Special Senses Anatomy Flashcards
What are the 3 main foramina into the orbit?
Optic foramen, superior orbital fissure and inferior orbital fissure
What structures go through the optic foramen
Optic nerve and ophthalmic artery
What structures go through the superior orbital fissure?
Cranial Nerves III, IV and VI, branches of ophthalmic division of Cr N 5 and ophthalmic veins
What structure goes through the inferior orbital fissure?
Maxillary division of cranial nerve V
What does the optic nerve carry?
Visual impulses
Where does the troachlear nerve arise?
Dorsal part of the midbrain
What does the trochlear nerve supply?
Superior oblique
What does the abducent nerve supply?
Lateral rectus
What does the oculomotor nerve supply?
The muscles of the eye and eyelid (except SO and LR) and carries the parasympathetic supply to the eye
Which sinuses are closely related to the orbit?
Frontal, ethmoidal and maxillary
What structures make up the fibrous coat of the eye?
Cornea (anterior 1/6) and Sclera (posterior 5/6)
What is the function of the ciliary body?
Suspends the lens and produces aqueous humor
What is the function of the iris?
To control the diameter of the pupil and therefore control the amount of light rays entering the eyeball
What is the function of the retina?
It has rods and cones which transform the light rays into nerve impulses
What is the function of the choroid?
Supplying blood to the outer layers of retina
What is the function of the aqueous humor?
To maintain intraocular pressure
What is the function of the vitreous humor?
To cushion the retina
What are the three intrinsic eye muscles?
Ciliaris, constrictor pupillae and dilator pupillae
What is the innervation of the intrinsic eye muscles?
Ciliaris and constrictor pupillae - parasympathetic (CrN 3)
Dilator pupillae - sympathetic (from plexus around the blood vessels
What are the four straight extrinsic muscles of the eye?
Medial, lateral, superior and inferior rectus
What are the two oblique extrinsic muscles?
Superior and inferior oblique`
Where do the recti muscles arise from?
Annular fibrous ring at the apex of the orbit
Where does the superior rectus arise from?
Roof of the orbit posteriorly
Where does the inferior oblique arise from?
Floor of the orbit anteriorly
What is the innervation of the extrinsic muscles?
SO - Trochlear (4)
LR - Abducent (6)
Everything else - Oculomotor (3)
What type of joint is found between the ossicles?
Synovial
What are the muscles found in the middle ear?
Tensor tympani and stapedius
Which part of the temporal bone houses the middle and inner ear?
Petrous part
Which cranial nerves go through the internal acoustic foramen?
CrN 7 (facial) and CrN 8 (vestibulocochlear)
What type of saliva is produced in the parotid gland?
Serous
What type of saliva is produced in the sublingual gland?
Mucous
What type of saliva is produced in the submandibular gland?
Mixed - serous and mucous
What type of epithelium is the filiform papillae?
Keratinised stratified squamous epithelium
What type of epithelium is the fungiform papilla?
Non-keratinised epithelium
What are the main contents of the orbit?
Eyeballs, extrinsic ocular muscles, ligaments supporting the eye, optic nerve, branches of the ophthalmic artery, lacrimal apparatus and eyelids
What structures make up the outer fibrous layer of the eye
Sclera - 5/6
Cornea - 1/6
What structures make up the middle vascular layer of the eye?
Choroid, ciliary body and iris
What structure makes up the inner sensory layer?
Retina
What is the name of the fluid found in the anterior segment of the eye?
Aqueous humor
What is the name of the gel found in the posterior segment of the eye?
Vitreous humor
What part of the eye produces aqueous humor?
Ciliary epithelium
What is the action of the ciliaris muscle?
Accommodation
What is the innervation of the ciliaris muscle?
Parasympathetic via CrN III
What is the action of the constrictor pupillae?
Pupillary constriction
What is the innervation of the constrictor pupillae?
Parasympathetic via CrN III
What is the action of the dilator pupillae?
Dilates the pupil
What is the innervation of the dilator pupillae?
Sympathetic innervation
What is the action of the medial rectus?
Adduction
What is the action of the lateral rectus?
Abduction
What is the action of the superior rectus?
Elevation, adduction and intorsion