special senses anatomy Flashcards
what is the olfactory nerve? (I)
smell
what is the vestibulocochlear nerve? (vIII)
hearing and balance
what is the optic nerve? (II)
vision
glossopharyngeal nerve? (IX)
swallowing and taste
what are the special senses nerves?
olfactory (I)
optic (II)
facial (vII)
vestibulocochlear (VIII)
glossopharyngeal (IX)
1,2,7,8,9
what are the 5 senses?
vision, taste, hearing balance and smell
what is the pupil?
the darkened hole at the middle of the iris.
what is the sclera of the eye?
whites covered by the bulbar conjunctiva. fibrous and elastic tissue, the outer layer of the eye. allows for the contrast of the eye to determine where a person is looking
what is the iris?
smooth muscle structure which controls the diameter of the pupil via 2 muscles.
what are the 2 muscles involved in the dilating and constricting of the pupil?
sphincter pupilae and dilator pupilae
what is the cornea?
avascular, most common structure for use in transplant for this reason, less likely to reject the tissue donated from someone else as It does not have its own blood supply.
how can the optic nerve be seen?
when using ophthalmoscope and performing fundoscopy. it appears as a solid white structure roughly in the middle of the retina. it is surrounded by the meningeal layers of the brain.
why does intercranial pressure impact vision?
the pressure will be transmitted along the nerve and causes bulging of the optic disc. this is called papillodema
what are the 3 layers of the eye?
fibrous, vascular, inner
what are the eyes made up of?
water and electrolytes
where is aqueous humour produced?
from cilary bodies in the anterior and posterior chambers of the eyes. this fluid circulates from anterior to posterior.
what is the function of aqueous humour?
maintains pressure inside the eye, provides nutrients that go to the eye and protects the eye.
what is the vitreous chamber?
contains vitreous humour
what Is vitreous humour?
a gel which occupies the space between the lense anteriorly and the retina posteriorly. it mainly contains phagocytes to remove cell debris and is mainly water with no vessels
where is the retina?
at the back of the eyeball
what is the retina?
the light sensitive layer of tissue of the eye and where the rods and cones for black white and colour vision.
where does the optic nerve take the impulses?
posteriorly towards the optic chiasm, radiation and then on to the occipital lobe.
where does tear production occur?
in the lacrinal gland
what is the function of tears?
-lubricates movement
-removes debris
-is washed across the eye from lateral to medial
-drains into the nose
where are the sinuses located?
orbital, nasal and oral cavities
what are 4 paranasal sinuses?
maxillary - under eyes
frontal - forehead
ethmoid and splenic - both posteriorly to nose
what controls the movement of the eyes?
cranial nerves III, IV and VI
How Many extraocular eye muscles do we have?
7
what are extra ocular eye muscles?
responsible for the movement of the eye (race and obliques) and keeping the upper eyelid open (elevator papebrae superiors)
function of the superior rectus?
elevation of the eyeball (also adduction of eyeball and medial rotation)
function of the inferior rectus?
depression of the eyeball (adduction and lateral rotation)
function of the medial recuts?
adducts the eyeball
function of the lateral rectus?
abducts the eyeball
function of the superior oblique?
depression of eyeball, abduction and medial rotation. supplied by trochlear nerve
function of the inferior oblique?
elevation, abduction and lateral rotation of the eyeball.
how do we remember which cranial nerves supply the extra ocular nerves?
LR6SO4
everything else supplied by the occulomotor nerve
what makes the nose specialised for its function?
-rich, superficial blood supply
-mucous provides moisture
-mucous and hairs trap particles
what must happen to incoming air?
-warmed
-humidified
-filtred
what is olfraction?
smelling
what is the purpose of the olfactory nerve?
converts chemical information into electrical information that the brain is able to understand.
acts as a defence mechanism eg dangerous smells
where is the olfactory nerve located?
superior surface of the nasal cavity
what is the purpose of the cochnea? (turbinates)
increase surface area
increase chance of olfactory exposure
what is the mandible?
the jaw bone
what is the tongue?
unusual muscle, boneless and is comprised of intrinsic and extrinsic muscles.
responsible for the movement of food for chewing, swallowing, speech and also taste.
what are the 2 parts of the tongue?
oral part - anteriorly
pharyngeal part - towards the back
what is the sublingual gland?
mucous secreting salivary gland
what is the buccal surface?
side of the mouth where the surface is towards the cheeks as a surface of the teeth. (inside)
what is the lingual surface?
surface that faces the tongue as a surface of the teeth.
what forms the floor of the mouth?
mylohyoid muscle and the overlying stratified squamous epithelium. it is a U shaped structure which the tongue sits in
what are the foliate papillae?
leaf like and vertical ridges on the side of the tongue
what are the fungiform papillae?
mushroom like on the front 2/3 of the tongue
what are the filiiform papillae?
threadlike and serve as a coating mechanism which create a rough and abrasive texture which helps in speaking, chewing and cleaning the oral cavity
what are the valiate papillae?
only about a dozen and contain minor salivary glands and some taste buds.
what are the foreman caecum?
primitive tract where the thyroglossal duct was and represents where the thyroid gland was in embryological development
what is the epiglottis?
elastic cartilage which helps close over the trachea during swallowing
what is the mandibular division of the trigeminal nerve?
carries sensory information from the front two thirds of the tongue and several other areas including the lower third of the face. the lingual nerve specifically is the nerve which carries those sensory fibres from the anterior 2/3rds of the tongue .
what is the chorda tympani?
branch of the facial nerves which carry taste fibres From the front two thirds of the tongue and runs through the middle ear. it joins the lingual nerve from the mandibular division of the trigeminal nerve
what 2 types of sensation can be felt from the anterior 2/3 of tongue?
general (lingual nerve) and taste sensation (chorda tympani)
what are the 3 components of the ear?
-external
-middle
-inner
what happens in the external ear?
-sound waves come in
-acts as a funnel and helps focus all the sound
what is the function of the inner ear?
responsible for hearing
semicircular canal - balance
where are the malleus, incus and stapes located?
in the temporal bone, these are the ossicles
what is the internal auditory meatus?
small hole located within the temporal bone, where the facial and vestibulocochlear nerve
what are the roles of the ear ossicles?
transmit vibrations though middle ear, responsible for transmission of sound (eg hearing)
3 bones
malleus - attached to tympanic membrane (ear drum)
incus - anvil
stapes - stirrup
what is the rocky part of the temporal bone?
petrous temporal bone
what makes up the tympanic cavity?
lateral wall - tympanic membrane (ear drum)
medial wall - vestibular window (oval window) opening into the vestibule of inner ear, closed by base of stapes
cochlear window (round window. opening into the cochlear portion of inner ear
what is the cochlea?
responsible for sound amplification
-conversion from vibration to electrical signal
-signaal transmitted via cochlear part of the vestibulocochlear nerve
semicircular canals help with balance and vestibular part of the vestibulocochlear nerve
what are photo receptors?
detect light waves eg eye
what are mechanoreceptors?
detect sound waves and pressure on the skin and inner ears
what is gustation?
taste
what are chemoreceptors?
detect the molecules in our food and the air around us
what makes up the fibrous layer of the eye?
cornea, sclera
form the dense fibrous layer of the eye
they are continuous with each other and give the eyeball shape and structure
where is the attachment site for extraoccular muscles?
sclera
what are the 3 components of the vascular layer of the eye?
ciliary body
choroid
iris
what is keratoconcus?
thinning of cornea resulting in coning shape - can cause blurring and double vision
what does the nasolacrimal duct do?
takes tears from lacrimal gland to nasal cavity - specifically to the opening under the inferior nasal meatus
which sinuses are under the eye?
maxillary
which sinuses are posterior to the nose?
ethmoid and sphenoid
which muscles must correct the eyeball to look straight ahead?
extra-ocular muscles
which cranial nerves control orbits of the eyes?
occulomotor
trochlear
abducens
3,4,6
what is the eardrum (tympanic membrane)?
tympanic membrane - the first point of contact with sound waves, it shakes the 3 bones of the middle ear
what is the function of the semicircular canals?
balance
how many pairs of semicircular canals do we have?
3
what are the Eustachian tubes?
they maintain pressure within the inner ear,
tube from the ear to the nasal sinus cavity
what structure links the middle ear with the pharynx
eustachian tubes
what is the function of the auricle? (pinna)
captures and directs sound waves towards the external acoustic meatus
what is the only part of the auricle not supported by cartilage?
lobule
what is the concha?
hollow depression in the middle of the auricle
what is the walls of the external 1/3 of the external acoustic meatus?
cartilage
what are the inner 2/3 of the external acoustic meatus formed by?
temoral bone
where does the tympanic membrane lie?
distal end of the external acoustic meatus
what is the blood supply like to the external ear?
external carotid artery
-posterior auricular artery
-superficial temporal artery
-occipital artery
-maxillary artery
what bone is the tympanic membrane connected to?
temporal bone
where does the middle ear lie?
within the temporal bone and extends from the tympanic membrane to the lateral wall of the inner ear.
what is the role of the tympanic cacvity?
amplify sound waves so they’re stronger when they reach the middle ear. does this using the ossicles
what is the superior oval window?
where they set the fluid in the inner ear into motion
what are the two sections of the labyrinth?
bony labyrinth and membranous labyrinth
what are the 3 main chambers of the cochlea?
scala vestibuli
scala media
scala tympani
what is the basilar membrane?
a stiff band of tissue that runs between the Scala media and Scala tympani
what are the fibres at the base of the cochlea like?
short and stiff
what are the fibres at the end of the cochlea like?
longer and looser
what do the short fibres resonate with?
high frequency pressure
what do the longer fibres resonate with?
low frequency waves
what makes up the membranous labyrinth?
cochlear duct, semi circular ducts, utricle and the saccule.
what does the bony labyrinth consist of?
cochlea, vestibule, three semi-circular canals
what are the epithelial cells of hearing called?
the organ of corti. located in the basilar membrane
Which structure is responsible for endolymph production?
Stria vascularis
which interleukin would reset the hypothalamic thermostat after infection?
interleukin 1
why do NSAIDs cause gastric irritation?
prostaglandins have an active role in the protection of the gastric mucosa
which structure is involved in determining pitch?
basilar membrane
what pathway do NSAIDs affect?
production of prostaglandins and thormoboxanes
which part of the eye regulates the amount of light detected by the photoreceptor cells?
iris
