Sunday, December 30, 2012
Sense of Sight
Hey
there! Have you ever wondered why we could see with our eyes? Let’s learn a
little something about our sense of sight today!
Our eye
is where the photoreceptors are.
They are the receptors which can detect light. When light is produced, the information
collected by the photoreceptor will be converted into images and sent to the
brain for the next process.
There are
3 layers to the wall of our eyes. The innermost layer is called Retina. There
are 2 very important types of cell at the Retina, known as Rod cell and Cone cell. These
two types of cell will be the agent that sends nerve impulses to our brains of
the information collected.
The Rod cells are like
a person who’s in charge of writing down information as records. However, these
cells only “write” in black and white, there for the information they produce
will not show other colours. These Rod cells are very sensitive to light and
shadow. If a strong light was introduced on them, they would temporarily
disintegrate, causing a blurry vision. Try and imagine this, when we enter a
dark room we could see nothing. But after a few moments, we could slowly see
the space and objects. This is because the Rod cells are taking time to adjust
themselves so that we could receive more light under a low light condition. But
the process consumes Vitamin A, which is why it is important for us to have a
balanced diet. This is why people who are lacking of Vitamin A could not see
properly at night, and this is called the night-blindness.
On the
other hand, the Cone cells are like artists who bring in the colours. Cone
cells help us to differentiate colours from what we see. People with
colour-blindness could not differentiate colours because of the lacking of Cone
cells.
Well,
that’s all for today. The sense of sight is one of the very important senses we
have. We must remember to protect our eyes
well.
Shared
by,
Words.
Translated
by,
Happy.
*Remark:
You can
find Vitamin A from food like seafood, dairy products, eggs, carrots, melons,
oranges, or yellow and green vegetables.
Labels: p. learning treasure box
English Materials
中文资料
