The Complex Process of Hearing by Eric Forbes

     To grasp how hearing works we must first start by understanding the make up of the ear.  The ear is made up of three main parts: 1) the outer ear, the ear canal; 2) second, the middle ear, the ear drum and the three small bones that make up the ossicular chain (the malleus, incus, and stapes); and 3) finally the inner ear, the cochlea and the auditory nerve (the cochlea is snail shell looking in shape, a coil like organ). These three parts make up one of the most important and delicate senses that we have (Hearing Link, n.d.). 

     Hearing is a complex process. We pick it up as a chain of vibrations in our ear, and this tiny action moves the three tiny bones within our ear. As the sounds travel back into the inner part of our ear, the vibrations pass through the cochlea. Located within the cochlea, there are tiny hair cells surrounded by fluid. As the vibrations move, the fluid moves and creates a response that will trigger your auditory nerve. Specific parts of the cochlea interpret different types of frequencies. The narrow end of the organ responds to low frequencies and the wider portion interprets higher frequencies. The nerve than transmits that signal to the brain, which in turn lets us hear whatever sound was being made (Listening and Spoken Language Knowledge Center, n.d.).

     Hearing is a huge part of our daily lives but unfortunately hearing can be damaged. According to the Mayo Clinic Staff (2015), there are three major ways that hearing can be damaged or lost. They are damage to the ear (old age, loud noise exposure, sudden changes in pressure, poking eardrum, etc.), a gradual buildup of earwax (buildup can cause sound waves to be muffled), and finally ear infections and abnormal bone growths or tumors.

References

Listening and Spoken Language Knowledge Center (n.d.) Alexander Graham Bell Association for the Deaf and Hard of Hearing. How Hearing Works. Retrieved March 12, 2017. http://www.agbell.org/learn/hearing-loss-explained/how-hearing-works.aspx

Hearing Link (n.d.). How the Ear Works. Retrieved March 12, 2017. https://www.hearinglink.org/your-hearing/how-the-ear-works/

Mayo Clinic Staff (2015). Diseases and Conditions Hearing Loss. Retrieved March 12, 2017.  http://www.mayoclinic.org/diseases-conditions/hearing-loss/basics/causes/con-20027684

Our Vision Process by Brenden Hall

    

             Human vision can be very complex and hard to understand. As humans we need the ability to see, to cope with our surroundings, but do we know how vision genuinely works? There are various steps required for the eye to form the images people see.

            First, the eye must gather light. Light rays are reflected off an object and enter the eyes through the cornea, which allows people to see that object. The cornea bends the rays that pass through the round hole of the pupil. The iris opens and closes, making the pupil bigger or smaller (American Optometric Association, n.d.).

When the pupil changes in size it means that it is regulating the amount of light being passed through the pupil. So when light passes through the pupil it first hits the lens. The lens is similar to a magnifying glass that reflects the light toward the back of our eye. The lens is constantly changing shape depending on whether we are looking at objects close to us or far away (Vision, n.d.).

Once the lens changes shape so it can bend the rays and focus the shape on the retina. The retina is the part of the eye that sits in the back, it is a thin layer of tissue that consists millions of tiny light-sensing nerve cells. These nerve cells are called rods and cones because of their noticeable shape (American Optometric Association, n.d.). Rods and cones are the first layer of cells to be activated by light. Rods see only black and white and are spread throughout the outside of the retina. Whereas cones see color and are located in the center of the retina known as the fovea. Since cones are located in the fovea humans see color objects better if they are directly in front of us. As for cones, they are located on the periphery of the retina we see black and white better in our peripheral vision (Vision, n.d.). These two distinguishable cells in the retina convert the light into electrical impulses, the optic nerve sends these impulses to the brain, which produces an image that allows humans the capability to see.

 

References

American Optometric Association (n.d.). How your eyes work. Retrieved April 18, 2017, from http://www.aoa.org/patients-and-public/resources-for-teachers/how-your-eyes-work?sso=y

Vision (n.d.). Retrieved April 18, 2017, from http://www.appsychology.com/Book/Biological/vision.htm