In this lesson, you will learn about the concept of sensation and the five distinct subsystems that comprise sensation.
Following the lesson, you will have the opportunity to test your knowledge with a short quiz.
The Invisible Work Force
Imagine you’re sitting at a park having a picnic on a sunny spring evening. You just finished taking a big psychology exam, and you are relaxing on the green grass without a care in the world.
The birds are singing, you feel the warmth of the setting sun on your skin, the aroma of dogwood trees in bloom is in the air, the taste of your favorite sandwich still on your tongue. Sounds pretty relaxing, right?Even though you might feel relaxed, your nervous system is hard at work, like an invisible workforce. In order to experience that relaxing day, you must first have the ability to internalize all those pleasant things that are going on around you at the park.
In other words, if your brain is not aware of the environment, then you can’t truly experience it.Sensation is the first step in the process of allowing your brain to experience the features and characteristics of the environment around you.
Definition of Sensation
Sensation is the process that allows our brains to take in information via our five senses, which can then be experienced and interpreted by the brain. Sensation occurs thanks to our five sensory systems: vision, hearing, taste, smell and touch. Each of these systems maintains unique neural pathways with the brain which allows them to transfer information from the environment to the brain very rapidly.
Without sensation, we would not be able to enjoy the sunny spring day at the park.Each sensory system contains unique sensory receptors, which are designed to detect specific environmental stimuli. Once detected, sensory receptors convert environmental stimulus energy into electrochemical neural impulses. The brain then interprets those neural messages, which allow the brain to experience and make decisions about the environment.
Let’s take a little bit closer look at the process of sensation by examining each of the five sensory systems involved.
The visual system transfers light energy, which occur naturally in the form of wavelengths, into neural messages via the eyes. This process is known as visuoreception.
The subtle qualities of the wavelengths, such as their height, width, and frequency, are detected by structures within our eyes. These subtle differences result in the experience of seeing different colors, shapes, and textures. Thinking back to the park, the ever-changing characteristics of those wavelengths create an image that your brain interprets as the setting sun.
The auditory system operates similarly to the visual system in that sounds are transmitted through the environment in the form of wavelengths.
Much like wavelengths of light, the qualities of the auditory wavelength will determine the qualities of the sound that is heard in the brain. Sound waves enter the ear, and once the wavelengths reach the middle ear, auditory structures convert these wavelengths into vibrations. The vibrations are transferred into neural impulses, which are sent directly to the brain. This process of detecting vibrations is referred to as mechanoreception. The singing birds in the park emit wavelengths of very specific size and frequency which are picked up by your ears, and you end up experiencing the bird’s song.
Our sense of touch is also facilitated by mechanoreception. Specially designed receptor cells under the skin are designed to sense the slightest amount of pressure.
We also have thermoreceptor cells under our skin which are able to detect temperature related to touch and temperature and convert that information into information that the brain can use. Remember that warm spring day? Thanks to both of these types of receptors, we can feel the soft grass and the warmth of the sun simultaneously.
Our sense of taste is responsible for transferring information from our mouths to our brain via chemoreception.
This process is facilitated by specialized chemical receptors on our tongues called taste buds. Chemicals in the food we eat contain a variety of characteristics and qualities. In much the same manner as our other sensory systems, our taste buds transfer information about the detected chemicals to our brain. Even though the food comes into contact with our taste buds, it’s our brain that determines how something tastes.
Depending on what you packed for your picnic, your tongue is capable of detecting one or more of the following tastes: salty, sweet, bitter, sour and umami (which is savory).
The final sense, smell, also operates via chemoreception. Rather than smelling with your tongue, you smell via specialized receptor cells that line the inside of your nasal cavity which are responsible for transferring the chemical information to your brain.
While your sense of taste is able to detect four distinct tastes, your sense of smell is not limited to specific smell-types, allowing you to experience a variety of smells. At the park, the dogwood blooms emit airborne chemical substances which eventually enter your nose and end up being interpreted by your brain as smell.
Sensation is the process of gathering environmental information and transmitting that information to the brain. Five sensory systems exist which allow us to collect environmental information. The visual, hearing, taste, smell and touch sensory systems all possess specialized receptor cells which enable them to detect unique environmental stimuli.
Sensation is the first part of experiencing our environments. It’s in the brain where we truly see, hear, smell, taste and touch.
Sensation – Important Terminology
|Sensation||The way in which the mind gathers environmental information and sends it to the brain for processing|
|Visual System||Transfers light energy through the eyes to the brain for analysis|
|Auditory System||Sound waves are transmitted through the ears and are processed by the brain|
|Touch||Receptors in the skin send signals that detect temperature, texture, or other physical sensations|
|Taste||Buds on the tongue send signals to the brain by way of chemoreception|
|Smell||Specialized cells within the nose are responsible for transferring chemical information to your brain|
By working through this lesson, you’ll confirm your readiness to:
- Describe the function of sensation
- Identify the five types of sensation