AGING: NORMAL AND ABNORMAL

---

[ CATS Home | About CATS | CATS Teaching Modules | Course Outline | Aging | UVM Department of Pathology | Other Pathology Sites | UVM College of Medicine | UVM ]

---

I. CELLULAR AGING
II. THEORIES OF CELLULAR AGING
III. AGING CHANGES IN ORGANS AND SYSTEMS
IV. DISEASES OF AGING

READING:

1. Cotran RS, Kumar V, Robbins SL, eds. Robbins Pathologic Basis of Disease, 5th edition, W.B.Saunders, Philadelphia, 1994: 32-33.
   
   
2. Schneider EL, Brody JA. Aging, natural death, and the compression of morbidity: another view. New Engl J Med 1983;309:854-855.
   
   
3. Schneider EL, Reed JD. Life extension. New Engl J Med 1985;312:1159-1168.
   
   
4. Rowe JW, Kahn RL. Human aging: usual and successful. Science 1987;237:143-149.
   
   
5. Rowe JW. Health care of the elderly. New Engl J Med 1985;312:827-835.
   
   
6. Schneider EL, Guralnik JM. The aging of America: impact on health care costs. JAMA 1990;263:2335-2340.
   
   
7. Olshansky SJ, Carnes BA, Cassel C. In search of Methuselah: estimating the upper limits to human longevity. Science 1990;250:634-640.

VOCABULARY
Terms with which you should be familiar:

Life expectancy
Life span
Urinary incontinence
Osteoporosis
Medicare
Medicaid
Nursing home
Hip Fractures
Rectangular survival curve
Senescence
Ageism
Chronic disease
Age related
Age dependent
Benign senescent forgetfulness
Progeria
Dementia
Plasticity

OBJECTIVES:

1. Understand aging as a normal biological function.
2. Understand aging as it relates to social, economic and health care issues in the United States.
3. Explore theories of cellular aging.
4. Explore aging in organ systems.
5. Clearly understand the concepts of life expectancy vs. life span, age related diseases vs. age dependent diseases.

Back to Top

Lecture 1: Aging: Cellular Aging, And Aging Changes In Organs And Systems: An Overview

Definition of Aging: "a decreasing ability to survive"

I. CELLULAR AGING

• Aged mitochondria have a decreased ability to survive hypoxic insult.
  
  
• Oxidative phosphorylation declines progressively.
  
  
• DNA and RNA synthesis of structural and enzymatic proteins declines progressively.
  
  
• Senescent cells have a decreased capacity for uptake of nutrients and for repair of chromosomal or genetic damage.
  
  
• Cells disclose morphologic features with increasing age.

II. THEORIES OF CELLULAR AGING

• "Wear and Tear" Theories
  
  
  • free radical theory
  • post-translational modifications (cross-linkage theory)
  • accumulation of waste products theory
  • error-catastrophe theory
    
    
• Genome-Based Theories
  
  
  • finite doubling potential of cells
  • somatic mutations
  • programmed aging

Back to Top

III. AGING CHANGES IN ORGANS AND SYSTEMS

• Immunity and Senescence
  
  
  • There is a progressive quantitative and qualitative diminution in the capacity to produce antibodies.
  • There is a commensurate tendency for aggregates of lymphocytes to appear in the bone marrow and other sites, and an increase in the development of autoimmune reactions and diseases.
  • There is a profound decline in T-lymphocyte function with age.
    
    
• Neuroendocrine Senescence
  
  
  • age-related development of hypertension possibly related to increased sympathetic system activity
  • impaired glucose intolerance
  • diminished thyroid function
  • decline in gonadal function
    
    
• The Brain and Senescence
  
  
  • selective loss of isolated neurons
  • no evidence that the function of the brain significantly deteriorates with aging
  • benign senescent forgetfulness vs. dementia
    
    
• Aging and the Cardiovascular System
  
  
  • diminished heart rate
  • cardiac output is maintained by adaptive mechanisms such as cardiac dilatation and greater stroke volume
  • isolated cardiac muscle appears to suffer little age dependent change in function
  • progressive rise in basal systolic blood pressure, possibly due to a loss of compliance of the aorta and major arteries with age
    
    
• Aging and the Kidney
  
  
  • progressive decrease in renal blood flow and glomerular filtration rate
  • as much as a 40% reduction in renal function in older persons
    
    
• Aging and the Lungs
  
  
  • less elastic and compliant with aging
  • tend to become expanded secondary to qualitative changes in elastin and collagen
    
    
• Aging and Body Composition
  
  
  • loss in muscle and bone mass, accompanied by an increase in fat mass
  • elderly who remain physically active have only moderate loss of skeletal muscle, mainly type II "fast twitch" fibers
  • ligaments and tendons stiffen
  • bone loss occurs in almost all postmenopausal women and elderly men
  • magnitude of bone loss is dependent on physical activity, nutrition, and hormonal changes
    
    
• Aging and Other Systems
  
  
  • liver mass decreases with age, as does hepatic blood flow
  • loss of melanocytes in hair follicles
  • skin changes: thinning, random decrease in melanocytes, atrophy of subcutaneous fat, and loss of elasticity and wrinkling

IV. DISEASES OF AGING

• Those over 65 in the US spend three times as much on health care as those under 65.
  
  
• At present only about 2.3% of people are over the age of 80, but this group accounts for 17% of the mortality in the US
  
  
• Age dependent disease: direct consequence of physiologic senescence
  
  
• Age related disease: occurs with increasing frequency with age
  
  
• The three leading causes of death in people 75 to 84 years of age are heart disease, cancer, and cerebrovascular disease.
  
  
• Issue of drug toxicity

Back to Top

Go Back to Aging

Go Back to Course Outline

---

[ CATS Home | About CATS | CATS Teaching Modules | UVM Department of Pathology | Other Pathology Sites | UVM College of Medicine | UVM ]

---

Questions? Comments? Send a message to the CATS guru: jkessler@salus.uvm.edu