The Sensory System & Sensory Disorder
The sensory system is the system the lets the human body experience life it is responsible for processing information. The system consist of receptors, neural pathways, and parts of the brain. The most recognize sensory are vision, hearing, taste, and smell. The sensory system is a component that is used to process sensory information. The receptors collect information that is called sensory information and it may lead to conscious awareness and when it does is called sensation. These receptors are called stimulus when this stimulus gives an electrical response is called stimulus transduction. The receptors are the peripheral ending of sensory neurons and they function by depolarizing neurons and producing action potentials. The Neural Pathway are photoreceptor cells with neurons called bipolar cells, which synapse with the photoreceptor cells.
The sound transmission in the ear, the outer ear directs and amplifies sound waves external auditory canal leads from the outside to the middle ear cavity. The tympanic membrane vibrates of the frequency of sound waves, the middle ear cavity amplifies the vibration in the tympanic the oval window. The inner ear has the Scala vestibule that is filled with fluid. The hearing of a human is audible range extends from 20 to 20,000 Hz. Pitch and loudness of the ear consist from the basilar membrane which is narrow and rigid the oval window but widens inside. High frequencies vibrate the narrow rigid part and low frequencies vibrate the membrane further inside. The stimulation of hair cells closets to the oval window produces the sensation of a high pitched sound while the stimulation of hair cells further in produces a deep bass sensation. Louder sound causes greater movement of the basilar membrane they also can cause permanent damage to the hair cells. The semicircular canals are filled with a fluid that moves when the head is rotated. Because each canal is oriented at 90 degrees to each other, they are capable of detecting rotation in any direction. An ampulla is located at the base of each semicircular canal. The ampulla contains cupola which are hair cells embedded in a gelatinous material. When the head rotates, fluid in at least one canal moves past the cupola, bending hair cells and triggering action potentials. The vertebrate ear of humans evolved from the lateral line system of fishes and therefore depend on bending hair cells in the outer ear, the auditory canal contains hair which functions to filter the air and modified sweat glands that produce ear wax Invertebrates
Vertebrate Chemoreceptors enable vertebrates to taste their food. These taste receptors are found mostly on the tongue as part of sensory organs called taste buds. Humans perceive five types of taste: bitter, sour, salty, sweet, and taste enables vertebrates to distinguish nutritious from noxious substances.Neurons from the tongue travel to the medulla oblongata and to the thalamus. From here, they are routed to the appropriate areas of the cerebral cortex.Olfactory receptors are chemoreceptors that detect odors.The sense of smell is more acute than that of taste. Most of our sensation of taste comes from smell. An olfactory receptor has several different receptor proteins embedded within the surface of its membranes. Each protein corresponds to the shape of a specific molecule to be detected. It is theorized that odors can be distinguished from one another because specific odors stimulate certain specific combinations of receptors; different odors stimulate other combinations.Unlike other sensory information, olfactory information does not go to the midbrain or thalamus. Instead, it passes directly to the cerebral cortex by the olfactory bulbs.Humans have about 12 million olfactory receptors compared to 4 billion in a bloodhound. Bloodhounds can track the path of an animal because they can smell individual cells that have fallen from the animal.
The structure of the eye has a ciliary body is an extension of the choroid layer. It functions with the suspensory ligament to attach and support the lens.The aqueous humor is a watery material between cornea and lens. The vitreous humor is gelatinous material within the eye.Focusing by the lens is called accommodation, focusing in humans is done by changing the shape of lens with ciliary muscles. These muscles are part of the ciliary body. The ciliary muscles surround the lens they are attached to the lens by suspensory ligaments. When distant objects are viewed, the ciliary muscles relax, putting tension on the suspensory ligaments. The taut ligaments pull the lens, causing it to become thinner. Nearby objects cause the ciliary muscle to contract, reducing the tension on the suspensory ligaments and allowing the lens to assume a thicker shape. The cornea bends light but the lens finishes focusing. As a person ages, their ability to focus their lens decreases. Glasses can correct for this loss of focusing ability. Focusing occurs when the eye is too long and the plane of focus is in front of the retina. Farsightedness occurs when the eye is too short and the plane of focus is behind the retina.
Vertebrate eyes contain two kinds of photoreceptors rods and cones. Rods cannot distinguish colors and do not provide sharp vision. They are more sensitive to dim light and are better at detecting motion than cones. They are most abundant in the periphery of the retina. Cones function in color vision they produce sharp images but require bright light. Most dense in an area in the back of the eye called the fovea this area has the greatest visual acuity. There are three types of cones, each responds to one color, either red, green, or blue because the visual pigment is slightly different for each color. Different combinations of red, green and blue produce other colors. For example, the brain interprets signals that come from red and green cones as yellow. The figure below shows how any of the colors can be produced as a combination of these three colors.
Sensory Processing Disorder is what is referred to as a hidden disability. It is referred to that because it is not observable to the casual eye of parents, teachers, and pople in the community. Unlike a disability which may be visible to casual observers, parents of children with SPD may not recognize the traits, and find themselves in awkward situations as a result of their child’s behavior. Because SPD is not a visible disability, the child may be treated unfairly for the behaviors associated with it, because observers assume it’s intentionally being exhibited to be disruptive. In fact, many of these behaviors are an effort by the child to regulate his/her nervous systems, which may be on overload. Because it takes extensive effort and focus to integrate input that should come naturally to a person’s nervous system, and because they are not always successful at the process, it becomes even more frustrating for the child- as well as the adults and the child’s peers who often have no idea what the child is experiencing, nor why they are reacting in a specific way.
In most workplaces and school environments a specific effort is made to provide comfort to the people who inhabit the areas. For example, there are areas specifically designated to include- or disallow specific allergens or annoyances, be it dust, smoke, noise, or peanuts. Keep in mind, smoke-free environments are a relatively new phenomenon, and were not automatically provided throughout history. This required a re-thinking of past practices, and a progression toward meeting the needs of a specific group of people. Whether that group is a majority, or minority is irrelevant in the eyes of the law. And yet, while many schools and workplaces don't question the implementation of steps to remedy environmental allergens and their outward physical responses and manifestations - many people are unaware of, or outwardly hostile toward people who react to sensory overload. This thought process runs contrary to the same laws that provide for other modifications made for people with disabilities in public use facilities. To deny access to these public zones- whether intentional or by default- is the same as denying curb cuts, wheelchair lifts, and other access modifications. This is a necessary process although the sensory system is and amazing part of anatomy the issue of sensory disability was deeply enforceable to be brought to the reader’s attention.