the eye Flashcards
which bones forms the orbit?
the frontal bone forms the roof of the orbit and parts of the medial and lateral walls
the zygomatic bone forms part of the lateral wall
the maxillary bone forms a large part of the floor of the orbit
what protects the orbital contents?
the orbital septum (made from strong connective tissue)
what supports the corners of the eyelids?
the medial and lateral palpebral ligaments
what is the function of the tarsal plates?
each tarsal plate physically protects the eye but also contains glands that release oily and watery secretions to lubricate the surface of the eye
what restricts the movement of the extraoccualr muscles?
the check ligament
what is the function of the suspensory ligaments?
support the position of the eye w/in the orbit
what cells are found in the macula?
rods and cones (the retinal cells that respond to light)
where is the anterior chamber of the eye?
the space between the lens and the cornea
what fills the anterior chamber of the eye?
aqueous humour
how is aqueous humour made?
made by the cells of the ciliary body
how is aqueous humour recycled?
recycled back into the veins at the junction of the cornea and sclera
what fills the posterior chamber of the eye?
vitreous humour that functions to support the retina bye gently pressing it to the choroid below
how does the vitreous humour in the posterior chamber support the retina?
by pressing it into the choroid below
the choroid has blood vessels that supply the retina and so they need to be kept in close proximity to help prevent damage to these vessels
what is the function of the extra ocular muscles?
move the eyeball w/in the orbit
what is the function of the intraoccular muscles?
change the shape of the structures inside the eyeball
what controls an increase in the size of the pupil?
the sympathetic nervous system
what happens to the pupil in danger and low light intensities?
the size of the pupil increases to let as much light as possible into the retina
what are the circular fibres around the iris called?
the sphincter pupillae
what happens when the sphincter pupillae contract?
they narrow the pupil, restricting the amount of light entering the eye and acting to protect the retinal cells from high light intensities
what controls a decrease in the size of the pupil?
the parasympathetic nervous system via the occulomotor nerve
what muscle increase the diameter of the pupil?
dilator pupillae
what muscle decreases the size of the pupil?
sphincter pupillae