Analysis Of The Internal And External Aging Process Biology Essay


All people, regardless of race, color, national origin, or sex, go through an aging process. It is an inevitable process that begins at conception. However, this process is difficult to examine because all body organs function together and their aging rates are all different. As many people know, physical changes occur while going through aging process. This paper will examine those changes and introduce some ways to make the process slower.

Researches have shown that there are two types of aging, which are intrinsic and extrinsic aging. Intrinsic aging is an aging caused by genes, and extrinsic aging is an aging caused by environmental sources. Intrinsic aging mostly begins in people's mid-twenties; this is the process that people cannot stop with current technology. People usually cannot feel immediately because it progresses slowly and gradually. Extrinsic aging, however, is the process that people can slow down by studying and practicing.

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The signs of aging process may be found in many parts of body organs. Among those, the aging of the skin is the most visible sign of the aging that concerns many people. When the aging process begins, many changes occur inside the body. Since skin protects a body from the environment, allows control the body temperature, and helps skin feel touch and pain, changes occurred in skin are significant. Largely, skin can be divided into three parts: the outer layer, middle layer, and inner layer. In the outer part, which is called epidermis, there are proteins, skin cells, and pigment. In the middle part, called dermis, there are nerves, blood vessels, hair follicles, and oil glands; this part helps carrying nutrients to the outer part. In the inner part there are blood vessels, sweet glands, and fat. Skin aging includes changes in all those skin layers. The production of elastin and collagen, a protein that enables skin to stretch, slows. The skin loses its elasticity. Along with, the number of pigment-containing cell decreases, and the remaining cells increase in their sizes. The blood vessels become more fragile, leading to bleeding under the skin. Such factors contribute to slow the process of replacement of dead skin cells in to new ones, causing many of the visible symptoms of aging. The signs are: wrinkle, freckle, dry and thin skin, hair color change, hair loss, incapability to sweat, bone shrinks, sagging of chin and neck, and less elasticity in skin. In addition to those, many other external factors act together to accelerate the process of aging. Among them, sun exposure is the most prominent factor. Other common factors are smoking, lack of exercise, exposure to cold weather, lack of sleep, sleeping positions, and alcohol. Sun exposure is very critical to skin. Without protection from the sun's rays, the skin will become more mottled. Freckles and age spots will be seen more frequently; more importantly, the risk of skin cancer will considerably increase by sun exposure. Another extrinsic aging factor, smoking is believed to be as damaging as sun rays. It increases skin wrinkles and depletes vitamin C. The vitamin C deficiency prevents skin from keeping itself plump and moist. Lack of exercise and exposure to cold weather are also aging factors since exercise gets the blood flowing and cold weather makes skin dry, respectively. Alcohol use progresses the aging process by swelling tiny blood vessels and increasing blood flow. By alcohol, those vessels can be damaged and make a skin's surface flushed. Sleeping is also another factor. It does not only make people to look tired, but also create dark circles and sagging skins. Over time, lack of sleep can develop into memory loss and depression. Position while sleeping is also important. If one sleeps in a same position for every night, after years, he/she will find wrinkles around the eyes. After they are created, the wrinkles remain in the face and will not be removed easily. As well as these factors, many other factors might influence the aging of skin. They are stress, repetitive facial expression, and gravity. They are all dangerous to those who want to maintain a healthy skin condition. Avoiding those factors is a way to save oneself from a danger of aging skin.

Although the aging process is not as obviously occurred in eyes as it does in skin, the process is gradually occurring and declining the eyes' ability to function. With aging, the quality of vision worsens. The worsening of vision is not related to eye diseases. Eye diseases can be a factor that makes eyes harder to see, but they are not always the reason for worse eyesight. Two main changes occurred while the eyes are undergoing the aging process: reduction of pupil size and loss of focusing capability. The reduction in size crucially causes the eyes to function less efficiently because the pupil size manages the amount of light reached to retina. It is estimated that a 60-year old man gets about one-third of the retinal illuminance than 20-year man does, which means, an older person needs additional lighting. The delayed rhodopsin regeneration in the eyes causes the dark adaptation of the eyes slower. The cornea becomes less sensitive; injuries may not be noticed. With aging, the retina becomes thinner. It makes the eyes to function far less efficiently because what retina does is to receive the focused light from the lens and send the light to brain to be interpreted. The fact that eyes become less able to produce tears also makes people more uncomfortable. People have to depend on eye drops or artificial tears solutions. As well, aging reduces a color discerning ability, especially blues and blue-greens. Many scientists believe such phenomenon is due to yellowing of the lens. Thus, it is a no surprise that older people's eyes do not work as quickly and efficiently as they did before. The less flexible and cloudier eyes become harder to fully rotate the eyes. Elders should give concentrate harder and need additional lights in order to see things clearly. Though it is still relatively easier to see simple objects, elders find it difficult to perceive a complex and organize the perceptions.

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As well, the changes in ears occur as a part of aging process. Ears have two jobs: maintaining balance and hearing, and both functions diminish over time. Humans can maintain balance by the fluid and small hairs in the inner ear that stimulate the nerve. When aging, the eardrum often thickens and influences the ear structures, making it more difficult to maintain balance. On the other hand, hearing also declines when aging. It is inevitable process that begins insidiously, and this hearing loss is called presbycusis. This ability starts to decrease in people's mid 40s. Hearing significantly declines especially in people who have been exposed to loud noises in their young years; mostly their ability to catch high-frequency sound diminishes. Since most of the consonants in speech have high-frequencies, elders find it difficult to understand and hear what people say. Some high frequency alphabets are "s", "sh", "ch", "c", "f", "v", "h", "t", and "th." Elders with hearing difficulties cannot hear these consonants and can only hear the vowels in the world, which makes the worlds to sound like mumbling. To comprehend what speaker says, elders should try to figure out what the mumbling might mean and look at the speaker's lips to find clues. In addition, brain's ability to translate words into information decreased with aging. Since the aged people have to depend on their brain ability to translate the words, the decreasing in the brain function is crucial. Another factor that affects the hearing is ear wax. Ear wax is the ear canal that is lined with hair follicles and glands that produce a cerumen , waxy oil. Although ear wax protects the ear by trapping dust and microorganisms, when ear wax is piled up, it blocks the ear from hearing as efficiently as it once did.

Mouth and nose are also affected as time passes by. People usually lose enjoyment in eating in their years due to decreased sense of taste and smell. People can smell by nerve receptors in the membranes of the nose; they can taste food by taste buds. There are about nine thousands taste buds that are responsible for sensing salty, sour, bitter, and sweet tastes. The decreased in taste sensation is primarily due to decreasing in number of taste buds. It usually begins at about age forty to fifty in women and at fifty to sixty in men. The remaining taste buds also start atrophying. When the sense of taste is lost, occasionally sense for sweet and salty tastes are lost first, and sense for bitter and sour tastes are lost then. With aging, less amount of sputum is created. This causes the mouth to be dried, which makes swallowing food more difficult and digestion less efficient. Smell sensation also diminishes. It is assumed that it is related to the loss of nerve endings in the nose. Often, the worsening of sense of smell begins at age seventies. Also, there are external factors that reduce the senses. Such factors are: smoking, tooth decay, use of certain medications, and nasal and sinus problems. The loss of smell and taste can have significant effects on people's lives. It makes people to lose their appetite and sometimes lead them to depression.

The sense of touch deteriorates along with aging too. Sense of touch includes awareness of pain, pressure, temperature, and one's body position; the body organs interact to perceive the touch sensations. This wonderful sense begins to diminish in people's mid 50s, primarily due to decrease in skin's sensitivity. As the skin losses its elasticity, loss of fats and nerve endings occurs below the dermis. The reduced cells may result in less responsive to cut, blister, or any other injuries as well as changes in temperature, which means longer delay to respond to the circumstance changes. It may lead to many types of infections. Other than infections, the decrease in number of cells causes difficulties in daily life. With reduced sense of touch, many people find it harder to catch balls, picking small objects, and do activities that require a complex hand works. Other than aging, there are many factors that change the sense: medication, brain surgery, nerve damage, and chronic diseases. It is really hard to tell which factor influences the change in sense the most, but it is certainly true that mainly aging goes along with the change. After mid 50s, people may experience a feeling of not perceiving their position. It can result in more risks of falling to the elders.

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As well as the external body organs' changes, the internal body organs go through the same aging process. As people age, bones undergo changes in their mass and density. Along with the change, a spinal vertebra is compressed, joints become less flexible, and the bones lose calcium and other elements. It is estimated that for people of age 40 or above, about 0.3 to 0.5% of the cortical bone mass is lost annually. The loss in androgen accelerates the decrease in bone mass and bone formation. For women, the changes become more dynamic after menopause. A sudden drop in estrogen, androgens, and progesterone follows the menopause. Insufficient amount of estrogen and androgen is likely to cause osteoporosis, a disease in which the bone becomes extremely porous. Human body is consisted of various types of bones. The spine is made up of bones called vertebrae. A cushion called intervertebral disk exists between each bone. The cushion loses fluids and causes the shortening of the trunk. While the trunk shortens, the long bones become more fragile. However, the long bones do not shorten as the trunk does, and it makes the body parts where long bones are, which are arms and legs, to be appeared longer. As well, the joints lose cartilages, which functions as a cushion between bones. With the change, arthritis, inflammation of joints, might occur. While bones are undergoing the changes, muscles also do change. With aging, they shrink and lose mass. Both in number and volume, the muscle fibers decrease. It makes people to react much slower. Tendons and strength are reduced, making it more difficult to endure stress and perform daily activities like picking up an object or catching a moving object. The blood circulation rate and metabolic rate slow. It is due to incapability of muscles to function most efficiently. The smaller quantity of blood is produced and circulates the body, causing not only people to be exhausted more quickly and easily, but also recovery to be longer. Also, the less capability of metabolism lessens the body's ability to convert food energy to body energy, which may result in obesity or other serious related diseases. Moreover, aging influences the joints. Aging restrains the joint movements and increases probability to be injured.

The nervous system undergoes the changes with aging. The nervous system can be divided into two categories: the central nervous system and the peripheral nervous system. The central nervous system is mainly referring to the brain and spinal marrow. It is the main processing center of the nervous system, which manages all the nerves in the body. The peripheral nervous system contains nerves that are apart from the brain. This system includes nerves in arms, muscles, and legs. Messages are perceived through the peripheral system and carried to the central nervous system through spine. Obviously, both systems are affected with aging. The brain and spinal marrow begin losing their mass; the loss causes atrophy of the body organs and nerve cell branches, which makes the transmitting of messages to be slower. Too much lost in the nerve cell might lead to demyelinization, a destruction of a myelin sheath. Sometimes, waste products are piled up and form an unusual structure called plaque. Lipofuscin might also form, which refers to a brown pigment left after breakdown of blood cells. Some main changes followed by atrophy in nervous systems are: inability to learn new materials and remember short-term memories, diminution of verbal and cerebral abilities, and slower reaction time. Since the peripheral nervous system is not able to fully function as one ages, the sense is lost which can lead to some dangers. When aging, there is also possibility for Alzheimer's disease. It is a disease affects memory and behavior in a very critical way. Dementia and delirium do not come naturally with aging. Instead, they can be caused by brain diseases such as Parkinson's disease or Alzheimer's disease. Not proper amount of blood sugar levels also may contribute to the brain disorders. Especially, people who have diabetes mellitus have higher risk of getting such behavioral or cerebral difficulties.

With aging, the body's ability to fight against germs and virus reduces. There is a reason why older people tend to get sick more easily than younger people do. In a body, there is an organ called thymus, in which immune cells are created, and it starts to diminish in people's mid 20s. It is estimated that only about fifteen percent of the thymus is left when in people's mid 40s. The reduction of T lymphocytes is crucial. Since the cells lose their ability to destroy viruses, bacteria, and harmful cells, the diminution of T lymphocytes increases the possibility to get infected. Thus, elders should be careful in protecting themselves from catching a disease.

Changes in heart and blood vessels also occur naturally as time goes by. There are two sides of the heart: the right side and the left side. The right side propels blood to lungs so that they can receive oxygen and pull carbon dioxide out of the body. The left side makes blood circulate the body. Throughout arteries, blood travels, and as the blood flows, their sizes are reduced. They become capillaries. Through the capillaries, oxygen and other energies are spread and carbon dioxide is gathered. Capillaries then returned the blood to the heart. These functions, as one ages, deteriorate. The cardiovascular system comes to be exposed to more possibility of getting diseases. It is no surprise that about forty percent of people who are sixty or older die by heart problems. With aging, the artistries become more stiffened, and it may lead to higher risk of heart diseases. The stiffer artistries result in higher blood pressure and less efficiency of the heart. They might cause hypertrophy. One's lifestyle contributes to the possible disease as well. Smoking, poor diets, lack of exercise, and high cholesterol are some main factors. The heart size increases and the heart wall thickens, making the heart's possible amount of blood to be decreased. It causes less amount of blood to circulate the body. The heart tissues degenerate gradually and become stiffer. Also the capillary walls are thickened. The thickening makes it harder to give out nutrients and oxygen to the body and collect the wastes. Baroreceptors, which are sense organs that help the body to maintain a proper blood pressure and balance, deteriorate with advancing ages. It makes elders to suffer from vertigo when they change their position. The amount of blood presents in the body also reduces; the number of blood cells in the blood vessels and the heart decreases. These are significant since they reduce one's ability to destroy foreign germs and viruses. Some normal problems that follow these changes are: Angina, arrhythmias, Aneima, Arteriosclerosis, heart failure, coronary artery disease, transient ischemic attacks, valve diseases, aortic stenosis, and other heart related diseases.

Like other organs, lungs undergo changes with advancing ages. Lungs have two major functions: receiving oxygen and sending carbon dioxide out. While breathing, air comes in and out. During the process, the air fills alveoli, small sacs. Around these alveoli, blood flows through capillaries. In the place where the sacs and capillaries meet, oxygen comes in and carbon dioxide goes out. However, while this process is completely precise and perfect, it does not have ability to filter. Therefore, many harmful elements might enter and hurt lungs. Some alien substances might be broken by the mucous membrane located in nose and bronchus. The substances that are blocked will be pulled out from the body in a form of sputum. However, cigarette smoke and sulfurous acid gas will pass through bronchus and enter into blood. As time passes by, those harmful substances will be piled up in the body and cause many respiratory diseases such as pneumonia. New alveoli are constantly created until the age of twenty, but after, the lungs begin to loss the tissues. Alveoli also decrease in their cell numbers; the lungs become less flexible. The maximum amount that one can inhale and exhale reduces. As well, the airways have more possibilities that they will be closed down. It is significant because the airways might be close while elders are sleeping.

Changes occur in the kidneys as well. What kidneys do is to cleanse blood and remove wastes from the body. This function is reduced along with aging. The cells that filter the blood, called nephrons, are reduced, making the body less able to cleanse the blood and pulling out wastes. The numbers of kidney cells decrease as well. This and the hardening of blood vessels around the kidney result in slower filtering speed. By the aging, dehydration may occur.

Then, how can people prevent those changes? Surely, there are numbers of ways to slow the rate of aging and reduce the effects of accompanying changes. To protect skin, it will be best for one to avoid ultraviolet rays from the sun. So many of harmful materials are present in the sun rays. When going out, one must use sunscreen to protect oneself from sun. Along with it, one also should try to eat a lot of fruits. Fruits contain plentiful amount of Vitamin C, which helps the skin to maintain a moist and fleshy condition. One should also quit smoking and drinking since they are critical to skin aging. Constant skin care is equally important. It is good for one to buy lotion and moisturizer and use them frequently. Too much use of beauty aids might be harmful to maintain a good skin condition. It will only stimulate the skin to develop in harmful ways. A fair amount of sleep is also needed. About eight hours of sleep is required for one to manage the stress and the health. One should regularly exercise, too. About thirty minutes a day should be spent in exercising. The exercise will help one maintain a good balance and health. The change in food eating habit is also helpful in preventing the aging. Excessive amount of salty, spicy, or sweet food is extremely harmful to people's health. The food also must not contain high degree of cholesterol, saturated fat, and trans-fat. He/she should always think of this fact and be careful when eating food. Biannual checking of one's cholesterol level and blood pressure will also be helpful. One should not read books or play games in cars or buses. Playing games in such environment makes his/her eyes tired and eventually results in losing the sight. Eating fruit and vegetable is helpful since carotenoids which are commonly found in vegetables and fruits improve the eyesight and prevent oneself from getting eye troubles. Lutein and Zeaxanthin found in carontenoids help improve the sight, widen extent of eyesight, increase the resolution, and shorten the recovery time of the eye's exhaustiveness. Folate is useful to protect oneself from hearing loss. It reduces homocysteine, which is thought to be the main factor that affects the hearing loss. The food that contains folate is kiwi, orange, strawberry, spinage, broccoli, bean, sweet potato, and asparagus. Hearing aids will be helpful for those already loss their hearing. To prevent nerve system from deterioration and oneself from dementia, one should practice and do activities that require hand and brain skills. Sudoku, puzzle, and games will be helpful. Eating a walnut and an egg yolk helps, too. One should not expose oneself in a cold weather too much; one should avoid where air is not clean.

Many changes occur as one ages, and those changes are inevitable and irreparable. Wrinkles appear on skin, eyesight decreases, hearing ability decreases, the sense of taste and smell is lost, the sense of touch becomes dull, the bones are weakened, the brain loses its efficiency and full ability, the immune system shrinks, the heart is thickened and lost its full ability to pump blood, and the lung deteriorates. However, though inevitable, there are ways to slow the changes. Doing regular physical activities and eating a lot of fruits and vegetables helps maintain a good health condition and make aging proceed more slowly. With deliberate care and effort, one can live a life more healthily and joyfully.

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