Module 1 Lesson 1 - 2
Completion requirements
Lesson 1 — Sensory Perception
Sensory Perception (pages 406-409)
Undoubtedly, you can name the five basic senses that allow you to gather information about your environment: sight, smell, touch, hearing, and taste.
To begin this lesson, read pages 406 to 409 of the textbook to explore the special type of cells, sensory receptors, that respond to stimulation from the environment. The senses are classified by the type of energy that stimulates the sensory receptors. Each sense has unique receptors for detecting changes. Types of sensory receptors include photoreceptors, mechanoreceptors, chemoreceptors, osmoreceptors, and thermoreceptors. These specialized nerve cells convert the energy stimulus into electrochemical energy called a nerve impulse. You will study the electrochemical transmission of nerve impulses in Lesson 6 of this module.
The changes, called sensations, are communicated to specific areas of your brain. Perception is the brain's interpretations of these sensations. Interestingly, the perceptions of your brain are different from everyone else's. Each brain is
unique!
Attempt the Try It activity below with another person to compare your perceptions! You will study the brain in future lessons.
Try It
Prepare three bowls of water – one with ice water, one with room temperature water, and one with water as hot as you would prepare for a hot bath. Put one hand in the ice water for several minutes, and then put it into the room temperature water.
How does the room temperature water feel in comparison to the ice water? The water should feel hot.
Put the other hand into the bowl with the hot water for several minutes. Now, put that hand into the room temperature water. The room temperature water should feel fairly cold.
Although both hands were placed in the room temperature water, the temperature felt different after the immersion of your hand in the ice water and the hot water. You are experiencing sensory adaptation.
Put the other hand into the bowl with the hot water for several minutes. Now, put that hand into the room temperature water. The room temperature water should feel fairly cold.
Although both hands were placed in the room temperature water, the temperature felt different after the immersion of your hand in the ice water and the hot water. You are experiencing sensory adaptation.
© Getty Images
Sensory Adaptation
After holding your hand in ice-cold water for several minutes, the pain of the cold is reduced. If the sensory receptors are stimulated repeatedly, sensory adaptation occurs because the brain filters out repetitive sensations. For example, factory workers no longer notice the hum of machinery after working for some time. If you worked in a feedlot where a large amount of animal waste is produced, do you think you would get used to the smell to the point where you would no longer notice the odour?