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Questions and Answers
Which of the following cranial nerves is responsible for the sense of smell?
Which of the following cranial nerves is responsible for the sense of smell?
How many pairs of cranial nerves are there in the human body?
How many pairs of cranial nerves are there in the human body?
What is the primary function of the Oculomotor nerve?
What is the primary function of the Oculomotor nerve?
Which cranial nerve is involved in voluntary mastication?
Which cranial nerve is involved in voluntary mastication?
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Which type of fibres can cranial nerves carry?
Which type of fibres can cranial nerves carry?
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The Abducens nerve primarily functions to:
The Abducens nerve primarily functions to:
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What is a unique characteristic of cranial nerves regarding their composition?
What is a unique characteristic of cranial nerves regarding their composition?
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Which cranial nerve is primarily associated with vision?
Which cranial nerve is primarily associated with vision?
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Where is the action potential initiated in myelinated sensory axons?
Where is the action potential initiated in myelinated sensory axons?
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What is a key characteristic of the graded potential (GP) in relation to the stimulus?
What is a key characteristic of the graded potential (GP) in relation to the stimulus?
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Which of the following statements about action potentials is true?
Which of the following statements about action potentials is true?
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The mechanism responsible for the graded potential depends on what factor?
The mechanism responsible for the graded potential depends on what factor?
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What is the result of the direct effect of mechanical stimuli on somatosensory mechanoreceptors?
What is the result of the direct effect of mechanical stimuli on somatosensory mechanoreceptors?
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Which type of sensory receptor primarily uses separate cells or G-protein-coupled mechanisms to influence channel activity?
Which type of sensory receptor primarily uses separate cells or G-protein-coupled mechanisms to influence channel activity?
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In the context of graded potentials, which ion is primarily responsible for depolarization due to greater driving force?
In the context of graded potentials, which ion is primarily responsible for depolarization due to greater driving force?
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Which of the following statements about graded potentials and action potentials is FALSE?
Which of the following statements about graded potentials and action potentials is FALSE?
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What coding strategy is responsible for the increased frequency of action potentials in individual axons with greater stimulus intensity?
What coding strategy is responsible for the increased frequency of action potentials in individual axons with greater stimulus intensity?
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Which of the following receptors adapts slowly or not at all?
Which of the following receptors adapts slowly or not at all?
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What results from increased stimulus strength in terms of neurotransmitter release?
What results from increased stimulus strength in terms of neurotransmitter release?
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Which type of coding strategy involves the recruitment of more individual receptors as intensity increases?
Which type of coding strategy involves the recruitment of more individual receptors as intensity increases?
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What is the primary effect of receptor adaptation?
What is the primary effect of receptor adaptation?
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How can increasing stimulus intensity affect the action potential frequency along an afferent neuron?
How can increasing stimulus intensity affect the action potential frequency along an afferent neuron?
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Which of the following statements best describes the nature of frequency coding?
Which of the following statements best describes the nature of frequency coding?
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What is the expected response of sensory receptors during prolonged exposure to constant stimulus strength?
What is the expected response of sensory receptors during prolonged exposure to constant stimulus strength?
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What is the primary function of muscle stretch receptors and joint proprioceptors?
What is the primary function of muscle stretch receptors and joint proprioceptors?
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Which of the following describes phasic receptors?
Which of the following describes phasic receptors?
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What sensation corresponds to the 'off response' in sensory receptors?
What sensation corresponds to the 'off response' in sensory receptors?
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How are peripheral nerve fibres primarily classified?
How are peripheral nerve fibres primarily classified?
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Which group of nerve fibres is characterized by being myelinated and having the fastest conduction velocity?
Which group of nerve fibres is characterized by being myelinated and having the fastest conduction velocity?
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What is a characteristic of Group C nerve fibres?
What is a characteristic of Group C nerve fibres?
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The smaller myelinated nerve fibres fall under which group designation?
The smaller myelinated nerve fibres fall under which group designation?
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Which type of receptors primarily relay signals regarding changes in pressure?
Which type of receptors primarily relay signals regarding changes in pressure?
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Which Roman numeral corresponds to sensory axons that are myelinated and have a diameter of 12-20 µm with a conduction velocity of 70-120 m/sec?
Which Roman numeral corresponds to sensory axons that are myelinated and have a diameter of 12-20 µm with a conduction velocity of 70-120 m/sec?
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What is the classification for sensory axons that are unmyelinated?
What is the classification for sensory axons that are unmyelinated?
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Which of the following structures is innervated by Aγ fibers?
Which of the following structures is innervated by Aγ fibers?
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What is the conduction velocity range for Aδ fibers?
What is the conduction velocity range for Aδ fibers?
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Which type of nerve fiber is responsible for sharp pain sensation?
Which type of nerve fiber is responsible for sharp pain sensation?
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Which Roman numeral corresponds to the thinly myelinated sensory fibers with a diameter of 6-12+ µm?
Which Roman numeral corresponds to the thinly myelinated sensory fibers with a diameter of 6-12+ µm?
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Which structure is innervated by Ia fibers?
Which structure is innervated by Ia fibers?
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What type of sensory signal is primarily carried by C-fibers?
What type of sensory signal is primarily carried by C-fibers?
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Which type of nerve fibers generally have the highest diameter and conduction velocity?
Which type of nerve fibers generally have the highest diameter and conduction velocity?
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Which type of axon is classified as having a diameter less than 2 µm?
Which type of axon is classified as having a diameter less than 2 µm?
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Which cranial nerves are associated with parasympathetic innervation?
Which cranial nerves are associated with parasympathetic innervation?
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From which sacral segments do preganglionic parasympathetic fibers arise?
From which sacral segments do preganglionic parasympathetic fibers arise?
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What type of fibers do cranial nerves carry?
What type of fibers do cranial nerves carry?
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Which of the following is NOT a special sense carried by cranial nerves?
Which of the following is NOT a special sense carried by cranial nerves?
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Which cranial nerve is responsible for hearing and balance?
Which cranial nerve is responsible for hearing and balance?
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What is the primary function of the sympathetic nervous system?
What is the primary function of the sympathetic nervous system?
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Which of the following describes sensory receptors?
Which of the following describes sensory receptors?
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What aspect of sensory receptors does NOT involve coding of sensory intensities?
What aspect of sensory receptors does NOT involve coding of sensory intensities?
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Study Notes
Peripheral Nervous System (PNS)
- The PNS is composed of bundles of axons
- Sensory (afferent) nerves carry information towards the CNS.
- Motor (efferent) nerves carry information away from the CNS.
- Autonomic nerves are involved in involuntary functions.
Nervous System Organization
- The nervous system has an organizational hierarchy.
- The nervous system is made up of central (CNS) and peripheral (PNS) divisions.
- The CNS includes the brain and spinal cord.
- The PNS includes nerves outside the CNS.
Autonomic Nervous System (ANS)
- The ANS has two branches: sympathetic and parasympathetic.
- The sympathetic system is involved in the "fight or flight" response.
- The parasympathetic system is involved in the "rest and digest" response.
- There are differences in structure and function between sympathetic and parasympathetic.
Cranial Nerves
- There are 12 pairs of cranial nerves.
- Cranial nerves have sensory, motor, or mixed functions.
- Cranial nerves originate inside the cranium and proximal spinal cord.
- These nerves carry information such as sensory information, motor signals.
- A few examples of cranial nerves are olfactory, optic, oculomotor, trochlear, trigeminal, abducens, facial, auditory, glossopharyngeal, vagus, spinal accessory, and hypoglossal nerves.
Spinal Nerves
- There are 31 pairs of spinal nerves.
- Spinal nerves have both sensory and motor functions
- Each spinal nerve has a dorsal and ventral root.
- The dorsal root carries sensory information into the spinal cord.
- The ventral root carries motor signals away from the spinal cord.
- Different spinal nerve regions innervate different parts of the body.
Sensory Physiology
- Sensory receptors are transducers.
- Sensory receptors convert various forms of energy into action potentials.
- Examples include photoreceptors (light), thermoreceptors (temperature changes).
- Some examples of receptors are nociceptors (pain), and mechanoceptors (mechanical stimuli).
- Exteroceptors respond to stimuli outside the body.
- Proprioceptors give information about the body's position and movement.
Sensory Receptor Classifications
- Mechanoreceptors: detect various mechanical stimuli, including touch, pressure, vibrations, and stretch.
- Thermoreceptors: detect changes in temperature.
- Nociceptors: detect painful stimuli.
- Photoreceptors: detect light stimuli.
Sensory Receptor Adaptations
- Tonic receptors: slowly or not at all.
- Phasic receptors: rapidly adapt.
How Stimulus Intensity is Coded
- Frequency coding: the greater the stimulus intensity, the greater the frequency of action potentials.
- Population coding: the greater the stimulus intensity, the more receptors are recruited.
The Sensory Receptor
- The generator potential (GP) is a graded potential.
- The GP is a depolarization or sometimes, hyperpolarization, depending on the type of receptor.
- The GP can be graded in amplitude.
Spinal Cord
- The spinal cord has a roughly X-shaped central grey matter containing neuronal cell bodies.
- The outer portion is white matter, containing axons of sensory and motor tracts.
- Dorsal root: carries sensory information.
- Ventral root: carries motor signals.
- Spinal nerves carry both sensory and motor information.
Reflexes
- Reflexes are automatic, stereotyped responses to stimuli.
- They do not require conscious thought.
- Reflex arc is the pathway followed during a reflex action.
Monosynaptic Stretch Reflex
- Involves two neurons and one synapse
- Activation of muscle stretch is a quick, direct and automated response.
Polysynaptic Flexor-Withdrawal Reflex
- Involves multiple synapses and interneurons
- Involves a pathway to withdraw body part from painful stimulus
Vestibular Systems
- The vestibular system is a sensory system of balance and orientation.
- It involves the bony labyrinth, hair cells, semicircular canals, utricle, and saccule.
- Semicircular canals: detect angular movement, resulting in information about head rotation.
- Utricle: detects linear movement and static tilt (gravity) in the front-back and left-right planes
- Saccule: detects linear movement and static tilt in the up-down plane.
- The vestibulo-ocular reflex is a reflex that help control eye movement during head movement
Auditory Systems
- The auditory system is a sensory system for hearing.
- It includes the outer ear, middle ear, and inner ear.
- Transfer of sound energy from air to fluid.
- Two types of deafness are conduction and sensorineural.
- The human ear has methods of protecting itself from loud noises.
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Description
Test your knowledge on cranial nerves and their functions, as well as the basics of sensory physiology. This quiz covers important concepts like the sense of smell, vision, and action potentials. Challenge yourself to see how much you really know about the nervous system!
