13. Aging

A set of vocabulary flashcards summarizing core terms and definitions from the lecture on physiological changes of normal aging.

Senescence

Irreversible, normal physiological changes that accumulate with age due to genetic and environmental influences.

Extrinsic Factors

Environmental influences on aging such as diet, exercise, toxins, sunlight, and socioeconomic stress.

Intrinsic Factors

Genetically programmed influences on aging inherited through DNA.

Damage-Based Theories of Aging

Explanations that emphasize accumulated cellular and molecular damage from the environment over time.

Programmed-Based Theories of Aging

Explanations proposing that aging follows a genetically predetermined timetable.

Error Theory

A damage-based theory stating that mistakes in informational molecules hinder correct cell reproduction.

Wear and Tear Theory

A damage-based theory that cells and tissues simply wear down with repeated use.

Free Radical Theory

A damage-based theory that accumulated oxidative molecules damage DNA and accelerate aging.

Neuroendocrine Theory

A damage-based theory suggesting reduced hormone production impairs cellular regulation with age.

Programmed Longevity

A programmed theory proposing sequential switching on/off of specific genes leads to senescence.

Endocrine Theory (Aging)

A programmed theory that biological clocks use hormones to set the pace of aging.

Immunological Theory

A programmed theory that a declining immune system increases vulnerability to disease and death.

Telomere

Protective DNA–protein caps at chromosome ends that shorten with each cell division.

Telomerase Theory

Theory that telomere shortening limits cell replication, and healthy lifestyle can slow this process.

Sarcopenia

Age-related loss of skeletal muscle mass, strength, and endurance.

Sarcopenia Etiology

Multifactorial causes including metabolic, endocrine, nutritional, genetic, and inactivity factors.

Sarcopenia Pathogenesis

Loss of motor units, reduced fiber size, impaired excitation–contraction, and fast-twitch fiber atrophy.

Effects of Sarcopenia

Weakness, slower gait, poor balance, increased falls, fractures, and prolonged recovery.

Progressive Resistance Training

Muscle-loading exercise that can slow or partially reverse sarcopenia and decrease fall risk.

Bone Composition Changes

With aging, bones shrink, lose density, discs dry out, and height decreases.

Osteoporosis

Chronic disease of low bone mass and quality leading to fragile bones and fracture risk.

Osteopenia

Bone density below normal but not low enough for osteoporosis (T-score between −1.0 and −2.5).

Bone Mineral Density (BMD) Testing

Measurement with DEXA to classify bone status as normal, osteopenic, or osteoporotic.

T-Score

Standard deviation comparison of a patient’s BMD to a young adult reference; ≤ −2.5 indicates osteoporosis.

Compression Fracture

Collapse of vertebral bodies; the most common osteoporotic fracture type.

Sensorimotor Changes

Loss of neurons, slower nerve conduction, reduced neurotransmitters, leading to slower reactions and higher fall risk.

Presbyopia

Age-related loss of near vision due to decreased lens flexibility.

Hyposmia

Reduced sense of smell commonly appearing after age 60.

Hypogeusia

Decreased taste sensitivity caused by fewer taste buds and less saliva.

Cardiovascular Changes with Aging

Enlarged chambers, thickened walls, stiffer vessels, slower heart rate, and higher blood pressure risk.

Maximal Aerobic Capacity (VO2max) Decline

Progressive reduction in the body’s ability to use oxygen during maximal exercise.

Respiratory Changes with Aging

Reduced alveolar surface, lung recoil, vital capacity, and respiratory muscle strength.

Aerobic Training Benefits

Slows VO2max decline, increases endurance, and improves respiratory function in older adults.

Integumentary Changes

Thinner dermis, reduced vascularity, fewer follicles, diminished thermoregulation, and delayed healing.

Melanocyte Loss

Decrease in pigment-producing cells raising skin-cancer and vitamin-D-deficiency risk.

Alzheimer’s Disease

Neurodegenerative disorder marked by amyloid plaques and tau tangles causing dementia.

Amyloid Plaque

Abnormal protein clusters in the brain associated with neuron degeneration in Alzheimer’s disease.

Neurofibrillary Tangle (Tau)

Twisted protein fibers inside neurons that disrupt function in Alzheimer’s disease.

Exercise Benefits on Cognition

Regular physical activity is linked to preserved gray matter and reduced risk of cognitive decline.

Gray Matter

Brain tissue responsible for movement, memory, and emotions that decreases with age without exercise.

Osteoarthritis Increase

Higher cartilage degeneration and stiffness leading to joint pain and reduced mobility in aging.

Joint Proprioception Decline

Age-related loss of position sense, especially in the knee and ankle, contributing to falls.

Apoptosis of Atrial Pacemaker Cells

Programmed cell death that slows intrinsic heart rate in older adults.

Endurance Loss in Muscle

Reduced ability of muscles to sustain activity because of sarcopenia and metabolic changes.

Lifestyle and Telomere Shortening

Healthy diet, exercise, and sleep can slow the telomere shortening associated with aging.