Sense Organs
The nervous system is responsible for sensing the external and internal environments of an organism, and for inducing muscle movement. Human sensation is achieved through the stimulation of specialized neurons, organized into five different modalities—touch, balance, taste, smell, hearing, and vision. The touch modality includes pressure, vibration, temperature, pain, and itch. Some animals are also able to sense magnetism and electric fields. Modality, timing, intensity, and location of the stimulus are the four features that allow the brain to identify a unique sensation.
Sensation Receptors
The neurons specialized to detect sensation are also called receptors because they are designed to receive information from the environment. Each receptor responds only to a stimulus that falls within a defined region, called its receptive field. The size of the stimulus can affect the number of receptors that respond, and the strength of the stimulus can affect how much they respond. For example, when a cat sits on your lap, a large population of receptors responds to the cat's weight, warmth, claws, and the vibrations from its purring.
Transduction refers to the transfer of environmental energy into a biological signal signifying that energy. Sensory receptors either transduce their respective stimuli directly, in the form of an action potential —the electrochemical communication between neurons—or they chemically communicate the transduction to a neuron.
This page contains 201 words.
Sense Organs article
Read the rest of this article.
This article contains 1,729 words
(approx. 6 pages at 300 words per page).
Order our Sensory system Article
