Special sense- 2 Flashcards
spherical, fluid-filled structure enclosed by three layers
eye
Layers of the eye
From outermost to innermost, these are:
The sclera/cornea
The choroid/ciliary body/iris
The retina
What happens to the pupil in bright light
- Parasympathetic stimulation
- Circular muscles cause pupillary constriction
What happens to the pupil in dim light
- Sympathetic stimulation
- Radial muscles cause pupillary dilation
light rays focus on
retina
Rods and Cones
Photoreceptors
True of False
The retina contains 20 times more rods than cones
True
High Sensitivity
Rods
Lower Sensitivity
Cones
Cone Vision Has ______ Acuity; Rod Vision Has ______ Acuity
High
Low
Provide Colour Vision
Cones
Provide Vision in Shades of Gray
Rods
There are ____ different photopigments, one in the _______ and ___________
—red, green, and blue cones.
Four
rods
one in each of three types of cones
Anterior cavity
clear watery fluid-filled that is continually formed and carries nutrients to the cornea and lens
Aqueous humor
Middle layer of nerve cells in the retina, important in retinal processing of light stimuli
Bipolar cells
Route of passage of the optic nerve and blood vessels
Blind spot
Middle layer of the eye
Pigmented to prevent scattering of light rays in the eye; contains blood vessels that nourish the retina
Choroid
Specialized anterior derivative of the choroid layer, forms a ring around the outer edge of the lens, produces aqueous humor and contains the ciliary muscle
Ciliary body
Circular muscular component of the ciliary body; attached to the lens via suspensory ligaments
- Important in accommodation
Ciliary muscle
Anterior, clear, outermost layer of the eye
Contributes most extensively to eyes refractive ability
Cornea
exact center of the retina, region with the greatest aquity
Fovea
Inner layer of nerve cells in the retina, important in retinal processing of light stimulus; form the optic nerve
Ganglion cells
Visible pigmented ring of muscle within the aqueous humor; varies size of the pupil by variable contraction, responsible for eye colour
Iris
Between the aqueous humor and vitreous humour; attaches to the ciliary muscle by suspensory ligaments
Provides variable refractive ability during accommodation
Lens
Area immediately surrounding the fovea
Macula lutea
First part of the visual pathway to the brain, leaves each eye at the optic disk (blind spot)
Optic nerve
Permits variable amount of light to enter the eye, anterior round opening in the middle of the iris
Pupil
Innermost layer of the eye, contains the photoreceptors ( rods and cones)
Retina
Tough outer layer of the eye, protective connective tissue coat; forms the visible white part of the eye
Sclera
Important in accommodation, suspended between ciliary muscle and lens
Suspensory ligaments
between the lens and retina
Semiliquid, jellylike substance that helps maintain spherical shape of the eye
Vitreous humor
