Textbook Notes (368,588)
Canada (161,988)
HLTC22H3 (102)
Anna Walsh (49)
Chapter 3

Chapter 3 notes

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Department
Health Studies
Course
HLTC22H3
Professor
Anna Walsh
Semester
Winter

Description
Chapter 3 - Theories of Aging Lack of integration of theories in gerontology o 3 diff. Aspects of age on whic theories can focus: characteristics of aging pop, the developmental or aging process, the way in which age is incorporated into the social structure o Gerontology has been a bottom-up discipline; starts from facts (systematic observation) that may be grouped loosely into models (which specify categories of variables that should be related) and only sometimes achieve status of theory (tries to explain or specify processes involved in a particular phenomenon) Rowe & Kahns theory of developmental aging & Ford and Lerners developmental systems theory are more models than theories Maruyamas deviation amplification model added component to von Bertalanffys classis systems theory model, which holds that most systems have deviation- countering mechanisms to maintain homeostasis o So if change occurs, mechanisms typically exist for countering that change and returning the organism to a steady rate o E.g blood pressure regualation, heart rate, respiratory rate, glucose regulation, DNA repair o Maruyama says that systems do & can change over time o Similar to chaos theory (shows how initially small changes can result in very large differences between systems & individuals) general model for aging and used to describe cascade effects in Cardiovascular functioning o But maruyamas model may be better bc it includes both positive & negative changes (maintaining homeostasis & promoting change) o Adwin & Stokols used this model to describe effects of environmental stress Biological processes fall into 2 categories o Those that promote homoestasis & decelerate aging process o Those that amplify deviations and accelerate aging process (free radicals) Biological Theories of Aging www.notesolution.com Genetic, molecularcellular, & system-level theories Genetic Theories: Avg life span of humans = 120 yrs Life span are inversely related to factor such as metabolic rate, length of time to maturation Programmed Cell Death (Apoptosis) Death gene gene that regulates sudden cell death (also called apoptosis) Genetic material is not static Damage to regulator proteins may be mechanism for cancer (uncontrolled cell profileration) Apoptosis mechanism for destruction of cells that have profilerated for specific purposes o E.g T-Cells in immune system, and need to be destroyed after having accomplished their task MORF mortality factor which controls the rate of a cells aging Positive correlation between life span of species, and number of times a cell will replicate Humans: number of times somatic cells can replicate is regulated by telomere length o Consist of specialized ends of DNA strands that help hold them together during mitosis o Dont completely unwind during mitosis o About 100 base pairs per cell lost during each replication o When several thousand base pairs are lost, the cell stops replicating and senesces o Telomeres can be restored by telomerase o Cancer cells have longer telomeres and ore active telomerese than normal cells www.notesolution.com
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