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The Effects of Aging
Transcript of The Effects of Aging
By Erin Johnson
The human body is made up of fat, lean tissue (muscles and organs), bones, and water. After age 30, people tend to lose lean tissue. Your muscles, liver, kidney, and other organs may lose some of their cells. This process of muscle loss is called atrophy. Bones may lose some of their minerals and become less dense (a condition called osteopenia, or at its later stage, osteoporosis). Tissue loss reduces the amount of water in your body.The amount of body fat goes up steadily after age 30 and may rise by as much as 30%. Fat tissue builds up toward the center of the body, including around the internal organs. However, the layer of fat under the skin (subcutaneous) gets smaller.
All of the eye structures change with aging. The cornea becomes less sensitive, so injuries may not be noticed. By the time you turn 60, your pupils decrease to about one third of the size they were when you were 20. The pupil may react more slowly in response to darkness or bright light. The lens becomes yellowed, less flexible, and slightly cloudy. The fat pads supporting the eyes decrease in amount and the eyes sink into their sockets. The eye muscles become less able to fully rotate the eye.
As you age, the sharpness of your vision (visual acuity) gradually declines. The most common problem is difficulty focusing the eyes on something close. This condition is called called presbyopia.
Taste and Smell
The number of taste buds decreases as you age. Each remaining taste bud also begins to lose mass (atrophy). Sensitivity to the four tastes often declines after age 60. Usually salty and sweet tastes are lost first, followed by bitter and sour tastes. In addition, your mouth produces less saliva as you age. This causes dry mouth, which can affect your sense of taste.
Sense of smell can diminish, especially after age 70. This may be related to loss of nerve endings in the nose and to less mucus being produced in the nose. Mucus helps odors stay long enough to be detected by the nerve endings. It also helps clear odors from the nerve endings.
Certain things can speed up the loss of taste and smell. These include diseases, smoking, and exposure to harmful particles in the air.
Aging of the Skin
Over time the epidermis thins. As the cell cycle slows, epidermal cells grow larger and more irregular in shape but are fewer. Wrinkles are produced from the shrinking of the dermis and the loss of some fat from the subcutaneous layer. Changes in the connective tissue reduce the skin's strength and elasticity. Sebaceous glands produce less oil as you age. This can make it harder to keep the skin moist, resulting in dryness and itchiness.The number of pigment-containing cells (melanocytes) decreases, but the remaining melanocytes increase in size. Aging skin thus appears thinner, more pale, and clear (translucent). Large pigmented spots (called age spots, liver spots, or lentigos) may appear in sun-exposed areas.
Aging of Hair
Hair color is due to a pigment called melanin, which is produced by hair follicles. These are structures in the skin that make and grow hair. With aging, the follicle makes less melanin. With aging nearly everyone has some hair loss. The rate of hair growth also slows.
Hair strands become smaller and have less pigment. So the thick, coarse hair of a young adult eventually becomes thin, fine, light-colored hair. Many hair follicles stop producing new hairs.