Lesson 3 - Vocabulary - SENSES
THE HUMAN SENSES
Read this brief article about the human senses:
Senses are the means by which many-celled animals, including human beings, tell what is happening in their environment, whether immediate or distant, thanks to the ability of the nerves and the brain to receive and react to stimuli such as light, sound, impact or texture. There is no firm agreement among neurologists as to exactly how many senses there are, because of differing definitions of what a sense is. In general, one can say that a "sense" is a faculty by which outside stimuli are perceived. Schoolchildren are routinely taught that there are five senses: sight, hearing, touch, smell and taste (a classification first devised by Aristotle), though it is generally agreed that there are at least nine different senses in humans, and a minimum of two more observed in other organisms.
A broadly acceptable definition of a sense would be "a system that consists of a sensory cell type (or group of cell types) that respond to a specific kind of physical energy, and that correspond to a defined region (or group of regions) within the brain where the signals are received and interpreted." Using this definition the following nine senses can be identified:
Sight or vision describes the ability to detect electromagnetic waves within the visible range (light) by the retina of the eye and the brain to interpret the image as "sight."
Hearing or audition is the sense of sound perception and results from tiny hair fibers in the inner ear detecting the motion of a membrane which vibrates in response to changes in the pressure exerted by atmospheric particles.
Taste or gustation is one of the two main "chemical" senses. It is well-known that there are at least four types of taste "bud" (receptor) which detect sweet, salt, sour, and bitter.
Smell or olfaction is the other "chemical" sense. There are hundreds of olfactory receptors in the nose, each binding to a particular molecular feature. The combination of the features of the odor molecule makes up what we perceive as the molecule's smell.
Touch or tactition is the sense of pressure perception, generally in the skin. There are a variety of pressure receptors that respond to variations in pressure.
Thermoception is the sense of heat and the absence of heat (cold), as perceived by the skin, including internal skin passages.
Nociception is the perception of pain by three types of pain receptors: cutaneous (skin), somatic (joints and bones) and visceral (body organs).
Equilibrioception is the perception of balance and is related to cavities containing fluid in the inner ear. There is some disagreement as to whether this also includes the sense of "direction" or orientation
Proprioception is the perception of body awareness and is a sense that people rely on enormously, yet are frequently not aware of. More easily demonstrated than explained, proprioception is the "unconscious" awareness of where the various regions of the body are located at any one time.
Study the way in which the five basic verbs referring to the physical senses are used. Then complete the rule about their use below:
Son: What is this stuff?. It looks strange and it smells funny.
Mum: Try it. I assure you it tastes good.
Son: But what is it?
Mum: It’s called “paella valenciana”. It’s a Spanish dish.
Son: A paella? Even the name sounds funny.
Mum: But it’s good. And anyway, it’s your dinner tonight.
Son: OK, I get the message. (He puts a little in his mouth). There, I’ve eaten some.
Son: It doesn’t taste too bad, but eating this white stuff feels funny.
Mum: This? Oh, it’s a piece of octopus.
Son: An octopus? Yuk!