accommodation.
- Facial Nerve (VII): Innervates salivary and lacrimal glands for secretion and vasodilation.
- Glossopharyngeal Nerve (IX): Regulates secretion of the parotid salivary gland.
- Vagus Nerve (X): Manages heart rate, bronchial secretion, gastrointestinal motility, and bile secretion.
- Sacral Division: Controls urination, defecation, and sexual arousal through pelvic nerves.
Centers Controlling Autonomic Nervous System
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Lower Centers:
- Spinal cord and brainstem (medulla oblongata and pons) manage simple reflexes.
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Higher Centers:
- Cerebral cortex regulates lower centers to modulate autonomic activities.
Pharmacology of the Autonomic Nervous System
- Anti-cholinesterase Agents: Inhibit breakdown of acetylcholine; reversible agents used medically to enhance parasympathetic function.
- Parasympatholytics: Block parasympathetic actions, e.g., atropine (muscarinic blocker) and curare (neuromuscular junction blocker).
- Catecholamines Release: Initiated by action potentials, leading to synaptic vesicle exocytosis that releases neurotransmitters into synapses.
- Inactivation of Catecholamines: Occurs via reuptake into adrenergic nerve endings or diffusion into body fluids.
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Description
Explore the intricacies of the nervous system in this quiz, focusing on its functional classification and the role of sensory and motor signals. Understand how the nervous system regulates both voluntary and involuntary functions across different body organs. Test your knowledge on the pathways and mechanisms that govern these critical processes.