Formed in December as a means of ending foreign domination of the chemical industry.
Extrinsic eye muscles aim the eyes for following moving objects and for convergence. Lacrimal apparatus Figure Chemical senses. Eyelids protect the eyes. Associated with the eyelashes are the ciliary glands, modified sweat glands, and the meibomian glands, which produce an oily secretion that helps keep the eye lubricated.
The conjunctiva is a mucous membrane that covers the anterior eyeball and lines the eyelids. It produces a lubricating mucus Figure 8. Three tunics form the eyeball.
The sclera is the outer, tough, protective tunic. Its anterior portion is the cornea, which is transparent to allow light to enter the eye.
Anterior modifications include two smooth muscle structures, the ciliary body, and the iris which controls the size of the pupil.
The retina is the innermost sensory coat, which contains the photoreceptors. Rods are dim light receptors. Cones are receptors that provide for color vision and high visual acuity. The fovea centralis, on which acute focusing occurs, contains only cones.
The blind spot optic disk is the point where the optic nerve leaves the back of the eyeball. The lens is the major light-bending refractory structure of the eye Figure 8. The lens shape is changed by the ciliary muscle for close focus.
Anterior to the lens is the aqueous humor; posterior to the lens is the vitreous humor. Both humors reinforce the eye internally. The aqueous humor also provides nutrients to the avascular lens and cornea. Errors of refraction include myopia, hyperopia, and astigmatism.
All are correctable with specially ground lenses. Overlap of the visual fields and inputs from both eyes to each optic cortex provide for depth perception. Eye reflexes include the photopupillary, accommodation pupillary, and convergence.
Hearing and Balance The ear is divided into three major areas Figure 8.
Outer ear structures are the pinna auricleexternal auditory canal, and tympanic membrane eardrum. Sound entering the external auditory canal sets the eardrum into vibration. These structures are involved with sound transmission only.
Middle ear structures are the ossicles and auditory tube within the tympanic cavity.Chemical senses In vertebrates, the senses of smell (olfaction) and taste (gustation) plus the so-called common chemical sense constitute the external chemical senses (as contrasted with internal chemoreceptors).
U.S. Senate Committee on Banking, Housing, and Urban Affairs. Second Staff Report on U.S. Chemical and Biological Warfare-Related Dual-Use Exports to Iraq and The Possible Impact on the Health Consequences of the War.
Oct 13, · As far as I am aware, of our 5 senses, touch, hearing sight, taste, smell, only taste and smell are chemical. The rest are all mechanical/ electrical stimulated senses.
Life would be very uninteresting without taste and smell, and most probably quite timberdesignmag.com: Resolved. Chemotaxis (from chemo-+ taxis) is the movement of an organism in response to a chemical stimulus. Somatic cells, bacteria, and other single-cell or multicellular organisms direct their movements according to certain chemicals in their environment.
This is important for bacteria to find food (e.g., glucose) by swimming toward the highest concentration of food molecules, or to flee from poisons. The chemical senses are the senses of smell (olfaction) and taste (gustation). Smell is a distant chemical sense, providing information about the chemical composition of substances before you come into the direct contact with them.
The Five Senses.
Quotations, Sayings, Quips, Poems, Reflections, Notes, Facts. Compiled with Comments by Michael P. Garofalo, M.S. Body-Mind, Embodied Cognition.