Sensing organs

Mode of Action. DDT and its analogues specifically affect the peripheral sense organs of insects and produce violent trains of afferent impulses that result in hyperactivity, convulsions, and paralysis. Death results from metaboHc exhaustion and the production of an endogenous neurotoxin. The very high lipophilic nature of these compounds faciUtates absorption through the insect cuticle and penetration to the nerve tissue. The specific site of action is thought to be the sodium channels of the axon, through inhibition of Ca " ATPase. 

Water is truly a crucial determinant of the fitness of the environment. In a very real sense, organisms are aqueous systems in a watery world. 

Helmholtz did important research on another sense organ, the ear, and explained how it was able to detect differences m pitch. He showed how the quality of a sound depended on the number, nature and relative intensities of the harmonics present in the sound. 

Berghard A., Buck L. and Liman E. (1996). Evidence for distinct signaling mechanisms in two mammalian olfactory sense organs. Proc Natl Acad Sci 93, 2365-2369. 

Muscles (heart, etc.) Stomach/intestine Liver Kidney (bowel) Reproductive organs Glands Brain (Chapter 9) Sense organs Digestion, fluid circulation, motion, mechanical work Major zones of digestion Major zone of synthesis Major external rejection ion/water balance Reproduction Chemical controls Electrical control Environmental detectors... 

Babel, J., Bischoff, A. and Spoendlin, H. Ultrastructure of the peripheral nervous system and sense organs. In Atlas of Normal and Pathologic Anatomy. St Louis Mosby, 1970, pp. 1-171. 

AS-C achaete-scute gene complex for sense organs CLN neuronal ceroid lipofuscinoses... 

Vijverberg, H.P.M., G.S.F. Ruigt, and J.V.D. Bercken. 1982. Structure-related effects of pyrethroid insecticides on the lateral-line sense organ and on peripheral nerves of the clawed frog, Xenopus laevis. Pestic. Biochem. Physiol. 18 315-324. 

Figure 19.17 The biochemistiy and physiology responsible for penile erection. Sexual activity itself begins with a state of arousal that leads to erection. Arousal results in part from stimulation of the sense organs. The hypothalamus coordinates the sensations and activates the autonomic nervous system. Sensory nerves from the skin of the penis and other erogenous zones stimulate the parasympathetic system. This activates nitric oxide synthase and the resultant nitric oxide, via cyclic GMP, causes vasodilation of the arterioles. This increases blood flow through the corpora cavernosa which then expands producing an erection. Pheromones secreted by the female can stimulate the odour detecting system in the nasal cavity of the male (Chapter 12 and see above). Stress, however, activates the sympathetic system releases cyclic AMP which can result in vasoconstriction of the arterioles. Other factors that can interfere with an erection are physical fatigue and alcohol.

Neurotoxicity can be defined as any adverse effect on the structure or function of the nervous system related to exposure to a chemical substance (US-EPA 1998, OECD 2004c). According to the TGD (EC 2003), neurotoxicity can be defined as the induction by a chemical of adverse effects in the central or peripheral nervous system, or in sense organs and a substance is neurotoxic if it induces a reproducible lesion in the nervous system or a reproducible pattern of neural dysfunction. ... 

Morphological (structural) changes in the central or peripheral nervous system or in special sense organs... 

Hazard of rapid control of BP In patients with very severe BP elevation, too rapid control of BP can precipitate syncope, cerebrovascular accidents. Ml and ischemia of special sense organs with resulting decrease or loss of vision or hearing. Patients with compromised circulation or cryoglobulinemia also may suffer ischemic episodes of affected organs. Although such events have not been unequivocally associated with minoxidil use, experience is limited. 

Organoleptic - properties of protein products manifested through the sense organs including odor (nose), color (eye), flavor (taste organs), brittleness (ear), and so forth. 

Consider a message originating with a nerve receptor in the skin or in another sense organ. A nerve signal passes via a sensory neuron (afferent fiber)... 

Like our other models of psi processes, the model of telepathy has been chosen to fit in with commonsense assumptions about the nature of the universe, particularly about the identity of brain and nervous system functions and mental processes. And like the other models, this may not reflect reality so much as it reflects our attachment to our conceptions. Thus, the information-flow route that seems most likely (from external target stimulus via the sense organs to the brain to the transmitting process to the percipient, possibly with representation in the conscious or unconscious mind) may not be the case. The information-flow... 

We deal with two major classes of information in perceiving and reacting to the world information about the environment or external world and information about what is going on in our own bodies. Information about the external world is taken in through the subsystem labeled Exteroceptors, the receptors for external stimulation. These include the eyes, ears, nose, and the other familiar sense organs. The network of receptors and... 

Another method employed rather frequently by neuropharmacologists involves measurement of transmission in sensory systems by the so-called evoked potential technique. A sense organ, e.g. the eye or the ear, is stimulated by a light flash or a loudspeaker click, and an afferent volley of nerve impulses is produced. This volley travels first through peripheral sensory nerve fibers and then through the afferent systems in the CNS to reach finally the so-called projection area of the cerebral cortex. 

The expression "sense illusion" proves that we are not yet fully conscious, or at least have not deemed it necessary to incorporate the fact into our ordinary language, that the senses represent things neither wrongly nor correctly. All that can be truly said of the sense-organs is that under different circumstances they produce different sensations and perceptions (1914, p. 10). (italics in original)... 

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