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Chapter 17 A&P
Special Senses
Question | Answer |
---|---|
outer ear is? | pinna, auditory canal, eardrum |
Middle ear is? | malleus, incus, and stapes to the oval window |
Inner ear is? | scalas vestibuli and tympani to the cochlear duct Stimulation of the organ of CortiGeneration of impulses in the cochlear nerve |
chemical senses are? | gustation (taste) and olfaction (smell) |
chemoreceptors respond to chemicals in aqueous solution: taste is? | to substances dissolved in saliva |
chemoreceptors respond to chemicals in aqueous solution: Smell is? | to substances dissolved in fluids of the nasal membranes. |
Olfactory receptors convey what? | nerve impulses to olfactory nerves, olfactory bulbs, olfactory tracts, and the cerebral cortex and limbic system. |
olfactory receptors are? | Olfactory receptor cells are bipolar neurons with radiating olfactory ciliaOlfactory receptors are surrounded and cushioned by supporting cells |
basal cells lie at? | the base of the epithelium |
the olfactory gland provides? | a muscus environ. to trap molecules for the olfactory receptors. |
olfactory receptors respond to? | several different odor-causing chemicals. |
olfactory receptors when bound to ligand these proteins initiate ? | a G protein mechanism which uses cAMP as a second messenger. |
cAMP opens what channels, and cuses what? | opens Na+ and Ca2+ channels, causing depolarization of the receptor membrane that then triggers an action potential |
taste buds are found where? | in the papillae of the tongue mucosa |
papillae comes in three types: which are? | filiform, fungiform and circumvallate |
Fungiform and circumvallate papillae contains? | taste buds. |
taste modalities are? | sweet, salt, sour, bitter, and umami |
Umami is? | evoked by monosodium glutamate. |
monosodium glutamate is? | savory type of sensation elicited by the amino acid glutamate. |
The epithelial chemosensory receptor cells synaptically what? | excited primary neurons. |
Each taste bud consists of three major cell types which are? | supporting cells, basal cells, and gustatory cells. |
supporting cells are? | insulate the receptor |
basal cells are? | dynamic stem cells |
gustatory cells are? | taste cells. |
circumvillae papillae also called what? | vallate papillae. |
cranial nerves VII, IX, and X carry impulses from? | taste buds to the solitary nucleus of the medulla. |
these impulses then travel to the thalamus and from there fibers branch to the? | Gustatory cortex (taste)Hypothalamus and limbic system (appreciate of the taste) |
olfactory receptors calls synapse with cells in the solitary nucleus (mitral cells) which in turn send fibers to? | the olfactory cortexthe hypothalamus, amygdala, and limbic system. |
the lens separates the internal eye into what type of segments? | aneterior and posterior. |
The posterior segment is filled with? | a clear gel called vitreous humor. |
Vitreous humor is? | Transmits lightSupports the posterior surface of the lens Holds the neural retina firmly against the pigmented layerContributes to intraocular pressure |
the eye is composed of two chambers which are? | anterior and posterior. |
the chambers of the eye: anterior chamber is? | between the cornea and iris. |
chambers of the eye: posterior is? | between the iris and lens. |
aqueous humor is? | a plasma like fluid that fills the anterior segment. |
aqueous humors function is? | Produced by the Ciliary processDrains via the canal of Schlemm (the Scleral venous sinus)Supports, nourishes, and removes wastes |
the eye is constructed of three layers what are these layers? | Fibrous Tunic(outer layer)Vascular Tunic (middle layer)Nervous Tunic(inner layer |
lens are? | A biconvex, transparent, flexible, avascular structure |
the lens allows and is composed of? | Allows precise focusing of light onto the retinaIs composed of epithelium and lens fibers |
Lens epithelium is? | anterior cells that differentiate into the lens fibers. |
lens fibers are? | cells filled with the transparent protein cyrstallin. |
with age the lens becomes less how? | becomes more compact and dense and loses its elasticity. |
focusing is? | Pathway of light entering the eye: cornea, aqueous humor, lens, vitreous humor, and the neural layer of the retina to the photoreceptors |
light is refracted how? | at the cornea, entering the lens, and leaving the lens. |
the lens curvature and shape allows for? | fine focusing of an image. |
what are zonular fibers? | The alterations of the shape of the lens are accomplished by relieving or allowing the tension exerted on the lens |
relaxation of the ciliary muscles allows the zonular fibers to pull on the? | lens, making the lens more flat for focusing far objects. |
contraction of ciliary muscles relieves the tension of the zonular fibers and causes? | the lens to become more round for accomodation of the close objects. |
when circular muscles of the iris contract the pupilliary diameter? this is done how? | decreases;this is done by parasympathetic innnervation via cranial verve 3. |
Contraction of the radially oriented muscles of the iris enlarge the? this is done how? | pupil;this is done through the sympathetic superior cervical ganglion, no cranial nerves involved. |
when light passes from one transparent medium to another its what changes? | speed and refracts (bends) |
Light passing through a convex lens the light is bent because? | is bent so that the rays converge to a focal point. |
when a convex lens forms an imagine by? | the image is upside down and reverse right to left. |
Light from a distance needs? | little adjustment for proper focusing. |
Far Point of vision is? | the distance beyond which the lens does not need to change shape to focus. |
close vision requires: accomodation which is? | changing the lens shape by ciliary muscles to increase refractory power. |
close vision requires: constriction which is? | the pupillary reflex constricts the pupils to prevent divergent light rays from entering the eye. |
Close vision requires: convergence which is? | medial rotation of the eyeballs toward the object being viewed. |
emmetropic eye is? | normal eye with light focused properly |
myopic eye which is ? | near sighted- the focal point is in front of the retina- corrected with concave lens. |
Hyperopic eye which is? | farsighted- the focal point is behind the retina. corrected with convex lens. |
pigmented layer is? | the outer layer that absorbs light and prevents its scattering. |
neural layer contains? | Epithelial Cell Photoreceptors that transduce light energyBipolar cells and Ganglion cells that form the optic nerve Amacrine and horizontal cells |
ganlion cell axons are? | run along the inner surface of the retinaleave the eye as the optic nerve. |
the optic disc is? | is the site where the optic nerve leaves the eye. Lacks photoreceptors (the blind spot) |
Rods and cones: the epithelia photon detectors: what are the rods? | respond to dim ligthare used for peripheral vision |
Rods and cones: the epithelia photon detectors: what are cones? | respond to bright lighthave high acuity color visionare concentrated in the fovea centralis. |
photopigments are? | undergo structural changes upon light absorption. |
retinal is? | the light absorbing part of all visual photopigments. |
photopigments are? | involved in vision contain a glycoprotein called opsin, and dervative of vitamin A called retinal. |
thre are four different opsins are? | A cone contains one of three different kinds of photopigments so there are three types of cones. permit the absorption of 3 different wavelengths (colors) of lightRods contain a single type of photopigment (rhodopsin) |
axons of the retinal ganglion cells form? | the optic nerve |
medial fibers fo the optic nerve decussate at the? | optic chiasm |
Most fibers of the optic tracts continue to the? | lateral geniculate body of the thalamus. |
Other optic tract fibers end in? | superior colliculi (initiating visual reflexes) and pretectal nuclei (involved with pupillary reflexes) |
optic radiations travel from and to? | from the thalamus and to the visual cortex. |
what is achieved by both eyes? | viewing the same image from slightly different angles. |
3-D vision results from? | cortical fusion of the slightly different images. |
what happens when only using one eye. | depth perception is lost and the observer must rely on learned clues to determine depth. |
what percent of all sensory receptors are in the eye? | 70% |
most of the eye is protected by? | a cushion of fat and the bony orbit |
accessory structures of the eye are? | eyebrows, eyelids, conjunctiva, lacrimal apparatus, and extrinsic eye muscles. |
the function of the eye brow is? | shading the eyepreventing perspiration from reaching the eye. |
orbicularis muscle is? | depresses the eyebrows |
corrugator muscles are? | move the eyebrow medially. |
there are 6 muscles the insert on the exterior surface of the eye ball...what are they? | 4 rectus muscles -- superior, inferior, lateral and medial2 oblique muscles -- inferior and superior |
eyelids or palpebrae is? | protect & lubricateepidermis, dermis, CT, orbicularis oculi m., tarsal plate, tarsal glands & conjunctiva |
tarsal glands are? | Provide oily secretions |
conjunctiva is? | palperbral and bulbarstops at corneal edge. |
how much of tears are produced each day? | 1 ml |
what is conjunctiva? | a thin transparent mucous membrane that line the inner aspect of the eyelids and is reflected onto the anterior surface of the eyeball. |
what is the function of the conjunctiva? | Lines the eyelids as the palpebral conjunctivaCovers the whites of the eyes as the ocular conjunctivaLubricates and protects the eye |
What is the action and controlling cranial nerve of the lateral rectus? | moves eye laterally; VI abducens |
What is the action and controlling cranial nerve of medial rectus/ | moves eye mediallyIII oculomotor |
What is the action and controlling cranial nerve of superior rectus? | Elevates eyeIII oculomotor |
What is the action and controlling cranial nerve of inferior rectus? | Depresses eyeIII oculomotor |
What is the action and controlling cranial nerve of Inferior oblique? | Elevates eye and turns it laterallyIII oculomotor |
What is the action and controlling cranial nerve of superior Oblique? | depresses eye and turns it laterallyIV trochlear |
frequency is? | the number of waves that pass a given point in a given time. |
Pitch is? | perception of different frequencies |
Amplitude is? | intensity of a sound measured in decibels |
Loundness is? | subjective iinterpretation of sound intensity. |
the tympanic cavity contains three small bones...what are the bones and what do they do? | malleus, incus, and stapesTransmit vibratory motion of the eardrum to the oval window.dampened by the tensor tympani and stapedius muscles. |
stapedius m. inserts onto stapes does what? | prevents very large vibrations of stapes from loud noises. |
Tensor tympani attaches to malleus does what? | limits movementsof malleus and stiffens eardrum to prevent damage. |
the bony labyrinth is? | Tortuous channels worming its way through the temporal boneContains the vestibule, the cochlea, and the semicircular canalsFilled with perilymph which is similar to extracellular fluid (a filtrate of spinal fluid) |
the membranous labyrinth is? | Series of membranous sacs within the bony labyrinthFilled with a potassium-rich fluid similar to intercellular fluid |
the vestibule is? | The central egg-shaped cavity of the bony labyrinthSuspended in its perilymph are two sacs: The saccule extends into the cochleaThe utricle extends into the semicircular canals |
the sacs: utricel and Saccule are? | House equilibrium receptors called maculaeRespond to gravity and changes in the position of the head |
vestibulocochlear Nerve (CN VIII): the vestibular branch of the CN VIII consists of 3 parts, which they are? | ampullary, utricular, and saccular nerves |
cochlear branch has? | spiral ganglion in bony modiolus |
the cochlea, a spiral, conical bony chamber does waht? | Extends from the anterior vestibuleContains the cochlear ductThe cochlear duct contains the organ of Corti, where the hearing receptors reside |
the organ of corti is composed of three separate chambers: they consist of ? | Scala vestibuli, the scala tympani which are continuous via the helicotrema, and the Scala media |
ear drum vibrations: what is the slow vibration mean? | response to low-pitched sounds |
Eardrum vibrations: Rapid vibrations is? | response to high-pitched sounds. |
Ossicles vibrate since? | malleus is attached to the eardrum. |
Stapes pushes on oval window producing? | fluid pressure waves in scala vestibuli and tympani |
Pressure fluctuation inside cochlear duct move the? | hair cells against the tectorial membrane |
microvilli are? | bent producing receptor potentials. |
The scalas tympani and vestibuli are continuous with the subarachnoid space of the brain | Are filled with perilymph similar to cerebral spinal fluid (extracellular fluid); high in Na + and low in K+ (similar to extracellular fluid)Scala vestibuli and Scala tympani are continuous with each other via the helicotrema (as mentioned) |
scala media is? | with endolymph which is different than the perilymph. The endolymph is similar to intracellular fluid; high in K+ and low in Na+ ; this fluid is produced by the Stria vascularis |
inner hair cells are responsible for? | sounds transductions and the outer hair cells modulate or fintune the sound perceived. |
Sound waves of low frequency (inaudible): are? | Travel around the helicotrema Do not excite hair cells |
Audible sound waves: are? | Audible sound waves:Penetrate through the oval window from vibrations of the StapesVibrate the basilar membraneExcite specific hair cells according to frequency of the sound |
Conduction deafness are? | Conduction deafness – something hampers sound conduction to the fluids of the inner ear (e.g., impacted earwax, perforated eardrum, osteosclerosis of the ossicles) |
Sensorineural deafness – are? | Sensorineural deafness – results from damage to the neural structures at any point from the cochlear hair cells to the auditory cortical cells |
Tinnitus – are? | Tinnitus – ringing or clicking sound in the ears in the absence of auditory stimuli |
Meniere’s syndrome –is? | Meniere’s syndrome – labyrinth disorder that affects the cochlea and the semicircular canals, causing vertigo, nausea, and vomiting |
Vestibular apparatus – is? and what does it do? | Vestibular apparatus – equilibrium receptors in the semicircular canals and vestibuleMaintains our orientation and balance in space and timeVestibular receptors monitor static equilibriumSemicircular canal receptors monitor dynamic equilibrium |
maculae are? | the sensory receptors for static equilibrium It contains supporting cells and hair cells Each hair cell has stereocilia and kinocilium embedded in the otolithic membrane |
Otolithic membrane – is? | jellylike mass studded with tiny CaCO3 stones called otoliths |
utricular hairs respond? | to horizontal movement |
Saccular hairs respond to? | vertical movement |
Otolithic movement in the direction of the kinocilia is? | Depolarizes vestibular nerve fibersIncreases the number of action potentials generated |
Movement in the opposite direction is? | Hyperpolarizes vestibular nerve fibersReduces the rate of impulse propagation |
cell types in the macula region are? | hair cells with stereocilia (microvilli) & one cilia (kinocilium)supporting cells that secrete gelatinous layer |
The three semicircular ducts, along with the saccule and utricle maintain dynamic equilibrium ARE? | anterior, posterior & horizontal ducts detect different movements (combined 3-D sensitivity) |
cristae is? | the semicircular ducts are the primary sensse organs of dynamic equilibrium |