Structure of the Human Eye

In today’s lesson we experimented (safely!) on our own eyes! We did activities to help us understand the jobs of some different parts of the eye: the iris regulates the amount of light that enters the eye, the lens focuses images, and the rod cells and cone cells in our retinas detect images. We learned that rod cells can register very small signals, and are important for our peripheral vision and our night vision, and cone cells allow us to see color and perceive fine details. We also learned about the arrangement of the rod cells and cone cells in the retina, and how our optic nerve (that has the very important job of carrying visual signals to our brains) gives us one “blind spot” in each eye. Even though we don’t notice this blind spot normally, we could find it in class! Ask your student how to find yours!

Estructura del Ojo humano

En la clase de hoy experimentamos (de manera segura), ¡con nuestros ojos! Realizamos una serie de actividades que nos permitieron entender el trabajo que realiza cada una de las diferentes partes de estos. El iris regula la cantidad de luz que entra a nuestro ojo, el lente enfoca las imágenes, las células de la retina, llamadas conos y bastones, son las que captan la luz. Aprendimos que los “bastones” pueden detectar niveles de luz muy leves y que son importantes para nuestra visión periférica y nocturna. En cambio los conos, nos permiten ver en color y percibir detalles. También aprendimos cómo se distribuyen los conos y los bastones en la retina, y cómo es que el nervio óptico (el cual transporta las señales visuales a nuestro cerebro) es el responsable del “punto ciego” en cada ojo. A pesar de que no nos damos cuenta de este “punto ciego”, lo pudimos experimentar en clases. Pregúntele a su hijo o hija cómo puede encontrar su punto ciego.


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Phillip has a BS and MS in Biology from Western Washington University, and is currently earning a PhD in Environmental Studies at Antioch University New England. His research interests are in tropical rainforest ecology and animal-plant interactions. He will be doing his doctoral dissertation research on tropical seed dispersal ecology in the montane rainforests of Rwanda. Phillip has taught though various adjunct positions at several colleges in New England, teaching biology, ecology, earth science, environmental science, and general science at Babson College, North Shore Community College, Wheelock College, Merrimack College, and Mount Ida College.

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