Rod+Cells+-+AMM

=Introduction= toc The human eye is depends on different types of cells. Picture an image of you sitting outside feeling your warm hand against the bright green grass and you are looking up to a big ball of light in the sky. This would not happen if you didn't have rods and the world would be heartless. =What is a Rod Cell?= Rod cells are a specialized neuron that converts light into vision. Rods are sensitive in the dark and they could only see black and white.The rod cell is located in the back of the eye which is called the retina. When the light strikes the cones and rods a nerve impulse travels to the cerebrum(largest part of the brain that interprets the senses) through the optic nerves. (it is a nerve which is connected to the brain to the eye) One optic nerve comes from the left eye and the other one comes from the right eye.Two things happen here, the brain turns every reversed image right side up and combines the images to make one image in all.

=What is Rhodopsin?=

Rod cells are responsible for detecting light/dark. They contain a pigment called rhodopsin. When light shines into the pigment it breaks down into two proteins: **Retina**-The layer of a receptor cells at the back of the eye in which a image is in focused and **opsin**- a protein that forms part of the visual pigment rhodopsin and is released by the action of light. Rhodopsin- a purplish-red light sensitive pigment present in the retinas of humans and many other animal groups.



=How does night blindness affect rod cells?=

Night blindness affects the rod cells because it  is a condition making it difficult or impossible to see in relatively low light. It is a symptom of several eye diseases. Night blindness may exist from birth, or be caused by injury or malnutrition(lack of proper nutrition, caused by not having enough to eat) It can be described as insufficient adaptation to darkness. Retinitis pigmentosa is a disorder in which the rod cell in the retina gradually lose their ability to respond to the dim light. Patients suffering from this genetic condition have progressive nyctalopia{ night blindness} and eventually their daytime vision may also be affected to other parts of their bodies or brain.



= = on the left is with your rod cells but on the right is when you don't have any rod cells.

= = = = =Differences Between Rods and Cones=

The rod cell is responsible for detecting the dim lights only with black and white.The cone is responsible for detecting the bright lights with colors. Also in retina, there are more rod cells than the cone cells. Lastly, defect in rods causes night blindness and defect in cones causes color blindness. There are 7 million rods and 2 million cones in the retina.

=Why do eyes water?=

Eyes water because s ome of the tears drain out of your eyes through tear ducts, or **lacrimal** ducts. These ducts are tiny tubes that run between your eyes and your nose. Each tear duct is like a tiny bathtub drain. When the tears fill up your eyes, they drain out through the tear ducts. You have two tear ducts — one near the inside corner of each eye. You can see these holes if you gently pull down your lower eyelid a bit. If tears are flowing quickly, like when you’re crying pretty hard, the ducts can't drain then all out that fast. Also the tear ducts keep your eyes moist and wash out dust and other foreign stuff that gets in there. Lacrimal ducts- a short tube in the inner corner of the eyelid through which tears drain into the nose.

Where your tear ducts are.. where your tear duct and other parts of your eye are located = = = = = = =Conclusion=

All your vision depends on your retina because with out your retina the world would be colorless and you would be able to see only black and white and some shades of gray. When you look up at the sky you could only see a big ball in the sky if you did not have your retina or rod cell.

=Glossary=

**Lacrimal** ducts- a short tube in the inner corner of the eyelid through which tears drain into the nose

**Retinitis pigmentosa** is a disorder in which the rod cell in the retina gradually lose their ability to respond to the dim light.

**Malnutrition**(lack of proper nutrition, caused by not having enough to eat)

**Nyctalopia**{ night blindness}

**Opsin**- a protein that forms part of the visual pigment rhodopsin and is released by the action of light.


 * Retina ** -The layer of a receptor cells at the back of the eye in which a image is in focused

**Rhodopsin**- a purplish-red light sensitive pigment present in the retinas of humans and many other animal groups.

**Cerebrum**(largest part of the brain that interprets the senses)

**Optic Nerves**. (it is a nerve which is connected to the brain to the eye

**Neuron**- a specialized cell transmitting nerve impulses: a nerve cell

= = =Reference=

“The Eye.” Science Aid. scienceaid.co.uk, n.d. Web. 19 Dec. 2014. . Padilla, Michael J., et al. Rod Cells--Prentice Hall Science Explorer. Boston: Pearson, 2009. Print. “SlideShare.” SlideShare. Linked In Corporation, n.d. Web. 23 Jan. 2015. . What Is Night Blindness?YouTube. YouTube, n.d. Web. 23 Jan. 2015. .

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