Special Senses in the Head and Neck Flashcards
What holes are found in the bony orbit?
Optic foramen
Superior orbital fissure
Inferior orbital fissure
What cranial nerves are found in the orbit?
Optic (II)
Oculomotor (III)
Trochlear (IV)
Abducent (VI)
Function of optic nerve
Passes from back of eyeball and carries visual impulses
What does the oculomotor nerve supply?
Inferior oblique Superior rectus Medial rectus Inferior rectus Levator palpebrae superioris
What does the trochlear nerve supply?
Superior oblique
What does the abducent nerve supply?
Lateral rectus
What is the orbit closely related to?
Sinuses
What is the fibrous coat of the eye?
Cornea
Sclera
What is the vascular coat of the eye?
Iris
Ciliary body
Choroid
What is the sensory coat of the eye?
Retina
What is the cornea?
Anterior 1/6 which is transparent and is a window to allow light rays to enter the eyeball
What is the sclera?
The opaque posterior 5/6 which gives attachment to muscles moving the eyeball
Function of the ciliary body
Suspends the lens
Produces aqueous humor
Function of the iris
Controls diameter of the pupil ; controlling the amount of light rays entering the eyeball
Function of the choroid
Supplies blood to outer layers of the retina
Function of the retina
Has light sensitive rods and cones which enable us to see
What is the ora serrata?
Anterior end of the retina
What happens at the optic nerve head?
Physical blind spot
What is the aqueous humor?
Watery fluid anterior to the lens
Function of aqueous humor
Helps to maintain intraocular pressure
Function of vitreous humor
Helps to cushion the retina
What is the vitreous humor?
A transparent gel posterior to the lens
Function of intrinsic ocular muscles
Control pupil diameter and helps alter lens curvature to enable us to see near objects
Function of extrinsic ocular muscles
Move the eye
What are the intrinsic eye muscles?
Ciliaris muscle in ciliary body
Constrictor pupillae in iris at pupillary border
Dilator pupillae - radially running muscle in the iris
What is the Ciliaris muscle innervated by?
Parasympathetic IIIn
What is the constrictor pupillae innervated by?
Parasympathetic IIIn
What is the dilator pupillae innervated by?
Sympathetic from plexus around blood vessels
What are the extra ocular muscles?
Medial rectus Lateral rectus Superior rectus Inferior rectus Superior oblique Inferior oblique
Where do the recti muscles arise from?
Apex of the orbit from an annular fibrous ring
Where does the superior oblique muscle arise from?
Roof of the orbit posteriorly
Lesser wing of sphenoid
Where does the inferior oblique muscle arise from?
Floor of the orbit anteriorly
Where do the recti muscles insert?
Sclera anteriorly
Where do the oblique muscles insert?
Sclera posteriorly
Where does the LPS insert?
Upper eyelid
Function of LPS
Elevation of eyelid
Another name for looking up
Elevation
Another name for looking laterally away from nose
Abduction
Another name for looking medially towards nose
Adduction
Another name for looking downwards
Depression
Another name for looking up and to the right
Dextro-elevation
Another name for looking up and to the left
Levo-elevation
Another name for looking down and to the right
Dextro depression
Actions of MR
Adduction
Actions of LR
Abduction
Actions of superior rectus
Elevation
Adduction
Intorsion
Action of inferior rectus
Depression
Adduction
Extortion
Actions of superior oblique
Intorsion
Depression
Abduction
Actions of inferior oblique
Extorsion
Elevation
Abduction
What is RADSIN used to remember?
Recti ADductors
Superiors INtortors
Nerve supply to the lacrimal apparatus
Parasympathetic from facial nerve
What happens to the lacrimal sack when blinking?
During each blink, eyelids spread tears evenly on the surface of the cornea
Tears drain through punctae on the medial side of each eyelid
Drains into the lacrimal sac which sits over the lacrimal bone
Then drains through the nasocralimal duct into the inferior meatus of the nasal cavity
What are the muscles of the middle ear?
Tensor tympani
Stapdieus
Function of the tensor tympani
Helps to dampen down some vibrations
What bone houses part of the middle and inner ear?
Temporal bone
What part of the skull does the facial nerve sit in from the brain?
Posterior cranial fossa
Goes into internal acoustic foramen
What travels through the internal acoustic foramen?
Vestibularcochlear nerve
Facial nerve
What foramen does the middle meningeal artery run through?
Foramen spinosum
Where does the MMA sit in relation to the dura mater and what does this result in if its bleeds?
Outside of the dura mater
Extradural haemorrhage
What kind of glands are salivary glands?
Exocrine
What type of cells in salivary glands are responsible for squeezing out secretions into the ducts?
Myoepithelial cells
3 types of salivary glands
Serous
Mucous
Mixed
What type of gland is the parotid gland and what colour does this stain on histology?
Serous
Dark staining
What type of gland is the sublingual gland and what colour does this stain on histology?
Mucous
Pale staining
What type of gland is the submandibular gland and therefore what colour does this stain on histology?
Mixed
Elements of both pale and dark staining
What epithelium is found on the tongue?
Stratified squamous epithelium (keratinised)
What fibres make up the tongue?
Skeletal muscle fibres
