Some of Chapter 4 Flashcards
visual acuity
the ability to see in fine detail
Light through the eye
Light passes through a clear smooth outer tissue called the cornea –>then sends it through the pupil –> colored part is the iris –>inside the iris, muscles control the shape of the lens and focus the light into the retina
cornea
clear, smooth outer tissue which bends light wave and sends it through the pupil
pupil
a hole in the colored part of the eye
iris
the colored part of the eye which is a douhgnut-shaped muscle that controls the size of the pupil and thus determines the amount of light that can enter the eye
lens
- shape is controled by muscles behind the iris
- bends the light again and focuses it onto the retina
retina
light-sensitive tissue linging the back of the eyeball
accommodation
the process by which the eye maintains a clear image on the retina
if eyeball is too long/short
if too long - images are focused in front of the retina leading to nearsightedness (myopia)
if too short - images are focused behind the retina, leading to farsightedness (hyperopia)
two types of photoreceptor cells in the retina contain:
rods and cones
cones
photoreceptors that detect color, operate under normal daylight conditions, and allow us to focus on fine detail
rods
photorecpetors that become active under low-light conditions for night vision
fovea
an area of the retina where vision is the clearest and there are no rods at all
blind spot
a location in the visual field that produces no sensation on the retina because the corresponding area of the retina contains neither rods noe cones and therefore has no mechanism to sense light
rceptive field
the region of the sensory surface that, when stimulated, causes a change in the firing of that neuron
