aging

Table of Contents

Introduction
Biological theories of aging
- Genetic theories
- Nongenetic theories
  - Wear-and-tear theory
  - Cross-linking theory
  - Autoimmune theory
  - theory
  - Oxidative damage theory
  - Psychosociological theory
Natural history of aging
- Reproduction and aging
- Species differences in longevity and aging
- The inheritance of longevity
Senescence in mammals
- Changes in body composition, metabolism, and activity
- Changes in structural tissues
- Tissue cell loss and replacement
- Mammalian cell cultures
- Changes in tissue and cell morphology
Aging at the molecular and cellular levels
- Aging of genetic information systems
- Aging of the immune system
- Aging of neural and endocrine systems
Internal and external causes of aging
- External environmental agents
  - Ionizing radiation
  - Temperature
  - Physical wear of nonrenewable structures
  - Infectious disease and nutrition
- Internal environment: consequences of metabolism
Anti-aging and longevity research
- Antioxidants
- Calorie restriction and longevity
- Sirtuins
- Rapamycin
- Stem cells
- Genetics and life span

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aging: Facts & Related Content

Written and fact-checked by The Information Architects of Encyclopaedia Britannica

Facts

Also Known As	ageing

Photos and Videos

centenarian; supercentenarian

rheumatoid arthritis

semelparity; wheat

aposematic coloration; tiger moth

squirrel; longevity among mammals

longevity: animals

Know how unlike humans some organisms like naked mole rats, rock fish, lobsters, and bristlecone pines can pause their aging process

Know how telomeres protect the ends of the chromosomes and over a while, it causes cellular aging

The secret to a longer life in Campodimele, Italy

Is there any benefit to red wine baths?

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Topics

human aging menopause old age middle age hexosamine-collagen ratio crow’s feet free-radical theory of aging dog years explained biological development agism metabolism death prenatal development coloration sex sleep photosynthesis mimicry birth nutrition

Dig Deeper: More Articles That Discuss This Topic

Key People

Bruce Ames

American biochemist and geneticist

English-born American biochemist and geneticist Jack W. Szostak.

Jack W. Szostak

American biochemist and geneticist

Elizabeth Blackburn

Elizabeth Blackburn

American molecular biologist and biochemist

Carol W. Greider

Carol W. Greider

American molecular biologist

Lillien Jane Martin

American psychologist and educator

M.F.K. Fisher

American author

Alex Comfort

British author

List

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