Sensation and Perception PDF

SENSATION and PERCEPTION Valliant Dale B. Acorda SENSATION  Learning Outcomes 1 Identify the specific parts of each sensory organ that is in charge with receiving information 2 Evaluate the credibility of information regarding sensation Identify various exceptiona...

SENSATION and PERCEPTION Valliant Dale B. Acorda SENSATION  Learning Outcomes 1 Identify the specific parts of each sensory organ that is in charge with receiving information 2 Evaluate the credibility of information regarding sensation Identify various exceptional development related to the 3 senses. 4 Apply concepts about the sensation by constructing an activity related to senses given As human Being, we perceive through our senses Which means: we are constantly performing a complex set of processes by which we take in sensory information convert it into a form usable by the brain and have the brain send signals to a relevant part of the body in order to tell it how to respond - all in a matter of milliseconds.  sensation and perception sensation is the process by which our senses gather information and send it to the brain. Sensations can be defined as the passive process of bringing information from the outside world into the body and to the brain. The process is passive in the sense that we do not have to be consciously engaging in a "sensing" process.  sensation and perception perception can be defined as the active process of selecting, organizing, and interpreting the information brought to the brain by the senses. Sensation occurs: A. sensory organs absorb energy from a physical stimulus in the environment. B. sensory receptors convert this energy into neural impulses and send them to the brain.  SENSORY RECEPTORS ARE SPECIALIZED SENSITIVE CELLS THAT RESPOND AND DETECTS STIMULUS. EXAMPLES OF SENSORY STIMULUS WOULD BE TOUCH, PRESSURE, PAIN, LIGHT, SOUND, POSITION IN SPACE, AND VIBRATION. THERE ARE THREE TYPES OF SENSORY RECEPTORS: THERE ARE THREE TYPES OF SENSORY RECEPTORS: 1. Exteroceptors- Receive sensory information from outside of the body. For examples: Visual, auditory, tactile, gustatory, and olfactory THERE ARE THREE TYPES OF SENSORY RECEPTORS: 2. Interoceptors- Receive sensory information from inside the body. Detect internal body sensation. Examples: from the viscera (hollow organs), stomach pain, pinched spinal nerves, and deep skin inflammation. It means to say that interoceptors are sensory receptor which receives stimuli from within the body, especially from the gut and other internal organs. THERE ARE THREE TYPES OF SENSORY RECEPTORS: 3. Proprioceptors- In here, the unconscious information received where in the detection of body position in space and movement happens. It means to say that proprioceptors are sensory receptor which receives stimuli from within the body, especially one that responds to position and movement. It is located in the muscles, tendons, and joints inside the body and semicircular canals of the inner ear. Here is an illustration of its function: Other than that we also have: Cutaneous receptors found at the distal ends of the primary sensory axon; they act as dendrites, in which threshold stimuli lead to the firing of an action potential at the initial segment of the primary sensory axon. Cutaneous receptors It responds to pain, temperature, pressure, vibration, and discriminative touch. Location: Superficial or deep layers of the skin, can be either exteroceptors (superficial) or interoceptors (deep). HERE IS AN ILLUSTRATION:  SENSORY ADAPTATION Sensory adaptation refers to a reduction in sensitivity to a stimulus after constant exposure to it. While sensory adaptation reduces our awareness of a constant stimulus, it helps free up our attention and resources to attend to other stimuli in the environment around us. All five of our senses are constantly adjusting to what's around us, as well as to us individually and what we are experiencing, such as aging or disease.  For example, imagine yourself walking into a house where fried fish and head cheese were prepared for dinner. You would probably pass out at the door, yet people who had been in the house for some time wouldn't be aware of the food odors. Similarly, smokers often don't get how much nonsmokers are bothered by the smell of tobacco smoke. Why? Because sensory receptors respond less to unchanging stimuli, a process called sensory adaptation. SIGHT/VISION The eye is the organ of vision. It has a complex structure consisting of a transparent lens that focuses light on the retina. The retina is covered with two basic types of light-sensitive cells-rods and cones. The Cone Cell The cone cells or cones, are photoreceptor cells in the retinas of vertebrate eyes including the human eye. They respond differently to light of different wavelengths, and are thus responsible for color vision, and function best in relatively bright light, as opposed to rod cells, which work better in dim light. The Cone Cell They are sensitive to color and are located in the part of the retina called the fovea, where the light is focused by the lens The Rod Cell The rod cells are type of photoreceptor cells in the eye found in the concentrated at the outer edges of the retina They are responsible for vision in low light conditions. The Rod Cell They are also not sensitive to color, but have greater sensitivity to light than the cone cells. These cells are located around the fovea and are responsible for peripheral vision and night vision. The eye is connected to the brain through the optic nerve. The Rod Cell Experiments have shown that the back of the brain maps the visual input from the eyes The visual system works on sensing and perceiving light waves. Light waves vary in their length and amplitude: a.) Wave length (also referred to as frequency, since the longer a wave, the less often/quickly it occurs) - affects color perception b.) Wave amplitude (this is the size/height of the wave) - affects brightness perception.  CORNEA the round, transparent area Cornea that allows light to pass into the eye.  LENS the transparent structure that Lens focuses light onto the retina.  RETINA inner membrane of the eye that receives information about light using rods and cones. Retina The functioning of the retina is similar to the spinal cord - both act as a highway for information to travel on.  PUPIL opening at the center of the iris Pupil which controls the amount of light entering the eye. Dilates and Constricts. RODS & CONS many more rods (approximately 120 million) than cones (approx 6.4 million).  CONS visual receptor cells that are important in daylight vision and color vision. The cones work well in daylight, but not in dim lighting. This is why it is more difficult to see colors in low light.  RODS visual receptor cells that are important in nighttime vision. Can only detect shades of gray.  FOVEA which is a tiny spot in the center, area of the clearest vision.  FACTS ABOUT SENSE OF SIGHT “We see when visible light is processed by the eye’s components and translated into neural impulses that are processed by the brain.” FACTS ABOUT People blink 15 times per minute on average SENSE OF SIGHT Everything would appear two- dimensional to a person with only one eye. Human eyes are made of over two million working parts Newborn babies see everything upside down until the brain learns to process everything right side up FACTS ABOUT Dolphins sleep with one eye open. Creepy? Or super smart? SENSE OF SIGHT The eyes are made up of over 2 million moving parts and the eye muscles are the most active muscle in the human body. Most people blink every 2-10 seconds and when we do blink we shut our eyes for around 0.3 seconds. would appear two-dimensional to a person with only one eye.  There are 3 types of color- FACTS ABOUT blindness: total color blindness, an SENSE OF inability to see one colour and an impairment, not loss, of normal SIGHT color vision. Color blindness is also more common in males At birth your eyes are about 70% of their adult size, but your nose and ears never stop growing. FACTS ABOUT The older we are the less tears we produce. SENSE OF SIGHT Your eyes begin to develop after 2 weeks of conception Visual defects vision defect, visual disorder, visual impairment. impairment of the amaurosis - partial or total sense of sight. loss of sight without pathology of the eye; caused by disease of optic nerve or retina or brain. Nearsightedness (myopia) is a common vision condition in which you can see objects near to you clearly, but objects farther away are blurry. It occurs when the shape of your eye causes light rays to bend (refract) incorrectly, focusing images in front of your retina instead of on your retina. It means to say that this is the inability to see far objects. Farsightedness (hyperopia) is a common vision condition in which you can see distant objects clearly, but objects nearby may be blurry. The degree of your farsightedness influences your focusing ability. It means to say that this is the inability to see near objects clearly. Presbyopia or old sightedness physiological insufficiency of accommodation associated with the aging of the eye that results in progressively worsening ability to focus clearly on close objects. Symptoms include difficulty reading small print, having to hold reading material farther away, headaches, and eyestrain. It is a condition where in a person is unable to focus clearly on near objects. AUDITION/HEARING AUDITION/HEARING  THE EARS The ear is the organ of hearing. It is the transduction of sound waves into a neural signal that is made possible by the structures of the ear. Soundwaves Soundwaves are vibrations in the air that are processed by the auditory system. Sound is a mechanical wave that results from the back and forth vibration of the particles of the medium through which the sound wave is moving. Soundwaves Soundwave is measured by: first, amplitude or the decibel. Secondly is the pitch by means of high/lowness of a sound determined by frequency measured by HERTZ where it is used commonly to measure wave frequencies, such as sound waves, light waves, and radio waves. As to fast or high; slow or low. Lastly the timbre or the complexity of sound THE HUMAN EAR  Knowing the basic structure of the ear is essential to understanding how hearing works.  THREE BASIC PARTS OF THE EAR  INTERNAL/ Inner Ear INNER EAR Liquid-filled cavity hollowed out of the temporal bone that transforms sound vibrations into nerve influxes to be interpreted by the brain.  MIDDLE EAR Middle Ear Air-filled cavity hollowed out of the temporal bone; it receives sounds from the external ear, amplifies them through the auricles and transmits them to the internal ear  EXTERNAL/ Outer Ear OUTER EAR Visible portion of the ear enabling sounds to be collected and directed to the middle ear through the acoustic meatus Auricle  Hearing loss can be categorized by which part of the auditory system is damaged. There are three basic types of hearing loss: CONDUCTIVE HEARING LOSS typically the result of obstructions in the outer or middle ear, perhaps due to fluid, tumors, earwax or even ear formation. This obstruction prevents sound from getting to the inner ear. Conductive hearing loss can often be treated surgically or with medicine. CONDUCTIVE HEARING LOSS It occurs when sound is not conducted efficiently through the outer ear canal to the eardrum and the tiny bones (ossicles) of the middle ear. Conductive hearing loss usually involves a reduction in sound level or the ability to hear faint sounds. SENSORINEURAL HEARING LOSS (SNHL) the most common type of hearing loss. It occurs when the inner ear nerves and hair cells are damaged, perhaps due to age, noise damage or something else. Sensorineural hearing loss impacts the pathways from your inner ear to your brain. SENSORINEURAL HEARING LOSS (SNHL) Most times, sensorineural hearing loss cannot be corrected medically or surgically, but can be treated and helped with the use of hearing aids. It occurs when there is damage to the inner ear (cochlea), or to the nerve pathways from the inner ear to the brain. SENSORINEURAL HEARING LOSS (SNHL) Most of the time, SNHL cannot be medically or surgically corrected. This is the most common type of permanent hearing loss. MIXED HEARING LOSS is just a combination of sensorineural and conductive hearing loss. As with any medical condition, it’s best to know what you “have” before deciding what to do about it. MIXED HEARING LOSS A consultation with a hearing professional can help determine the type, cause and degree of your hearing loss. FACTS ABOUT 1 HEARING  FACTS ABOUT HEARING 1 The eardrum moves less than a billionth of an inch in response to sound. 2 In World War I parrots were kept on the Eiffel Tower in Paris because of their remarkable sense of hearing. When the parrots heard enemy aircraft, they warned every one of the approaching danger long before any human ear would hear it.  FACTS ABOUT HEARING 3 Sometimes if you have damage to your ears, your perception of taste may be off because the nerves (called the Chorda Tympani) run through the ear and connect the taste buds on the front of your tongue to your brain. Sometimes people who have had ear surgery experience a change in their sense of taste. It does not mean that hearing loss directly correlates to an inability to taste.  FACTS ABOUT HEARING 4 Ear infections are more common in children because of their developing immune systems and differences between their Eustachian tubes (at more of a horizontal angle) than those of adults. 5 Earwax has been useful to anthropologists for studying mankind’s early migratory patterns. 6 Sitting close to loudspeakers at concerts (which can reach about 120 decibels) can damage your hearing in just 7.5 minutes!  FACTS ABOUT HEARING 7 At the age of 65, one in three adults has some hearing loss; however, a majority of the people who suffer from hearing loss are under age 65. 8 Hearing loss is the third most common health problem in the United States. 9 Excessive noise exposure is the #1 cause of hearing loss.  FACTS ABOUT HEARING 10 The bones in the middle ear (malleus, incus, and stapes) are the body’s smallest bones. All three can fit together on the surface area of a penny. 11 37% of children with hearing loss fail at least one grade. 12 The outer ear never stops growing throughout one’s lifetime. 13 The middle ear is about the size of an M&M.  FACTS ABOUT HEARING 14 The inner ear is no larger than a pencil eraser in circumference. 15 Not all living creatures hear with ears. Snakes use jawbones, fish respond to pressure changes, and male mosquitoes use antennae.  SMELL/ OLFACTION The olfactory system, or sense of smell, is the sensory system used for smelling (olfaction). Olfaction is one of the special senses, that have directly associated specific organs. Most mammals and reptiles have a main olfactory system and an accessory olfactory system. It is a chemical sense that occurs when chemicals in the air reach receptor cells in the nasal cavities. FACTS ABOUT SENSE OF SMELL People can detect at least one trillion distinct scents. Women have a better sense of smell than men. Humans have 7 primary odours that help them determine objects and if your nose is at its best you can tell the difference between a staggering 4,000 – 10,000 smells. Humans can tell the difference between 10,000 different odors. But s m e ll often it is difficult to name the odors. FACTS ABOUT SENSE OF SMELL Each human has their own distinct odor. Scent cells are renewed every 30 to 60 days. You can smell fear and disgust. Age-related loss of smell is linked to race. Loss of smell may signal future illnesses. s m e ll FACTS ABOUT SENSE OF SMELL As you get older your smell gets worse, so children are more likely to have a better sense of smell Everyone has a unique smell except for identical twin. Taste is about 75% smell. Dogs have nearly 44 times more scent cells than humans. s m e ll FACTS ABOUT SENSE OF SMELL Dogs can be 10,000 times more sensitive to odors than humans. Yet, a individual human olfactory receptor is no less sensitive than a dog's. Decline in smell may predict death within five years. s m e ll PARTS OF THE NOSE OLFACTORY RECEPTORS Smell (olfactory) receptors and taste receptors are chemoreceptors, which means that chemicals dissolved in liquids stimulate them. Smell and taste function closely together and aid in food selection because we usually smell food at the same time we taste it.  People who have a smell disorders either have a decrease in their ability to smell or changes in the way they perceive odors. Here are some of the smell disorders: HYPOSMIA OR MICROSMIA a reduced ability to detect odors. It is a reduced ability to smell and to detect odors. Some of the causes of olfaction problems are allergies, nasal polyps, viral infections and head trauma. ANOSMIA OR SMELL BLINDNESS is the inability to detect odors. In rare cases, someone may be born without a sense of smell, a condition called congenital anosmia. It is the loss of the ability to detect one or more smells. Anosmia may be temporary or permanent. It differs from hyposmia, which is a decreased sensitivity to some or all smells.  PAROSMIA is a change in the normal perception of odors, such as when the smell of something familiar is distorted, or when something that normally smells pleasant now smells foul. Parosmia is a term used to describe health conditions that distort your sense of smell. If you have parosmia, you may experience a loss of scent intensity, meaning you can't detect the full range of the scents around you.  PHANTOSMIA It is the medical word used by doctors when a person smells something that is not actually there. It is also called a phantom smell or an olfactory hallucination. The smells vary from person to person but are usually unpleasant, such as burnt toast, metallic, or chemical smells. GUSTATION/ TASTE  SENSE OF TASTE Taste, or gustation, is a sense that develops through the interaction of dissolved molecules with taste buds. Currently five sub-modalities (tastes) are recognized, including sweet, salty, bitter, sour, and umami (savory taste or the taste of protein).  SENSE OF TASTE Taste, or gustation, happens when chemicals stimulate receptors in the tongue and throat, on the inside of the cheeks, and on the roof of the mouth. These receptors are inside taste buds, which in turn are inside little bumps on the skin called papillae. Taste receptors have a short life span and are replaced about every ten days. Recently, researchers have suggested the presence of a fifth taste called umami. The spice monosodium glutamate (MSG) has an umami taste, as do many protein-rich foods. Sweet, sour, salty, bitter and savory tastes can actually be sensed by all parts of the tongue. Only the sides of the tongue are more sensitive than the middle overall. This is true of all tastes – with one exception: the back of our tongue is very sensitive to bitter tastes. This is apparently to protect us so that we can spit out poisonous or spoiled foods or substances before they enter the throat and are swallowed.  TASTE DISORDERS TASTE DISORDERS Hypogeusia is a reduced ability to taste things (to taste sweet, sour, bitter, or salty substances). The complete lack of taste is referred to as ageusia. Causes of hypogeusia include the chemotherapy drug bleomycin, an antitumor antibiotic as well as zinc deficiency. TASTE DISORDERS Dysgeusia a persistent taste, usually unpleasant. It is also known as parageusia which is a distortion of the sense of taste. It is also often associated with ageusia, which is the complete lack of taste, and hypogeusia, which is a decrease in taste sensitivity. The sensation of something as “hot” or “spicy” is quite often described as a taste. Technically, this is just a pain signal sent by the nerves that transmit touch and temperature sensations. The substance “capsaicin” in foods seasoned with chili causes a sensation of pain and heat – and this does not happen through the sensory cells specialized for taste. FACTS ABOUT TASTE bitter gourd coffee dark chocolate  1. EVERYONE HAS A DIFFERENT NUMBER OF TASTE BUDS AND WE HAVE OVER 10.000 TASTE BUDS IN OUR MOUTH THAT GET REPLACED EVERY 2 WEEKS 2. YOU CAN’T TASTE WELL THE FOOD IF YOU CAN’T SMELL. FACTS ABOUT 3. SOME OF YOUR TASTE PREFERENCES ARE GENETIC. TASTE 4. SUGAR CRAVINGS HAVE A BIOLOGICAL BASIS. 5. IN GENERAL GIRLS HAVE MORE TASTE BUDS THAN BOYS.  TASTE BUDS ARE MORE SENSITIVE AFTER A 6. NIGHT’S SLEEP, BUT CAFFEINE, SPICY FOOD, SMOKING AND ALCOHOL DULLS THE SENSES AND IT GENERALLY TAKES 24 HOURS FOR THEM TO RE-CLEANSE. 7. EATING SWEET FOODS HELPS FORM A MEMORY OF A MEAL. FACTS ABOUT CATS HAVE A WEAK SENSE OF TASTE. THEY 8. HAVE ONLY 473 TASTE BUDS, HUMANS HAVE TASTE 10,000. THE ROLE OF OLFACTORY SENSES IS CLEARLY STATED IN PHYSIOLOGY OF TASTE. ONION AND STRAWBERRY TASTE THE SAME WAY IF THE EYES AND NOSE ARE TIGHTLY CLOSED TACTILE/ TOUCH SENSE OF TOUCH Our skin acts as the protective barrier between our internal body systems and the outside world. It’s not only the body’s largest sensory organ, but it’s also the largest organ–period. SENSE OF TOUCH The skins “sense of touch” is what gives our brains a wealth of information about the natural environment, including temperature, humidity, and air pressure. SENSE OF TOUCH Most importantly, this sense of touch lets us feel physical pain–a necessity for avoiding injury, disease, and danger. SENSE OF TOUCH It is truly amazing how much information we receive about the world through our sense of touch, and although we still don’t know all the ins and outs of how the skin perceives touch, what we do know is interesting. SENSE OF TOUCH The sense of touch is really a collection of several senses, encompassing pressure, pain, cold, and warmth. The senses of itch and tickle are related to pressure, and burn injuries are related to pain. SENSE OF TOUCH Touch receptors are stimulated by mechanical, chemical, and thermal energy. HERE IS A PHOTO THAT ILLUSTRATE THE HUMAN SKIN: HERE ARE THE RECEPTORS THAT INVOLVES IN THE SENSE OF TOUCH: HAIRBULBS the bulbous expansion at the base of a hair from which the hair shaft develops. It is responsible of why we feel different “Pressures” HERE ARE THE RECEPTORS THAT INVOLVES IN THE SENSE OF TOUCH: FREE NERVE ENDINGS an unspecialized, afferent nerve fiber sending its signal to a sensory neuron. Afferent in this case means bringing information from the body's periphery toward the brain. It is responsible of why we feel “Pain” HERE ARE THE RECEPTORS THAT INVOLVES IN THE SENSE OF TOUCH: RUFFINI CYLINDERS A cutaneous nerve ending suspected as the mediator of warmth. It is responsible of why we feel “warmth” HERE ARE THE RECEPTORS THAT INVOLVES IN THE SENSE OF TOUCH: KRAUSE END BULBS this is a nerve terminals in skin, mouth, and other parts, consisting of a laminated capsule of connective tissue enclosing the terminal, branched, convoluted ending of an afferent nerve fiber; generally believed to be sensitive to cold. This is why we experience and feel “cold’. FACTS ABOUT SENSE OF TOUCH Our brain pays wildly disproportionate attention to touch on different parts of your body The skin is the largest organ in the body and detects touch via receptors for pain, pressure, movement, cold and heat. Our sense of touch gets worse as you age. We have more pain nerve endings than any other type and we have over 100 touch receptors in each fingertip and sex organs Touch is the first sense to develop in humans, and may be the last to fade. FACTS ABOUT SENSE OF TOUCH The least sensitive part of our body is the middle back and the most sensitive parts are lips, neck, face, hands, tongue and feet. A touch of any kind can reduce the heart rate and lower blood pressure. Touch is mysteriously crucial for a baby's development Touch shapes first impressions of people in weird way