Why do we leave cookies out for Santa? The answer is that he feels hungry after traveling the world and through the chimney. He senses this hunger with his sensory receptors. Why are Christmas songs different than Halloween songs? The music sets a tone that affects the way people feel. Without hearing it would be hard to understand the different moods.These are just a few examples of how sensory receptors are usedduring the Christmas holiday. Let’s explore what they are and whatelse they do.
Sensory receptors-•· Include our “special senses(vision, hearing, balance, taste, and smell)” (2).•· Have receptor potential which is what causes areflex (2). It is like a tea pot that heats and once it hits acertain point causes the whistling sound. Once the potentialis at its climax, it causes the body to react.•· Allows the brain to interpret sensations with thespecial senses (registering heat, cold) (2).•· Receptors adapt after a period of time. An examplefrom Anthony’s Textbook of Anatomy and Physiology 17thEdition is how when a person first puts on clothes he canfeel the material but after a while does not sense it at all.
Distribution•· Receptors are not distributed equally throughoutthe body.•· Receptors in the general source organs producesomatic senses (2).•· The two-point discrimination test proves thatthere are more receptors in some areas of the body thanothers (receptors in finger tips > receptors of skin onthe back) (2).
4.Visceroceptors•· Internal and “within body organs” (2).•· Internal stimuli cause a reaction (2).Examples: receptors that sense the craving ofgingerbread men, wanting eggnog, and realizing youcan’t eat anymore cookies or drink anymore applecider. 3. Proprioceptors•· Are a type of visceroceptors.•· Located in “skeletal muscle, joint capsules,and tendons” (2).•· Identify body movement.Examples: Help us to realize when we walk, when weraise our hands, sit still, and stand tall.
3. Thermoreceptors•· “Activated by change in temperature” (2).Examples: Why we wear jackets in the winter and shorts in thesummer, and why Santa has long sleeves, long pants, snowboots, and a hat. His cheeks are always rosy because thewinds in the air whip against his cheeks as he flies overneighborhoods.4. Nociceptors•· Senses pain (2).Examples: What Tim Allen experienced after falling of the rooftrying to tie up Frosty in Christmas with the Kranks.5. Photoreceptors•· “Found only in the eye” (2).•· “Responds to light” (2).Examples: When your eyes adjust on Christmas morning afterbeing in the dark to waking up in the bright early morning.
Taste Taste Buds are the sense organs that respond to gustatory, or taste, stimuli. They are located in the lining of the mouth and on the soft palate, most are on the small elevated projections of the tongue called papillae. As chemoreceptors, the taste buds, like olfactory receptors, tend to be quite sensitive but fatigue easily. Neural Pathway connects one part of the nervous system with another and usually consists of bundles of elongated, myelin-insulated neurons. Neural pathways serve to connect relatively distant areas of the brain or nervous system. Nervous impulses generated in the anterior two thirds of the tongue travel over the facial nerve (2).
Hearing The Pressure Wave: The sound waves we hear travel through air just like the waves travel through the slinky. The above illustration shows the relative conformations of air molecules as they transmit a sound wave downward. Soud travels through the air and along the outer and middle ear as a series of compressions (crests) and rarefractions (troughs) of air molecules. These patterns of molecules stimulate parts of the ear as described below to create the perception of sound. How the Ear Perceives Sound: The audirory canal (a.k.a. the outer auditory meatus) brings what you hear from the outside of the ear to the middle ear. At the end of the auditory canal, there is a thin layer of skin called the tympanic membrane (more commonly called the ear drum). The waves of sound hit the ear drum, and get further transferred onto the three small bones in the middle ear collectively known as the auditory ossicles: incus (anvil), stapes (stirrup), and malleus (hammer).
These structures act as a chain, which lead through an opening in the bone between the middle and the inner ears. The middle ear is filled with air, and the inner ear is filled with fluid, so this opening is covered by a thin membrane to keep them separate. This membrane allows the sound waves to be transmitted into the inner ear, and finally to a bundle of 30,000 nerve fibers each representing a different frequency. Noise is filtered out of this signal and the brain interprets the signal. The brain’s interpretation of sound gives it an added property: pitch. This is basically how the brain interprets the frequency. The higher the frequency, the higer the pitch. Since frequency is the inverse of the period, the longer the wavelength, the lower the pitch. The amplitude of the wave translates into how loud the brain takes the sound to be. Wave addition contributes to the rich complex sounds the we hear each day. A voice is just the addition of many simpler waves to give a unique sound. If two waves are added together, and they happen to have the same amplitude, the compressions of one are in the same position as the rarefractions of the other (and vice versa) the end result is no sound. This is how your noise cancelling headphones work. They take in sounds from the outside, and emit a wave that has just the right properties to cancel them out.
• Proprioception doesnt come from any specific organ, but from the nervous system as a whole. Its input comes from sensory receptors distinct from tactile receptors — nerves from inside the body rather than on the surface. Proprioceptive ability can be trained, as can any motor activity. (21) Without proprioception, drivers would be unable to keep their eyes on the road while driving, as they would need to pay attention to the position of their arms and legs while working the pedals and steering wheel. And I would not be able to type this article without staring at the keys. If you happen to be snacking while reading this article, you would be unable to put food into your mouth without taking breaks to judge the position and orientation of your hands. (21)
VISION: THE EYE The eye is the body’s sensory organ for vision. This organ converts the energy of light into electrical nerve impulses that are interpreted by the brain. Approximately five sixths of the eyeball is hidden in the socket. There are three layers of tissue in the eye. The three layers of tissue are the sclera, the choroid, and the retina (2). The anterior layer of the sclera is called the cornea and lies over the iris, the colored part of the eye. The middle or choroid part of the eye contains many blood vessels and large amounts of pigment. The iris or the colored part of the eye, consists of circular and radial smooth muscle fibers arranged to form a doughnut shaped structure. The hole in the middle is called the pupil. The iris attaches to the ciliary body (2).
Process of seeingFormation of retinal Image Refraction of light rays Accommodation of lens Constriction of pupil Convergence of eyes
Role of Photopigments Rods- photopigment in rods is rhodopsin; highly light sensitive; breaks down into opsin and retinal; separation of opsin and retinal in the presence of light causes an action potential in rod cells; energy is needed to reform rhodopsin retina Cones- three types of cones are present in the retina, with each having a different photopigment; cone pigments are less light sensitive than rhodophsin and need brighter light to breakdown
Questions Deer can’t see color so wearing bright orange vests don’t scare them off. It keeps other hunters from shooting people with those vests instead of mistaking their movements as an animal. Nearsighted means you cant see very good far and farsighted means you cant see very well near.
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