chapter three physical changes. why do we age?—biological theories rate-of-living theories limited...

CHAPTER THREECHAPTER THREEPhysical ChangesPhysical Changes

Why Do We Age?—Biological Theories

Rate-of-Living Theories• Limited energy to expend in a lifetime • Excess calories may reduce lifespan

Cellular Theories

• Limited number of times a cell can divide (Hayflick limit)– Telomeres (tips of chromosomes) become shorter with

each cell division • Cross-linking

– Tissue becomes stiffer with age

• Free radicals– Reactive chemicalscause cellular damage

Programmed Cell Death Theories

• Aging may be programmed into genetic code– Cells may be pre-programmed to self-

destruct

• Changes in Skin– Why does our skin wrinkle?

• Four-step process– Outer layer becomes thinner

because of cell loss– Collagen fibers lose flexibility– Elastin fibers lose ability to keep

skin stretched out– Underlying fat layer diminishes

– Environmental factors affecting skin

• Sun exposure• Smoking

– Other skin changes• Pigment-containing cells decrease• Age spots, moles• Varicose veins

Changes in the body that occur with age

Changes in the Hair– Hair loss caused by destruction of

germ centers that produce hair follicles

– Graying caused by cessation of pigment production

– Other hair changes• Males do not lose facial hair.• Females gain facial hair.

– Caused by hormonal changes

Changes in the body that occur with age

• Attributes of the aging voice:– Lowering in pitch– Increased breathlessness and trembling– Slower and less pronounced pronunciation – Decreased volume

• May be due to normative changes or poor health

Changes in the body that occur with age

• Decrease in height with age– Between mid-50s and mid-70s men lose about 1

inch and women 2 inches– Compression of the spine – Changes in posture

• Weight gain then loss– Usually a weight gain between 20 and 50– Usually a weight loss throughout the older

years– How different between men and women?

• Research suggests that one lives longer with a normal body weight

Changes in Body Build

• Muscles– Strength loss: age 70, up to 20%; age 80, up to 40%– No difference in the rate of muscle change between men

and women

Changes in Mobility

Changes in Mobility

• Bones– Loss begins in

the late 30s, accelerates in the 50s, and slows in the 70s

– Osteoporosis: loss of bone mass; leading cause of broken bones in older women

Changes in Mobility

• Joints– Osteoarthritis occurs when the bones beneath cartilage

become damaged– Rheumatoid arthritis is a disease of the joints

Changes in Vision• Structural changes in the eye

– Decreased ability to allow light into the eye– Adaptation between light and dark is slower– Presbyopia: difficulty focusing on close objects– Cataracts: spots develop on the lens, clouding

vision– Glaucoma: pressure in the eye may result in

loss of peripheral vision

Changes in Vision

• Retinal Changes– Macular degeneration: loss of receptor cells

in the eye– Diabetic retinopathy: may result in blindness

Changes in Hearing

• Due to normative age-related changes• Due to loud environment

– Presbycusis: Reduced sensitivity to high-pitched tones Hearing Loss Simulation - YouTube

• With age there is a loss of touch only on smooth skin of the hand

• Temperature regulation is sometimes more difficult in older adults

Changes in Somesthesia

• Kinesthesis is ones sense of where they are in space; involving muscles and joints

• Vestibular system is in the inner ear and helps with balance and movement– Fear of falling, dizziness, vertigo increase with age

• Environmental hazards– Loose rugs– Slippery floors– Hip protection

• Tai Chi—– Helps maintain banlance

Changes in Balance

• Taste receptor cells do not change in quantity across the lifespan

• Taste is dependent on smell• Smell diminishes after age 60 and

sometimes can be used to diagnose Alzheimer’s disease

Changes in Smell and Taste

• Underlying cause of diminished capacity– Accumulation of fat deposits– Stiffening of the heart muscle

Changes in the Cardiovascular System

• Congestive heart failure: cardiac output declines, heart gets larger—most common cause of hospitalization for those over 65

• Angina pectoris: chest pain due to insufficient oxygen supply to heart

• Myocardial infarction (MI): blood supply is severely reduced; pain may or may not be present

Cardiovascular Disease: #1 cause of death

• Atherosclerosis: build-up of fat deposits; may lead to CVA

• Cerebrovascular accident (CVA) or stroke: blood flow to brain is cut off

• Hypertension: high blood pressure

Cardiovascular Disease: #1 cause of death

• Respiratory Diseases– Chronic obstructive pulmonary disease (COPD), includes:

• Emphysema– Destruction of membranes around the air sacs in the lungs– 82% self-induced by smoking

• Chronic bronchitis– Bronchial passageways become irritated by dust, fumes, air pollution,

etc.– More common with people over 45

Changes in the Respiratory System

Changes in the Female Reproductive System

– Perimenopause• Transition to menopause involving changes in reproductive

organs and sexual functioning• Genital organ change begins in the 40s

– Menopause• The point at which the ovaries cease to release eggs

– Hormone Replacement Therapy (HRT) – No physiological reason why most women cannot

continue sexual activity into old age.– Climacteric: the transition from reproductive to non-

reproductive years

Changes in the Male Reproductive System– Unlike menopause, no event to mark male reproductive changes

• Gradual decline in testosterone levels• Decrease in sperm production (30% between 30 and 60)

– Prostate cancer a real threat– Impotence/Erectile Dysfunction: treatable with drugs such as Viagra

• Psychological Implications– For healthy adults, sexual activity is a lifelong option.