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Flashcards in Module 10: Special Senses Deck (313)
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211

Growth and Development of the Child

• Male and Female Same growth rate up to 10yrs
• 11-13y.o, female estrogen, growth spurt up to 14-16y.o
• 13-17y.o, male testosterone, growth spurt more delayed than females hence tend to be taller.

212

Behavioral Growth (Infant)

• Immature Nervous system (incompletely myelinated)
• Nervous system not fully functional at birth
• At birth infant Brain mass is only 26% of adult brain mass and 55% at 1 yr. Reaches adult proportion at 2 yrs.

213

• A process of gradual and spontaneous change, resulting in maturation through childhood, puberty, and young adulthood and then decline through middle and late age

Aging

214

• The process by which the capacity for cell division, growth, and function is lost over time, ultimately leading to an incompatibility with life

Senescence

215

Life Expectancies of Filipinos

• At birth, females: 73.24 years
• At birth, males: 68.93 years

216

Maximum Life Potential

• The oldest age to which any human has ever lived
• The oldest fully authenticated age to which any human has ever lived is 122 years and 164 days, by Jeanne Louise Calment.
• She was born in France on February 21, 1875, and died at a nursing home in Arles, Southern France on
• August 4, 1997.

217

• Demonstrated by fibroblasts in vivo
• Fibroblasts will continue to divide until they are dense enough and come in contact with one another (Contact Inhibition)
• Explained by: Telomeres
- stretches of DNA at the end of chromosomes
- serve as handles by which chromosomes are moved during the telophase of meiosis.
- Irreversibly shortened each time a cell divides
- When the telomeres become too short, the cell can no longer divide

Hayflick’s Limit or Phenomenon

218

• Entropy-producing agents slowly disrupt cellular macromolecular constituents
- Free Radicals - modify macromolecules primarily through oxidation (oxidative damage)
- Glucose - nonenzymatic attachment to proteins and nucleic acids

Loose Cannon Theory

219

• Smaller mammals tend to have high metabolic rates and thus tend to die at an earlier age than larger mammals.

Rate of Living Theory

220

• A specific physiologic system--usually the neuroendocrine or immune system--is particularly vulnerable (presumably to entropic processes) during senescence.
• Failure of the weak system accelerates dysfunction of the whole organism.

Weak Link Theory

221

• Errors in DNA transcription or RNA translation eventually lead to genetic errors that promote senescence.

Error Catastrophe Theory

222

• One of the oldest theories of aging and no longer has high credibility
• Aging is under direct genetic control.
• It suggests that the rate of aging within each species has developed for the good of each species.
• Individual variation develops because of maladaption, exposure, and lifestyle.
• In the wild, such maladapted individuals tend to die out and the well-adapted ones persist, altering longevity in the best interest of the species.

Master Clock Theory

223

• Refers to the common complex of diseases and impairments that characterize many of the elderly.
• However, persons age very differently: some acquire diseases and impairments, and others seem to escape specific diseases altogether and are said to have died of old age. The latter may maintain an active healthy life until death.

Normal Aging

224

• Refers to a process by which deleterious effects are minimized, preserving function until senescence makes continued life impossible

Successful (Healthy) Aging

225

Changes in the Organ Systems (The Integumentary System: Skin Aging)

Intrinsic Aging vs Photoaging

Intrinsic Aging:
• subtle but important alterations of cutaneous function that are presumed to be due to time alone

Photoaging
• due to preventable chronic exposure to ultraviolet (UV) radiation superimposed on intrinsic aging

226

Functional changes characteristic of aged skin include declines in:

• cell replacement - barrier function
• wound healing
• immunologic responsiveness
• thermoregulation

227

Epidermis (Aging)

• Decreased epidermal turnover rates = 30-50%
• Decreased linear growth rates for hair and nails
• Consistent flattening of the epidermal-dermal junctions
- Compromises communication and nutrient transfer from the dermis to the epidermis
- Greater epidermal-dermal separation = skin prone to breaks
• Decline in Vitamin D production

228

Dermis (Aging)

• 20% Loss of dermal thickness
• 50% Loss of mast cells
• 30% Loss of venular cross-sectional area

Resulting in:
• Decreased inflammatory response
• 60% Decreased basal and peak cutaneous blood flow
- Pallor, decreased temperature, impaired thermoregulation
- Senescence of eccrine, apocrine and sebaceous glands
• Dysregulation of collagen synthesis and degradation
• Loss of elasticity

• Alteration of mucopolysaccharides
Resulting in:
- Fragmentation
- Impaired wound healing
- Loss of skin turgor

229

Subcutaneous Fat (Aging)

• Overall loss of volume of subcutaneous fat
Results in:
- Impaired thermoregulation
- Impaired cushioning; decreased ability to diffuse pressure over bony prominences = increased risk for sores, bruising

230

Appendages (Aging)

• Decreased density of cutaneous sensory end organs
Resulting in:
- Reduction in sensations of light touch, vibration, corneal sensitivity, two-point discrimination, and spatial acuity
- Increase in cutaneous pain threshold by about 20%

231

Changes in the Aging Skeletal System

• Wear and tear
• Thinning of cartilage pads between joints; less lubricating fluid
• Changes in the curvature of the spine
• More bone resorption than deposition

232

Muscular System: Sarcopenia (Aging)

• Decreased muscle bulk A decrease in muscle bulk is common and is not significant unless accompanied by a loss of function.
• Hand muscles are particularly affected; the interosseous and thenar muscles of the hands atrophy with age.

233

Changes in the cardiovascular system (Aging)

• Decreased heart rate (as low as 40bpm)
• Decrease in cardiac output
• Hardening of the arteries
• Increased pressure inside the blood vessels
• Immobilization and inactivity increases the risk of thrombosis
• More affected by gravitational and postural changes

234

Changes in the Nervous System: Senility is inevitable…myth or fact?

FACT:
• Not all elderly are senile
• We will be forgetful
• Forgetfulness Vs. Alzheimer’s disease

235

Cognitive Decline in the Elderly

• Changes in the Brain
- Less neurons
- Less synapses
- Decreased neurotransmitters

236

Respiratory System (Elderly)

• Decreased respiratory rate (12-16bpm)
• Decreased lung volumes and capacities

237

Digestive System (Elderly)

• Loss of dentition
• Loss of taste buds
• Less GI secretions - Difficulty in swallowing
• Decreased capacity of stomach
• Decreased peristalsis
- Constipation
- ...At risk for malnutrition

238

Immune System (Elderly)

• Decreased capacity of the innate system to provide protection
- Altered skin and mucous membranes
- Decreased saliva

• Decreased circulating lymphocytes
• More prone to some infectious diseases
• With increased morbidity and mortality (poorer outcomes)
• Immunizations needed
- Flu vaccine yearly
- Pneumococcal vaccine
- Tetanus vaccine
- Zoster vaccine

239

Excretory System (Elderly)

• Loss of nephrons
• Shrinking of kidneys
• Decline in kidney function
• More pliant urinary bladder
- Lower threshold
- Weak muscles -> Urinary Incontinence

240

Endocrine System (Elderly)

• Decrease in the activity of glands
• Decrease in circulating hormones
• Increased resistance of receptors