PNS Exam 1 with 100% correct answers 2024

what does the nervous system do for the body? - answer--enables it to react to continuous changes in its internal and external environments -also controls and integrates the various activities of the body such as circulation and respiration structurally, the nervous system is divided into what? - answer-CNS and PNS functionally, the nervous system is divided into what? - answer-somatic nervous system (SNS) and autonomic nervous system (ANS) what are the two main cell types of nervous tissue? - answer-neurons and neuroglia what is a neuron? - answer--structural and functional unit of the nervous system specialized for rapid communication what is a neuron composed of? - answer--cell body with processes called dendrites (carry impulse to body) and axon (carry impulse away from body) what substances make up myelin? - answer-lipids and protein substances what effect does myelinating an axon have? - answer-increases the velocity of impulse conduction where and how to neurons communicate? - answer--communicate at synapses -use neurotransmitters which are chemical agents relased or secreted by one neuron which may excite or inhibit another neuron how many more times abundant are neuroglia than neurons? - answer-5 times are neuroglia excitable cells? what do they do? - answer--no they are non-excitable -they support, insulate and nourish the neurons in the CNS, neuroglia include what? - answer--oligodendroglia -astrocytes -ependymal cells (lines brain ventricles) -microglia in the PNS, neuroglia include what? - answer--satellite cells around neurons in the spinal and autonomic ganglia -neurolemma (Schwann) cells the CNS consists of what? - answer-brain and spinal cord what are the principle roles of the CNS? - answer--integrate and coordinate incoming and outgoing neural signals -carry out higher mental functions like thinking and learning what is a collection of cell bodies in the CNS called? - answer-a nucleus what is the definition of a tract? - answer-a bundle of nerve fibers (axons and/or dendrites) connecting neighboring or distant nuclei of the CNS brain and spinal cord are composed of what? - answer-gray and white matter what constitutes the gray matter? - answer-nerve cell bodies what forms the white matter? - answer-the interconnecting fiber tract system describe the appearance of transverse sections of the spinal cord - answer--gray matter appears as "H-shaped" embedded in matrix of white matter -struts of H are horns and there are right and left posterior (dorsal) and anterior (ventral) gray horns what are the three membranous layers around the brain and spinal cord? - answer--pia mater -arachnoid mater -dura mater *collectively constitute the meninges* what and where is the pia mater? - answer--innermost meningeal layer -delicate, transparent covering around the brain and spinal cord what is located between the pia and arachnoid mater? - answer-CSF what is the dura mater? - answer-the thick, tough, outermost layer around the brain and spinal cord what does the peripheral nervous system consist of? - answer--nerve fibers and cell bodies that conduct impulses to or away from the CNS -PNS is organized into nerves that connect the CNS with peripheral structures what does the peripheral nerve FIBER consist of? (not the nerve as a whole...) - answer--axon, its neurolemma and surrounding endoneurial connective tissue what does the neurolemma consist of? - answer-neurolemma cells (Schwann cells) that immediately surround the axon (separating it from other axons) describe the two classes of nerve fibers that the neurolemma in the PNS creates - answer-1. neurolemma of myelinated nerve fibers consists of neurolemma cells specific to an individual axon, organized into a continuous series of enwrapping cells that form myelin 2. neurolemma of unmyelinated nerve fibers are composed of cells that do not make up such a myelin sheath and multiple axons are separately embedded within the cytoplasm of each cell what type of nerve is usually unmyelinated? - answer-cutaneous nerves what does the peripheral NERVE (as a whole) consist of? - answer--bundle of peripheral nerve fibers (fascicles) -connective tissue that surround and bind the nerve fibers and fascicles together -blood vessels (vasa nervorum) that nourish the nerve fibers and their coverings what are the names of the three coverings that support and protect the peripheral nerves? - answer-1. endoneurium 2. perineurium 3. epineurium what is the endoneurium? - answer-immediately surrounding the neurolemma cell and axon what is the perineurium? - answer-a layer of dense c.t. that encloses the nerve fibers surrounded by the endoneurium -provides effective barrier against penetration of the nerve fibers by foreign substances what is the epineurium? - answer--thick c.t. sheath that surrounds and encloses a bundle of fascicles forming the outermost covering of the nerve -includes fatty tissue, blood vessels and lymphatics what is a collection of nerve cell bodies outside the CNS calleD? - answer-a ganglion (sometimes a plexus) what types of ganglia are there? - answer-1. motor (autonomic) 2. sensory what are afferent fibers? - answer--sensory -convey neural impulses to the CNS from the sense organs and from sensory receptors in various parts of the body what are efferent fibers? - answer--motor -convey neural impulses from the CNS to effector organs (muscles and glands) peripheral nerves are either ____ nerves or ____ nerves - answer-cranial; spinal cranial nerves exit the cranial cavity through what? - answer-a foramina in the cranium how are cranial nerves identified? - answer-by a descriptive name or a Roman numeral how many cranial nerves arise from the brain? which dont? - answer-11 out of the 12; CN XI doesn't arise from the brain, it arises from the superior part of the spinal cord spinal nerves arise from the spinal cord as what? these converge to form two ____ _____ - answer-rootlets; nerve roots what does the anterior (ventral) root consist of? - answer-motor fibers passing from nerve cell bodies in the anterior horn of spinal cord gray matter to effector organs located peripherally what does the posterior (dorsal) root consist of? - answer-sensory fibers from cell bodies in the spinal sensory or posterior (dorsal) root ganglion that extend peripherally to sensory endings and centrally to the posterior horn of the spinal cord gray matter the posterior and anterior nerve roots unite to form what? where? - answer--mixed spinal nerve -found within or just proximal to the intervertebral foramen the mixed spinal nerve immediately divides into what? - answer-two primary rami (posterior/dorsal ramus and an anterior/ventral ramus) what types of fibers do the primary rami carry? - answer-they carry both sensory and motor fibers what is the definition of a dermatome? - answer-unilateral area of skin innervated by the fibers of a single spinal nerve what is the definition of a myotome? - answer-unilateral muscle mass receiving innervations from the fibers conveyed by a single spinal nerve unlike dermatomes, innervations of zones of skin supplied by cranial nerves have little _____ - answer-overlap what are the two general types of fibers conveyed by cranial or spinal peripheral nerves? - answer-somatic fibers and visceral fibers what are the two different types of somatic fibers? - answer-general sensory fibers and somatic motor (general somatic efferent) fibers what do general sensory or general somatic afferent fibes transmit? - answer-sensations from the body to the CNS what might the sensations from the body be? - answer--exteroceptive sensations from skin (pain, temp, touch, pressure) -pain and proprioceptive sensations from muscles, tendons and joints what are proprioceptive sensations? - answer--subconscious -providing information regarding joint position and tension of tendon and muscles that are combined with input from the vestibular apparatus of the internal ear, resulting in awareness of the orientation of the body and limbs in space, independent of visual input what do somatic motor fibers transmit? - answer-impulses to skeletal (voluntary) muscles what are the two types of visceral fibers? - answer--visceral sensory (general visceral afferent fibers) -visceral motor (general visceral efferent fibers) what do visceral sensory fibers transmit? - answer--pain -subconscious visceral reflex sensations concerning distension, blood gas and blood pressure levels from hollow organs and blood vessels to the CNS what do visceral motor fibers transmit? - answer--impulses to smooth (involuntary) muscle, cardiac muscle and glandular tissue -presynaptic and postsynaptic fibers work together to conduct impulses from the CNS to smooth muscle or glands what type of neuron is present in visceral and general sensory processes? - answer-pseudounipolar neurons (cell bodies located outside of CNS in spinal or cranial sensory ganglia) motor fibers of peripheral nerves are axons of what type of neurons? where are the cell bodies located? - answer-multipolar (cell bodies of somatic motor and presynaptic visceral motor located in gray matter of brain stem and spinal cord; cell bodies of postsynaptic motor neurons located outside CNS in autnomic ganglia) some cranial nerves convey ____ sensory like smell, sight, hearing, balance and taste - answer-special motor fibers conveyed by cranial nerves to striated muscle are classified as somatic or what? - answer-branchial motor, referring to muscle tissue derived from pharyngeal arches in the embryo olfactory: sensory, motor, mixed? - answer-sensory primary olfactory neurons are what cell type? and where are they located? - answer-bipolar; located in olfactory mucosa (Bowman's membrane) secondary olfactory neurons are found where? - answer-olfactory bulb (which is nucleus of termination) optic: sensory, motor, mixed? - answer-sensory optic nerve fibers arise from where? - answer-ganglionic layer of the retina optic nerve fibers form the optic _____ and then optic ______ to reach the what? - answer-chiasma; tracts; to reach the lateral geniculate body (metathalamus) oculomotor: sensory, motor, mixed? - answer-motor with parasympathetic nerve what is the apparent origin of the oculomotor nerve? - answer-interpeduncular fossa oculomotor supplies what muscles? - answer--5 extrinsic eye (superior rectus, inferior rectus, inferior oblique, medial rectus, levator palpebrae superioris) -2 smooth muscles of eye as parasympathetic nerve (ciliary body, sphincter pupillae) trochlear: sensory, motor, mixed? - answer-motor trochlear is the ___ cranial nerve - answer-smallest what is the apparent origin of the trochlear nerve? - answer-dorsal side of the midbrain what does the trochlear nerve innervate? - answer-superior oblique muscle (inferior lateral view) trigeminal: sensory, motor, mixed? - answer-mixed trigeminal is the ____ cranial nerve - answer-largest trigeminal apparent origin is where? - answer-side of the pons what are the three divisions of the trigeminal nerve? - answer-ophthalmic, maxillary, mandibular what are the sensory fibers of trigeminal from? - answer-most cutaneous and mucus membranes and internal structures of the face what do the motor fibers of trigeminal innervate? - answer--primary muscles of mastication (masseter, temporalis, medial and lateral pterygoid) -swallowing (deglutition) -middle ear muscle (tensor tympani) -soft palate muscle (tensor veli palatini) abducens: sensory, motor, mixed? - answer-motor abducens innervates what muscle? - answer-lateral rectus (abduct the eye) what is the apparent origin of abducens? - answer-anterosuperial aspect of the medulla oblongata or anterior inferior pontine sulcus facial: sensory, motor, mixed? - answer-mixed with parasympathetic nerve what is the apparent origin of the facial nerve? - answer-sulcus between the olive and the restiform body (lateral bundle of inferior cerebellar peduncle) sensory division of facial is also known as what? - answer-nervus intermedius what does the sensory division of facial receive? - answer-taste buds from the anterior 2/3 of the tongue and mucus membrane the motor division of the facial nerve innervates what? - answer-facial, scalp and external ear muscles what does the parasympathetic nerve of the facial nerve innervate? - answer-mucus glands of the nose and mouth, lacrimal glands and two small salivary glands vestibulocochlear: sensory, motor, mixed? - answer-sensory what is the apparent origin of the vestibulocochlear nerve? - answer-immediately lateral to the facial nerve between the olive and restiform body cochlear nerves arise from where? - answer-cochlear (hair) cells of hearing in the inner ear vestibular nerve arises from where? - answer-vestibule of the inner ear for equilibrium glossopharyngeal nerve: sensory, motor, mixed? - answer-mixed with parasympathetic nerve what is the apparent origin of glossopharyngeal? - answer-immediately caudal to the vestibulocochlear nerve between the olive and restiform body sensory fibers of glossopharyngeal for general sensation are from where? - answer-pharynx and posterior 1/3 of the tongue sensory fibers for taste are from where for glossopharyngeal? - answer-taste buds of the posterior 1/3 of the tongue somatic motor fibers of glossopharyngeal innervate what? - answer-stylopharyngeus parasympathetic secretomotor fibers from glossopharyngeal innervate what? - answer-parotid gland and smaller glands in the back of the oral cavity vagus: sensory, motor, mixed? - answer-mixed with parasympathetic parasympathetic nerves of vagus innervate what? - answer-most of thoracic and abdominal organs up to left colic (splenic) flexure somatic sensory fibers from vagus receive sensations from what? - answer-same visceral organs somatic motor fibers from vagus innervate what? - answer-palatal, pharyngeal and laryngeal muscles spinal accessory: sensory, motor, mixed? - answer-motor spinal accessory is formed by what? - answer-cranial and spinal roots cranial root arises from where? - answer-medulla oblongata and joins the vagus nerve what does the cranial root innervate? - answer-somatic muscles of pharynx, larynx and palate spinal root arises from where? - answer-upper five cervical cord levels between ventral and dorsal nerve roots spinal root enters the cranial cavity through what? - answer-foramen magnum where does the spinal root exit the cranial cavity and what does it innervate? - answer-leaves through jugular foramen -innervates SCM and trapezius hypoglossal: sensory, motor, mixed? - answer-motor what is the apparent origin of the hypoglossal nerve? - answer-anterolateral sulcus of the medulla oblongata between the pyramids and the olive what does the hypoglossal nerve innervate? - answer-both extrinsic and intrinsic muscles of the tongue what are the motor cranial nerves? - answer-III, IV, VI, XI and XII what are the senosry cranial nerves? - answer-I, II, VIII what are the mixed cranial nerves? - answer-V, VII, IX, X what are the parasympathetic cranial nerves? - answer-III, VII, IX, X olfactory nerve is often described as an extension of what? - answer-the CNS primary olfactory neurons are what type of neuron? where are they located? - answer-bipolar; located in olfactory epithelium/mucosa on the superior nasal concha and the adjacent part of the ethmoidal perpendicular plate what is the olfactory vesicle? - answer-the superficial end of the olfactory neuron tapers into a thin shaft that slightly extends beyond the surface of the epithelium each olfactory vesicle is attached by numerous ____ that do what? - answer-olfactory cilia that detect odorant (inside mucus) what are fila olfactoria? - answer-nerve fibers or axons of the olfactory neurons gathered into 15-20 bundles fila olfactoria passes through the ____ ___ ___ ____ ______ to synapse on secondary olfactory neurons that are what type of cells? where are they located? - answer-cribriform plate of the ethomoid; synapse on mitral cells and some tufted cells in the olfactory bulb what is a unique feature of olfactory receptor neurons? - answer-they are continually replaced throughout life by differentiation of stem cells in the olfactory mucosa what are the 7 layers of the laminar structure of the olfactory bulb from the surface inwards? - answer-1. olfactory nerve layer 2. glomerular layer 3. external plexiform layer 4. mitral layer 5. internal plexiform layer 6. granule cell layer 7. olfactory nerve tract the olfactory nerve layer consists of what? - answer-unmyelinated olfactory neurons which are continually turned over with the receptor cells the glomerular layer consists of what? - answer-thin sheet of glomeruli where the incoming olfactory axons divide and synapse on terminal dendites of secondary neurons such as mitral, tufted and periglomerular cells the external plexiform layer contains what? - answer-the principal and secondary dendrites of mitral and tufted cells the mitral layer is what? - answer-a thin sheet composed of the cell bodies of mitral cells what do the mitral cells do in the mitral layer? - answer-sends a single principal dendrite to a glomerulus and secondary dendrites to the external plexiform layer and a single axon to the olfactory tract the mitral layer also contains a few ____ cell bodies forming the nucleus of ______ for olfaction - answer-granule; termination the internal plexiform layer contains what? - answer-axons, recurrent and deep collaterals of mitral and tufted cells, and granule cell bodies the granule cell layer contains what? - answer-majority of granule cell bodies and their superficial and deep processes, together with numerous centripedal (out) and centrifugal (in) nerve fibers which pass through the layer this granule cell layer is extended into the olfactory tract as what? - answer-scattered medium-sized multipolar neurons which constitute the anterior olfactory nucleus the olfactory nerve tract extends to where? - answer-the anterior olfactory nucleus in the posterior end of the olfactory tract and becomes the olfactory trigone which splits into the medial and lateral olfactory striae what are the principal neurons in the olfactory bulb? - answer-mitral and tufted cells and their axons form its output through the olfactory tract what are the main intrinsic neurons in the olfactory bulb? - answer-periglomerular and granule cells periglomerular cells distribute their axons _____ and terminate within the ______ regions - answer-laterally; extraglomerular granule cells are similar in size to _____ cells but have no ____ - answer-periglomerular; axon granule cells ramify and terminate in what layer? what type of influence do they have on output of neurons in the olfactory bulb? - answer-external plexiform layer; inhibitory influence the medial stria ends in relation to the _____ area which consists of the _____ area and the _____ area - answer-subcallosal; paraolfactory; paraterminal the subcallosal area is connected with the _____ by way of the cingular gyrus - answer-parahippocampus the lateral stria continues to the ____ ______ and passes to the ____, ______, ______ (Brodmann area 34), and _____ area on the medial aspect of the temporal lobe and to the entorhinal area - answer-gyrus semilunaris; parahippogyrus; amygdaloid body; uncus; piriform the olfactory brain or ____ is connected with visceral brain through the ____ - answer-uncus; fornix do olfactory fibers have any sort of covering? - answer-no. they are extrememly minute damage to any part of the olfactory system may result in what? - answer-hyposmia or anosmia all the neural elements of the eye are derived from what? - answer-optic vesicle of the prosencephalon the optic nerve is an extension of the ____ - answer-brain the optic nerves are composed of axons of ______ neurons in the ______ ____ - answer-multipolar; ganglionic layer the axons of the multipolar neurons form what? - answer-the layer of the optic nerve in the eyeball the wall of the eye ball consists of what three layers? - answer-1. fibrous tunic (outer) 2. vascular tunic of uvea 3. internal or sensory tunic of the eye or retina the fibrous tunic is made up of what two parst? - answer-1. sclera 2. cornea what portion does the sclera make up and what does it do? - answer-occupies the posterior 4/5ths to maintain the shape of the eyeball what portion does the cornea make up and what does it do? - answer-anterior 1/5th and is transparent for light passage the vascular tunic or uvea is made up of what 3 parts? - answer-1. iris in the anterolateral part 2. ciliary body in the anterolateral part 3. choroidea in the posterior part the retina is a thin delicate membrane which is composed of what 10 layers? - answer-1. internal limiting membrane 2. layer of optic nerve fibers 3. ganglionic layer of the retina 4. inner plexiform layer 5. inner nuclear layer 6. outer plexiform layer 7. external nuclear layer 8. external limiting membrane 9. rods and cones or Jacob's membrane 10. pigmented epithelium the retina has what two different types of cells? - answer-1. vertically elongated supporting glial cells of Muller between the internal and external limiting membranes 2. transversally connecting horizontal cells in the outer plexiform layer and the macrine cells in the inner plexiform layer all the optic nerves in the layer of the nerve fibers converge towrad the _____ ___ or ____ ____, which is located just medial to the what? - answer-optic papilla or optic disc; posterior central axis or posterior pole at the optic disc the nerve fibers are redirected _____ and penetrate the ____ and ____ where it is called ____ ____ - answer-backward; choroid and sclera; lamina cribrosa the optic nerve enters the cranial cavity through the what? - answer-optic canal in the lesser wing of the sphenoid bone the right and left optic nerves form the what? - answer-optic chiasma on the chiasma sulcus (of sphenoid) where the optic fibers from the nasal half of both eyes decussate the optic tracts run around the ____ ____ to the what? - answer-cerebral peduncles; to the lateral geniculate bodies the optic tracts are composed of what? - answer-optic fibers from the lateral half of the eye on the same side and nasal half of the eye on the opposite side what are the three nuclei of termination locations? - answer-1. lateral geniculate body 2. the pretectal area 3. superior colliculus what is the principle nucleus of termination for the optic nerve? - answer-lateral geniculate body the lateral geniculate bodies project as what to the what? - answer-project as the optic radiation to the Brodmann area 17 including cuneus gyrus some optic nerve fibers pass to the pretectal area for what? - answer-the reflex movement of the sphincter pupillae or the phincter muscle of the pupil through the Edinger-Westphal nucleus and ciliary ganglion for the parasympathetic nerve some optic nerve fibers pass to the superior colliculus for what? - answer-the reflex movement of the head and neck through the nuclei of the ocular muscles and the ventral column of the cervical cord the right and left cortical center of vision are connected through the ____ ____ forming the what? - answer-corpus callosum forming the major forceps or the forceps posticus what do you get from an optic tract lesion? - answer-hemianopia or hemianopsia what do you get by peripheral degeneration of the visual field? - answer-tunnel vision what are the three sheaths enclosing the optic nerve? - answer-1. outer sheath 2. intermediate sheath 3. inner sheath what is the outer sheath? - answer-derived from the dura mater; thick and fibrous; blends with sclera what is the intermediate sheath? - answer--from arachnoid mater -thin and separated from the outer by the subdural space and from the inner by the subarachnoid space what is the inner sheath? - answer--from the pia mater -vascular and closely invests the optic nerve Papilloedema - answer--consequence of an intracranial neoplasm caused by incrased pressure due to excess fluid in the general subarachnoid space, which extends as far as the lamina cribrosa the oculomotor nerve is a true peripheral nerve with a what? - answer-neruolemma and medullary sheath what is the nucleus of origin called? where is it located? - answer-nucleus of oculomotor nucleus; located on the ventral side of the cerebral aqueduct near the third ventricle in the midbrain the nucleus of the oculomotor nerve consists of how many somatic nuclei for what? - answer-5 somatic nuclei for the 5 extrinsic eye muscles what is the 6th nucleus called for the oculomotor parasympathetic nerve? - answer-Edinger-Westphal nucleus or the accessory oculomotor nucleus of the eye fibers from the nucleus of the oculomotor nerve and the Edinger-Westphal nucleus pass through what to emerge where? - answer-pass through the tegmentum, red nucleus, and medial part of the substantia nigra to emerge in the oculomotor sulcus, just medial to the cerebral peduncle the oculomotor nerve passes forward through what? - answer-the CSF of the interpeduncular cistern the oculomotor nerve passes through the ____ wall of the _____ ___ and then exits through the what? - answer-lateral wall of the cavernous sinus and exits the skull through the superior orbital fissure in the orbital socket, the oculomotor nerve splits into the what? - answer-superior ramus and inferior ramus the superior ramus divides into what? - answer-1. nerve for the levator palpebrae superioris 2. nerve to the superior orbital rectus the inferior ramus divides into the what? - answer-1. nerve to the inferior rectus 2. nerve to the medial rectus 3. nerve to the inferior oblique visceral branches from the Edinger-Westphal nucleus (preganglionic efferent fibers) synapse where? - answer-ciliary ganglion the postganglionic fibers are called what? what do they innervate? - answer-short ciliary nerves; they innervate the ciliary body and sphincter muscle of the pupil or contrictor pupillae on the lateral wall of the cavernous sinus the oculomotor nerves communicate with what? - answer-1. ophthalmic nerve for the proprioceptive fibers form the 5 extrinsic eye muscles 2. internal carotid plexus for the sympathetic vasomotor nerves the cortical center for the oculomotor nerve is in the what? to control what? - answer-superior frontal gyrus (Brodmann area 8) to control conjugate eye movement with the cranial nerves IV and VI how many neurons do the sympathetic and parasympathetic efferent paths involve? - answer-two neurons from the CNS to the effector tissues what are the two neurons involved? - answer-1. pregangionic neurons are in a nucleus of origin 2. postganglionic neurons are in a visceral ganglion (otic, submandibular, ptergopalatine, celiac) or ganglionated plexus motor nerves have communicating ____ fibers ____ synapses - answer-proprioceptive fibers without synapses what does the sympathetic nervous system control? - answer-all visceral structures except the constrictor pupillae through the vascular system and somatic nervous system to reach most of the tissues where are the sympathetics located? - answer-preganglionic neurons of the symapthetic nerve are lateral intermediate substance cells in the lateral horn of cord levels T1-L2/L3 fibers from the lateral intermediate substance pass through the ____ spinal roots and give a ___ ___ ___ to the sympathetic or paravertebral ganglia where they synapse with postganlionic neurons - answer-anterior; white ramus communicans what do the fibers from the upper thoracic sympathetic trunks do versus the lower thoracic sympathetic trunks? - answer--upper thoracic sympathetic trunks ascend to the cervical ganglia -lower thoracic and upper lumbar sympathetic trunks descend to lower lumbar, sacral and coccygeal ganglia with interganglionic rami many cranial nerves and their branches have communication with what? - answer-postganglionic sympathetic fibers from the superior cervical ganglion which are pilomotor, secretomotor and vasomotor nerves the major sympathetic nerves into the head arise from where? - answer-apex of the superior cervical ganglion called the internal carotid nerve the internal carotid nerve becomes the what? - answer-internal carotid plexus what is the nucleus of origin of the trochlear nerve? where is it located? - answer-nucleus of trochlear nerve which is located in the midbrain on the anterior side of the cerebral aqueduct at the level of the lower part of the inferior colliculus the fibers from the nucleus of the trochlear nerve do what? - answer-pass posterior ward through the tegementum of the mesencephalon and decussate with the opposite trochlear nerve in the tectum and leave the midbrain at the lower margin of the inferior colliculi trochlear nerve is the only cranial nerve to leave the brain stem at its ___ aspect - answer-dorsal the trochlear nerve descends in the _____ space and enters the dura mater at the margin of the ____ ____ and continues through the ____ wall of the ___ ___ - answer-subarachnoid; cerebellar tentorium; lateral; cavernous sinus the trochlear nerve communicates with what? - answer--ophthalmic nerve of the trigeminal from the Gasserian or trigeminal ganglion for proprioceptive fibers of the superior oblique muscle -with the internal carotid plexus of the sympathetic nerve for the blood vessel of the superior oblique muscle what is the cortical center of the trochlear nerve? - answer-the superior frontal gyrus (brodmann area 8) with cranial nerve III and IV a lesion affecting the trochlear nerve will cause the eye to not be able to look what way? - answer-down and lateral the somatic motor portion of trigeminal innervates what muscles? - answer-1. muscles of mastication (masseter, temporalis, medial and lateral pterygoid) 2. muscles of deglutition (anterior belly of digastric and mylohyoid) 3. tensory veli palatini 4. tensor tympani muscle what is the apparent origin of trigeminal? - answer-upper anterolateral border of the pons what are the two roots of the trigeminal nerve? - answer-1. sensory root which is larger and superior 2. motor root which is smaller and arises from a nucleus of origin in the upper pons in the upper margin of the rhomboid fossa the sensory fibers of trigeminal consist of what? - answer-central processes from pseudounipolar neurons of the Gasserian or trigeminal (semilunar) ganglion the gasserian or trigeminal ganglion is located in the dura mater fold on the what? - answer-trigeminal impression of the petrosal portion of the temporal bone what is the largest sensory ganglion in the body and what does it hold? - answer-gasserian ganglion and it holds primary sensory neuron of the trigeminal nerve what are the three nuclei of termination for the central processes from the trigeminal ganglion? - answer-1. mesencephalic nucleus located lateral to the cerebral aqeduct and anterior to the superior and inferior colliculi 2. pontine nucleus in the mid pons 3. spinal nucleus in the medulla oblongata thats continuous with the substantia gelatinosa of Roland in the spinal cord the spinal nucleus of trigeminal is also for what other nerves? - answer-V, VII, IX, X what are the three divisions of trigeminal? - answer-1. ophthalmic nerve which is the upper, smallest and purely sensory 2. maxillary nerve which is intermediate in size and position and purely sensory 3. mandibular nerve which is largest and motor and sensory mixe the ophthalmic nerve is the ____ division of trigeminal and purely ____ - answer-superior; sensory the ophthalmic nerve is the ____ and arises from where? - answer-smallest; arises from the anteromedial part of the trigeminal ganglion the ophthalmic nerve passes fowards through what? - answer-the lateral wall of the cavernous sinus inferior to the oculomotor and trochlear nerves the ophthalmic nerve is joined by filaments from what? what else does it communicate with? - answer-joined by the internal carotid plexus of the sympathetic nerves and communicates with proprioceptive fibers of the oculomotor, trochlear and abducens nerve what does the ophthalmic supply that adheres to the trochlear nerve to tentorium cerebelli? - answer-recurent meningeal branch or tentorial nerve just before entering the orbit through the superior orbital fissure it divides into what three branches? - answer-lacrimal, front and nasociliary lacrimal nerve: it is the ___ branch and enters the orbit through where? - answer-smallest; enters orbit through the lateral part of the superior orbital fissure the lacrimal nerve receives a branch from what nerve as secretormotor fibers (parasympathetic nerve)? - answer-zygomaticotemporal branch of the zygomatic nerve of the maxillary nerve what does the lacrimal nerve innervate? - answer-the lacrimal gland and lateral side of the conjunctiva of the upper eyelid the frontal nerve is the ____ branch of the ophthalmic division - answer-largest the frontal nerve enters the orbit through the what? - answer-the superior orbital fissure above the levator palpebra superioris and runs forward about midway into the orbit, the frontal nerve divides into what? - answer-the smaller supratrochlear nerve and a large supraorbital nerve the supratrochlear nerve runs ____ and _____ and passes above the what? - answer-medially and forward and passes above the trochlea of the superior oblique the supratrochlear nerve gives off a _____ branch to the _____ nerve of the nasociliary nerve - answer-descending branch to the infratrochlear nerve the supratrochlear nerve arises on the _____ and sends fibers to where? - answer-forehead -sends fibers to the medial side of the conjunctiva and skin of the upper eyelid the supraorbital nerve emerges where? - answer-on the forehead through the supraorbital nortch or foramen the supraorbital nerve ____ and divides into a small ____ and large ____ branch to supply what? - answer-ascends; medial; lateral; supplies skin of scalp up to lamboid suture and front sinus mucosa nasociliary nerve is ____ in size and more ____ - answer-intermediate; inferior the nasociliary nerve enters the orbit through the what? - answer-medial part of the superior orbital fissure within the common tendinous ring then runs to the medial wall of the orbital cavity the nasociliary nerve gives off the ___ ___ branch - answer-anterior ethmoidal the anterior ethmoidal branch passes through the what? - answer-the anterior ethmoidal foramen and canal entering the cranial cavity the anterior ethmoidal branch then runs forward on what and does what? - answer-runs foward on the cribriform plate and gives off anterior meningeal branches to the anterior cranial fossa and descends through a slit at the side of the crita galli into the nasal cavity the anterior ethmoidal branch supplies what? - answer-1. a medial internal nasal branch to the front part of the nasal septum 2. a lateral internal nasal branch to the anterior part of the lateral wall of the nasal cavity the anterior ethmoidal branch emerges as the ____ ___ nerve where? what does it supply? - answer-external nasal nerve; supplies the skin of the ala, apex and nasal vestibule the nasociliary nerve communicates with the ____ ganglion which gives off ___ ___ nerves - answer-ciliary ganglion (ganglionic branches for sensory fibers); short ciliary nerves long ciliary nerves accompany ___ ___ nerves from the ciliary ganglion which pierce the what? - answer-short ciliary; pierce the sclera near the optic nerve long ciliary nerves run forward between what? what do they supply? what else do they contain? - answer--run foward between sclera and choroid to distribute to ciliary body, iris and cornea -contain sympathetic fibers from superior cervical ganglion nasociliary nerve gives off the ____ nerve near the anterior ethmoidal foramen - answer-infratrochlear the infratrochlear nerve joins the filament from the ____ nerve and leaves orbit and supplies what? - answer-supratrochlear; supplies medial side of eyelids skin and side of nose, the conjunctiva, lacrimal sac and lacrimal caruncle the ____ ____ nerve from the nasociliary nerve leaves the orbit through the posterior ethmoidal foramen and supplies what? - answer-posterior ethmoidal; supplies the ethmoidal air cells and sphenoid sinus