Normal Changes in Anatomy Clinical Manifestations and Disease Outcomes and Physiology
Cardiovascular
Increase in thickness of left ventricular wall, involving both myocyte hypertrophy and increase in collagen deposition secondary to decreased turnover of these cells1,2
Myocardial thickening combined with lipofuscin deposits, fatty infiltration, and fibrosis2
Dilation of left atrium3
Loss of about 10% of pacemaker cells every decade4
Increased fibrosis, myocyte hypertrophy, and calcium deposition5
Increase in dilation, elasticity and rigidity of arterial walls, with decrease in sensitivity to receptor-mediated agents6–8 Increase in peripheral resistance and decrease in central arterial compliance6–8
Respiratory
Decrease in number and elasticity of parenchymal
1. Decrease in early diastolic cardiac filling, increase in cardiac filling pressure and lower threshold for dyspnea
2. Left ventricular stiffness and thus a fourth heart sound
3. Lone atrial fibrillation
4. Sinus arrest or tachy–brady syndrome
5. Prolonged PR and QRS intervals and right
bundle branch block 6. Atherosclerosis
7. Systolic hypertension 8. Stroke
1. Gradual loss of elastic recoil of lungs
elastic fibers, the latter in part because of decrease in collagen levels1,2,4
Less effective ciliary action3 Less compliant and stiffer chest wall3
2. Smaller airway size, with airway collapse in lower lung zone
3. Increase in susceptibility to respiratory infections
4. Decrease in both quiet breathing (effort- independent)
Weaker respiratory muscles
and diaphragm, the latter by
about 25%3,5,7 2
Decrease in forced expiratory volume and forced vital capacity (30% by age 80)6,7 Increase in residual volume by about 20 mL/year6,7
Gastrointestinal
Increase in tongue varicosities1
Decrease in saliva production1
Increase in nonperistaltic spontaneous contractions of esophagus2
Decrease in stomach acid production3,4
Decreased gastric acid clearance5
Slowed gastric emptying after fatty meal, prolonging gastric distention6
Decrease in gut-associated lymphoid tissue7
Atrophy of large intestine mucosa8
Decrease in tensile strength of colonic smooth muscle8 Decrease in effectiveness of colonic contractions and sensitivity of rectal wall9 Decrease in calcium absorption10
Atheromata in large intestine vessels11
Decrease in liver size and blood flow12
Decrease in pancreatic mass and enzyme reserves13
mismatching (acceptable PaO2 = 100 – [0.32 ×
age])
7. Decrease in pulmonary reserve and exercise
tolerance
1. Increase in oral infections and gum disease 2. Dysphagia
3. Atrophic gastritis (in those >70 years, the
incidence of atrophic gastritis is 16%)
4. Decrease in vitamin B12 and iron absorption
5. Gastroesophageal reflux disease
6. Increasing meal-induced satiety
7. Impaired response to gastric mucosal injury,
thus increasing risk of both gastric and
duodenal ulcers
8. Increase in diverticulosis 9. Frequent constipation
10. Bone loss
11. Chronic intestinal ischemia
12. Impaired clearance of drugs requiring phase I
metabolism
13. Decrease in insulin secretion and increase in
insulin resistance
5. Decrease in forced breathing (effort-dependent) 6. Decrease in PaO due to ventilation–perfusion
Hyperplasia of pancreatic duct13
Increase in pancreatic cyst formation, fatty deposition and deposition of lipofuscin granules in acinar cells13
Urinary
Decrease in number and length of functional renal tubules1
Increase in tubular diverticula and basement membrane thickness1
Altered vascular pattern, atherosclerotic changes, altered arteriole-glomerular flow and focal ischemic lesions2
Decrease in creatinine clearance and glomerular filtration rate, the latter by about 10 mL/decade3 Decrease in concentrating and diluting capacity of kidneys4
Decrease in serum renin and aldosterone by about 30– 50%4
Decrease in vitamin D activation5
Immunologic/Hematologic
Average decline in function, including more stimulus and time required for activation1 Decrease in T-cell function1 Decrease in naive T cells and increase in memory T cells2 Gradual decrease in B-cell function3
Decrease in response of naive B cells to new antigens2 Atrophy of thymus4–6
Loss of ability of hematopoietic stem cells to self-renew7
1. Impairs permeability and decreased ability to resorb glucose
2. Decreased renal blood flow with a selective loss of cortical vasculature
3. Decrease in elimination of drugs and toxins (Given a decrease in renal drug elimination among older adult patients, clinicians must dose drugs for these patients with care. When hepatic clearance of drugs requiring phase I metabolism is also impaired, these drugs must be dosed with particular care)
4. Fluid and electrolyte abnormalities causing increased volume depletion and dehydration, hyperkalemia and decrease in sodium and potassium excretion and conservation
5. Vitamin D deficiency
1. Less primary and secondary responses to infection
2. Reduced body’s ability to mount immune response to new pathogens
3. Production of abnormal antibodies
4. Decrease in production and functioning of T
lymphocytes
5. Decrease in proliferation of natural killer cells
6. Decrease in production of cytokines needed for
maturation of B cells
7. Dysfunctional immune system
8. Slight decrease in average values of both
hemoglobin and hematocrit
Decrease in rate of erythropoiesis and incorporation of iron into red blood cells8
Sensory Organs
Vision
Loss of periorbital fat1–3 Laxity of eyelids1–3 Thickening and yellowing of lens combined with lipid infiltrate accumulations (arcus senilus)4
Increase in fibrosis of iris5 Increase in lens size and rigidity due to constant formation of central epithelial cells at front of lens6 Progressive increase in annular layers of lens7 Compression of central components that become hard and opaque7
Decrease in lacrimation Hearing
Thickening of tympanic membrane and loss in its elasticity as well as in efficiency of its ossicular articulation9
Decrease in the elasticity and efficiency of ossicular articulation10
Increasing deficit in central processing11,12
Smell and Thirst
Decrease in smell detection by about 50%13
Decrease in thirst drive14 Impaired control of thirst by endorphins14
Dermatologic
Decrease in skin elasticity1 Decrease in barrier function2 Slower cell replacement3
1. Sunken eyes
2. Senile entropion and ectropion
3. Increase in vulnerability to conjunctivitis
4. Decrease in transparency of cornea
5. Decreases accommodation and slows dark
adaptation (as dark adaptation decreases with age, a person’s continuing recognition of objects in subdued light requires double the illumination every 13 years)
6. Presbyopia
7. Increase in rate of cataract formation
8. Dry eye syndrome
9. Conductive deafness affecting low-frequency
sounds
10. Sensorineural hearing loss of high-frequency
sounds
11. Difficulty discriminating source of sound
12. Impaired discrimination of target from noise
13. Diminished ability to enjoy food and decrease in
appetite
14. Dehydration
1. Lax skin
2. Dry skin
3. Rough skin with delayed healing
Ineffective DNA repair4 Altered mechanical protection and decrease in sensory perception5
Decrease in immunologic and inflammatory responses6 Decrease in sweating and effectiveness of thermoregulation7
Decrease in vitamin D production8
Loss of melanocytes at base of hair follicles9
Slowing of linear nail growth10
Nervous System
Central Nervous System1–3
Decrease in weight of brain and cerebral blood flow by about 20%1–3
Decrease in number and functioning of nerve cells1–3 Less fluid and stiffer cell membranes in brain neurons1–3
Irregularity in structure of internal membranes1–3 Accumulation of lipofuscin and tangled neurofibrils1–3 Decrease in ability of neuron to grow branches of both axons and dendrites4
Peripheral Nervous System
Age-related changes in somatic motor function5 Slower action potentials and spreading of muscle cell contraction6,7
Lower peak strength of muscle contractions, with slower relaxation7
Musculoskeletal
Muscle
Decrease in muscle fibers (mainly type II—fast switch)1
4. Increase in rate of photocarcinogenesis
5. Greater susceptibility to injury
6. Chronic low-grade infections and impaired
wound healing, with persistent wounds and
weak scars
7. Tendency toward hyperthermia and greater
vulnerability to both heat and cold 8. Osteomalacia
9. Gray hair
10. Nails thicker, duller and more brittle, opaque and yellow, with development of longitudinal ridges
1. After age 70, gradual decrease in vocabulary, with increase in semantic errors and abnormal prosody
2. Increased forgetfulness in noncritical areas, which does not affect function or impair recall of important memories
3. After age 80, slower central processing, which prolongs time to complete tasks
4. Decrease in fine motor control
5. Decrease in cells that can be stimulated and
decrease in maximum strength of muscular
contractions
6. Prolonged time required for impulses to arrive,
muscle cells to contract and movements to be
initiated
7. Decrease in maximal muscle strength when
performing quick movements
1. Decrease in muscle mass (sarcopenia), leading to lean body mass
2. Thin, bony appearance to hands
Replacement of lost muscle tissue with tough fibrous tissue2
Bone
Decrease in vitamin D absorption, which decreases osteoblasts3
Decrease in bone formation and modeling by osteoblasts and osteoclasts, impairing bone microarchitecture3–6
Joints
Decrease in thickness of articular cartilage, though not in nonarticular cartilage8 Stiffer collagen, resulting in disordered cartilage matrix7
Endocrine
Pituitary gland
Minimal changes but on average, decrease in pulsatile secretion pattern, including nocturnal pulsatile secretion of prolactin1,2
Pineal gland
Decrease in diurnal melatonin rhythm3,4
Thyroid gland
Atrophy, with increased fibrosis and nodule formation5 Decrease in T4 production in the very old (if aging is normal, blood thyroxine concentration continues unchanged even though T4 production decreases)5
Parathyroid glands
In women over 40 years of age, increase in parathyroid hormone and decrease in metabolism, with associated decrease in 1,25 (OH) vitamin D levels and changes in bone mineral homeostasis6
3. Brittle bone
4. Greater susceptibility to fracture, with slower
healing
5. Osteoporosis
6. Dorsal kyphosis
7. Less ability to handle mechanical stresses
8. Joint breakdown, including inflammation, pain,
stiffness, and deformity
9. Overall decrease and limitation in movement
10. Decrease in arm swing and steadiness of walking
1. Decrease in size of various structures 2. Decrease in lean body mass to fat ratio 3. Insomnia
4. Deficit in free-radical defenses
5. Increase in rate of hypo-and hyperthyroidism 6. Vitamin D deficiency
7. Orthostatic hypotension
8. Masculinization of postmenopausal women 9. Decrease in immune function increasing the
risk of infection and cancer
10. Changes in skin, hair, muscle and bone and
decrease in body fat, despite increase in leptin 11. Skin changes, increase in LDL and decrease in
bone minerals
12. Decrease in body fat
Adrenal gland
Moderate decrease in aldosterone secretion7
In postmenopausal women, increase in androgen secretion8
Thymus
Decrease in immune function9
Male gonads
Large decrease in estrogen and progesterone11
After age 70, decrease in leptin12