Showing posts with label vision. Show all posts
Showing posts with label vision. Show all posts

The 5 Senses plus 3 more

Thursday, February 27, 2020


Beyond the 5 Senses

The human body is an amazing machine that is constantly monitoring the environment. Your body uses the 5 main senses, vision, hearing, smell, taste, touch along with other senses like
proprioception, thermoception, and equilibrioception to keep you alive and active in the world around you.

5 Senses


Your senses are a combination of receptors gathering data and then sending this information to your brain that processes the data.

In order to read this article, light must pass through the cornea, and pupil to the retina. The retina contains receptors called rods and cones that detect black and white along with red, green, and blue. This information is sent down the optic nerve to your brain that converts this information to a picture.

Your ears allow you to hear. The outside portion of your ear is designed to capture sound waves. The sound is funneled down the ear canal to the eardrum. The eardrum vibrates like a drum and sends these vibrations to 3 small bones. The hammer, anvil, and stirrup. also called the malleus, incus, and stapes. The stirrup sends vibrations to the cochlear which in turn sends impulses to your brain.

Your nose is designed to capture smells. When you breathe molecules from the air enter your nostrils and make their way to the back of your nose to a patch of skin called the olfactory bulb. It has a layer of receptors called olfactory nerves that sense smells and send signals through the olfactory tract to your brain.

Your tongue allows you to taste and is covered with bumps called papillae that contain taste buds. These receptors send taste information along cranial nerves to the brain.

Your skin helps you sense the environment. The skin contains several types of receptors. Mechanoreceptors detect pressure, vibrations, and texture. Thermoreceptors detect changes in temperature, and pain receptors detect pain. These receptors then send messages to your brain.

Proprioception helps your body know where it is in space.
For example, when you are hitting a pinata, proprioception gives your body feedback so that you know the location of your arm and hand.

Thermoception is your sense of temperature and allows us to sense if we are hot or cold. This allows us to sense if the environment is too hot or cold. When the temperature gets hot, say above 104 degrees Fahrenheit 40 degrees celsius a receptor is triggered and others are triggered when it is cold. Once triggered the receptors send a signal to your brain which alerts you of the temperature and you can then decide what to do.

Close your eyes and try to balance on one foot. This activity triggers your sense of balance called, equilibrioception which is our sense of balance. Your inner ear has three fluid-filled canals and tiny hairs that sense the location of your head and sends this information to your brain. Your brains then send this information to your eyes, joints, and muscles.

How does the human eye work?

Wednesday, February 12, 2020



How do your eyes convert light into an image that you can see?


Your eyes allow you to see the world around you, in fact, your eyes allow you to watch this video above, but how do your eyes transfer the light energy into impulses that your brain can interpret?

When rays of light bounce off an object like a dog, they first strike your eyes and pass through a structure known as the cornea.
The cornea is a clear membrane, like a window, and covers the front of the eye.
When light passes through the cornea it then passes through a fluid-filled chamber and reaches the pupil. The pupil is an opening through which light enters the eye.
In bright light the pupil is small and in dark light, the pupil opens and is larger.
This is a result of the iris. The iris is a ring of muscle that surrounds the pupil and regulates the amount of light entering the eye.
The iris also gives the eye its color based on the amount of pigment it contains.
When light passes through the pupil it will strike the lens, which is convex in shape.
A convex lens is thicker in the middle compared to the edges.

convex concave lens



Because of the way the lens of the eyes bends the light the image it produces is upside down and reversed. Muscles that are attached to the lens adjusts its shape which allows the light to be clear and in focus.
After passing through the lens the light passes through a jelly-like fluid and reaches the back of the eye onto a surface called the retina. The retina covers the back of your eye and is filled with tiny receptors called rods and cones.

There are over a hundred and thirty million receptor cells. There are two types of receptors, rods, and cones. 
Rod's work best in dim light and allow you to see black and white.
Cones on the other hand cones work better in bright light and enable you to see colors. 
There are three types of cones, red, green, and blue which allows you to see colors around you.

rods and cones of eyes



After the light strikes the rods and cones nerve impulses travel down the optic nerve to the occipital lobe of your brain. At the occipital lobe, the reversed image is turned right-side-up and also combines the images from each eye to make one image.

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