Special Senses: Sight, Hearing, Smell, Taste Flashcards
Structure and function of the eye
- S = 3 layers (fibrous outer layer is sclera and cornea, middle layer is vascular = choroid, iris, ciliary body, inner layer is nervous tissue = retina)
- F = vision: to detect light and convert to nerve signals to process visual input
What is A and what is its structure and function?
Sclera
- S = tough white fibrous outer layer of the eye
- F = maintains shape of eye
What is B and what is its structure and function?
Choroid
- S = vascular membrane behind the retina
- F = supplies nutrients to retina, absorbs light from retina
What is D and what is its structure and function?
Cornea
- S = transparent outermost layer, convex in shape
- F = begin the process of refracting light onto the lens
What is F and what is its structure and function?
Pupil
- S = opening in iris
- F = regulates amount of light let in: if dark, pupil dilates to let more light in and if light, pupil constricts to let less light in
What is E and what is its structure and function?
Iris
- S = coloured part of the eye, made of smooth muscle
- F = regulates amount of light let in by causing the pupil to dilate/constrict
What is I and what is its structure and function?
Lens
- S = highly elastic, transparent biconvex structure
- F = refracts light onto the retina for clear vision
What is H and what is its structure and function?
Ciliary muscles
- S = smooth muscle attached to suspensory ligaments
- F = controls lens shape for the refraction of light onto the retina, produces aqueous humour
What is C and what is its structure and function?
Suspensory ligaments
- S = thin fibres that connect the ciliary muscles to the lens
- F = allow the ciliary muscles to change the shape of the lens
What is K and what is its structure and function?
Retina
- S = nervous tissue lining the inside surface of the eye. contains photoreceptors (rods = motion, black/white and cones = central vision, colour)
- F = receives light signals and converts them into neural signals for interpretation by the brain
Macula and fovea
Function centre of retina - provides greatest clarity of vision
What is L and what is its structure and function?
Optic nerve
- S = cranial nerve that originates in the retina
- F = transmits messages from retina to occipital lobe
What is J and what is its structure and function?
Vitreous humour
- S = fluid located in posterior chamber of eye
- F = give shape to eye, provide nutrients
What is G and what is its function?
Aqueous humour (aqueous= anterior)
- Maintains pressure within the eye
Name 7 accessory structures to the eye
Eyebrows, eyelids, eyelashes, lacrimal glands, conjunctiva, eye socket, skeletal muscles surrounding the eye
Function of eyebrows and eyelashes
Protect the eyes by trapping foreign particles (dust, sweat, pathogens) to prevent them from entering the eyes
Function of eyelids (skin= integumentary)
Protect eye from injury, spread moisture when we blink to provide lubrication and prevent dryness
Structure and function of conjunctiva
- S = lines inside of eyelids and covers sclera
- F = produce mucus and tears for protection and lubrication
Function of lacrimal glands
Provide conjunctiva with nutrients and drain wastes, secrete fluid for lubrication of the eye, produce tears which contain enzymes to prevent bacterial infection
Structure and function of eye socket
- S = bony cavity that holds the eye
- F = keep eye in place and provide protection
Function of the skeletal muscles surrounding the eye
- Control eye movements and coordination between L and R eyes
- If there is an imbalance it can lead to diplopia (double vision)
Explain the process of vision
- Light bounces off objects and reflects towards eye
- Enters eye and refracted through pupil by cornea
- Lens refracts light onto retina
- Retina converts to nerve impulses
- Optic nerve carries impulses to occipital lobe
- Brain interprets signals > vision
Ways to maintain healthy eyes
- Balanced diet> too much fat can damage macula
- Sleep> allows eyes to rest and lubricate
- Wash hands to prevent chance of pathogens entering eyes
- Wear sunglasses to protect eyes from UV damage
Kerat/o
Conjunctiv/o
Cornea
Conjunctiva
Lacrim/o
Blephar/o
Lacrimal gland
Eyelid
Core/o
Chrom/o
Pupil
Colour
Irid/o
Phot/o
Iris
Light
Opt/o
Pupill/o
Vision
Pupil
Ocul/o
Retin/o
Eye
Retina
Dacry/o
Phac, phak/o
Lacrimal gland
Lens of the eye
Ophthalm/o
Iri/o
Eye
Iris
Scler/o
Corne/o
Sclera
Cornea
Chromat/o
Cor/o
Color
Pupil
OS
OU
Left eye
Both eyes
OD
VA
Right eye
Visual acuity
VF
-opia
Visual field
Condition of the eye
What is WNL for the pupil constriction reflex?
Pupils equal and responsive to light
Nystagmus
Presbyopia
Repetitive/uncontrolled eye movements
Abnormal condition of inability to focus eyes due to old age
What are cataracts?
Degenerative disease caused by clouding of the lens
What is glaucoma
Build up of fluid/pressure in the eye
Structure and function of the ear
- S = outer ear, middle ear, inner ear
- F = detect sound waves and convert to nerve signals as well as balance and equilibrium
What is a sound wave?
‘Chain reaction’ sequence of molecules in the air vibrating
Structure and function of the outer ear
- S = contains pinna/auricle and auditory canal
- F = collect sound waves
What is M and what is its structure and function?
Pinna/auricle
- S = external ear flap (outer ear)
- F = to concentrate and collect sound waves into the auditory canal
What is L and what is its function?
Auditory canal
- Transmit sound waves from pinna to eardrum (outer ear)
Structure and function of the middle ear
- S = tympanic membrane (eardrum) and ossicles (malleus/hammer, incus/anvil, stapes/stirrup)
- F = to transmit sound waves
What is K and what is its structure and function?
Tympanic membrane (eardrum)
- S = oval shaped membrane in middle ear
- F = transmit sound waves from auditory canal to ossicles and protect middle ear from foreign particles
What is A and what is its structure and function?
Ossicles
- S = small bones in middle ear (B= malleus/hammer, C= incus/anvil and D= stapes/stirrup)
- F = transmit sound waves from tympanic membrane to cochlea, amplify sound waves
Structure and function of the inner ear
- S = cochlea and vestibular system
- F = process sound waves, balance and equilibrium
What is I and what is its function?
Cochlea (inner ear)
- Transform sound waves into neural signals
What is N and what is its structure and function?
Vestibular system (inner ear)
- S = semi-circular canals (F) and vestibule (E)
- F = detect movement and changes in body position through displacement of stereo cilia (hair-like cells) and sends info to cerebellum to maintain balance/equilibrium
3 SENSORY structures involved in equilibrium/balance
- Vestibular system in inner ear
- Eyes
- Proprioception (perception of body movement)
3 structures in the ear involved in equilibrium/balance
- Vestibule
- Vestibular nerve
- Semicircular canals
What is J and what is its function?
Eustachian tube
- Maintains pressure and drains middle ear, links middle ear to nasopharynx
What is G and what is its function?
Vestibular nerve
- Transmits messages from vestibule to brain regarding balance and equilibrium
What is H and what is its function?
Cochlear nerve
- Transmits messages from cochlea to brain to interpret sound
Describe the process of hearing
- Sound wave generated in external environment
- Pinna/auricle collects and concentrates sounds to auditory canal
- Auditory canal directs sound to eardrum which vibrates
- Ossicles (malleus/incus/stapes) transmit and amplify sound
- Sound waves passed to fluid in cochlea, activating stereocilia (hair cells) which generates a nerve impulse
- Signal transmitted to brain via cochlea nerve
How to maintain healthy ears
- Avoid exposure to loud sounds
- Wear earplugs
- Keap ears dry and clean
- Regular exercise to promote circulation for waste and nutrient transport
- Avoid cleaning ear wax (protection)
Ot/o
Tympan/o
Ear
Eardrum
Aur/i,o
Son/o
Ear
Sound
Acou/o
Myring/o
Hearing
Eardrum
Ech/o
Audi/o
Sound
Hearing
Staped/o
Stapes (middle ear bone)
Tinnitus
Vertigo
Condition of ringing in the ears
Spinning sensation
Describe the process of smell
- Air enters nasal cavity where it is warmed, filtered and moistened
- Chemoreceptors on roof of nasal cavity detect airborne chemicals (odourants)
- Sensory message sent to brain via olfactory nerve
Describe the process of taste
- Food enters into the mouth, chemicals dissolve into saliva
- Chemoreceptors in tongue/roof of mouth detect tastants
- Sensory info sent to brain via facial nerve, vagus nerve, glossopharyngeal nerve
What is the function of taste?
Protective > foul taste will initiate gag/vomiting reflex to remove dangerous foods
What are papillae?
Bumps on tongue
- Help grip food during mastication
5 taste sensations
Sweet (sugars), sour (H+ ions/acidity), salty (Na+/Cl-), bitter (amino acids in vegetables), umami (savoury flavour in meat etc)
Olfaction
Gustation
Sense of smell
Sense of taste
Phantosmia
Presbyosmia
Condition of smelling an odour that is not actually there
Condition of loss of smell due to old age
Ageusia
Parosmia
Abnormal condition of loss of taste
Abnormal condition of distorted sense of smell
-osmia
Presby-
Smell/odour
Elderly/aged
Agnosia
-geusia
Inability to classify, contrast or identify odour
Taste
