Information about Five senses
There are 5 senses. Each sense has a specific purpose.
How do we hear?
A: Your ears pick up and send information about sounds to your brain in the form of nerve impulses. Sounds are collected in the outer ear and are sent into the ear canal to the eardrum (the eardrum is a thin tissue which separates the outer ear from the middle part of the ear). Three small bones in the middle part of the ear make sounds louder. In the inner part of the ear, there are spaces filled with liquid. One of the liquid-hearing receptor cells inside are like tiny hairs. Sounds from the middle part of your ear cause liquid inside the cochlea to move around. Mocemanet of this liquid bends like hair-like receptor cells. The receptor cells send impulses to the auditory nerve which goes to the brain. The brain receives impulses from the auditory nerve and gives meaning to the sound impulses.
Q: Why do we have to ears?
A: We have two ears because the sounds hits one ear a fraction of a second before the other and produces stronger vibrations. It helps you tell what direction the sounds come from.
Q: How are ears related to feeling dizzy? balance?
A: If the vestibular organs are damaged or diseased, they send too many or too few impulses to the brain. The brain interprets these abnormal messages as an imbalance of the body. The person then has a false feeling of motion or dizziness. This condition is called vertigo. A person whose vestibular organs have been destroyed by gradually learn to depend entirely on eye sight and other senses to maintain balance.
Q: What can cause deafness?
A: Deafness can be caused before a baby is born. A child can inherit deafness. A mother who has rubella or some over viral infection while she is pregnant can have deaf or otherwise a handicapped child. A premature baby, before the full nine months or a full-term baby experiecing a difficult birth with accompanied with lack of oxygen, has a possibility of being deaf. One other thing is after birth. A person can have an illness that can result in hearing loss.
Q: What other disorders/diseases are associated with hearing?
A: Other than deafness, there are many diseases associated with hearing. Some of these are otitis media (infection of the middle ear), otosclerosis (infection of the auditory ossicles), and meniere's disease (disorder of the inner earmarked by periodic attacks of hearing loss). All of these diseases are caused by birth defects or injuries.
The ears contain structures for both the sense of hearing and the sense of balance. The eighth cranial nerve (vestibulocochlear nerve made up of the auditory and vestibular nerves) carries nerve impulses for both hearing and balance from the ear to the brain.
Smell – The Nose knows
The smells of a rose, perfume, freshly baked bread and cookies...these smells are all made possible because of your nose and brain. The sense of smell, called olfaction, involves the detection and perception of chemicals floating in the air. Chemical molecules enter the nose and dissolve in mucous within a membrane called the olfactory epithelium. In humans, the olfactory epithelium is located about 7 cm up and into the nose from the nostrils.
The Olfactory System
Q: How do we smell? Where are smell receptors located?
A: Every time we breath, air flows through the nasal cavity. The turbinates (shelves of bones) makes the air flow down through the back of the mouth into the throat. Some air that flows into your mouth pastes the olfactory organs. Any odor molecules in the air will past by and get stuck to the mucus in your nose. The sensory hairs sense the odor and transmit messages to your brain. Your brain, therefore knows the odor. The smell receptor cell is located high up behind your nose. The receptor is sensitive to chemicals in the mucus in your nose.
Q: What disorders/diseases are associated with smell?
A: There are many smell diseases/disorders. One of them is Sinusitis. People of all ages can have Sinusitis. It is when there is an inflammation or infection of the air pockets on either side of and behind the nose. It is caused be viruses, fungi (molds), and maybe allergies. Another disease/disorder is phantom sensations. People of all ages also can have this. Phantom sensations are when there is presence of unpleasant or disordered tastes and smells. They can also be the presence of tastes or smells that other do not perceive. Lastly, halitosis (also all ages) is when there are burning sensations in your mouth or nose. It can be perception of bad breath.
Hair cells are the receptors in the olfactory epithelium that respond to particular chemicals. These cells have small hairs called cilia on one side and an axon on the other side. In humans, there are about 40 million olfactory receptors; in the German Shepherd dog, there are about 2 billion olfactory receptors.
No one knows what actually causes olfactory receptors to react - it could be a chemical molecule's shape or size or electrical charge. The electrical activity produced in these hair cells is transmitted to the olfactory bulb. The information is then passed on to mitral cells in the olfactory bulb.
The olfactory tract transmits the signals to the brain to areas such as the olfactory cortex, hippocampus, amygdala, and hypothalamus. Many of these brain areas are part of the limbic system. The limbic system is involved with emotional behavior and memory. That's why when you smell something, it often brings back memories associated with the object.
As you probably know, when you have a cold and your nose is stuffed up, you cannot smell very well. This is because the molecules that carry smell cannot reach the olfactory receptors.
Q: What is taste? Describe the parts of the tongue.
A: Taste is when you determine the flavor and palatability of food. Taste gives you signals of dangerous gases and toxic food. All over your tongue, there are little bumps called taste buds. There are four different types of taste buds. You can taste sweets in the front of your tongue and sour taste at both sides of your tongue At the back, you taste bitter things. All over your tongue, you taste salty things.
Q: What disorders/diseases are associated with taste?
A: There are many tongue disorders. Lumps or ulcers on your tongue can be a problem for people of all ages. It is caused by a papillae disorder. When you have lumps or ulcers on your tongue, you can get tumors if they aren't treated quickly. Glossitis and a geographical tongue are also cause by papillae disorder. It affects all people and results in inflammation of the tongue. It is caused by bacteria build-up and leads to fungal infection and a dark-colored tongue.
Eyes - Sight
Q: How do we see? Describe the parts of the eye.
A: To see what we do now, the light bounces off the object you are looking at, into the pupil. The ligh crosses your lens and the images gets focused. The object you are looking at turns upside down. The object your are looking at shines on the back of the eye. The part is called the retina. A retina contains two types of photoreceptors called rod cells and cone cells. Rod and cone cells helps you to see colors and sharp details. Then, the optic nerve carries the picture you see and your message goes to the brain. What that brain does after the message goes to the brain is that it turns the picture the right side up. The second thing the brain does is that they figure out what you are seeing and what you should do.
Q: Why do we have two eyes?
A: We have two eyes because having two eyes increases your angle of vision. It helps you to judge depth. Having two eyes allows us to see 180 degrees and three-dimensional objects.
Q: What is nearsightedness and farsightedness? How is it corrected?
A: When people grow older, their lens loses its elasticity. The flattened shape and the viewing of the near objects get difficult when distance objects are still clear. This condition is called presbyopia (or farsightedness). You can use corrective glasses. They bring near objects to focus. There is another type of farsightedness called hypermetropia. Hypermetropia can be caused by having an eye ball that is shorter than normal. People with myopia (or nearsightedness) have eye balls that are longer than normal. A nearsighted person has difficulty seeing distant objects but can read books easily. Nearsightedness is caused by the stress of working for a long period of close work. Nearsightedness usually begins when you are a kid. When you have nearsightedness or farsightedness, there is a way to cure you. Most older people wear contact lens to make them see better. You can use glasses when you are younger. For contact lens or glasses, there are certain types. For correcting short site, you use concave lens and for long sight people, they use convex lens.
Q: What is color blindness?
A: Color blindness is one of the diseases some humans have. Color blindness is when they can't really notice the color red, green, blue-violet, and other combinations. Color blindness is always an inherited disorder caused by genetic defect on X Chromosome. Color blindness mostly occurs primarily in mails. Most males have color blindness because they have one X Chromosome and females have two X Chromosome.
Q: What are other disorders/diseases associated with sight?
A: Other disorders/diseases we have with sight are Cataracts, Astigmatism, and blindness. Cataracts are a disorder that gradually develops in your lens of your eye. It gets cloudy or darkened. Cataracts develop by change in the chemical composition of the lens. Cataracts are most often found around people over the age of 55. Astigmatism is a vision that occurs at the front surface of your eye (the cornea). It is not irregular shape when your eye is focusing properly on the back of your eye. Astigmatism could occur at all ages. Blindness is a disorder that people of all ages suffer from. Usually, it is caused by either improper birth or an injury. When you are blind, it may be caused by a blockage of light or by a disease of the optic nerve.
Q: What is touch? Where are touch receptors located?
A: Touch is to use your skin to have physical contact with another object. Touch receptors are located in clusters around your skin. They look like onions or jelly material. When the are squeezed, the layers rub against each other causing an electrical nerve. The most sensitive touch receptors are located at your face, back of your neck, chest, arm (upper), fingers, soles of your feet, and between your legs.
Q: What kind of sensory receptors are in your skin?
A: This is a chart showing all of the sensory receptors in skin; the name, function, and location.
Q: How is the skin used to control temperature of your body?
A: Skin works with the hypothalamus. Regions of the hypothalamus contain heat and cold sensitive cells. The hypothalamus responds by increasing the number of nerve impulses transmitted by the brain. That lets the skin adjust.
When you get hot, it is called hyperthemia. Your skin tries to prevent it from going over 37 degrees Celsius (99 degrees Fahrenheit). Sweat glands in your skin are activated which cools the skin and body (after the sweat evaporates). The arteriovenous anastomis also opens which causes the flow of blood the increase. It's basically used as a cooling system. The good thing about blood is that it also adjusts according to the skin temperature. If it is too hot, blood can be used for cooling. If it is too cold, blood is used for warming up. Another thing that also changes is that the arrector pilli relaxes, letting hair stick holding the water down onto the skin, which allows the water to cool. Finally, your blood vessels open so that more blood can enter.
There is also a name for when you are too cold, hypothermia. "Too Cold" for your body is when your temperature is under 36.5 degrees Celsius (under 97 degrees Fahrenheit). The arteriovenus anastomosis closes (so that blood knows to warm instead of cool), letting blood flow increase. Also, the arrector pilli tightens, not allowing hair to stick and not keeping water cool you so you will not be colder. Goose pimples/goose bumps will also form, they have no use to humans but for other mammals, it makes you warmer. Goose pimples are when the muscles in your hair follicles contract. Shivering also helps you warm up. It increases the muscle activity in your body and produces heat. Lastly, the blood vessels close so there is less heat loss.
But how? Well, basically, your brain knows when, and therefore sends messages to the hypothalamus which makes the skin adjust accordingly.
Q: How does your skin get rid of human waste? What kind of waste is it getting rid of?
A: Your skin lets out human waste by sweating. Sweating consists of salt and water. It lets out this waste only when you are hot. Sweat comes from the pores of your skin and is a system of cooling. When you are hotter, during a hot season, you let out more waste in the form of sweat. The sweat glands in your skin trigger sweat and are connected to pores. The hypothalmus tells the brain when to trigger sweat and your brain controls the skin to do so.
Q: Why do we have hair? Why do we have fingerprints?
A: Hair is used for warmth and also help you cool down. Hair grows from the follicles in the Epidermis. Cells at the root will divide and push upward, causing hair to grow up. At a certain height, the hair dies and kertin hardens it. Melanin controls the hair color that you have.
Fingerprints are "replacing" hard. Wherever there is no hair, there are fingerprints. Fingerprints are tiny ridges on your fingers and toes which enable those parts to be more sensitive to touch. No two people's fingerprints are the same. Fingerprints are formed naturally, many months before you are born.
Q: What happens when you have acne, cuts, bruises?
A: Acne usually occurs during puberty when there is a change in your hormone levels. That causes extra keratin to produce, which leads to blackheads, and finally acne.
Cuts and bruises are formed when your skin is punctured. These are caused when blood vessels bleed into the surrounding tissue. After you bleed, platelets and other substances allow scabs to grow. The scab helps protect the injured area until new skin growns and the scab falls off.
Q: What disorders occur in your skin?
A: Three basic disorders occur in your skin (there are too many to mention all). They are acne, skin cancer, and eczema.
Acne usually occurs in teenagers. It is when extra keratin is made, leading to blackheads then acne.
Skin cancer can come to people of all ages. It is when your skin is exposed to too many ultraviolet rays.
Eczema occurs in children aged 5 and up. A rash forms, usually on the chest, elbow, and/or knees. Skin looses water and becomes dry which causes itchyness. This skin disorder is very hard to cure but usually goes away at a certain age.
Q: What disorders/diseases are associated with touch?
A: There are three main disorders/diseases that are most common. Here is a quick review telling about all of them:
Attention Defict Disorder, otherwise known as ADD occurs in people of all ages. Basically, it makes your sense of touch much more sensitive than other people. It is caused when things aren't being filtered through your brain properly.
Another disorder is Tactile defensiveness, which also can be a problem for people of all pages. People with this disorder have a tendency to react negatively to the sensation of touch and possibly trigger anxiety or panic.
Sensory Intergrative Dysfunction is another disorder. It usually occurs in kids. It makes people uneasy, have poor balance, and have under or over sensitivity to touch. The main cause is that there is a dysfunction in the central nervous system