What are the Results of Aging (biology of aging) Winter 07 Lecture 4 – Chapter 4

Werner’s Syndrome Pathological Aging: Premature Aging Progeria Developmental

Vision Hearing Taste Smell Skin** Hair Weight

Skin The membranous tissue forming the external - covering largest organ New skin: Young skin: 3 to 4 wks Older Skin: 4 to 5 wks Epidermis squamous, basal cells & melanocytes Dermis collagen (support structure, 75%) Loss of Collagen (thinner & finer) & elastin fibers (connective tissues more rigid, less flexible) fat tissue atrophy of sweat glands blood vessels fragile (angiomas) Lack of turnover of new cells

Hair Loss of melanin in follicles life cycle of 4 to 5 years strand become smaller Genetic  whites earlier

Height & Weight Men in HT Women -2 in HT Men & Women Metabolism slows down 3% every 10 years so by 65  20% reduction

So, does obesity contribute to risk of death in older adults… Diehr et al. (2002) N = 4,317 older adults yrs Examined the relationship between BMI and Mortality Longitudinal Study (wt/height X 704.5) No correlation between WT & Mortality …in fact higher risk of death if lower wt. BMI of 20 (5’5” 120 lbs) or lower Higher mortality rate than higher BMIs (Women) 10% or more weight loss since 50 (both men & women) Higher death rate (15.9% & 30.3%)

The Senses Vision Hearing Taste Smell

Visual impairment: most common sensory problem 95% wear glasses (across cultures) pupil 1/3 size (iris more rigid) (by 60 vs 20) 5% cannot read 20% cannot drive Vision

Normal Vision Problem in lens  Cataracts protein clumping together Problem in the macula (fovea) Macular Degeneration: loss of acuity and center vision

ear structures deteriorates eardrum often thickens inner ear bones and other structures are affected 30%: 65 & up significant hearing impairment 25%- between 65 and 74 50%- 75 & up difficulty hearing 10dB reduction in hearing sensitivity each decade after 60 older men more likely to have hearing loss than older women Earlobes increases ¼ longer ( cartilage) & fatter Hearing

9,000 taste buds 40 to 50 in women 50 to 60 in men After 60 loss of sensitivity: sweet & salty 1 st to go Taste

smell receptors decreases increases the threshold for smell after 50 the sense of smell decreases rapidly 80: reduced by about half Size increases ½ in wider & ½ in longer ( cartilage) Smell

Interior Skeletal System Heart Brain Reproductive System

Skeletal System bone density is lost (women after menopause)menopause trunk becomes shorter (disks lose fluid - thinner) vertebrae lose some of minerals (bone also becomes thinner) spinal column becomes curved and compressed long bones (arms & legs) brittle (mineral loss)long bones no change length  arms and legs look longer when compared to shortened trunk.

Osteoporosis: resorption of bone by clasts = thin, fragile, brittle

Heart Generally, maintains size Except left ventricle walls thicken (enlarges) Isolated systolic hypertension Arteries loss elasticity: “hardening of the arteries” (arteriosclerosis) *narrowing of passage in artery due to plaque (atherosclerosis) 120 = systolic  contract pushing blood out = diastolic  ventricles refill with blood BP

Leading cause of death COPD 5. Pneumonia

Brain

Max weight at 20 (3 lbs): loss of 10% over lifetime No widespread loss of neurons! Maintains most Neurons: Frontal, Parietal Striate Loss in nucleus Basalis Acetylchoiline memory

Hub of motor activity: responsible for initiating and integrating movements become bright with age due to iron accumulation No health problems are associated with this change Basal Ganglia The MRI images below show a healthy 87 year old brain, next to a healthy 27 year old brain. (MRIs courtesy of the Oregon Brain Aging Study.)The MRI images below show a healthy 87 year old brain, next to a healthy 27 year old brain. (MRIs courtesy of the Oregon Brain Aging Study.) MRI of healthy 87 year old brain, next to a healthy 27 (MRIs courtesy of the Oregon Brain Aging Study.)

As the brain becomes smaller as a result of the gradual, life-long loss of brain cells, this area increases in size to fill the space Subarachnoid

Memory center of the brain There is some cell loss associated with healthy aging, but this by itself does not indicate significant memory loss Hippocampus

Hollow spaces filled with CSF Like the subarachnoid space, these spaces increase in size as the brain becomes smaller with age Ventricles

Myelination: communication channel for the brain's information processing gray matter White matter changes in appearance with aging. The reason for these changes is unclear, but it may be related to the normal slowing of information processing in the brain with age White Matter

white matter decrease increase in ventricles increases in CSF Gray matter okay!

Dopamine Acetylcholine D2 receptors DA slows metabolism Aging brain  plasticity Dendrites!!

Reproductive system - Female Females: Menopause: end of fertility loss of estrogen & progesterone fat deposits in breasts loss of skin elasticity facial hairs 50%: : before 45, 25% after 2 to 3 years to complete No ovum Decrease in size: uterus, cervix, vagina

Andropause: testicular tissue mass decreases testosterone: same decreases slightly sperm still produced erectile function impaired No abrupt change… Fertility issues (94 yr old) Prostate enlarges (50%) Reproductive system - Male

Women longer time to respond to sexual stimuli orgasms less intense shorter duration Men longer to achieve full erection takes longer to orgasms fewer genital spasms longer to 2 nd erection

Aged Aged Aged 70 and older Sexually Active * Women93%81%65% Men98%91%79% Sexually Active, reporting sexual activity at least once a week * Women73%63%50% Men90%73%58% Sexually Active, reporting a high level of sexual enjoyment * Women71%65%61% Men90%86% 75%* Includes sex with a partner or alone (masturbation) Survey of over 10,000 people (42% responding)