bio aging ch 5.txt

  1. Life expectancy through life
    • Increased 7.2 years in 3 centuries from 1500-1830
    • Increased 57% in last 80 years!
    • Maximum lifespans, have NOT changed as dramatically
  2. Robin Holliday
    • distinction b/w normal and pathological aging is ARTIFICIAL
    • Argues that need to attack age-related illnesses in PREVENTATIVE fashion
    • Aging can be treated as a subclinical condition
  3. Trivial vs Non-trivial aging categories
    • Trivial: Do not contribute to increasing mortality risk. ie graying of hair
    • Non-trivial: Do contribute to age-associated mortality risk. ie hardening of arteries (arteriosclerosis)
  4. Plasticity and aging patterns
    • Aging often measured at pop. level
    • 1. pop vary based on environmental or historical effects
    • 2. pop can vary based on Heterogeneity (heterogeneity increases as population gets older)
    • a. Heterogenetiy can be attributed to environmental diff such as diet, exercise, exposure to toxins
    • b. or genetic (Down's syndrome and Hutchinson-Gilford progeria)
  5. General Age-related changes in humans
    • 1. increase in body weight until midlife, then decline after
    • 2. increase in organ size until midlife, then decline after
    • 3. body comp, muscle mass decreases and adipose tissue increase
    • 4. Type I aging: growth and repair not able to keep pace with age-related damages
  6. Skin related changes with aging
    • Skin has 3 layers, composed of integumentary and immune functions. ie Keratinocytes prevent nutrient and water loss, Langerhans cells present antigens to T cells to prevent infection.
    • Dermal papillae connecting the epidermis to dermis DECREASES in surface area, resulting in Looser skin
    • Dermis becomes thinner w/age: due to increase of collagen and elastin fibers
  7. Bone and cartilage with aging
    • Cartilage: as it ages, becomes more yellow and undergoes alterations resulting in less flexible and MORE brittle
    • Bone: Ostoblasts outnumber osteoclasts until 30-40, then process reverses
    • Osteoporosis: loss of bone W/OUT changing mineral-to-protein ratio. Total bone mass declines. Increase in Parathyroid Hormone (PTH)
    • Osteoarthritis: calcification of bone (results in INCREASE of mineral-to-protein ratio)
  8. Skeletal muscle and aging
    • declines with age, although can be reversed with exercise
    • Decline may be due to free radical damage
  9. Cardiac changes with aging
    • Heart rate variability: Greatest at young age, then DECLINES with age
    • Mean arterial pressure variability (MAP): Lowest in young, INCREASES with age
  10. Blood vessel changes with age
    • Major cause of increasing cardiovascular mortality with age
    • Systolic blood pressure (SBP): Increases steadily with aging, but Low calorie diet can decrease
    • Diastolic blood pressure (DBP): Tends to Increase until late life(above 80yrs), then it tends to decline
    • Pulse Pressure (PP): SBP - DBP = PP. Increases with age due to STIFFENING of arteries
  11. Artery hardening types
    • Arteriosclerosis: Hardening of arteries, occurring progressively with age. Physiological
    • Atherosclerosis: buildup of fatty plaques on arterial walls. Occurs progressively on high calorie diet, can be reversed with drugs, diet, exercise, removing excess iron. Pathological*is reversible.
    • Both Increase risk of heart attack through occlusion of coronary arteries and stroke (3 types)
  12. 5 types of stroke
    • Ischemic: blood vessels blocked by plaques
    • Thromoembolic: Plaque forms, then flows to another part of vessel, where it blocks in new location
    • Hemorrhagic: blood vessel ruptures, causing interstitial fluid LOSS
    • Cerebrovascular: brain
    • Pulmonary: kidney
  13. Respiratory system with aging
    • Loss of alveoli fxn: less surface area for gas exchange
    • FEV and Vital capacity (VC) decrease as result
    • Decrease in Minute Respitory volume (MRV)
    • Emphysema: decreased ability to EXHALE (Tidal Volume TV Decrease)
    • Bronchitis: decrease ability to INHALE (Respitory rate RR decreases)
  14. Average Minute respitory volume (AMRV)
    Tidal Volume (TV) X Respitory rate (RR) = AMRV
  15. Emphysema results in…
    • Loss of ability to Exhale
    • Decrease in TV (Tidal Volume)
  16. Bronchitis results in…
    • Decrease in ability to Inhale
    • REspitory Rate DECREASES
  17. Changes in Digestive system with aging
    • Decrease in gastrointestinal motility: due to decrease in smooth muscle contraction
    • Decreased secretion of digestive enzymes: lead to longer digestion time, results in increase in COLON cancer risk
    • Decreases Ca absorption rates: due to Vit. D deficiency
  18. Excretory system changes with aging
    • Kidneys undergo progressive decline in renal blood flow and glomerular filtration
    • Diabetes: cause glomerular damage & INCREASE kidney failure risk
  19. Nervous system changes with aging
    • Weight of brain and spinal cord Decrease with age
    • Increase in LIPOFUSCIN: biomarker of aging?
    • Neurotransmitter decline
    • decrease in AcetylCoA: loss of short->long term mem
    • decrease in dopamime: parkinsons results, decrease in motor control
    • decrease in melatonin
    • decrease in mental abilities
    • Increase in Vocabulary up until 2yrs prior to death
    • decrease of sensory
  20. Alzheimers and aging
    • Most common dementia in elderly
    • Loss of short term, then long term memory
    • Increase in Amyloid precursor protein (APP): alpha helices become beta sheets
    • neurofibrillary tangles (thickening of microtubules, ubiquitin protein increase in diameter)
    • neuritic plaques (from degraded mitochondria or other organelles)
    • Decrease in Vitamin E in Alz patients: suggest free radicals as hypothesis for origin of this dementia
    • Aluminum in H2O also may show more support for free radical theory
  21. Immunity changes with aging
    • involution of thymus: shrinking of thymus, begins after puberty. T-cell immunity declines more Dramatically vs. B cell immunity due to this
    • Hormone injections showed improved immunity
  22. Reproductive system and aging
    • Increase in melatonin levels associated with prevention of FSH and LH, therefore early menarche in women (early menopause) and decrease in fertility for men
    • Puberty (during growth spurt): levels of melatonin decline, removing inhibition of GnRH by hypothalamus, which stimulate sexual maturation
    • Loss of reproductive abilities at old age can INCREASE reproductive fitness: it allows for increased likelihood for mother to bring grandchildren to maturity
  23. Metabolic changes with aging
    • Body heat correlated with body water content
    • Body water decreases with age
    • Decrease in mitochondrial DNA: suggest that Basal metabolic rate decreases with age may be cause of loss of body water decline
    • Decrease adiposite responsiveness
    • Decreased hormone responsiveness
    • Decreased detox of drugs by liver
Card Set
bio aging ch 5.txt
ch 5 bio aging