Embedded Files
Chapter 16
Sense Organs
Topic of lesson
Vision: It is the perception of objects in the environment by means of the light they emit or reflect. Light is visible electromagnetic radiation. Human vision is limited to wavelengths ranging from about 400 to 700 nm.
Learning objectives
At the end of the lesson, the student should be able to
- describe the anatomy of the eye and its accessory structures;
- discuss the structure of the retina and its receptor cells;
- explain how the optical system of the eye creates an image on the retina;
- discuss how the retina converts this image to nerve signals.
Pre-assignment
Watch the video: Vision: Crash Course A&P #18
Activity
- Teacher guides the students to review about the visible spectrum. Human vision is limited to wavelengths ranging from about 400 to 700 nm.
- Students brainstorm what they know about vision and eyes. Teacher writes down the information on the whiteboard.
- Two students face each other, observe the area around the eye and try to identify the external parts of eye by using the figure from the textbook.
- Show a diagram of the accessory structures of the orbit and students discuss about the usage and importance of them.
- Students watch the video of "Structure and Working of Human Eye" on their iPads and finish the worksheet "Structure of The Eye".
- Teacher explains in details about how the retina converts image to nerve signals and introduces three principal cell layers including photoreceptor cells(rod and cone), bipolar cells, and ganglion cells.
- Then students will check the retina cross-section slide under the microscope and finish labeling the retina layers on the worksheet.
- *Students who finish both assignments early will be given a clear glass ball to create an upside down image, take a picture of it and upload it to their digital portfolios. Explain in their own words how the optical system creates an upside down image on the retina.
Resources
- Science notebook for taking notes
- Structure of The Eye worksheet, Retina Layers labeling worksheet
- Retina cross-section slides, Microscopes
- iPads for watching the video and taking pictures
Alignment with NGSS
Disciplinary Core Ideas
- LS1.A: Structure and Function
- The neural components of the retina consist of three principal cell layers. Progressing from the rear of the eye forward, these are composed of photoreceptor cells, bipolar cells, and ganglion cells. Systems of specialized cells within organisms help them perform the essential functions of life. (HS-LS1-1)
- LS1.D: Information Processing
- The conversion of light energy into action potentials occurs in the retina. Photoreceptor cells absorb light and generate a chemical or electrical signal. Each sense receptor responds to different inputs (electromagnetic, mechanical, chemical), transmitting them as signals that travel along nerve cells to the brain. The signals are then processed in the brain, resulting in immediate behaviors or memories. (MS-LS1-8)
Science and Engineering Practices
- Constructing Explanations and Designing Solutions
- Two students face each other, observe the area around the eye and try to identify the external parts of eye by using the figure from the textbook. Students watch the video of "Structure and Working of Human Eye" on their iPads and finish the worksheet "Structure of The Eye". Construct an explanation based on valid and reliable evidence obtained from a variety of sources (including students’ own investigations, models, theories, simulations, peer review) and the assumption that theories and laws that describe the natural world operate today as they did in the past and will continue to do so in the future. (HS-LS1-1)
- Developing and Using Models
- Students who finish both assignments early will be given a clear glass ball to create an upside down image, take a picture of it and upload it to their digital portfolios. Explain in their own words how the optical system creates an upside down image on the retina. Develop and use a model based on evidence to illustrate the relationships between systems or between components of a system. (HS-LS1-2)
Crosscutting Concepts
- Structure and Function
- Teacher introduces three principal cell layers including photoreceptor cells(rod and cone), bipolar cells, and ganglion cells, then students check the retina cross-section slide under the microscope and finish labeling the retina layers on the worksheet. Complex and microscopic structures and systems can be visualized, modeled, and used to describe how their function depends on the relationships among its parts, therefore complex natural structures/systems can be analyzed to determine how they function. (MS-LS1-2)
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