Biology of Aging exam review 1

Theory of aging is valid if it meets:

1) occurs commonly in all members of a given species 2) must be progressive with time 3) must produce changes that cause organ dysfunctions that ultimately cause a particular body organ or system to fail.

Monsignor C. Fahey: there are two ages all animals including humans live through.

1) young and learning to survive 2) old enough to reproduce

world health organization

60-75 elderly, 76-90 old, over 90 very old

Humans created a third age

human life is now about 50% longer than necessary for the continuation of the species

Senility

the physical and mental deterioration associated with old ageth

Where is water mainly stored?

within individual cells (intracellular water), the spaces between the cells (extracellular water)

Free Radical Theory:

Free radicals are cellular chemicals containing an unpaired electron. They are formed as by-products of various normal cellular processes involving interactions with oxygen. Free radicals usually react with cellular proteins and unsaturated fats causing them to be chemically altered which in turn alters normal functioning of these molecules. Free radical theory suggests that there may be a gradual accumulation of free radicals in cells with time that may contribute to changes associated with the aging process. The production of new free radicals can be inhibited by antioxidants. Research has shown that free radicals are neutralized by antioxidants in young cells. Research also shows us that longer lived species have more antioxidants than do shorter lived species. In general, these results suggest that in aging cells antioxidants either are rendered or are overwhelmed by increasing numbers of free radicals or that older cells may produce fewer antioxidant enzymes.

Geriatrics x2

Health care delivery for the elderly. Branch of medicine that treats the conditions and diseases associated with age. Those physicians who practice geriatrics attempt to differentiate the aging process from disease.

Geriatrics

Health care delivery for the elderly. The branch of medicine that treats the conditions and diseases associated with aging and old age.

Gene Mutation Theory:

It is well accepted that mutations occur in the genes of cells during life. Gene mutation theory suggests that the accumulation of cells with altered structure and function that result over time may lead to aging malfunction and death. What are some of the possible causes of gene mutations over the span of one's life?

What are some factors that may influence longevity of human life?

Lifestyle, nutrition, environmental, genetics, gender, changes in healthcare/medicine

Structural Changes of aging:

Loss of height beginning at age 30 and progressing slowly. Gradual muscle deterioration Loss of elasticity of tissues Weight changes, Men increase weight through their mid-fifties then lose weight. Women gain weight through their sixties, then lose weight. Women's weight loss is usually slower than men's.

Body Functional Changes:

Movement becomes more difficult as joints stiffen and muscle strength lessens. The exchange of oxygen and carbon dioxide in the lungs becomes less efficient causing difficulty breathing. Changes in the heart muscle and walls of the arteries may cause an elevated blood pressure Changing in the functioning of the GI tract may cause an alteration of diet. Urinary system changes cause an increase in frequency of urination.

Gene Theory

The Gene theory also states that aging is programmed but suggests that the programming is due to one or more harmful genes within each organism. Some believe these harmful genes become active only late in life and alter physiology in ways that lead to functional decline associated with aging and death. Also suggested that human life span is an inherited trait. There are a number of studies on twins that show support for this suggestion. There is considerable similarity in age at death for identical twins (monozygous twins) when compared. The problem, little firm evidence to support the theory.

Senescence

The group of deleterious effects that lead to a decrease in the efficient functioning of an organism with increasing age and to an increased probability of death. Tends to be more restrictive then aging, refers to the stage of old age characteristics, implies pathological effects.

Autoimmune Theory:

The immune system functions to protect an individual from invasion by foreign substances. Antigen: foreign substance or invader. Antibody: specialized protein the body makes to fight the antigen. And alert the bodies defensive cells. The autoimmune theory suggests that, with advancing age, the immune system is no longer able to faultlessly distinguish foreign proteins from the body's own proteins. Antibodies against the body's own protein may be formed in older persons. The body's own immune system starts to attack and destroy the body's own cells. Two sources also suggest that new antigens may appear in later years from the result of mutations that cause the body's altered proteins to be recognized as foreign invaders. Autoimmune disease...

Cross-sectional studies

The parameters to be studied are measured and compared at the same time for persons within various age groups. Allows an average value to be determined for any particular aging variable measured.

Senility

The physical and mental deterioration often associated with old age

Aging

The process of growing old, regardless of chronological age

Demography

The statistical study of human populations collectively, including geographic changes and trends in births, marriages, diseases, and deaths. Provide vital basic information in many aging studies.

Wear-and-Tear Theory:

The wear-and-tear theory supports the concept that aging is a programmed process. It suggests that each animal and perhaps each cell, has a specific amount of metabolic energy available to it and that the rate at which this energy is used determines the animal's length of life. Experimental evidence for this theory was provided by demonstrating that rats kept in a cold environment and those with restricted food consumption both showed considerable increases in life span. Reduction in caloric intake is the most effective known method for modifying the apparent rate of aging in rats. As of yet, there is no conclusive evidence of similar results in humans.

mean longevity

average longevity of a population

Longetivity

duration of life of an individual

Nucleotide

forms genes, it is created by the joining together of a sugar, a base, and a phosphate molecule. Join together to create DNA.

Test body compositional changes by:

measuring the total body water by administrating an indicator compound that enters the body water and then determining the dilution of the indicator. (estimates fat in the body). Or measure the specific gravity in the body

Physiological Age

A measure of functional capacity

Chronological Age

Age measured in years

Longevtiy

Duration of life. Mean and maximum measures

Proteins most effected by cross-linking enzymes and collagen

E

Body compositional changes:

Reduction in water mass, due to an increase in fat to lean tissue ratio. Skin gets thinner with age. Loss of lean tissue, causing decreases in leg and arm mass. Most organs show an age-related loss of mass. Decrease in intracellular water content

Gerontology

The scientific study of the process of aging and the problems associated with aging.

longitudinal study

Began by making the measurements on over 1,000 male subjects. Most studies done with short-lived animals such as rotifers, paramecia, and fruit flies. Makes it easier to study life-death.

Senescence

Biological aging, the change in the biology of an organism as it ages after maturity

Accumulation-of-Errors Theory:

Accumulation-of-errors theory suggested that cellular dysfunction, and ultimately cell death, could result from the accumulation of random errors in the mechanism by which new proteins are synthesized. This theory suggests that aging is caused by an accumulation of errors in protein synthesis with time which in turn also affects enzyme activity negatively. The validity of this theory is generally considered to be highly questionable due to lack of research.

The free radial theory suggests that there may be a gradual accumulation of free radicals in cells with time and that, as they exceed threshold concentrations, they may contribute to changes commonly associated with aging

T

Cellular Garbage Theory:

These "garbage" molecules are thought to interfere with normal cell functioning by causing damage in certain cellular components including: Proteins Nucleic acids This theory suggests that the accumulation of both inert and reactive substances can interfere with normal cell functioning and contributes to aging. As cells age they accumulate increased amounts of various substances within their cytoplasm. Free Radicals Aldehydes Histones Lipofuscins (yellow-brown pigments)

Aging by Program:

This theory suggests that there is some type of chronometer in the human body that controls the aging process. Some suggest that the hypothalamus in the base of the brain is involved. The hypothalamus is the central control center for several hormonal systems involved in regulation in the body. Information from the hypothalamus is carried to cells through nerves and hormones. As we age, the ability to communicate with cells through nerve impulses and chemical messengers declines with age and may contribute to the aging process. It has also been suggested that there may be an internal cellular clock in individual cells that controls or restricts the cells division process over time.

Cross-linkage Theory:

When proteins are denatured past a certain point, they are irreversibly altered. Ex. Cooking an egg... Denaturation is caused by the formation of cross-links between the strands of the protein's peptide structure. Proposes that with age and the formation of new cross-links, some proteins in cells are irreversibly altered structurally over time. This alteration effects normal functioning of the proteins and ultimately causes dysfunction of the cells, tissues, and organ systems made up of those cells. The proteins most often mentioned as being affected are enzymes and collagen. Enzymes: are proteins that are responsible for many chemical processes in the body. They are referred to as organic catalysts because they accelerate the rate of all chemical reactions and regulation in the body. Collagen: is a very common supportive tissue type in all parts of the body. It is composed of protein fiber embedded in an intercellular matrix. When the structure of collagen is altered, the structure of the organ in which it is located is also affected. This, in turn, alters the normal functioning of that organ. Ex. Over time the elasticity of blood vessels declines do to changes in collagen in the vessels. As we age, our cardiovascular system becomes less functional. As we age collagen production in the body seems to increase. Producing of excess collagen is termed fibrosis. The increase of collagen in the body equates to less elasticity and reduced functional capacity at both the cellular and organ system levels. "old and stiff" Examples of systems affected?

gerontology

study of the process of aging and of all aspects biological, sociological, historical, problems of aging

Water mass

young man: 60% body weight young woman: 52% body weight old man 54% body weight old woman 46% body weight change of ratio of lean to fat, reducing space available to accommodate water.