Download - 05.18.09: Physiology of Aging
![Page 1: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/1.jpg)
Author: Brent C. Williams, M.D., M.P.H., 2009
License: Unless otherwise noted, this material is made available under the terms of the Creative Commons Attribution – Share Alike 3.0 License: http://creativecommons.org/licenses/by-sa/3.0/
We have reviewed this material in accordance with U.S. Copyright Law and have tried to maximize your ability to use, share, and adapt it. The citation key on the following slide provides information about how you may share and adapt this material.
Copyright holders of content included in this material should contact [email protected] with any questions, corrections, or clarification regarding the use of content.
For more information about how to cite these materials visit http://open.umich.edu/education/about/terms-of-use.
Any medical information in this material is intended to inform and educate and is not a tool for self-diagnosis or a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional. Please speak to your physician if you have questions about your medical condition.
Viewer discretion is advised: Some medical content is graphic and may not be suitable for all viewers.
![Page 2: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/2.jpg)
Citation Key for more information see: http://open.umich.edu/wiki/CitationPolicy
Use + Share + Adapt
Make Your Own Assessment
Creative Commons – Attribution License
Creative Commons – Attribution Share Alike License
Creative Commons – Attribution Noncommercial License
Creative Commons – Attribution Noncommercial Share Alike License
GNU – Free Documentation License
Creative Commons – Zero Waiver
Public Domain – Ineligible: Works that are ineligible for copyright protection in the U.S. (17 USC § 102(b)) *laws in your jurisdiction may differ
Public Domain – Expired: Works that are no longer protected due to an expired copyright term.
Public Domain – Government: Works that are produced by the U.S. Government. (17 USC § 105)
Public Domain – Self Dedicated: Works that a copyright holder has dedicated to the public domain.
Fair Use: Use of works that is determined to be Fair consistent with the U.S. Copyright Act. (17 USC § 107) *laws in your jurisdiction may differ
Our determination DOES NOT mean that all uses of this 3rd-party content are Fair Uses and we DO NOT guarantee that your use of the content is Fair.
To use this content you should do your own independent analysis to determine whether or not your use will be Fair.
{ Content the copyright holder, author, or law permits you to use, share and adapt. }
{ Content Open.Michigan believes can be used, shared, and adapted because it is ineligible for copyright. }
{ Content Open.Michigan has used under a Fair Use determination. }
![Page 3: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/3.jpg)
Spring 2009 M1 Human Growth & Development 3
Physiology of Aging
Brent C. Williams, MD, MPH Associate Professor of Medicine
University of Michigan
![Page 4: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/4.jpg)
4
Intended Learning Outcomes Distinguish usual from successful aging. Describe the major age-associated changes in
human physiology. Understand the “anti-aging” effects of
exercise. Be able to assess nutritional status of older
adults, including risks from medications. Appreciate the importance of functional
assessment of older individuals.
![Page 5: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/5.jpg)
5
What is Aging?
Ed from Ohio, flickr
![Page 6: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/6.jpg)
6
Aging
is not a disease occurs at different rates
• among individuals • within individuals
does not generally cause symptoms
![Page 7: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/7.jpg)
7
Characteristics of Mammalian Aging
cellular and physiologic deterioration increased mortality with age
following maturation increased vulnerability to disease decreased ability to adapt to stress
• impaired homeostasis
![Page 8: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/8.jpg)
“Normal” Aging as:
Optimal – Best example or idealized Usual - most common Universal – seen in all humans All are influenced by:
• Genetics - Lifestyle • Physiology - Socioeconomics
8
![Page 9: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/9.jpg)
9
Problems with Normal Aging
heterogeniety
normal does not imply without risk
normal does not imply natural
![Page 10: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/10.jpg)
10
![Page 11: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/11.jpg)
From Usual to Successful Aging – Clinical Approach
Normalizing - Helps patients understand what to expect • Adjust to likely changes (e.g., sleep/wake,
bowels, balance, benign forgetfulness) • Identify potential symptoms of disease
(sleep apnea, depression; hypothyroidism; gait disorder; cognitive impairment)
11
![Page 12: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/12.jpg)
Usual to Successful Aging for Clinicians (contʼd)
Maintain or improve modifiable causes of age-related change • Exposures (UV radiation, noise) • Psychological well-being (social isolation) • Cognition (mental inactivity) • Nutrition (cholesterol, sodium, calcium) • Exercise (fitness, strength, balance)
12
![Page 13: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/13.jpg)
13
Most people live nowhere near their limits. They settle for an accelerated aging, and early
and precipitous fall. They give aging a bad name.
George Sheehan, M.D.
![Page 14: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/14.jpg)
14
Intended Learning Outcomes Distinguish usual from successful aging. Describe the major age-associated changes in
human physiology. Understand the “anti-aging” effects of
exercise. Be able to assess nutritional status of older
adults, including risks from medications. Appreciate the importance of functional
assessment of older individuals.
![Page 15: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/15.jpg)
15
What is normal (clinically expected) aging physiology?
![Page 16: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/16.jpg)
16
Aging Physiology
Source Undetermined
![Page 17: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/17.jpg)
17
Overview of Aging Physiology
Skin Body
Composition Vision Special Senses Nervous System
Musculoskeletal System
Renal GI Cardiovascular
![Page 18: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/18.jpg)
18
Aging Skin
Source Undetermined
![Page 19: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/19.jpg)
19
Source Undetermined
![Page 20: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/20.jpg)
20
Aging and Central Adiposity
Source Undetermined
![Page 21: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/21.jpg)
Source Undetermined
![Page 22: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/22.jpg)
Source Undetermined
![Page 23: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/23.jpg)
23
Age-Associated Factors - Vision
visual acuity (cataracts, macular degeneration)
dark adaptation peripheral vision
(glaucoma) contrast sensitivity accommodation
Source Undetermined
![Page 24: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/24.jpg)
24
Age-Associated Factors-Special Senses
Auditory and Vestibular • Presbycusis: high frequency hearing loss • Vestibular dysfunction
Smell Oral/Dental
• Teeth: 40% of elderly are edentulous • Taste • Salivary function Pearson Scott Foresman,
wikimedia commons
![Page 25: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/25.jpg)
25
Age-Associated Factors-Nervous System
CNS: decrease in nerve cell number
basal ganglia atrophy dopamine and muscular
rigidity step height reaction time PNS: decreased vibratory
sensation Gray’s Anatomy, wikimedia commons
![Page 26: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/26.jpg)
26
Age-associated Factors: Musculoskeletal system
30% loss in muscle mass 3rd to 8th decade - sarcopenia.
Osteoarthritis • weight bearing (spine/knees/1st metatarsophalangeals) • repeated strain (distal interphalanges/1st carpometacarpals)
Osteopenia/-porosis (80% women >65 y/o osteopenia) • decreased activity, dietary calcium, estrogen withdrawal
![Page 27: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/27.jpg)
27
Aging Renal Physiology
GFR 30-46% Tubular function Renal plasma flow ~50% CrCl = [(140 - age) x (BW)]/[72 x SrCr ]
• Multiply x 0.85 for females • BW in kg (LBW or IBW with edema or obesity)
Gray’s Anatomy, wikimedia commons
![Page 28: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/28.jpg)
28
Absorption: GI Physiology
GI absorptive cells GI motility or normal Sphincter activity GI blood flow Gastric acid secretion Active transport
Source Undetermined
![Page 29: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/29.jpg)
29
Wikimedia commons
![Page 30: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/30.jpg)
30
Afterload: Vascular Changes
![Page 31: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/31.jpg)
31
Summary: Age-associated changes in cardiovascular physiology
Maintenance of resting left ventricular function.
Decreased ability to compensate for stress or impaired LV function. • Blunted heart rate response to exercise requires a compensatory increase in stroke volume to increase cardiac output.
![Page 32: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/32.jpg)
32
![Page 33: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/33.jpg)
33 Source Undetermined
![Page 34: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/34.jpg)
34
Mar
atho
n Ti
me
Source Undetermined
![Page 35: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/35.jpg)
35
"I don't know if I'll do it next year. ... But wait until I hit that magic 95-year-old age group."
John Besson, Jr., after finishing the 2002 Portland Marathon, and lowering the 90+ U.S. best from 7:25 to 6:48
2:00:00
2:37:30
3:15:00
3:52:30
4:30:00
5:07:30
5:45:00
6:22:30
7:00:00
20 30 40 50 60 70 80 90 100 Age (years)
Source Undetermined
![Page 36: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/36.jpg)
36
Intended Learning Outcomes Distinguish usual from successful aging. Describe the major age-associated changes in
human physiology. Understand the “anti-aging” effects of
exercise. Be able to assess nutritional status of older
adults, including risks from medications. Appreciate the importance of functional
assessment of older individuals.
![Page 37: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/37.jpg)
37 Source: Vita et al., NEJM 338:1035, 1998
Aging, Health Risks and Cumulative Disability
Longitudinal study of 1741 U Penn alumni Health Risk in 1962 (age mean 43 yrs.)
determined from BMI, smoking, and exercise; low, moderate, high
Disability index determined in 1986: 100% greater in high than low risk group (1.02 vs, 0.49; P<0.001)
Progression in disability postponed by 7 years.
![Page 38: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/38.jpg)
Vita et al., NEJM 338:1035, 1998
![Page 39: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/39.jpg)
39
![Page 40: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/40.jpg)
40
Rather than seeking permission to exercise, you should have to get
permission to be sedentary.
Maria Fiatarone, M.D.
![Page 41: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/41.jpg)
41
Aging: A state of chronic exercise deficiency?Only 29% of elderly report any regular exercise.
![Page 42: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/42.jpg)
42
Benefits of Exercise
Weight loss • Decrease central adiposity • Increase lean body mass
Blood pressure decline Aerobic capacity increase Insulin sensitivity increase Increase bone mass Increase muscle strength Increase perceived well being
![Page 43: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/43.jpg)
43
Source Undetermined
![Page 44: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/44.jpg)
44 Source Undetermined
![Page 45: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/45.jpg)
45
Intended Learning Outcomes Distinguish usual from successful aging. Describe the major age-associated changes in
human physiology. Understand the “anti-aging” effects of
exercise. Be able to assess nutritional status of older
adults, including risks from medications. Appreciate the importance of functional
assessment of older individuals.
![Page 46: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/46.jpg)
Protein-Calorie Malnutrition Among Older Persons
5-12% in community
30-61% hospitalized
40-85% in long-term care facilities.
46
![Page 47: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/47.jpg)
47
Inadequate Nutrition Among Older Individuals
Increases severity of disease Increases possibility of physical
limitations due to decreased musculature Decreases functional status Can increase drug effects due to changed
metabolism and/or weight loss
![Page 48: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/48.jpg)
48
Importance of Nutrition for Older Adults
Older Adults are at increased risk of inadequate diet from: • Diseases - acute/chronic
» half of hospitalized older patients are malnourished. • Physical limitations • Inability to chew and poor oral health • Social isolation/depression/low income • Impaired functional status • Alcohol use and abuse • Drug - nutrient Interactions
![Page 49: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/49.jpg)
Causes of Malnutrition
Medications Oral factors Wandering (dementia) Emotional probs Neoplasia Hyperthyroidism etc Anorexia Enteric problems
Late-life paranoia Eating problems Swallowing disorders Low-salt /chol
Social problems
Source: Morley Ann Int Med 1995;123:850-859
49
![Page 50: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/50.jpg)
50
Assessing Nutritional Status Screening tools (e.g. DETERMINE; Mini-Nutritional
Assessment) to identify patients at risk. Anthropometric data
• BMI, percent weight change • Changes in body composition
Albumin, cholesterol Vitamin levels - 25-OH-D3, B12
Involuntary weight loss > 10% (high specificity)
![Page 51: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/51.jpg)
51
Food Check List
Activities of Daily Living • What are they able to do?
Food intake • Food preparation capability or food
provided • What is being consumed?
» Total amount of food » Types of food (fruits, vegs, protein
foods, grains) » Fluids: Water especially
![Page 52: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/52.jpg)
52
Medication Check List
Number of medications Possible nutrient-drug interactions Vitamin B12 status (B12 is less absorbed
with increasing age due to less intrinsic factor being produced in the stomach)
Vitamin D status (low milk intake, no sunshine)
![Page 53: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/53.jpg)
53
How Drugs Affect Nutritional Status Approximately 34 million Americans are 65
years or older yet they consume 30% of all medications. • Average patient taking 3 to 7 medications at one time.
Medications alter food intake, absorption, metabolism and excretion of nutrients.
Decreases in appetite, taste and smell. May cause GI disturbances such as nausea,
constipation, and/or diarrhea.
![Page 54: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/54.jpg)
54
Dietary Recommendations for Older Individuals
Adequate protein (1.0 gm/kg rather than 0.8). Ample fruits and vegetables for nutrients and
to avoid constipation. Optimal Calcium intake for men and women >
age 65: 1500 mg daily Whole grain products (nutrient density and
fiber). Ample fluids, especially water.
![Page 55: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/55.jpg)
55
Intended Learning Outcomes Distinguish usual from successful aging. Describe the major age-associated changes in
human physiology. Understand the “anti-aging” effects of
exercise. Be able to assess nutritional status of older
adults, including risks from medications. Appreciate the importance of functional
assessment of older individuals.
![Page 56: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/56.jpg)
56
True or False?
The majority of older people are self sufficient.
![Page 57: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/57.jpg)
57
Katz Activities of Daily Living (ADL) Scale
![Page 58: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/58.jpg)
58
Instrumental Activities of Daily Living Definition: Things you needed to do for
yourself when you went off to college. • Grocery Shopping • Meal preparation • Driving or using public transportation • Taking medications • Laundry • Using telephone • Managing finances • Housework
![Page 59: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/59.jpg)
59
Instrumental Activities of Daily Living Definition: Things you needed to do for
yourself when you went off to college. • Grocery Shopping • Meal preparation • Driving or using public transportation • Taking medications • Laundry • Using telephone • Managing finances • Housework
![Page 60: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/60.jpg)
60
ADL/ IADL Limitations
National Health Interview Survey, 1999 data. CDC. NCHS.
![Page 61: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/61.jpg)
61
Self-rated Health
Source Undetermined
![Page 62: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/62.jpg)
62
Intended Learning Outcomes Distinguish usual from successful aging. Describe the major age-associated changes in
human physiology. Understand the “anti-aging” effects of
exercise. Be able to assess nutritional status of older
adults, including risks from medications. Appreciate the importance of functional
assessment of older individuals.
![Page 63: 05.18.09: Physiology of Aging](https://reader034.vdocument.in/reader034/viewer/2022051818/5498770cac7959412e8b55f7/html5/thumbnails/63.jpg)
Additional Source Information for more information see: http://open.umich.edu/wiki/CitationPolicy
Slide 5: Ed from Ohio, flickr, http://www.flickr.com/photos/ed_aisela/206151319/, CC:BY-NC-SA, http://creativecommons.org/licenses/by-nc-sa/2.0/deed.en Slide 10: Rowe and Kahn, Science 237:143, 1987 Slide 16: Source Undetermined Slide 18: Source Undetermined Slide 19: Source Undetermined Slide 20: Source Undetermined Slide 21: Source Undetermined Slide 22: Source Undetermined Slide 23: Source Undetermined Slide 24: Pearson Scott Foresman, Wikimedia Commons, http://commons.wikimedia.org/wiki/File:Ear_4_%28PSF%29.png Slide 25: Gray’s Anatomy, Wikimedia Commons, http://commons.wikimedia.org/wiki/File:Gray715.png Slide 27: Gray’s Anatomy, Wikimedia Commons, http://commons.wikimedia.org/wiki/File:Gray1127.png Slide 28: Source Undetermined Slide 29: Wikimedia Commons, http://commons.wikimedia.org/wiki/File:Illu_artery.jpg Slide 32: Fleg et al., J App Physiol, 1993 Slide 33: Source Undetermined Slide 34: Source Undetermined Slide 35: Source Undetermined Slide 38: Vita et al., NEJM 338:1035, 1998 Slide 43: Source Undetermined Slide 44: Source Undetermined Slide 60: National Health Interview Survey, 1999 data. CDC. NCHS. Slide 61: Source Undetermined