Gastrointestinal Aging: Changes and Consequences

• Age-Related Changes

Gastrointestinal Aging

• Changes include poor dentition, decreased number of taste buds, and reduced muscle strength for chewing.
• Saliva production and ptyalin in saliva decrease.
• The gag reflex weakens.
• Gastric acid secretion is reduced.
• Emptying of the esophagus and stomach slows down.
• Intrinsic factor production decreases.
• Bile thickens, and the gastric mucosa thins.
• The ability of the small intestine to absorb sugars and lipids is reduced.
• Hepatic enzymes and storage capacity decline.

Gastrointestinal Aging Consequences

• Taste sensation is reduced, leading to decreased appetite.
• Chewing ability is diminished.
• Digestion of starch becomes less efficient.
• Swallowing difficulties may arise.
• Indigestion and flatus are more common.
• There is an increased risk of pernicious anemia.
• Problems with bowel elimination may occur.
• Tolerance for fats decreases.
• Potential changes in drug metabolism can occur.
• Difficulty gaining weight may arise.

Genitourinary Aging

• The number of nephrons decreases.
• Glomerular filtration rate and tubular reabsorption decline.
• The renal threshold changes.
• Blood flow to the kidneys decreases.
• Bladder capacity reduces from 500 ml to 250 ml.
• The elasticity and tone of the bladder decrease.
• The muscle tone of the urethra diminishes.
• Benign prostatic hyperplasia (BPH) is common in males.

Genitourinary Aging Consequences

• Creatinine clearance decreases.
• The ability to concentrate urine diminishes, increasing the risk of urinary retention.
• Urinary incontinence becomes more prevalent.
• Urinary frequency and nocturia increase.
• The function of kidneys to clear drugs declines, increasing the risk of side effects.

Musculoskeletal Aging

• Muscle cells atrophy, resulting in generalized symmetrical muscle wasting.
• Bones demineralize.
• The cartilage surface of joints deteriorates.
• Intervertebral discs thin.
• Cartilage loss occurs in the vertebral column.
• Muscle tissue loses elasticity.
• Kyphosis develops.

Musculoskeletal Aging Consequences

• Muscle strength declines significantly after age 70.
• Height loss may occur, with an average of two inches lost between ages 20 and 70.
• The chance of osteoporosis increases.
• Reduced flexibility and joint range of motion.
• Mobility decreases.
• The risk of falls increases.
• Gait changes occur.
• One's body image can change

Cardiovascular Aging

• The amount of collagen and fat increases in cardiac muscle.
• Valves thicken and become more rigid.
• Oxygen utilization decreases.
• The myocardium hypertrophies, but the heart size is not greatly affected by age.
• Coronary artery blood flow decreases.
• Peripheral resistance increases.
• Myocardial irritability increases.
• Blood flow to all organs decreases.

Cardiovascular Aging Consequences

• Stroke volume and cardiac output decrease.
• The ability to increase heart rate in response to stress diminishes.
• Aortic volume and systolic blood pressure increase.
• Resting heart rate does not change significantly.
• The risk of extra systoles increases.
• Electrocardiogram changes may occur.

Hearing Aging Changes

• The number of nerve cells in the 8th cranial nerve decreases causing inability to hear/acutely hear sounds.
• Cerumen production increases, as does the amount of keratin in cerumen.
• The ossicles of the ear atrophy and become rigid.
• The eardrum loses elasticity.

Hearing Aging Consequences

• Presbycusis (hearing loss due to age-related changes in the inner ear) occurs.
• High-frequency loss occurs first.
• Tone discrimination loss develops.
• Following conversations becomes more difficult.
• Cerumen impaction is common.
• Social isolation may occur.

Integumentary Aging

• The epidermis thins and atrophies.
• The strength and elasticity of the skin decreases.
• Blood flow diminishes, leading to vascular fragility.
• Subcutaneous fat is lost.
• The size and function of sweat glands decrease.
• Sebaceous secretions decrease.
• Melanocytes "cluster.”
• The number of nerve cells decreases.
• Scalp, pubic, and axilla hair become thinner and gray.
• Nasal and ear hair thicken.
• Facial hair appears in women.
• Blood supply to the nailbeds diminishes, creating longitudinal striations in nails.
• "Debris" accumulates under the nails.

Integumentary Aging Consequences

• Increased susceptibility to infection, trauma, malignant lesions, and pressure ulcers.
• Skin becomes dry, scaly, and wrinkled.
• Skin turgor decreases.
• Ability to maintain body temperature and homeostasis is reduced, and baseline temperature may be lower than normal.
• The rate of healing slows down.
• Absorption of drugs by the subcutaneous route slows.
• "Liver Spots" develop.
• Nails thicken, grow more slowly, become brittle and yellowed, and the risk of splitting and infections of the nails increases.

Visual Aging Changes

• The lens yellows, becomes more opaque and rigid.
• Pupil size decreases.
• Accommodation diminishes.
• Intraocular fluid absorption becomes less efficient.
• The visual field narrows.
• Lacrimal secretions decrease.
• The number of cones in the retina decreases.

Visual Aging Consequences

• Presbyopia-inability to focus properly.
• Depth perception is distorted.
• Color discrimination declines.
• Stronger light is needed.
• Sensitivity to glare increases.
• The cornea becomes drier.

Respiratory Aging

• Lung elasticity decreases.
• The number of alveoli decreases, while their size increases.
• The diameter of alveolar ducts and bronchioles increases.
• Ciliary action decreases.
• The anteroposterior chest diameter increases.
• Respiratory muscles weaken.
• The coughing reflex weakens.
• The costal cartilages calcify.

Respiratory Aging Consequences

• Residual capacity increases by 50%.
• Vital capacity decreases.
• Mobility of the bony thorax is reduced.
• Arterial blood oxygen level decreases.
• Oxygen uptake during exercise decreases.
• The risk of infection increases.
• Dead air space increases.
• Exercise tolerance declines.
• Gas exchange diminishes.

Neurological Aging

• The number of neurons decreases.
• Brain weight decreases.
• Histological changes in the brain include increased intracellular pigment, decreased protein synthesis, and senile plaques.
• The rate of impulse conduction in peripheral nerves slows.
• Sleep patterns change.
• Dopamine and other essential enzymes in the brain are depleted.
• Lipofuscin accumulates.
• The brain's cholinergic reserve may be diminished.

Neurological Aging Consequences

• Adaptability decreases.
• The response to stimuli slows down.
• Sensation decreases.
• Proprioception is impaired.
• Gait changes occur.
• Deep tendon reflexes decrease.
• Voluntary movement slows down.
• Sleep pattern disturbances are more common.
• Susceptibility to changes in environmental temperature increases.
• Short-term memory declines.