WEBVTT 1 00:00:00.522 --> 00:00:06.190 Animals, including humans, need to constantly interact with their environment. 2 00:00:06.191 --> 00:00:14.392 These interactions enable them to move, to eat, to reproduce and to escape from enemies. 3 00:00:14.393 --> 00:00:19.460 They are made possible by the senses that animals possess. We count 5. 4 00:00:19.461 --> 00:00:20.792 Vision 5 00:00:20.793 --> 00:00:22.026 Vision, hearing 6 00:00:22.027 --> 00:00:23.300 Vision, hearing, smell 7 00:00:23.301 --> 00:00:24.423 Vision, hearing, smell, taste 8 00:00:24.424 --> 00:00:27.035 Vision, hearing, smell, taste, touch. 9 00:00:27.036 --> 00:00:29.674 Depending on the species and its way of life 10 00:00:29.675 --> 00:00:33.070 this or that sense may be more or less developed. 11 00:00:33.071 --> 00:00:37.380 Thus the mole, which lives underground, does not need a good sense of vision 12 00:00:37.381 --> 00:00:41.951 but its senses of smell, hearing and touch are highly developed. 13 00:00:43.337 --> 00:00:48.012 For its part, the eagle needs to detect the slightest movement on the ground 14 00:00:48.013 --> 00:00:52.026 and its vision is particularly sharp. 15 00:00:53.498 --> 00:00:56.972 Each sense is associated with an organ. 16 00:00:58.749 --> 00:01:02.092 Thus, among humans, the eye is the organ of vision 17 00:01:02.093 --> 00:01:04.047 the ear that of hearing 18 00:01:04.048 --> 00:01:06.189 the nose that of smell 19 00:01:06.190 --> 00:01:08.465 The tongue is the organ of taste 20 00:01:08.466 --> 00:01:12.018 and the skin that of touch. 21 00:01:12.019 --> 00:01:15.545 The sense organs contain a large number of receptors. 22 00:01:15.546 --> 00:01:18.862 These detect what are called stimuli. 23 00:01:20.875 --> 00:01:26.026 It is the sensory nerves that transport the nerve message to a specific part of the brain 24 00:01:26.027 --> 00:01:29.595 which interprets it in order to construct our perception. 25 00:01:30.932 --> 00:01:36.965 Let’s take the example of the eye. The retina is located at the back of the eye. 26 00:01:36.966 --> 00:01:43.679 It is covered with millions of photosensitive cells that transform light into nerve messages. 27 00:01:43.680 --> 00:01:48.119 These messages are then carried to the brain by the optic nerve. 28 00:01:48.120 --> 00:01:53.474 The area of the brain that is dedicated to vision is called the visual cortex. 29 00:01:53.475 --> 00:01:59.874 It is at the back of the brain, and it is in this region that nerve messages are interpreted. 30 00:01:59.875 --> 00:02:02.875 Our memory then plays a major role in giving significance to the perceived image.