List accessory organs of the eye.
Eyelids, eyebrows, conjunctiva, lacrimal apparatus,extrinsic muscles. text for more
Where do tears come from and how are they spread across the eye and removed from the orbital region?
Tears come from the lacrimal gland, tears are spread by the eyelids, removed from the orbital region by lacrimal sac and conveyed into nasolacrimal duct and into the nasal cavity.
What enables the extrinsic muscles of the eye to precisely align the eyes?
muscles have fewest fibers per motor unit
Why is the cornea transparent?
it is avascular and contains few cells
Describe how accommodation is accomplished
if tension on the suspensory ligaments relaxes, the elastic capsule rebounds and the lens surface becomes convex. This occurs when the eye focuses on close objects.
Describe the structure of the retina
contains photoreceptors, text for more
Where is vision most acute?
Where are the rods most concentrated?
peripheral regions of the retina
What is the vitreous body and what does it do?
vitreous humor combined with collagen fibers, supports the internal structures of the inner eye and helps maintain the shape of the eyeball.
what does it mean to be trichromatic?
three sets of cones
Discuss the pathway of light into the eye.
light waves are refracted by the cornea and lens to focus an image on the retina.
How is an image projected onto the retina? What does this require in order for us to see the image correctly?
it is projected by the cornea and the lens. It required the visual cortex to interpret correctly.
What forms the optic nerve?
nerve fibers from the retina
What is the optic chiasma?
where the optic nerves enter the brain and cross
Describe the pattern of nerves through the optic chiasma, the optic tracts, and into the visual cortex.
What are the 2 senses associated with the ear?
hearing and equilibrium
Describe the external ear. What does it do?
collects sound waves, outer portion is the auricle, consists of elastic cartilage that continues to grow throughout our lifetime. external auditory meatus passes into the temporal bone, hairs near the opening that guard the tube. Lined with modified sweat glands called ceruminous glands that secrete cerumen or ear wax. Helps to prevent the tympanic membrane from drying out and losing flexibility. text for more
Describe the middle ear. What do these structures do?
text for more
What is the tympanic reflex? Why is it important?
protects the inner ear from the effects of loud sounds. Made of 2 small skeletal muscles.
Describe the inner ear.
text for more.
Distinguish between the osseus and membranous labyrinths. Which has perilymph? Endolymph?
osseus labryinths is a bony canal. Membranous labryinths is a tube that lies within the osseous membrane. Perilymph is a fluid that is secreted by the bony canal and separates the 2 labyrinths. endolymph is in the membranous labyrinth.
Describe the cochlea and its function.
part of the inner ear and houses the spiral organ. text
Describe a hairing receptor.
Describe the organs of static and dynamic equilibrium.