Special Sense Organ Flashcards
Senses
divided into special senses and general senses
Special Sense
senses that have localized sense organ
Vision
- organ: eye
- occibital lobe
- optic nerve(2)
Hearing
- organ: ear
- temporal lobe
- vestibular cochlear nerve(8)
Equilibrium
- organ:ear
- cerebellum
- vestibular cochlear nerve(8)
Taste
- organ:tongue
- gustation nerve
Smell
- organ:nose
- temporal lobe
- olfaction nerve(1)
General Senses
-receptors that are scattered/ distributed throughout the body
Cutaneous
- located at or near the surface of the body
- provide information about the external environment
- ex. touch,pressure,temp,pain
Internal Organ Receptors
- located in blood vessels and internal organ
- provide information about the internal environment
Proprioceptor
- located in musles tendon joints
- provide information about body position and movement
The EYE
- receptors for visual stimuli
- system for bending light rays(refractive apparatus)
- lacrimal apparatus
- accessory muscles
- nervel supply
- nerve supply
Coats of the eyeball
- eyeball sits in orbit
- wall is made of layers
- layers are called coats or tonic
- layers are different in front vs. the back
- overmost coat=fibrous tunic
Outer Coat
-Sclera(back): tough connect tissue, white due to collagen, avascular
- Cornea(front): transparent, avascular, bulges forword slightly
- cornea is part of the refractive apparatus
MIddle Coat(Vascuar Layer)
- Choroid-connective tissue and blood vessels, contains dark brown pigment
- dark brown pigment prevents scattering/reflecting off the light inside the eye
Ciliary Body(muscle)
- holds the lens in place, controls the shape of the lens (accommodation)
- the lens is the only part of the refractive apparatus that can change
Lens
- biconvex, adjustable part of the refraction system bi-convex=bulges out on both sides
- only adjustable part of the refraction system
- lens is clear
- thickness of the lens can be adjusted
- adjustment in thickness gives accomadation
Iris(muscle)
- colored
- made up of 2 sets of muscle fibers
- 2 set of muscle fibers control size of pupil
Pupil
pupil is an opening in the lens
- controls amount of light that eneters the eye
- in bright light pupil constricts
- in dark light the pupil dilates
Inner coat
retina: 2nd tunic, nervous tunic
- somplex structure that lines the back 2/3rd of the eye
- contains photoreceptors(visual receptos)
- rods detect the presense of light
- cones detect color
- optic disc
Rods
- detect light
- found in edges of the retina
- responsibe for night vision
Cones
- detect color
- found in center of the retina
Reaction of retina
- when light strikes the retina
- rods and cones generate impulses which are transmitted to the optic disc
- optic disk is the area where the optic nerve connects to the retina
- optic disk does not contain photoreceptors
- optic disk is blind spot
Posterior cavity(chamber of the eye)
- btw the lens and retina
- filled with vitreous body(viterous humor)
- vitreous body is gel-like material that fills the posterior cavitiy and keeps the retina in place
Anterior cavity(chambers of the eye)
- btw lens and cornea
- filled with aqueous(humor)(=watery fluid) body
- aqueous body is constantly being made and drained
- increase itnraocular pressure is not drained
Extrinsic Muscles of the Eye
Intrinsic muscles: inside the eye(iris(size of pupil and capillary body(thickness of lens))=control pupil and lens movement
Extrinsic muscles of the eye
- control movement of eyeball
- found outside the eye
- movement of each eye controlled by 6 muscles to produce convergence
- convergence: both eyes are directed to one visual field this is what gives us binocular vision
Sensory Nerve
1) Optic Nerve(Cranial Nerve 2)
- transmits visual impulses from the eye to the brain
2) Ophthalmic Nerve: Cranial Nerve 5
Motor Nerve of the EyE
1) Oculomotor Nerve(Cranial Nerve 3)
- supplies intrinsic muscles of the eyes
- most of the extrinsic muscles of the eye
- headlinging nerve
2) Trochlear Nerve(Cranial Nerve 4)
- supplies 1 nerve
3) Abducens Nerve(Cranial nerve 6)
- supplies 1 nerve
Conjunctiva
muscous membrane that covers the eye and lines the eyelid
Lacrimal Apparatus
- makes tears
- lacrimal gland: upper outer corner of the orbit
- nasolacrimal duct: connects eye with the nasal cavity
Pathway for sight
- light passes through
- Cornea-Aqueous Body-Pupil-Lens-Vitreuos Body-Photo receptors on the retina-optic nerve
Physiology of vision
Refraction: bending of light rays, lens is the only adjustable part of the refractive apparatus
- accomodation: ability to focus on near and far objects, reaction of the retina(when light hits retina)
- reaction of retina-PERRLA
Erros of Refraction
Myopia=nearsightedness
Hyperopia=farsightedness
Presbyopia=as you get old
Astigmatism=irregular curvature of the cornea
Strabismus=cross eyed
Amblyopia=lazy eye
External Ear
Pinna/Auricle=directs sound waves to the external auditory meatus
- External Auditory Meatus: through temporal bone, line w/ thin layer of skin, has cereminus glands maker cerumin, cereumin protects and lubricated the tympanic membrance
- Tympanic membrance: a thin membrane that vibrates when sound waves hit it
Middle ear
- cavity that has two parts
- Eustachian Tube:
- opens to back of throat,
- extends from the middle ear to pharynx in adults,
- narrow and slanted,
- equalizes pressure on both side of tympanic membrane
Ossicles:
- 3 smalls bones
- transmit vibratio0n from tympanic membrane to the inner ear
- malleus=hammer=closest to tympanic membrane
- incus=anvil=middle ear
- stapes=strriup
Internal Ear
- Labrynth maze=extrememly complex structure
- endolymph-fluid found inside bony labrynth
- perilymph=fluid btw bony labrynth and membranous labrynth
- fluid transmits sound vibrations to hair cells in the cochlea
- hair cells are part of orgam of corti, this is what we hear with
- different hair cells hear different vibration/frequency
- hairs are nerve fibers
- that sensory information is transmitted by vestibular cochlea cranial nerve then goes to the tempral lobe
Cochlea
- part of the inner ear responsible for hearing
- ossicles will transmit vibration
- describe as labrynth
- 2 labrynth one inside the other
- bony labrynth=made in bone
- inner labrynth=membranous
Semicircular Canal
- responsible for sense of equiibrium
- (2) receptors
- dynamic equilibrium-when moving
- static equilibrium-when still
Conduction Deafness
- hearing loss resulting from interfering of the passage from ossicle in inner ear
- something happening to the ossicles and tympanic membrane
Senorineural Deafness
-result from prolonged exposure to lound sounds hair cells die
Otosclerosis
- bone disorder
- hereditary
- prevents the vibration of the stapes
Presbycusis
slows progressive hearing loss that accompanies aging
-usually lower tones and frequency are heard better
Taste receptors
- sweet: tip of tongue
- salt: anterior sides
- sour: posterior sides of tongue
- bitter: posterior surface of tongue
Smell receptors
olfactory receptors:
- located in epitheal of superior part of nasal cavity(roof of nasal cavity)
- smell transmitted to brain by cranial nerve 1 then going to the temporal lobe
Touch
-meisner receptor
Pressure
-Pechinner receptor
Temp
-crouse receptors
Position
proprioceptors, how you are arranged in space
Pain
free nerve endings
Visceral Senses
- Hunger/Thirst- Triggered by internal changes , hunger receptor detect changes in blood nutrient level, thrist receptors detect changes in electrical communication
Visceral Senses
- Hunger/Thirst- Triggered by internal changes , hunger receptor detect changes in blood nutrient level, thrist receptors detect changes in electrical communication
