908
UNIT SIX
cease or shorten. He or she sleeps more, and might not even
get out of bed on some days. Conversation lags. Gradually,
the loss of interest in everyday activities extends to eating.
This parallels physical changes, such as difF culty swallowing,
that make eating increasingly difF cult. The person might F rst
give up eating meats, then F brous vegetables, until it is clear
that softer foods are preferred. The person might eat and drink
astonishingly little, and the family might feel the need to try to
force eating—which could cause the dying person discomfort.
Dry mouth is common. The caregiver can provide ice chips or
popsicles, or frequently wet the mouth with a swab.
been chronically ill and is receiving comfort care, certain signs
of impending death may appear, often in a sequence. A per-
son may exhibit some or all of these signs. Health-care profes-
sionals view the dying process in two stages—preactive dying
and active dying.
Preactive dying may take up to three months. During
this time, some people are aware of what is happening and
begin the psychological process of coming to terms with their
mortality. A month or more before death, the person starts
to withdraw, losing interest in news from the outside world
and possibly requesting that visits from friends and relatives
TABLE
23.9
|
Stages in Postnatal Development
Stage
Time Period
Major Events
Neonatal period
Birth to end of fourth week
Newborn begins to carry on respiration, obtain nutrients, digest nutrients, excrete wastes, regulate body
temperature, and make cardiovascular adjustments
Infancy
End of fourth week to one year
Growth rate is high; teeth begin to erupt; muscular and nervous systems mature so that coordinated
activities are possible; communication begins
Childhood
One year to puberty
Growth rate is high; primary teeth erupt and are replaced by secondary teeth; high degree of muscular
control is achieved; bladder and bowel controls are established; intellectual abilities mature
Adolescence
Puberty to adulthood
Person becomes reproductively functional and emotionally more mature; growth spurts occur in skeletal
and muscular systems; high levels of motor skills are developed; intellectual abilities increase
Adulthood
Adolescence to old age
Person remains relatively unchanged anatomically and physiologically; degenerative changes begin
Senescence
Old age to death
Degenerative changes continue; body becomes less able to cope with demands; death usually results from
mechanical disturbances in the cardiovascular system or from diseases that aF
ect vital organs. Signs of
approaching death may appear in a common sequence
TABLE
23.10
|
Aging-Related Changes
Organ System
Aging-Related Changes
Integumentary system
Degenerative loss of collagenous and elastic ±
bers in dermis; decreased production of pigment in hair follicles; reduced activity of sweat
and sebaceous glands; skin thins, wrinkles, and dries out; hair turns gray and then white
Skeletal system
Degenerative loss of bone matrix; bones become thinner, less dense, and more likely to fracture; stature may shorten due to compression
of intervertebral discs and vertebrae
Muscular system
Loss of skeletal muscle ±
bers; degenerative changes in neuromuscular junctions; loss of muscular strength
Nervous system
Degenerative changes in neurons; loss of dendrites and synaptic connections; accumulation of lipofuscin in neurons; decreases in
sensation; decreasing e²
ciency in processing and recalling information; decreasing ability to communicate; diminished senses of smell
and taste; loss of elasticity of lenses and consequent loss of ability to accommodate for close vision
Endocrine system
Reduced hormonal secretions; decreased metabolic rate; reduced ability to cope with stress; reduced ability to maintain homeostasis
Cardiovascular system
Degenerative changes in cardiac muscle; decrease in lumen diameters of arteries and arterioles; decreased cardiac output; increased
resistance to blood ³
ow; increased blood pressure
Lymphatic system
Decrease in e²
ciency of immune system; increased incidence of infections and neoplastic diseases; increased incidence of autoimmune
diseases
Digestive system
Decreased motility in gastrointestinal tract; reduced secretion of digestive juices; reduced e²
ciency of digestion
Respiratory system
Degenerative loss of elastic ±
bers in lungs; fewer alveoli; reduced vital capacity; increase in dead air space; reduced ability to clear airways
by coughing
Urinary system
Degenerative changes in kidneys; fewer functional nephrons; reductions in ±
ltration rate, tubular secretion, and tubular reabsorption
Reproductive systems
Male
Reduced secretion of sex hormones; enlargement of prostate gland; decrease in sexual energy
´emale
Degenerative changes in ovaries; decrease in secretion of sex hormones; menopause; regression of secondary sex characteristics
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