Animal Behavior: Instinct Sensory Receptors and Perception Sensory receptors are special nerve cells specialized for transmitting information according to the different types of external stimuli they respond to. For example Mechanoreceptors fire when the cell membrane is deformed, and so transmit tactile information. Photoreceptors contain pigments which fire when chemically altered by light. Chemoreception Chemoreception is the identification of chemical substances and their concentrations. This sensory mechanism is found in even the most primitive life forms. The mechanism is not completely understood, but it is known that receptor sites on cell membranes recognize specific molecules. Whether this occurs by chemical reaction, molecular shape, or some combination of the two is not known. There are two types of chemoreceptors. Exteroreceptors detect chemicals from the external environment while interoreceptors detect chemicals within the body. The familiar senses of taste and smell are both forms of chemoreception. Many animals release pheromones to cause a specific response by the receiving organism.
This is the end of the preview. Sign up
access the rest of the document.