Flashcards in Module 10: Special Senses Deck (313)
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.
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.
• A process of gradual and spontaneous change, resulting in maturation through childhood, puberty, and young adulthood and then decline through middle and late age
• The process by which the capacity for cell division, growth, and function is lost over time, ultimately leading to an incompatibility with life
Life Expectancies of Filipinos
• At birth, females: 73.24 years
• At birth, males: 68.93 years
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.
• 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
• 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
• Smaller mammals tend to have high metabolic rates and thus tend to die at an earlier age than larger mammals.
Rate of Living Theory
• 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
• Errors in DNA transcription or RNA translation eventually lead to genetic errors that promote senescence.
Error Catastrophe Theory
• 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
• 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.
• Refers to a process by which deleterious effects are minimized, preserving function until senescence makes continued life impossible
Successful (Healthy) Aging
Changes in the Organ Systems (The Integumentary System: Skin Aging)
Intrinsic Aging vs Photoaging
• subtle but important alterations of cutaneous function that are presumed to be due to time alone
• due to preventable chronic exposure to ultraviolet (UV) radiation superimposed on intrinsic aging
Functional changes characteristic of aged skin include declines in:
• cell replacement - barrier function
• wound healing
• immunologic responsiveness
• 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
• 20% Loss of dermal thickness
• 50% Loss of mast cells
• 30% Loss of venular cross-sectional area
• 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
- Impaired wound healing
- Loss of skin turgor
Subcutaneous Fat (Aging)
• Overall loss of volume of subcutaneous fat
- Impaired thermoregulation
- Impaired cushioning; decreased ability to diffuse pressure over bony prominences = increased risk for sores, bruising
• Decreased density of cutaneous sensory end organs
- Reduction in sensations of light touch, vibration, corneal sensitivity, two-point discrimination, and spatial acuity
- Increase in cutaneous pain threshold by about 20%
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
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.
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
Changes in the Nervous System: Senility is inevitable…myth or fact?
• Not all elderly are senile
• We will be forgetful
• Forgetfulness Vs. Alzheimer’s disease
Cognitive Decline in the Elderly
• Changes in the Brain
- Less neurons
- Less synapses
- Decreased neurotransmitters
Respiratory System (Elderly)
• Decreased respiratory rate (12-16bpm)
• Decreased lung volumes and capacities
Digestive System (Elderly)
• Loss of dentition
• Loss of taste buds
• Less GI secretions - Difficulty in swallowing
• Decreased capacity of stomach
• Decreased peristalsis
- ...At risk for malnutrition
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
Excretory System (Elderly)
• Loss of nephrons
• Shrinking of kidneys
• Decline in kidney function
• More pliant urinary bladder
- Lower threshold
- Weak muscles -> Urinary Incontinence