Introduction to Geriatrics Theories Of Aging Lecture PDF

Introduction to Geriatrics Theories Of Aging Dr : Alaa Abdelmonem Lecturer at ECU Aging is a fundamental process that affects all of body systems and tissues. The rate and the magnitude of change in each system may differ from one person to another, but total body decline is an inevita...

Introduction to Geriatrics Theories Of Aging Dr : Alaa Abdelmonem Lecturer at ECU Aging is a fundamental process that affects all of body systems and tissues. The rate and the magnitude of change in each system may differ from one person to another, but total body decline is an inevitable part of life for everyone. Gerontology: It is the study of the social, psychological and biological aspects of aging. Geriatrics: It is a branch of medicine that studies the disease of elderly. Classification of Geriatric's Biological age groups:  The young old: from the age of 65 to 75 years old.  Adult old: from age of 75 to 85 years old.  Oldest old: older than 85 years old.  Theories of aging Aging may be viewed as a continuum of events that occur from conception to death. There are many theories about the mechanisms of age related changes. No one theory is suffi ciently explains the process of aging. Biologic, social, and psychological theories of aging attempt to explain and explore the various dimensions of aging. 1) BIOLOGIC THEORIES OF AGING Are concerned with answering basic questions regarding the physiologic processes that occur in all living organisms as they chronologically age. These age related changes occur independently of any external or pathologic influence. 2) SOCIOLOGIC THEORIES OF AGING Focused on the rules and relationships within which individuals engage in later life 3) PSYCOLOGIC THEORIES OF AGING Influenced by both biology and sociology and address how a person respond to the tasks of their life. 4) EMERGING THEORIES OF AGING - Neuroendocrine theory - DNA damage theory of aging - Metabolic theory of aging  BIOLOGIC THEORIES OF AGING Stochastic Theories Non stochastic theories 1 Free radical theory. 1 Programmed theory. 2 Error theory. 2 Immunity theory. 3 Wear and tear theory. 4 Cross linkage theory. Oxidative stress damage theory  Oxidative free radical theory demonstrates that aging is due to oxidative metabolism and the effect of free radicals  Free radicals are produced when the body uses oxygen, such as with exercise.  Free radicals are chemical species that arise from atoms as single, unpaired electrons. Because a free radical molecule is unpaired, it is able to enter reactions with other molecules, especially along membranes and with nucleic acids.  Free radicals are thought to react with proteins, lipids, deoxyribonucleic acid (DNA), and ribonucleic acid (RNA), causing cellular damage; this damage accumulates over time and is thought to accelerate aging.  Mitochondria: Known as the “powerhouses of the cell,” mitochondria produce the energy necessary for the cell's survival and functioning. Through a series of chemical reactions known as krebs cycle, mitochondria break down glucose into an energy molecule known as adenosine triphosphate (ATP) which is used to fuel various other cellular processes.  Mitochondrial deterioration caused by free radical activities causes a significant loss of cell energy and greatly decreases metabolism. How to delay mitochondrial deterioration Decrease calories in order to lower weight (obesity triggers the inflammatory process in the body).  Maintain a diet high in nutrients, including antioxidants. Avoid inflammation. Minimize accumulation of metals in the body that can trigger free radical reactions.  Wear and tear theory The wear and tear theory of aging is an idea proposed by German biologist, Dr. August Wiesmann , in 1882. The theory suggests that aging results from a gradual deterioration of the cells and tissues of the body via wear and tear, oxidative stress, exposure to radiation, toxins, or other deteriorative processes. It suggests that living organisms “wear out” over time with repeated use and increased stress on the body. This concept is similar to the idea that objects such as automobiles deteriorate or wear out as they are used repeatedly over time.  Programmed theory of cellular death The theory describes Cellular response to aging as the cells decide to commit suicide or stop dividing which triggers the apoptosis sequence or death of the cell. The cells of a multicellular organism are members of a highly organized community. The number of cells in this community is tightly regulated—not simply by controlling the rate of cell division, but also by controlling the rate of cell death. If cells are no longer needed, they commit suicide by activating an intracellular death program Each time the cell divides it ages even more.  Neuroendocrine theory Experts believe hormones, which control the function of organs, could be behind the aging process. as we move through the stages of life, our hormone levels fluctuate; aging means that we produce more of some hormones and less of others (mostly the latter).  Hormonal changes in old age  The most common consequence of aging-related hormonal changes is menopause. Around age 50, women's ovaries begin producing decreasing amounts of estrogen and progesterone; the pituitary gland tries to compensate by producing more follicle stimulating hormone (FSH).  Hormonal changes in old age Estrogen: Responsible for setting off puberty, regulates the menstrual cycle, maintains pregnancy , and aging effect for the skin, regulate cholesterol production and keeps bones strong for women and men too  While menopause is normal some of the symptoms can be irritating :  Hot flashes  Vaginal dryness  Insomnia  Irritability/depression  Osteoporosis  During menopause, lower levels of estrogen have a big impact on your skin. Less estrogen makes you prone to thinning, sagging, and wrinkling. For men: andropause It's not "male menopause," exactly — for one thing, it doesn't happen to all men — but about 20 percent of men over age 60 and 30-50 percent of men over age 80 will experience andropause, a significant decline in testosterone production. The symptoms might include the following:  Decrease in muscle mass and overall strength  Decrease in bone mineral density  Low libido and erectile dysfunction  Decreased energy and depression  Cognitive impairment  Parathyroid hormone levels rise with age, which may contribute to osteoporosis as it normally maintains a proper balance between calcium in the blood stream and in tissues that depends on calcium for proper functioning  Growth hormone fuels childhood growth and helps maintain tissues and organs throughout life. It's produced by the pituitary gland — located at the base of the brain. Beginning in middle age, however, the pituitary gland slowly reduces the amount of growth hormone it produces.  GH secretion in adulthood. GH deficiency in adults is associated with fatigue, decreased energy, depressed mood, decreased muscle strength, decreased muscle mass, thin and dry skin, increased adipose tissue, and decreased bone density. Vitamin D has the properties of both a hormone and a vitamin and is necessary for mineral homeostasis, maintain normal blood levels of calcium and phosphorus, aids in the absorption of calcium, helping to form and maintain strong bones, promotes an overall increase in the strength of the immune system, assists in the maintenance of joint and muscle comfort, as well as the maintenance of a healthy mood, supports breast, colon, and prostate health. vitamin D3 or Cholecalciferol is the naturally occurring form of vitamin D that is synthesized in the skin from endogenous or dietary cholesterol upon exposure to sunlight  A longitudinal study in sunny New Mexico showed that vitamin D levels decline in older persons, even with adequate sun exposure.  Aging Changes in neurological system 1 Brain 2 Spinal cord 3Peripheral nervous system o Brain Brain function varies normally as people pass from childhood through adulthood to old age. During childhood, the ability to think and reason steadily increases, enabling a child to learn increasingly complex skills. After a certain age, which varies from person to person, brain function declines. Some areas of the brain decrease in size by up to 1% per year in some people but without any loss of function. Thus, age-related changes in brain structure do not always result in loss of brain function. However, a decrease in brain function with aging may be the result of numerous factors that include changes in brain chemicals (neurotransmitters),changes in nerve cells themselves, toxic substances that accumulate in the brain over time, and inherited changes.  Different aspects of brain function may be affected at different times: Short-term memory and the ability to learn new material tend to be affected relatively early. Verbal abilities, including vocabulary and word usage, may begin to decline later. Intellectual performance—the ability to process information (regardless of speed)—is usually maintained if no underlying neurologic or vascular disorders are present. Reaction time and performance of tasks may become slower because the brain processes nerve impulses more slowly. o Spinal cord As people age, the disks between the back bones (vertebrae) become hard and brittle, and parts of the vertebrae may overgrow. As a result, the disks lose some of their capacity to cushion, so more pressure is put on the spinal cord and on the branches of the nerves that emerge from it (spinal nerve roots). The increased pressure may injure nerve fibers at the point where they leave the spinal cord. Such injury can result in decreased sensation and sometimes decreased strength and balance. o Peripheral nerves As people age, peripheral nerves may conduct impulses more slowly and release neurotransmitters is impaired, resulting in decreased sensation, slower reflexes, and often some clumsiness. Nerve conduction can slow because the myelin sheaths around nerves degenerate.  Neurological symptoms Disorders that affect the brain, spinal cord, and nerves are called neurologic disorders.  Neurologic symptoms: symptoms caused by a disorder that affects part or all of the nervous system can vary greatly because the nervous system controls so many different body functions. Symptoms can include all forms of pain, including headache and back pain. Muscles, skin sensation, the special senses (vision, taste, smell, and hearing), and other senses depend on nerves to function normally. Thus, neurologic symptoms can include muscle weakness or lack of coordination, abnormal sensations in the skin, and disturbances of vision, taste, smell, and hearing. Neurologic disorders can interfere with sleep, making a person anxious or excited at bedtime and thus tired and sleepy during the day.  Aging Changes in Specific Organ Systems 1-Eyes Presbyopia (Losing the ability to see up close) due to hardening & thickening of the lens Decreased visual acuity because of narrowed pupil. additional problems with depth and color perception. Having trouble distinguishing colors, such as blue from black. Needing more time to adjust to changing levels of light Ears-2 high sound frequencies lost and impaired speech discrimination More prone to excess (ear wax) ,occlusion of ear canal, which becomes narrower.