neuro / eyes week 9 Flashcards
(23 cards)
what is the nervous system?
the nervous system allows communication between the brain and the rest of the body
what specialized cells make up the nervous system?
neurons
what is the function of axons?
Axons are pathways that carry action potentials from the body of one neuron to the body of another neuron
what happens when an electrical signal reaches a synapse?
the electrical signal is converted to a chemical signal, which can then cross the synapse
What body parts make up the central nervous system?
the brain and the spinal cord
neurons are?
special cells that translate information to the brain and within the brain along pathways called nerves
The best way for most people to visualize the nervous system is to think of a ????
highway that runs through all the other organ systems
Neurons are ___________ that vary in shape,
depending on their role in the body.
living cells
A ________ triggers your sense of touch sight,
stimulus
The iris is the
Colorful, flexible part of the eye that
controls the pupil with smooth muscles
the cornea is the ?
outer protective layer
the lens is….
Flexible and soft, focuses images
with the help of smooth muscles
Images are
projected here onto
numerous visual
cells and neurons
what is the RETINA
WHAT determines
HOW and WHERE an image is focused?
The shape of the LENS
The small area on the back of your retina
where the images are projected when you
look DIRECTLY at something is called the ???
Fovea
BLACK-AND-WHITE vs. COLOR is
detected by light-sensitive visual cells
embedded in your retina.
These are known as what?
RODS
Black & white
(night vision)
CONES
Color
vision
what are more densely
packed in the FOVEA near the
center of your retina?
Images are
projected there when you look
directly at something.
CONES
CONES and
RODS are
embedded in
the RETINA.
Neurons link
them to the
optic nerve.
CONES (for COLOR vision) are most common
in the CENTER of your retina (FOVEA)
(in back, where most images are projected).
What do rods do?
RODS (for BLACK & WHITE vision) are more
common around the EDGES
Less detail, but you can still things in the “corner of
your eye…”
CONES are of 3 types:
some respond to RED
light, some to BLUE,
some to GREEN.
Your BRAIN reads the
signals and INVENTS
the other colors
WHAT IS THE TAPETUM LUCIDUM??
A shiny layer in the retina that lies
BEHIND the rods and cones.
It helps AMPLIFY dim images in darkness.
If any light rays MISS your rods or cones, the tapetum
lucidum can mirror them back outwards so they pass
through the rod-cone layer again for a second try at making an image.
do humans have a tapetum lucidum?
NO!
What condition can result from different
mixes of rods and cones in the retina, or damage
to an area of the brain where colors are perceived.
It occurs in MEN more often than in WOMEN.
Color blindness
Most common is
red-green deficiency.
It can involve trouble with
telling red from orange or
green, or distinguishing
colors on the spectrum
from red to green.
Your EYES see things ___________
so your BRAIN has to FLIP the images.
UPSIDE DOWN…
