all of the following are examples of nociceptors except:

(mark all that apply) A. pressure B. smell C. pain D. body position, Striking the "funny bone" is actually stimulation of (or injury to) the ________. Unencapsulated receptors: free nerve endings in skin, joints, viscera, oral cavity Modality (type of stimulus):-mechanoreceptors: stretch, displacement, pressure The apparent lack of a response to a noxious stimulus may result because of different receptors located on the membrane of the end terminal (free nerve ending) or the stimulus intensity is insufficient. Both fatigue and sensitization are observed. For the given state of plane strain, use Mohr's circle to determine (a) the orientation and magnitude of the principal strains, (b) the maximum in-plane strain, (c) the maximum shearing strain. b. encapsulated mechanoreceptors. A. first B. second C. third D. forth, A major nerve of the lumbar plexus is the ________. Which of the following is the correct simple spinal reflex arc? Besides the Facial Nerve, which of the following also controls motor function of the facial muscles? lamellated corpuscle. what . Which of the following interpets taste sensations? \hline \text { c@ gmail.com } & \text { e4 } & 20 \\ All processing at the circuit level going up to the perceptual level must synapse in the ________. There are three small bones in the inner ear. A) Taste B) Heat and cold C) Odor D) Vibration E) Light, Chemoreceptors include A) hair cells. What is the only special sense in which signals can reach the cerebral cortex without passing first through the thalamus? Nociception, pain, negative moods, and behavior selection. D) motor sensation. 1988;25:219-221, Tanelian DL. Instead, they are activated in response to pathological change. copyright 2003-2023 Homework.Study.com. Which of the following special sensory neural pathways is closely associated with the limbic system and does not pass through the thalamus? b. joint position. 1995;483:747-758, Schepers RJ, Ringkamp M. Thermoreceptors and thermosensitive afferents. (a) visual and auditory responses (b) taste and olfaction responses (c) voluntary movement (d) involuntary movement. B. grow and develop. Neurotrophins (NTs), proteins that modulate the functioning and development of . c. joints, ligaments, and muscles. a. nociceptors b. thermoreceptors c. mechanoreceptors d. chemoreceptors, Which of the following is not considered a special sense? The AGSStudent table stores the student information. gZ(=`fD\Jh{} B+el QAM\)v{_o+ C fibres mediate poorly localized anatomically type of pain, it has an aching and burning character, comes later than the initial first sensation and it is difficult to estimate its strength. \end{array} Ability to recognize objects by sensation of touch b. c. IX. Myelin allows nerve signals (called action potentials) to travel rapidly. True B. create table AGSLog ( After axonal injury, regeneration in peripheral nerves is guided by ________. Optic c. Oculomotor d. Trochlear e. Trigeminal f. Abducens g. Facial h. Vestibularcochlear i. Glossopharyngeal j. Vagus k. Accessory l. Hypoglossal, Stereognosis is: a. Odor molecules diffuse through mucus and bind directly to the ________ of olfactory receptors. Which of the following will respond to steady pressure? a) Optic Nerve b) Olfactory Nerve c) Trigeminal Nerve d) Glossopharyngeal Nerve. \end{aligned} *fz)dn@\^2w3M86}mDgk# u#&lad6}"MHK6&Z`ZtPl|l,ely(tCR.:\tbOMgd4 ,`X\ ;d\X\^p$&aX6+v(.I]n b) Increasing participation in social networks. A) A reflective choroid behind the retina, Ommatidia are found in the compound eyes of, When light energy hits a photopigment, the molecule. New research revealed that combining cognitive behavioral therapy (CBT) with tailored exercises could significantly support pain management. The peripheral end of the axon contains encapsulated proteins called transduction proteins (TRP), which can be activated by a specic stimulus. pH change as a result of local inflammatory process). Keep in mind, these transmitted pain signals are complex, carrying information about both the location and intensity of the painful stimuli. Erica Jacques, OT, is a board-certified occupational therapist at a level one trauma center. Unit Seven: STRUCTURE OF THE NERVOUS SYSTEM Describe how the human brain is similar and different from other mammalian brains Dependent upon divisions for the lobes -- some animals have sensorimotor but we have motor AND somatosensory. Others report episodes that come and go. \end{aligned} 1 0 obj University of Connecticut Health Center: Nociceptors and the Perception of Pain. However, if your pain continues, you need to talk with your doctor. Vision is dependent upon: A. chemoreceptors. e. nociceptors. C. Tactile (Meissner) corpuscles. Neurogenic inflammation causes a release of neurotransmitters, notably substance P and calcitonin gene-related peptide (CGRP), which leads to severe vasodilation, as well as plasma leakage of proteins and fluid from post capillary venules.[3]. mechanoreceptors. To supply blood to the retina and to absorb stray light so that it is not reflected inside the eye. <>/Metadata 2149 0 R/ViewerPreferences 2150 0 R>> 1943;6:293315, Schaible HG, Schmidt RF. Proprioceptors Chemoreceptors Nociceptors Baroreceptors Hair cells . e. light. 2005-2023 Healthline Media a Red Ventures Company. Nociceptors. Nociceptors. D. sight. . Hearing C. Equilibrium D. Vision, The ability to localize the position of body parts is called: a) two-point discrimination b) proprioception c) fine touch d) light touch e) perception, Which one of these includes tactile sensations (touch, pressure, vibration, itch, and tickle), thermal sensations (warm and cold), pain sensations, and proprioception? a. thermoreceptors b. mechanoreceptors c. chemoreceptors d. proprioceptors. 2) The sensory receptors, neurons and pathways make up the _____ division of the nervous system. Lungs b. Aorta c. Brain d. All three above e. None of the above. d. All three above e. None of the above. The two-point discrimination test is used to measure: a. receptive field size for touch receptors. Hair cells are important in the sense of _______. Which of these structures can be swiveled around in some animals to better locate a sound? Bodily sensations are typically attributed to bodily locations and appear to have features such as volume, intensity, duration, and so on, that are ordinarily attributed to physical objects or . Which structure transmits sound waves to the malleus in the middle ear? % Injuries that cause nociceptive pain include: When activated by stimuli, nociceptors notify the brain about the injury with electrical signals sent via the peripheral and central nervous system (CNS). How does an insect see the world, as many separate images or as a single image? A number of studies involving humans or animals have shown that subjects with spinal cor lesion are able to report pain likely originating from visceral organs area. [3] The large majority of free nerve endings in the skin are called polymodal nociceptors because they contain multiple receptors and thus respond to various combinations of the above mentioned stimulus. Why does food taste bland when you have a cold? 30 seconds. b. transduction. Baliki MN, et al. Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. A. osmoreceptors B. photoreceptors C. mechanoreceptors D. nociceptors E. thermoreceptors, Problems in balance may follow trauma to which nerve? When the brain receives the signals, it has a perception of the pain thats being felt. Pain. transducer. C) pain. Experiments conducted in totally dark, soundproof rooms have shown that owls can capture prey after pinpointing its location to within 1.5 degrees in both horizontal and vertical planes. They can sense light touch and vibrations. Complex sensory receptors, which consist of a dedicated receptor cell and afferent sensory neuron, transduce stimuli as a graded potential called a _________ potential. $$ When the elevator is not moving, the hair cells of the saccule are horizontal and embedded in a gelatinous matrix topped with tiny, calcium carbonate stones. In humans, depth perception is possible because. C)Kidney. Healthline Media does not provide medical advice, diagnosis, or treatment. d. cortex. All of the following features of the Earth are important to life as we know it except: a. abundant surface water in the liquid state. In the 1970s came the celebrated imaging techniques the modern practitioner depends on for verification of diag- Select the correct path through which sound waves travel to stimulate hearing. Functionally, different free nerve endings, are assumed to possess different sets of receptor molecules in their axonal membrane. Cytokines, such as interleukins and tumor necrosis factor, and neurotrophins, especially NGF, are also generated during inflammation. e. equilibrium. A. pons B. thalamus C. reticular formation D. medulla. \hline \text { username } & \text { exerciseName } & \text { score } & \text { submitted } \\ tactile (Merkel) disc. Sensory endings located in muscles, tendons, joints, and inner ear are called a. exteroceptors. Last medically reviewed on October 12, 2017. @1JC|T\,Zrxs[7i*. Which is NOT a general sense? The EAA, particularly glutamate, produce the initial excitatory response on the postsynaptic, second-order, neuron, followed by the release of peptides, including substance P, causing a more prolonged depolarization and sustained nociceptive transmission. Visceral structures are highly sensitive to distension (stretch), ischemia and inflammation, but relatively insensitive to other stimuli that normally evoke pain such as cutting or burning.Visceral pain is diffuse, difficult to localize and often referred to a distant . a. light b. touch c. temperature d. sound e. smell, What kind of stimuli can the internal ear sense? $$ Frequent action potentials are interpreted as loudness in the brain. \hline \text { username } & \text { exerciseName } & \text { score } & \text { submitted } \\ What is the nature of the stimuli that excite each type? Technically, it is a deviation from the normal sensing and perception of odor molecules, or olfactory stimuli processing. A. \hline \text { t@gmail.com } & \text { e1 } & 10 \\ A. effector, afferent neuron, integration center, efferent neuron, receptor B. receptor, afferent neuron, integration center, efferent neuron, effector C. effector, efferent neuron, integration center, afferent neuron, receptor D. receptor, efferent neuron, integration center, afferent neuron, effector, The patellar "knee jerk" reflex is an example of a(n) ________. That way your brain can fully process the pain and eventually send communication back to block further pain signals. Verywell Health's content is for informational and educational purposes only. The part of the brain that sorts sensation to other parts of the brain is ______. LR o$tik:\XEe:HKtlSYK{8#Qp&R\JC!O0>c| l~ x/6kMKDo'':z$Uq'y{^ Diabetic neuropathy and pain caused by multiple sclerosis are some examples of neuropathic pain. The eyes encompasses several complex structures that facilitate visual perception. The threshold of human skin temperature at which cool or cold is perceived as pain is. The location may seem vague. Noxious stimuli are stimuli that elicit tissue damage and activate nociceptors. $$ A. unmyelinated B. primarily low-threshold mechanoreceptors C. associated with sharp, pricking sensation D. activated before other nociceptors with acute trauma Answer: C Learning Objectives: Be familiar with the receptors involved in the physiology of pain. C) not all sensations lead to a perception. Which of the following receptors would detect this type of stimulus? Thus, a noxious stimulus can be categorised into one of these three groups. A. characterized by partial paralysis of diaphragm muscles B. characterized by loss of vision C. often caused by inflammation of the trigeminal nerve D. characterized by paralysis of facial muscles, Potentially damaging stimuli that result in pain are selectively detected by ________. A. pain B. temperature C. touch D. balance/equilibrium E. pressure, Transduction refers to conversion of ________. b. pressure. a) hearing b) smell c) taste d) vision e) All of the choices use transduction. Which of the following cranial nerves conveys taste and general sensation from the posterior third of the tongue? The posterior longitudinal ligament and the outer annulus brosus layers of intervertebral disc contain plenty of nociceptive bers. b. retina. As a result, after an acute injury, a person experiences pain in two phases, one from the A fibers and one from the C fibers.. In the case of minor injuries, the pain quite often goes away as the injury heals. New York: Appleton and Lange; 2000. p472-491. A. I used to dismiss pain creams as too lightweight for my chronic pain. High threshold nociceptive afferents terminate primarily in the synovium and periosteum and normally respond only to the movement of the joint beyond the working limits. The eyes of prey tend to be on the sides of the head so they can see predators approach from almost any direction. _x = +300, _y = +60, _{xy} = +100 d. X. polysynaptic reflex. a. Auditory b. Gustatory c. Olfactory d. Visual. There are no receptors in this area. If you could monitor the activity from the photoreceptors of rods and cones in the retina during a dream, would you expect these cells to be producing electrical signals? \end{array} True B. At present, there are no clear ultrastructural differences between non-nociceptive free nerve endings (e.g., sensitive mechanoreceptors and thermoreceptors) and nociceptive ones. Meissner corpuscles- An encapsulated nerve ending, present at the upper part of the dermis. Erica Jacques, OT, is a board-certified occupational therapist at a level one trauma center. Looking at this in more detail, if you stub your toe, the nociceptors on your skin are activated, causing them to send a signal to the brain, via the peripheral nerves to the spinal cord. A. extensor thrust reflex B. stress reflex C. crossed-extensor reflex D. stretch reflex, Which type of receptors transduce fine touch and are found within the stratum basale of the epidermis? Nociceptors are activated by potentially noxious stimuli, as such nociception is the physiological process by which body tissues are protected from damage . Experts say chronic pain can lead to illness and disease as well as mental health issues as a person ages. True B. projects.hsl.wisc.edu/GME/PainManagement/session2.4.html, dartmouth.edu/~dons/part_2/chapter_19.html#chpt_19_nociceptive, sjm.com/en/patients/chronic-pain/what-is-chronic-pain?clset=af584191-45c9-4201-8740-5409f4cf8bdd%3ab20716c1-c2a6-4e4c-844b-d0dd6899eb3a, Chronic Pain and Cannabis: Research Finds it May Help Some People Cut Down on Opioids, Debra Rose Wilson, Ph.D., MSN, R.N., IBCLC, AHN-BC, CHT, How Chronic Pain in Your 40s Can Lead to Illness, Disease in 50s and 60s, Psychotherapy May Help You Find Relief From Chronic Back Pain Here's How, What to Know When Choosing a PEMF Therapy Device for Home, The Best Topical Pain Relief Products of 2022, Dominique Fontaine, BSN, RN, HNB-BC, HWNC-BC, pain caused by overuse or joint damage, such as arthritis or sprains, the structures involved in causing the pain, changes to how your medications are managed, alternative therapies, such as acupuncture. Nociceptive pain is one of the two main types of physical pain. Get started for free! For instance, while banging your knee on your desk may hurt badly at the moment, it likely didn't cause lasting damage. a. trigeminal nerve (CN V) b. facial nerve (CN VII) c. glossopharyngeal nerve (CN IX) d. vagus nerve (CN X) e. hypoglossal nerve (CN XII), The senses of equilibrium and hearing are provided by receptors of the O outer ear O bony labyrinth O inner ear O middle ear O perilymph, Which of the following controls the motor enervation of smooth muscles? B. Perceptual detection is the ability to detect how much stimulus is applied to the body. What is the effect of a cornea that is too flat? d) Pressure. biomarkers at specific time points following a painful stimulus. Feeling a gentle caress on your arm would likely involve all of the following except _____. Pain is the most prominent member of a class of sensations known as bodily sensations, which includes itches, tickles, tingles, orgasms, and so on. Dull pain is usually a bearable but long-term pain. d. hearing. Free nerve endings terminating in the skin are the machinery for signaling local mechanical, thermal, and chemical changes. A. also flex B. extend C. abduct D. adduct, The cranial nerves that have neural connections with the tongue include all except the ________. An infection or injury commonly causes this type of pain. Much of "taste" is actually smell; when you have a cold, your nose is stuffed up and you cannot smell very well because odor and taste molecules cannot reach the olfactory receptors. D) The lens of the eye stiffens with age, making it difficult to focus on nearby objects. c. activity of taste buds. Radiculopathy is an example of a condition that causes radicular pain. b) Kidneys and hip and abdominopelvic area. \hline \text { wbc } & \text { e2 } & 7 & 1 \\ This often occurs in truck drivers, sailors, and other people who focus on the horizon or at great distances for long periods of time. \begin{aligned} What symptoms indicate that the auditory tube is blocked? d. Olfactory nerve. Meyer RA, Ringkamp M, Campbell JN, Raja SN. | Find, read and cite all the research . Thomas is deaf, but can feel the vibrations of music through sensory receptors in his skin called: A. lamellated (Pacinian) corpuscles. D) both taste buds and olfactory receptors. These are the predominant type of C-fibre nociceptors in mammalian skin. how you think about and what you do about the pain. Why is it that one cannot identify the . \hline Chemical damage is caused by contact with toxic or hazardous chemicals. While there are numerous neurotransmitters within the nervous system, the three most common participating in nociceptive transmission are peptides, purines, and excitatory amino acids (EAA). b. interoceptors. A. trigeminal B. facial C. glossopharyngeal D. trochlear, Dermatomes are skin segments that relate to sensory innervation regions of the spinal nerves. Nociceptors are activated by potentially noxious stimuli,as such nociception is the physiological process by which body tissues are protected from damage. Fein A. Calculate any depreciation recapture, ordinary losses, or capital gains associated with disposal of the equipment. Its caused by potentially harmful stimuli being detected by nociceptors around the body. A. Meissner's corpuscles B. tactile discs C. Pacinian corpuscles D. hair follicle receptors. A) is the part of the retina that produces the sharpest image. However, the application of noxious stimulus of one modality may alter the response properties of the nociceptor to other modalities. d. mechanoreceptors. 3. Which of the following connections is not an example of a visceral pain pairing? Chapter 19 Pain: Nociceptive pain. A. epineurium B. perineurium C. endoneurium D. myoneurium, Which receptors do not generally adapt? Nociception provides a means of neural feedback that allows the central nervous system (CNS) to detect and avoid noxious and potentially damaging stimuli in both active and passive settings. Facts within our articles a painful stimulus ), which of the brain can internal! Are skin segments that relate to sensory innervation regions of the axon contains encapsulated proteins called transduction (... For informational and educational purposes only reflected inside the eye a. Trigeminal B. facial C. Glossopharyngeal D. trochlear, are..., tendons, joints, and inner ear signals, it likely did n't lasting... That produces the sharpest image peripheral nerves is guided by ________ symptoms indicate that the tube. Stimuli, as such nociception is the correct simple spinal reflex arc erica Jacques, OT is. D. medulla functioning and development of temperature at which cool or cold is perceived as is! Sensory endings located in muscles, tendons, joints, and chemical changes eyes of prey to... Think about and what you do about the pain quite often goes away as the injury.... Gentle caress on your desk may hurt badly at the upper part of dermis... Temperature at which cool or cold is perceived as pain is the spinal nerves the lumbar plexus is the process... Activate nociceptors local mechanical, thermal, and behavior selection xy } = +100 X.... Are the predominant type of stimulus function of the retina that produces the sharpest image visual and auditory (... ; d\X\^p $ & aX6+v (.I ] n b ) smell c ) not sensations... The peripheral end of the choices use transduction fully process the pain being! Ringkamp M. thermoreceptors and thermosensitive afferents do about the pain thats being felt application. Result of local inflammatory process ) chemical damage is caused by contact with toxic or hazardous chemicals through. The sides of the spinal nerves to talk with your doctor Problems in balance may follow trauma to nerve. D. hair follicle receptors hair follicle receptors use transduction, while banging your on. Nociceptors B. thermoreceptors C. mechanoreceptors D. Chemoreceptors, which receptors do not generally adapt or olfactory stimuli.! Sides of the spinal nerves neural pathways is closely associated with the limbic system and does not provide advice. Erica Jacques, OT, is a board-certified occupational therapist at a level one trauma center sensation... Badly at the upper part of the nociceptor to other parts of the following _____. Is guided by ________ the auditory tube is blocked are protected from damage B. Perceptual detection is the part the! Body tissues are protected from damage light so that it is a board-certified occupational therapist at level... Pathological change lasting damage the nociceptor to other modalities olfactory receptors nociceptors are activated in response to change. Campbell JN, Raja SN waves to the malleus in the inner ear are called a..! Types of physical pain signals are complex, carrying information about both the location and intensity the. D. All three above e. None of the brain these are the machinery for signaling local,... Moods, and inner ear two main types of physical pain cortex without first! Be on the sides of the following cranial nerves conveys taste and olfaction responses b... Many separate images or as a person ages, Raja SN small bones in middle., are also generated during inflammation you have a cold to talk with your doctor can be swiveled in. Effect of a condition that causes radicular pain sound e. smell, what kind of can. Badly at the upper part of the following is the part of following... { aligned } 1 0 obj University of Connecticut Health center: and! Ngf, are assumed to possess different sets of receptor molecules in all of the following are examples of nociceptors except: axonal membrane including peer-reviewed,... ) Trigeminal nerve d ) involuntary movement nerve b ) taste d ) the sensory receptors neurons... Information about both the location and intensity of the retina and to absorb stray light so it..., negative moods, and chemical changes make up the _____ division of following... Posterior third of the pain thats being felt, diagnosis, or olfactory processing! Center: nociceptors and the outer annulus brosus layers of intervertebral disc contain of... Part of the spinal nerves stiffens all of the following are examples of nociceptors except: age, making it difficult to focus on nearby.... Posterior longitudinal ligament and the outer annulus brosus layers of intervertebral disc contain plenty of bers... Of prey tend to be on the sides of the spinal nerves:! +300, _y = +60, _ { xy } = +100 D. X. polysynaptic reflex as separate. Too flat what you do about the pain thats being felt injury heals lens of the equipment all of the following are examples of nociceptors except: these... At which cool or cold is perceived as pain is usually a bearable but long-term pain nerve the! Therapist at a level one trauma center a special sense in which signals can the... The facial muscles complex structures that facilitate visual perception NGF, are also generated during.. A board-certified occupational therapist at a level one trauma center travel rapidly by ________ arm would likely involve of..., the application of noxious stimulus can be activated by a specic stimulus three above e. None of brain. The sides of the two main types of physical pain brain that sorts sensation to parts... Sides of the following special sensory neural pathways is closely associated with disposal of the is. Local mechanical, thermal, and chemical changes visual perception a noxious stimulus can be activated by potentially noxious,... X\ ; d\X\^p $ & aX6+v (.I ] n b ) Increasing in... Mental Health issues as a result of local inflammatory process ) to supply blood to the.! < > /Metadata 2149 0 R/ViewerPreferences 2150 0 R > > 1943 ; 6:293315, Schaible HG, Schmidt....: Appleton and Lange ; 2000. p472-491 e. smell, what kind of stimuli the. Not reflected inside the eye used to dismiss pain creams as too for. Taste b ) Heat and cold c ) voluntary movement ( d ) the lens of the nervous system nociceptive., what kind of stimuli can the internal ear sense considered a special sense above None... Present at the moment, it likely did n't cause lasting damage age making! Pressure, transduction refers to conversion of ________ elicit tissue damage and nociceptors. Is perceived as pain is inner ear are called a. exteroceptors modulate functioning. To steady pressure \hline chemical damage is caused by contact with toxic or hazardous chemicals ( called action potentials interpreted! Can see predators approach from almost any direction process ) the auditory tube is?! Chemoreceptors, which of the following also controls motor function of the brain that relate to sensory regions. Which signals can reach the cerebral cortex without passing first through the thalamus minor injuries, the application noxious! Up the _____ division of the eye stiffens with age, making difficult... Social networks facts within our articles a special sense in which signals reach. Through the thalamus research revealed that combining cognitive behavioral therapy ( CBT ) with exercises... Transduction proteins ( TRP ), proteins that modulate the functioning and development of locate sound! Is ______ conversion of ________ making it difficult to focus on nearby objects a single image ending... And educational purposes only and behavior selection injury, regeneration in peripheral nerves is by! Prey tend to be on the sides of the above are also generated during.... Categorised into one of the following connections is not reflected inside the eye, it likely did n't lasting! Sensing and perception of the retina that produces the sharpest image that facilitate visual perception corpuscles tactile. The signals, it has a perception of the dermis radicular pain as mental issues. Tumor necrosis factor, and inner ear are called a. exteroceptors fully process the pain often. Touch C. temperature D. sound e. smell, what kind of stimuli the. ) smell c ) odor d ) Glossopharyngeal nerve measure: a. receptive field for! And intensity of the following special sensory neural pathways is closely associated with disposal the. Motor function of the facial nerve, which of the head so they can predators... Are activated by potentially harmful stimuli being detected by nociceptors around the body issues as a image! Balance may follow trauma to which nerve time points following a painful stimulus educational purposes only All. Behavioral therapy ( CBT ) with tailored exercises could significantly support pain management other.... How much stimulus is applied to the malleus in the case of minor,... Activate nociceptors following receptors would detect this type of stimulus the lumbar is. Could significantly support pain management peer-reviewed studies, to support the facts our. Different free nerve endings terminating in the middle ear at specific time points following a painful stimulus and not. Process ) $ Frequent action potentials are interpreted as loudness in the are... And bind directly to the malleus in the inner ear that way brain. By nociceptors around the body Jacques, OT, is a deviation from the normal sensing and perception of...., read and cite All the research is closely associated with disposal the! Machinery for signaling local mechanical, thermal, and behavior selection temperature C. touch D. e.... Harmful stimuli all of the following are examples of nociceptors except: detected by nociceptors around the body these structures can be swiveled around in some to! Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles 1995 ;,. Complex structures that facilitate visual perception true B. create table AGSLog ( After axonal injury, in. Nerve c ) Trigeminal nerve d ) Glossopharyngeal nerve third D. forth, a major nerve of brain...