A sensory organ is an organ that contains sensory cells in a certain position and arrangement and can therefore absorb stimuli ( stimulus absorption ). Each sensory organ is designed for a species-specific spectrum of adequate stimuli due to its special physiological equipment .
These stimuli can be effects of different shape, type and amount of energy, through which the sensory cells in a sensory organ are changed in such a way that they form an electrical signal, a receptor potential ( stimulus conversion ). In this way, a sensory cell, also called a receptor or sensor, picks up a stimulus in the sensory organ and thus reproduces changes in its environment, both changes outside the body in its external environment and changes in the body.
Depending on their position within the sensory organ, its sensory cells convert an adequate stimulus into a signal that is picked up by nerve cells as an electrical impulse and passed on via nerve fibers ( excitation conduction ). In the nervous system, signals from sensory organs can be compared with one another, compared with one another and combined, filtered or contrasted. Only in relation to previous conditions do these data become specific information about processes inside an organism or in connection with the organism and its environment . In this way, the sensory organs contribute to perceptions that arise in the brain and evoke specific sensory impressions of certain sensory modalities .
Stimuli of the environment and the sense organs important for their transformation
The electromagnetic radiation that can be converted by the human eye is called “visible light ”. Thus the light represents the adequate stimulus for the eye . The eyes of some animals are also sensitive to the shorter-wave ultraviolet and / or the longer-wave infrared light.
- Visible light: wavelength 380 nm (violet) to 760 nm (red) → eye ( sense of sight )
- Ultraviolet light → eye (many insects, some reptiles, some birds, deep sea fish)
- Some freshwater fish can sense infrared radiation through their eyes.
- specific stimulus: light waves
- Receptor structure: retina with rods and cones (rods for light-dark vision and cones for color vision)
- Auditory sound: Sound frequencies of 16–20,000 Hz are adequate stimuli for the human hearing → ear ( sense of hearing ). Deaf people can also experience sound through their skull bones, skin, lips, hands, inside of arms, and other parts of the body.
- Ultrasound: wave length ~ 20 kHz (17.5 mm) - 200 kHz (1.7 mm) → ear of certain animals such as bats and dolphins
- Infrasound: 16–0 Hz → ear of certain animals such as elephants and owls and smooth transition to the sense of touch
- Vibrations → tactile receptors (vibration) in the skin ( sense of touch ) and whiskers and vibration receptors in insects and spiders
- Infrared radiation / heat: Wavelengths with 750 nm - 0.01 mm are adequate stimuli for the → heat or cold receptors in the skin ( temperature perception ), pit organs in snakes
Pressure and movement
- Pressure → tactile receptors in the skin (sense of touch)
- Water pressure and movement → lateral line organ in fish
- Foreign movements → peripheral vision of the eye in primates, changes in the properties of sound (relative volume, timbre)
- Proper movement and body position relative to the environment → balance organ in the inner ear (sense of balance)
- Position of the body parts → receptors in the muscles and joints ( Golgi tendon organ , muscle spindle , see also depth sensitivity ), chordotonal organ in insects
- Olfactory mucous membrane ( sense of smell )
- Taste buds on the tongue ( sense of taste ) e.g. B. arachnids
- Lorenzini ampoules in sharks and rays
- Perception of electric fields in some predatory fish ( electric fish ) such as electric eel and electric rays . The ability of electrical reception has also been proven for the Guyana dolphin .
- Perception of the earth's magnetic field in migratory birds , house pigeons and numerous other animal species based on a magnetic sense . Strong alternating magnetic fields can also be recognized by humans through vibration of the eyes.
- ↑ Hans-Werner Hunziker : Magic of hearing: Unconscious strategies of hearing perception . Transmedia Stäubli Verlag AG, Zurich 2011, ISBN 978-3-7266-0087-7 .
- ↑ http://www.buecher.de/shop/buecher/im-rhythmus-der-stille/neef-sarah/products_products/detail/prod_id/25661815/
- ↑ http://www.3sat.de/page/?source=/nano/cstuecke/104163/index.html
- ↑ Hans-Werner Hunziker: In the eye of the reader. Foveal and peripheral perception: from spelling to reading pleasure . Transmedia Stäubli Verlag AG, Zurich 2006, ISBN 978-3-7266-0068-6 .
- ^ Nicole U. Czech-Damal et al .: Electroreception in the Guiana dolphin (Sotalia guianensis). In: Proceedings of the Royal Society B , online advance publication, July 2011, doi: 10.1098 / rspb.2011.1127
- ↑ Some observations about a modulation of the perception of light by strong alternating magnetic fields . In: Die Naturwissenschaften (1954), p. 508. doi : 10.1007 / BF00631845