Special Senses Flashcards
what protects the eye
eyelashes
eyebrows
lacrimal gland = tear secretion
where is the optic chiasm located
directly infront of/above the pituitary gland
what is the optic tract
optic nerve pathway
what is the functions of tears
wash away irritating materials
protect against infection
prevent drying of conjunctiva
what is made up of the lacrimal apparatus and its role
secrete and drain tears
1 lacrimal gland + ducts
2 lacrimal canniculi
1 lacrimal sac
1 nasolacrimal duct
what is the tear journey through the lacrimal apparatus
lacrimal gland: exocrine, lateral aspect of the eye in the frontal bone. which secretes tears via the lacrimal duct: water, salt, immunoglobulins and lysozyme
tears drain into the lacrimal cannaliculi separated by the carnicle
tears then drain into the nasolacrimal duct which opens into the NC
is the retina photosensitive
yes
what are the photosensitive nerve cells called
rods and cones
what do rods do
dim the light
what is the blood supply of the eye
ciliary arteries, central renal artery and central retinal vein
what does the extrinsic eye muscle do
controls eye movements
4 rectus muscles allow, U, D and lateral oblique allows side to side
what does the intrinsic eye muscles do
involuntary
controls the amount of light that enters the eye
what are the three parts of the ear
external
middle
internal
what does the external part of the ear do
collects sound waves and channels them inwards
what does the middle part of the ear do
conveys sound vibrations
what does the inner part of the ear do
houses the receptors for hearing and balance
describe the ear pathway
ear canal -> ear drum -> cochlea + eustachian tube
what do the ceruminious glands do
secrete cerumen [wax] which contains lysozyme and immunoglobulins
prevents foreign materials from reaching the tympanic membrane [ear drum]
where is the cochlea found
inner ear
what are the three parts of the cochlea
scala vestibuli
scala media
scala tympani
what contains auditory receptors
supporting cells and cochlea hair cells
what does the semi circular canals do
provide information on the head position so we are able to maintain balance, posture, focussing on both eyes
NO AUDITORY FUNCTION
what are the semi circular canals composed of
a bony outer wall, inner membrane tubes
what impulses relate to the semi circular canals
from the cerebellum, eyes and sensory receptors are coordinated and efferent nerve impulses pass to the cerebrum and skeletal muscles
what do sound waves travel in
pitch and volume
loud noises cause damage to the sensitive hair cells of the spiral organ
describe structures that sound waves travel to
tympanic membrane -> ossicles -> oval window -> cochlea -> vestibulocochlear nerve -> primary auditory cortex
where is the origin of smell
NC
where are the specialised olfactory nerves [chemoreceptors] found
in the roof of the NC above the superior nasal conchae
what are the sensory receptors of taste called
chemoreceptors
where is sweet taste found on the tongue
tip
where is salty taste found on the tongue
tip
where is sour taste found on the tongue
sides
where is bitter taste found on the tongue
back
how does taste come about
signals travel along the medulla oblongata, some signals are projected to the hypothalamus and the LS and some to the thalamus
what can smell and taste trigger
salivation and gastric secretion
chemoreceptors are also triggered when a foreign substance travels the body
where are the olfactory and optic nerves found
cerebrum
where are the 10 cranial nerves found minus O&O
BS
olfactory nerve
smell
optic
return info from retina to brain
oculomotor
innovates extraocular muscle movement, eye movement and upper eyelid movement
trocochlear
operates superior oblique eye muscles, ONLY MOTOR SIGNALS
trigeminal
general sensory nerve of head
facial
serves taste buds, on upper 2/3 enables facial muscle movements
glossopharyngeal
serves posterior 1/3 taste buds
abducens
side to side eye movement
vestibulocochlear
hearing and balance
hypoglossal
tongue movement
accessory nerve
spinal and cranial sections, motor nerve stimulating neck muscle movements
vagus
taste buds in throat, stimulates muscles in chest that aid digestion
what are the cranial nerves
O,O,O,T,T,F,G,A,V,H,A,V
what are the three layers of eye tissue
- outer fibrous = sclera + cornea
- middle vascular = choroid + body
3 inner nervous tissue = retina
labyrinthitis
origin: ear
caused by infections
symptoms: vertigo, nausea, hearing loss, pain and puss
cataracts
origin: eye
causes visual impairments due to the opacity of the lens
symptoms: vision changes and eye colour changes
trigeminal neuralgia
origin: facial nerve
caused by compression of the trigeminal nerve
symptoms: ++ pain, burning sensation
acoustic neuroma
caused by a benign tumour between the middle ear and brain
symptoms; hearing loss, balance issues, headache
SCC (pinna)
surgery, topical chemo, RT
RT = 45Gy in 10 with electrons
acoustic neuroma treatment
watch and wait
surgery
SRS
VMAT = 50Gy in 30
ocular melanoma treatment
surgery, cyrotherapy, brachytherapy [radioactive disc on the eye]
retinoblastoma symptoms and treatment
eye bulging, vision changes
eye removal, chemo, RT
40-45Gy in 20-25
risks of ocular melanoma
skin and hair type
atypical mole syndrome
primary acquired melanosis
UV exposure
blue eyes
ear cancer risks
fair skin
UV exposure
middle ear: repeated infections, prior RT and HPV
inner ear: unknown
ear cancer presentation
lump in canal
face weakness
ear bleeds
tinnitus
headache
visible mass [skin only]
discharge
pain
hearing loss
ear treatment
surgery
chemo
RT
what is ear primary treatment
surgery
removal of:
ear canal
part or all of temporal bone
middle ear
inner ear
LN around ear
if not all tumour removed RT is needed
what cancer type is common in inner ear
adeno carcinoma
where are most ear cancers invasions from
parotid cancers
what is T1 ear cancer
middle ear, no face numbness, not in nearby bone
T2 ear cancer
grown outside area, numbness or is affecting nearby bone
T3 ear cancer
grown into nearby SG (PG) or base of skull
what do chemoreceptors detect
environment changes and stimulate changes to maintain homeostasis
what are chemoreceptors important in
respiration and circulation (measure CO2)
where are chemoreceptors found
medulla oblongata and nose
