Week 12 Flashcards
How many pairs of spinal nerves are there?
31
8 cervical
12 thoracic
5 lumbar
5 sacral
1 coccygeal
How many pairs of cranial nerves are there?
12
Name each cranial nerve and function
Olfactory - smell
Optic - vision
Oculomotor - eye movements
Trochlear - eye movements
Trigeminal - motor to muscles of mastication and general sensory to face
Abducens - eye movements
Facial - muscles of facial expression
Vestibulocochlear - hearing and balance
Glossopharyngeal - swallowing, taste
Vagus - wandering nerve supplying, heart, lungs, gut
Spinal accessory - neck muscles
Hypoglossal - tongue muscles
What are the special senses?
Vision - optic nerve
Taste - glossopharangeal and facial
Hearing and balance – vestibulocohlear
Smell - olfactory
What is the sclera of the eye and composition? Function?
White of the eye/outer layer
Fibrous and elastic tissue
Determining where someone is looking
What is the iris of the eye? Function? Composition?
Coloured part of eye
Controls diameter of pupil
Smooth muscle
2 muscles in iris of eye?
spincter pupillae and dilator pupillae
when do pupils get wider?
in the dark
Most common structure for transplant? Why?
Cornea
Avascular
Less likely to reject tissue from someone else as no blood
When can the optic nerve of the eye been seen? What does it look like?
When using opthalmoscope
Performing fundoscopy
Solid white sturtcure in middle of retina
What is the optic nerve surrounded by? What happens to it when there is intercranial pressure?
Meningeal layers
Will be transmitted along nerve and cause bulging of optic disc
What is papillodema?
bulging of optic disc
when is intercranial pressure increased?
bleed or tumour
What is keratoconus?
thinning of cornea resulting in coning shape
causing blurring and double vision
surgery/cornea transplant required
what is jaundice? what can it indicate?
yellowing of eye/sclera
indicates blood disorders or liver problems
Main composition of eyes?
water and electrolytes
What is within anterior and posterior chambers of the eye? What is it made from? Circulation? Function?
Aqueous humour
ciliary bodies
circulates from anterior to posterior
maintains pressure in eye, provides nutrients to eye, protects eye
What is in vitreous chamber of eye? Composition?
Contains vitreous humor
gel between lens and retina
contains phagocytes to remove cell debris
mainly water and no blood vessels
Function of retina? What is contained here?
light sensitive layer of tissue
rods - black
cones - colour vision
Were does optic nerve take impusles from pupil?
pupil to vitreous humor
retina
optic nerves to optic tract
some info passes to other side by optic chiasm
then occipital lobe
Where are tears produced? Function?
lacrimal gland
- lubricates movement
- removes debris
- tears go from lateral to medial and drains into nose
function of nasolacrimal duct?
takes tears from lacrimal gland to nasal cavity
to opening under inferior nasal meatus
what is the canal containing nasolacrimal duct called?
nasolacrimal canal
Name parts of the eye
Name bones of the orbit
which orbit bone is one of the thinnest in the body?
lacrimal
why is the nose ,more anterior of the orbit?
allows wider lateral gaze of each eye in bony orbits
where are the paranasal sinuses?
maxillary - under eye
fronal - forehead
ethmoid and spenoid - posterior to nose
function of sinuses?
reduces weight of skull
allows circulation of mucous
resonance of sound
what happens when eyeball is herniated?
double vision/diplopia
eyeball passes into maxillary sinus
how many ethmoid sinuses are there?
30-40
what cavities have sinuses?
orbital
nasal
oral cavities
function of extraocular muscles?
corrects eyeball position to look straight ahead
eyes usually point laterally and superiorly
what cranial nerves control extra ocular muscles?
III
IV
VI
How many extra ocular musclea are there? functions?
7
movement of eye
keeps upper eyelid open
which types of extraocular muscles move the eyes?
recti and obliques
which types of extra ocular muscles keep eyelids open?
levator palpebrae superioris
Function of superior rectus?
elevation of eyeball
function of inferior rectus?
depression of eyeball
function of medial rectus?
adducts eyeball
function of lateral rectus?
abducts eyeball
funcions of superior oblique?
depresses eyeball
abduction
medial rotation
functions of inferior oblique?
elevation
abduction
rotation of eyeball
which nerve innervates most extraocular muscles?
oculomotor nerve III
what muscle does the trochlear nerve innervate?
superior oblique
what muscle does the abducent nerve innervate?
lateral rectus
functions of nasal cavity?
warms
humidifies
filters air
why is nasal cavity suited to its function?
- rich, superficial blood supply (warmth)
- mucous supplies moisture
- mucous and hair traps particles
function of olfactory nerve? where is it found?
- converts chemical info (smells) to electrical
- superior surface of nasal cavity
- defence mechanism (e.g. poisoning)
function of tongue?
moves food for mastication
swallowing
speech
taste (tongues upper surface)
2 parts of tongue?
oral part anteriorly
pharangeal part at back
function of sublingual gland?
mucous secreting salivary gland
name parts of the tongue
what is the buccal surface?
side of mouth where surface is at teeth
what is lingual surface?
surface that faces bottom of tongue
what is the floor of the mouth formed by?
mylohyoid muscle
overlying stratified squamous epithelium
U shaped
Name parts of mouth
What is the fungiform papillae?
mushroom like on front 2/3 of tongue
what is foliate papillae?
leaf like and vertical ridges on side of tongue
what are filiform papillae?
threadlike and serve as coating mechanism
creates rough and abrasive tecture for speaking and chewing
what are vallate papillae?
only a dozen
minor salivary glands
some taste buds
what are foramen caecum?
primitive tract where thyroglossal duct was
represents where thyroid gland was in embryological development
what is epiglottis?
elastic cartilage closes over trachea in swallowing
name parts of the tongue
what is the chorda tympani?
branch of facial nerve
carries taste fibres from front 2 thirds of tongue
where does chorda tympani run through? what does it join?
middle ear
lingual nerve from mandibular division of trigeminal nerve
function of mandibular division of trigeminal nerve?
carries sensory info from front 2/3 of tongue and lower 1/3 of face
what cranial nerves does lingual nerve carry axons from?
V3 and VII
function of glossopharangeal nerve in tongue?
taste and general sensation from posterior 1/3
function of hypoglossal nerve in tongue?
motor control of most tongue muscles
where does facial and vestibulocohelear nerve enter middle ear?
internal auditory meatus in temporal bone
2 parts of temporal bone?
squamous (flat part)
petrous (rocky)
function of ear ossicles?
transmit vibrations through middle ear
3 ear ossicles?
malleus
incus
stapes
what is malleus attached to?
tympanic membrane
what is on the lateral wall of tympanic cavity?
tympanic membrane aka ear drum
what is on the medial wall of tympanic cavity? what is it closed by?
vestibular window/oval window
opening into vestibule of ear
closed by base of stapes
cochlear/round window
opening into cochlea of inner ear
how do soundwaves get to brain?
enter through external auditory meatus
tympanic membrane vibrates
malleus, incus and stapes vibrate
oval window vibrates
fluid in scala vestibuli vibrates
vibration hits round window
stereocilia transmits info to vestibulocohlear nerve
function of cochlea?
sound amplification
converts vibration to electrical signal
signal transmitted to vestibulocochlear nerve
function of semicircular canals?
balance
vestibulocohlear nerve
what links pharynx to ear? function?
eustachian tube
maintains pressure in middle ear as same level as pharynx
why do childrens ears get infected more easily?
auditory tube in children is smaller
infection in throat can pass to middle ear
otitis media
Where can temperature be recorded? How?
axilla, rectum, ear
thermometer/electronic probe
Why is tympanic membrane / ear temperature usually recorded in hospitals?
minimally invasive
reflects core temperature: close to internal carotid artery and tympanic membrane blood supply
What is the instrument used to examine the ear? What studtucre does this show?
Otoscope
Tympanic membrane (pearly grey/translucent appearance)
What is otitis media? when is it common?
middle ear infection/inflammation, associated with collection of fluid
first year of life
clinical features of middle ear infection?
otalgia/earache
decreased hearing
fever, vomiting, irritability, tugging at ear, poor feeding
what is the shape and arrangement of steptococcus pneumoniae?
gram positive (blue) cocci in chains
what is sensorineural hearing loss?
disease of the cochlea/organ of corti/CN VIII or more CNS pathways
what is conductive hearing loss?
failure of conducting mechansims of outer and middle ear to transmit sound to fluids of inner ear
how are sound waves converted to electrical signals?
- sound waves collected by pinna and travel down ear canal
- tympanic membrane stretched across end of external auditory canal and air molecules vibrate at same frequency of sound wave
- vibrations transmitted and amplified through ossicles to oval window
- oval window to scala vestibuli and then scala media (cochlear duct)
- pressure waves across cochlear duct vibrate basilar membrane where organ of corti located
- stereocilia bend and open ion channels in plasma membrane of hair cell and depolarise it
- receptor potential created, hair cells release exitatory neurotransmitted which excites afferent cochlear neurons
what does the prefix ot mean?
the ear
what is suppuration?
pus production
what embrological component makes up the mucosal surface of the anterior 2/3 of tongue?
first branchial arch endoderm
what does the first branchial arch endoderm form?
tuberculum impar (midline)
lateral lingual swellings
what embrological component makes up the posterior 1/3 of tongue?
third branchial arch endoderm
what does the third branchial arch endoderm form?
cupula
what innervates the anterior 2/3 of tongue?
trigeminal nerve for touch and pain
facial nerve for taste
what innervates the posterior 1/3 of tongue?
glossopharangeal nerve
what forms the intrinsic and extrinsic muscles of the tongue?
mesoderm in upper neck (occipital somites)
what innervates the tongue muscles?
hypoglossal nerve
label the tongue
function of intrinsic muscles in tongue?
change shape of tongue
what muscle of the tongue is not inner vated by the hypoglossal nerve?
palatoglossus
structure and function of lingual tonsils?
produce antibodies
lymphoid tissue
what is the foramen caecum?
where thyroid gland developed in early life
what is the circumvallate papillae? how many?
boundary between anterior and posterior tongue
12
function of fungiform papillae?
taste buds here
function of filiform papillae?
rough surface of manipulation of food
5 primary tastes?
sour
salty
sweet
bitter
savoury/unami
what is sour taste component?
acid, H+
what is salty taste comonent?
sodium
what is sweet taste component?
glucose
what makes up bitter?
coffee
beer
blue cheese
olive
what makes up savory/unami taste?
glutamate - ramen
why is btterness most sensitive taste?
protects against poisoning
why are sweet, salt, sacory and sour all associated with pleasure?
to incentivise nutrition
how is taste carried to brain? anterior 2/3 of tongue
lingual nerve (first branch of trigeminal) then chorda tympani then facial nerve then brain stem
how is taste carried to brain , posterior 1/3 of tongue?
glossopharangeal
where do taste fibres synapse in brain?
solitary nucleus of medulla, thalamus, gustatory cortex
how is pungency aka chilli mediated?
pain/temperature receptors
how is collness/menthol mediated?
temperature receptors
what does temperature of food enhance?
release of odorants to nose
how can ear surgery damage to chorda tympani damage taste?
if bilateral, unpleasant metallic taste in mouth
what happens if durgery to sublingual and submandibular salivary glands damages lingual nerve?
loss of taste unilaterally and loss of common sensation in floor of mouth and tongue
what happens in quiet breathing?
laminar airflow over inferior intubate
what happens when you sniff?
turbulence to mix air and send odorants to roof of nose
where does olfactory mucosa lie? what is above?
below cribiform plate
olfactory bulbs
where do odorant molecules in the air dissolve?
nasal mucus
what is smell detected by?
detectors on dendrites of olfactory cells
how many active smell genes in human?
400
where does olfactory nerve project to in brain?
amygdala
hippocampus
parahippocampal gyrus
what sensory modality doesnt relay primarily to thalamus?
smell
goes straight to limbic system instead
what is kallmann syndrome?
congenital anosmia
congenital in children
how can anosmia be acquired?
chronic rhinosinusitis
neurological disorders aka parkinsons
base of skull fracture
brain tumor
covid
how can lack of smell risk health?
smoke alarm
off food
how many taste receptord are there?
5
what is majority of taste>
smell
why has life expectancy increased?
improements in public health
what does public health respond to?
societal health concerns
science, ethics
definition of public health?
collective action for sustained population-wide health improvemetn
what is in the first wave of public health? when was it?
1830-1900
public health interventions e.g. handwashing and wateer
what was the miasma paradigm of disease? when was it?
first wave
disease was caused by bad air
what was the second wave of public health? when?
1890-1950
germ theory
scientific rationalism
what are the 3 components of germ theory?
host
vector - air, water
agent - viruses and bacteria
what was the third wave of public health?
1940-1980
emergence of nhs
social housing
what is health?
state of physical, mental and social well being
what is the biophyscosocial model of health?
third wave
mental health at centre
what is the forth wave of public health?
1960-2000
risk factors and life style central concern
social inequalities
what are the health concerns of today?
health inequalities
obesity
population growth and ageing demographic
human impacts on planets life support systems
climate change
what is health protection?
set of activities in public health
- ensuring safety and wuality of food/air/environent
- preventing transmission of communicable diseases
- managing outbreaks
what exactly is sound?
vibration of medium
spreads out as wave of pressure
spreads outwards from a source
what is hertz a measure of?
pitch
what is herts exactly?
frequency in cycles per second
what is range of human hearing?
20-20k
how do you measure loudness of sound?
decibels
what is 3db?
twice the sound energy
what is 10db?
10x sound energy
twice perceived loudness
what is thereshold in hearing?
quietest sound heard at each frequency
what is sound pressure defined as?
db spl
what is measuring sound pressure against hearing theresholds in young adults with normal hearing?
dB HL
what medium is required for sound?
something thats particle vibrates
air, water, rock
what is freuqency made from?
number of vibrations per second
what is loudness of sound?
strength of vibrations
what is the loudest sound you can hear?
100 trillion times energy of quietest
what is an audiogram?
hearing test
what is the outer ear made of?
pinna
ear canal
what is the middle ear made of?
tympanic membrane
ossicles
what is the inner ear made of?
cochlea
vestibule
why do we have to ears? why?
localisation of sound - allows you to determine where sound is coming from
due to inter aural time difference, and difference in loudness
function of pinna?
amplifies and filters incoming sounds
filtering at certain frequencies
how long is the ear canal?
2.5cm
how much do pinna and canal increase pressure by?
20dB
why is frequecy filtering useful?
sound localisation in vertical and front back planes
function of oval window?
amplifies sound by concentrating energy
function of 3 ossicle system?
amplification
sensitivity to high-frequency sounds
stronger bite
what is the first branchial arch form?
malleus and incus
what does second branchial arch form?
stapes
2 protective muscles in middle ear? function?
stapedius reflex
tensor tympani
protects against loud sounds
what does eustachian tube connect?
connects nasopharync to middle ear
functions of eustachian tube?
allows air to enter and leave middle ear
keeps air pressure in middle ear space same as ambient atmospheric pressure
why is it important to have middle ear at same pressure as pharynx?
allows tympanic membraen to vibrate
dysfunction of eustachian tube?
blocked feeling
poor hearing
when is eustachian tbe open/closed?
open - swallowing
closed - rest
what is conductive hearing loss caused by?
ear canal - wax, foreign body
tympanic membrane - perforation
ossicles - congenital fusion, damage in infection
middle ear space - fluid instead of air
what is sensorineural hearing loss?
congenital and not acquired
how can you get sound to inner ear alternatively?
cochlear impant
how is sound amplified in the ear?
tympanic membrane has larger surface area than oval window
function of vestibular apparatus?
contains sensory structures for balance and head movements
function of cochlea?
sensory epithelium for hearing
organ of corti
how does vibration get to the cochlea?
oval window faces into vestibule
vestiuble contains sensory epithelia
vestibule leads into scala vestibuli (upper cochlear duct)
pressure waves travel along scala vestibuli and back through scala tympani (lower part)
waves terminate at round window
function of organ of corti?
sensory epithelium containing auditory hair cells
function of stria vascularis?
regulates ionic and metabolic functions of scala media
4 parts of organ of corti?
spiral ganglion
auditorynerve fibres
tectorial memvrane - above
basilar membrane - sits on
when is frequency stiff and light?
high frequency
base of cochlea
when is frequency flexible and heavy?
low frequency
apex of cochlea
where do hair cells originate? what do they form and where?
epithelial origian - remeble cells lining stomach
stereocillia form bundle at apical pole of hair cell
what membrane does the cochlea sit on?
basilar membrane
how are stereocilia arranged?
shortest to tallest
what happens when stereocilia are pushed towards the tallest?
depolarisation
potassoim channels open, potassium flows into cells from endolymph
what happens when stereocilia are pushed towards shortest?
hyperpolarisation
potassium channels closed
what are inner hair cells innervated by?
afferent
lateral efferent
what are outer hair cells inervated by?
medial efferent
what happens when outer hair cells are stimulated by movement of basilar membrane?
change shape and stiffness
reverse transduction
cochlear amplifier
what is reverse transduction by outer hair cells?
feeding energy back into basilar membrane when stimulated
how do outer hair cells act as a coclear amplifier?
increases amount of vibration on basilar membrane at point of macimal vibration
other function of outer hair cells?
improves frequency selectivity
what are are otoacoutic emmisions? when are these important?
outer hair cells move in response to noise, can measure this
screening test for hearing loss in babies
what can hair cells in ear be sensitive to?
infection, ototoxins, noise
aging
sensorineural hearing loss
what happens if you lose inner hair cells?
no signal to brain
can loss a lot of hearing
what happens if outer hair cells are lost? how much hearing loss?
basilar vibration insufficiently amplified
approx 50 db loss in hearing
loss of sound discrimination
how do hearing aids work?
microphone - amplifier - speaker
make everythign louder
corrects conductive hearing loss
what do you lose with hearing aids?
lose discrimination of sound
lose dynamic range
central processing affects
how is pitch encoded?
position of hair cells
how do cochlear implants work?
stimulates spiral ganglion cells if severe hearing loss due to loss of hair cells
what can solve hearing loss if auditory nerve lost? why would auditory nerve be lost?
can put hearing implant onto cochlear nucleus in brainstem
tumor on nerve
results arent great
why doesnt stroke/cns damage cause hearing loss?
above cochlear nuclei representation is bilateral
what is tonotopic map? where is this maintained to?
arrangement of frequencies
primary auditory cortex
where is sound processed?
come from neurons in spinal ganglion of cochlea
travel in CN VIII
synapse in cochlear nuclei (junction of medulla and pons)
how is impendance mismatch overcome?
The transmission of mechanical energy
from the air to the fluid of the cochlea by the middle ear.
Which interleukin can reset the thermostat in the hypothalamus?
IL-2
What is IL-2 involved in?
T cell proliferation/differentiation
what protein in the organ of corti can cause deafness? where is it?
alpha tectorin
tectorial membrane
Which molecule protects the stomach lining?
prostagandins made by cox-1
which cochlear structure causes endolymph production (fluid in ear)?
stria vascularis
organ of corti function?
vibrations converted to electrical signals
which part of eye regulates amount of light taken to photoreceptor cells?
iris
what activity do nsaids inhibit?
cyclooxygenase
name 2 eicosanoids?
thromboxane
prostaglandins
function of lipooxygenase?
produces leukotrienes
leukotriene function?
inflammatory mediator
what does cyclooxygenase produce?
eicosanoids
which structure determines pitch?
bending of basilar membrane
what does the stria vascularis line?
scala media
What would indicate loss of hearing in an otoacoustic emmisions test?
reflected sound only - 1 recorded sound
differences betwene inner and outer hair cells?
inner:
more afferent inputs
primary receptor
transducer
kidney bean shape
outer hair cells:
more efferent inputs
secondary receptor
amplifier
straight shape
