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Ageing


Ageing Process and Symptoms

The ageing process occurs over all the body and for everyone, but the pace may be different depending on the type of organ or individual. Certain cells in our tissues simply stop working after a while. When enough tissue is rendered dysfunctional, we come face to face with the
Ageing Symptoms 1 Ageing Symptoms 2 Ageing, 2015 Update debilitation of ageing. However, these cell deaths do not happen all at the same time. Some tissues remain viable for many decades, some wear out rather quickly. And ageing does not occur in the same way in every human being. It turns out that people's lifestyles also has additional influence on ageing. Table 02 lists the ageing symptoms for a few selected organs and biological functions to illustrate "how we age". Number inside the parenthesis indicates the age when ageing kicks in. More details can be found in Figure 03a and 03b for some of the organs.

Figure 03a Symptoms 1 [view large image]

Figure 03b Symptoms 2 [view large image]

Figure 04a Ageing, 2015 Update
[view large image]

Figure 04a is a 2015 update for the onset of ageing and ways to slow down its progression.


Organ/Function Ageing Symptoms
Abnormal Growth Cancers, hyperplasia, and macromolecular aggregates become common.
Arteries Cholesterol and calcium buildup, walls thicken, arteries harden, high blood pressure, risk of heart attack.
Bladder (65) Connective tissue weaken, lower capacity to store urine, and reduced efficiency of emptying content.
Blood White blood cell and red blood cell count decrease.
Body Weight Weight declines between age 55 and 75, due mostly to loss of lean tissue, muscle mass, water, and bone.
Bones (35) Loss of bone cells accelerates at about age 35, bones become porous and brittle in the demineralizing process. Osteoporosis is common in women.
Brain (20) Gradual loss of brain tissue ( 5-10% by age 90), slow reaction, faltering memory, insomnia.
Breast (35) Mammary (milk secreting) glands reduce in size, as does the breast.
Ear (55) Gradual loss of the ability to hear higher frequencies, starting around age 30; hair grows in auditory canal.
Eye (40) More far-sighted, problem with focusing, difficulty in adjusting to light intensity, perception of hues altered.
Face Wrinkles, facial hair, bags under the eyes, double chin, longer ears, thinning cheek.
Fat Fat content and distribution change, storage increases
Hair (30) Graying, thinning, balding.
Heart (40) Thickening of heart wall, gradual lose of effectiveness as a pumping machine.
Hormones The level of several hormones, e.g., GH, DHEA, IGF§, ... falls with age, may be a major cause on ageing.
Immunity Body's power to combat infection declines; auto-immune responses increase.
Joints Cartilage becomes cracks and frays, cushioning fluid gets thinner, tendons and ligaments are less resilient.
Kidneys (50) Weight & volume of the kidneys shrink, marked reduction in the cleansing of impurities from the blood.
Liver (70) The ageing process does not affect adversely the liver.
Lungs (20) Lose elasticity and capacity (40% between ages 20 and 80), increasing difficulty to oxygenate blood.
Metabolism (55) Ability to metabolize sugar decreases with age, reduction of food intake may prolong life.
Muscles (30) Loss of muscular mass, partly due to un-use, other causes include loss of blood flow and energy supply.
Nerve Demyelination - loss of myelin covering of nerve fibers, which is characteristic of neurological disorders.
Nose (60) Ability to smell declines after age 65, amount of reduction varies widely between individuals.
Prostate (50) Reduction in semen making after 60, enlargement in size may cause difficulty to urinate.
Reaction Time Mental and physical responses to specific stimuli become slower.
Reproductive
System (35)
Women go through menopause at ages of 45 - 50, reduced level of estrogen affects the whole body.
Men's reproductive change with age is more like a reduction than a cessation.
Skin (25) Wrinkles (related to decreased mitochondrial function), dryness, dark spots.
Teeth (40) Teeth gum recession
Thermoregulation Response to changes in environmental temperature becomes impaired.
Tongue (60) Sense of taste loses only gradually with age, with equal reduction of all flavors.
Voice (65) Voice becomes weak and muffled

Table 02 Ageing Symptoms

§GH - growth hormone, DHEA - dehydroandrosterone, IGF - insulin/insulin-like growth factor.

An American man's average life span is more than five years shorter than a woman's. Differing hormone levels and lifesytle choices may explain the disparity. Table 03 lists the leading causes of death in the U.S. separately for men and women.

Men Women
01 Heart disease Heart disease
02 Cancer Cancer
03 Accidents Stroke
04 Stroke Chronic obstructive lung disease
05 Chronic obstructive lung disease Diabetes
06 Diabetes Alzheimer's disease
07 Pneumonia and influenze Accidents
08 Suicide Pneumonia and influenze
09 Kidney disease Kidney disease
10 Live disease Blood infections

Table 03 Leading Causes of Death in the U.S.


With the discovery in the 1980s that mutations in single genes can significantly extend lifespan in the nematod C. elegans, ageing began to be viewed as malleable by methods used to understand and manipulate development and disease. At present, hundreds of mutant genes can increase
Ageing, Delayed by Healing Damage longevity in model organisms, including nematodes, yeast, fruitflies and mice. Most act in evolutionarily conserved pathways that regulate growth, energy metabolism, nutrition sensing and/or reproduction. Examples include genes encoding components of the insulin/insulin-like growth factor 1 (IGF-1) signalling (IIS) pathway, the target of rapamycin (TOR) pathway, and the mitochondrial electron transport chain. In most cases, lifespan extension occurs when activity of the component is diminished. This abatement is thought to reduce somatic damage and/or increase somatic maintenance and repair. The appreciation that lifespan is plastic and under negative influence by genes that favour growth or procreation fuels hopes of finding small molecules (drugs) that target the pathways affected by pro-longevity mutations.

Figure 04b Ageing, Delayed by Healing Damage [view large image]

Figure 04b shows the way to prolong lifespan by healing whatever damage inflicted on the cell. Such method is currently in active research by investigators.

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