physiologic

Chapter 3: Physiologic Changes

Learning Objectives—Lesson 3.1

  • Describe the most common structural changes observed in the normal aging process.

  • Discuss the impact of normal structural changes on the older adult’s self-image and lifestyle.

  • Describe the most commonly observed functional changes that are part of the normal aging process.

  • Discuss the impact of normal functional changes on the older adult’s self-image and lifestyle.

  • Identify the most common diseases related to aging in each of the body systems.

  • Differentiate between normal changes of aging and disease processes.

  • Discuss the impact of age-related changes on nursing care.

The Integumentary System

Structure

  • Epidermis

  • Dermis

  • Subcutaneous tissue

  • Hair

  • Nails

Expected Age-Related Changes

  • Senile lentigo: Flat brown spots on the skin (age spots).

  • Seborrheic keratosis: Benign, wart-like growths on the skin.

  • Cutaneous papilloma or skin tags: Small, benign tumors on the skin.

  • Crow’s feet or wrinkles: Fine lines around the eyes due to loss of elasticity.

  • Faded or gray hair color: Decreased melanin production; hair may also thin.

  • Hair distribution patterns change: Changes in body and facial hair.

  • Fingernails grow more slowly: Nails take longer to grow and may become brittle.

  • Toenails become thicker: Thicker toenails develop due to changes in circulation.

  • Xerosis (dry skin): Reduced moisture content leading to dryness.

  • Senile purpura: Purple spots resulting from blood vessel fragility.

Common Disorders Seen with Aging

  • Melanoma, basal cell carcinoma, and squamous cell carcinoma: Increased risk for skin cancers.

  • Pressure injuries: Problems with skin integrity due to immobility.

  • Inflammation and infection: A range of conditions including:

    • Rosacea: Chronic skin condition that causes redness.

    • Contact, allergic, and seborrheic dermatitis: Skin inflammation due to allergens.

    • Herpes zoster: Shingles, a viral infection causing painful rash.

    • Fungal, yeast, and bacterial infections: Increased susceptibility.

    • Infestation with scabies: A condition caused by a mite.

    • Hypothermia: Reduced ability to regulate temperature.

The Musculoskeletal System

Bones

  • Composition:

    • Protein

    • Calcium

    • Phosphorus

  • Needed for strong bones:

    • Adequate intake of vitamins A, C, and D.

    • Weight-bearing activity (standing and walking).

    • Hormone balance.

Vertebrae

  • Composed of small bones forming a strong, flexible structure supporting the head.

  • The spinal cord passes through the spinal canal.

  • Intervertebral disks: Fibrous pads that cushion vertebrae and absorb impact from walking and other activities.

Joints, Tendons, and Ligaments

  • Joints: Where bones meet.

  • Bursa: Fluid sac providing lubrication in joints.

  • Tendons: Connect muscles to bones.

  • Ligaments: Connect bones to each other.

Muscles

  • Cardiac muscle: Located only in the heart; maintains blood circulation.

  • Smooth muscle: Found in walls of hollow organs (blood vessels, stomach, intestines, bladder).

  • Skeletal muscle: The largest muscle tissue type; responsible for moving the bones.

Expected Age-Related Changes

  • Decrease in bone calcium: Reduces bone density and strength.

  • Greater risk of fracture: Increased fragility of bones.

  • Loss of height: Due to compression of vertebrae and loss of intervertebral discs fluid.

  • Loss of teeth: Resulting from periodontal disease and other factors.

  • Less fluid in intervertebral disks: Leading to less cushioning and flexibility.

  • Decrease in blood supply to muscles: Reduced muscle function.

  • Decrease in tissue elasticity: Affects overall mobility.

  • Decrease in muscle tone and mass: Known as sarcopenia.

Common Disorders Seen with Aging

  • Osteoporosis: Condition characterized by weakened bones.

  • Degenerative joint disease: Includes various forms:

    • Osteoarthritis: Degeneration of joint cartilage.

    • Rheumatoid arthritis: Autoimmune disorder affecting joints.

    • Bursitis: Inflammation of the bursa.

    • Gouty arthritis: Caused by uric acid crystallization.

The Respiratory System

Upper Respiratory Tract

  • Includes air passages of the nose, mouth, and throat above the chest cavity.

  • Nasopharynx: Connected to the middle ear by eustachian tubes, maintaining air pressure.

  • Larynx (Voice Box): Composed of cartilage rings; vocal folds for sound production.

  • Epiglottis: Prevents food from entering the airway.

Lower Respiratory Tract

  • Comprises lower trachea, bronchial passages, and alveoli within the chest cavity.

  • Trachea: Connects the larynx to bronchial passages, branching into major bronchi.

  • Alveoli: Tiny air sacs; functional units of respiration where gas exchange occurs.

Air Exchange (Respiration)

  • Ventilation:

    • Inhalation (Inspiration): Breathing in air.

    • Exhalation (Expiration): Breathing out air.

  • Regulation: Governed by neurological and chemical factors. Most breathing is involuntary but can be conscious.

Expected Age-Related Changes

  • Less body fluids: Affecting overall respiratory efficiency.

  • Fewer cilia: Leading to decreased ability to clear mucous.

  • Fewer macrophages: Reducing immune response in lungs.

  • Decreased tissue elasticity: Affecting ability to expand and contract lungs.

  • Less muscle strength and endurance: Compromising respiratory function.

  • Fewer capillaries: Reduced oxygen diffusion area.

  • Greater calcification of cartilage: Reducing flexibility of the airways.

Common Disorders Seen with Aging

  • Chronic obstructive pulmonary disease (COPD): Includes emphysema and chronic bronchitis.

  • Asthma: Chronic condition affecting airways.

  • Influenza: Viral infection of the respiratory system.

  • COVID-19: Impact on respiratory function.

  • Pneumonia: Infection causing inflammation of the air sacs.

  • Tuberculosis: Bacterial infection affecting lungs.

  • Lung cancer: Increased incidence with age.

The Cardiovascular System

Heart

  • Located centrally in the thoracic cavity between the lungs; a muscular organ.

  • Chambers:

    • Right atrium and right ventricle

    • Left atrium and left ventricle

  • Pericardial membranes: Surround the heart,

    • Fibrous pericardium

    • Parietal pericardium

    • Epicardium (visceral pericardium)

Blood Vessels

  • Arteries: Carry blood away from the heart; primarily oxygenated blood (except pulmonary artery).

  • Veins: Carry blood toward the heart; primarily deoxygenated blood (except for four pulmonary veins).

Conduction System

  • Establishes heart rhythm through specialized cells:

    • Sinoatrial node: Natural pacemaker of the heart.

    • Atrioventricular node

    • Bundle of His

    • Right and left bundle branches

    • Purkinje fibers

    • Ventricular myocardium

Expected Age-Related Changes

  • Less cardiac muscle tone: Affecting strength of contractions.

  • Larger heart size: Thickening of the left ventricular wall.

  • Decrease in cardiac output: Reduced efficiency in pumping blood.

  • Decrease in elasticity: Of heart muscle and blood vessels.

  • Fewer pacemaker cells: Leading to arrhythmias.

  • Decrease in baroreceptor sensitivity: Affecting blood pressure regulation.

  • Lower incidence of valvular calcification: Compared to older age.

  • Greater risk of atherosclerosis: Hardening and narrowing of arteries.

Common Disorders Seen With Aging

  • Coronary artery disease: Blockage of coronary arteries.

  • Coronary valve disease: Dysfunction impacting blood flow.

  • Cardiac arrhythmias: Irregular heartbeat.

  • Heart failure: Inability to pump enough blood.

  • Cardiomegaly: Enlargement of the heart.

  • Peripheral vascular disease:

    • Occlusive peripheral vascular problems.

    • Varicose veins.

    • Aneurysm.

    • Hypertensive disease.

The Hematopoietic and Lymphatic Systems

Blood

  • General Functions:

    • Transportation of nutrients, waste products, blood gases, and hormones.

    • Regulation of fluid-electrolyte balance, acid-base balance, and body temperature.

    • Protection against pathogenic attacks (via white blood cells) and blood loss (via clotting mechanisms).

  • Components:

    • Plasma

    • Erythrocytes (red blood cells)

    • Leukocytes (white blood cells)

    • Platelets

Lymph System

  • Lymph vessels, fluid, and nodes:

    • Absorb fluid and proteins from tissues.

  • Spleen: Produces lymphocytes and monocytes entering the bloodstream.

    • B lymphocytes: Recognize antigens on foreign cells.

    • Helper T cells: Detect antigens and induce B cells to produce antibodies found in plasma.

Expected Age-Related Changes

  • Greater plasma viscosity: More concentrated blood.

  • Decrease in red blood cell production: Anemia risks.

  • Less mobilization of neutrophils: Impacting immune response.

  • Greater immature T-cell response: Decreased production of effective immune cells.

Common Disorders Seen With Aging

  • Anemia: Decreased red blood cells.

  • Leukemia: Cancer of blood-forming tissues.

The Gastrointestinal System

Oral Cavity

  • Food enters via mouth and is prepared for digestion.

  • Teeth: Mechanically process food; normal adult has 28-32 permanent teeth.

Tongue

  • Highly flexible muscle; controlled by cranial nerves.

  • Papillae: Taste buds located on tongue's upper surface; aid in mechanical digestion.

Salivary Glands

  • Excrete saliva, composed mainly of water and containing amylase for starch digestion.

Esophagus

  • Hollow muscular tube from pharynx to stomach; cardiac sphincter prevents food from moving back.

Stomach

  • Muscular sac for mechanical and chemical digestion; lined with mucous membrane to protect walls.

    • Special glands secrete mucus, enzymes, and hydrochloric acid; food becomes chyme before entering small intestine.

Small Intestine

  • Approximately 20 feet long; three segments:

    • Duodenum

    • Jejunum

    • Ileum

  • Completes digestion and absorbs nutrients.

Large Intestine

  • About 5 feet long with five segments:

    • Ascending colon

    • Transverse colon

    • Descending colon

    • Sigmoid colon

    • Rectum

  • Major functions include absorption of water, minerals, vitamins, and storage of waste.

Expected Age-Related Changes

  • Increased dental caries and tooth loss.

  • Decreased thirst perception.

  • Decreased gag reflex:

  • Less muscle tone in sphincters.

  • Decreased saliva and gastric secretions: Affecting digestion.

  • Decreased gastric motility and peristalsis.

  • Smaller liver size: Less efficiency in enzyme production.

Common Disorders Seen with Aging

  • Hiatal hernia: Upper part of stomach bulging through diaphragm.

  • Gastroesophageal reflux disease (GERD): Acid reflux condition.

  • Gastritis and ulcers: Inflammation and sore in stomach lining.

  • Diverticulosis and diverticulitis: Pockets in bowels leading to inflammation.

  • Cancer: Higher risks with aging.

  • Hemorrhoids: Swollen veins in the rectum.

  • Rectal prolapse: Rectum protruding through anus.

The Urinary System

Kidneys

  • Bean-shaped organs flanking the spine; functional unit is nephron.

  • Function to remove wastes, regulate fluid and electrolyte balance; produce 1-2 L of urine daily.

Ureters and Bladder

  • Ureters: Tubes transporting urine from kidneys to bladder.

  • Bladder: Muscular sac that can hold 1000 mL urine, located in the pelvic cavity.

Characteristics of Urine

  • About 95% water; remainder includes waste products and salts.

  • Typically clear; color ranges from pale yellow to dark amber; may vary based on diet's acidity.

Expected Age-Related Changes

  • Fewer functional nephrons: Reducing kidney efficiency.

  • Decreased blood supply affects kidney function.

  • Decrease in muscle tone and tissue elasticity impacting bladder function.

  • Altered perception to void; potential nocturnal urine production increase (more in men after enlargement of the prostate).

Common Disorders Seen with Aging

  • Urinary incontinence: Loss of bladder control leading to involuntary leakage.

  • Urinary tract infection: Increased vulnerability due to urinary retention trouble.

  • Chronic kidney disease: Progressive loss of kidney function.

The Nervous System

Central Nervous System

  • Medulla: Controls vital functions.

  • Pons and midbrain: Manage respiration, integrates reflexes.

  • Cerebellum: Coordinates unconscious movements.

  • Hypothalamus: Autonomic nervous system and hormone secretion.

  • Cerebrum: Controls movement, judgment, sensory functions, and problem solving.

Peripheral Nervous System

  • Cranial nerves and spinal nerves: Detect changes and relay information to the CNS.

  • Impulses: Transmit from brain/spinal cord to end organs; injured nerves may regenerate.

Expected Age-Related Changes

  • Fewer brain cells and nerve fibers: Reduction in neuroplasticity and functional capacity.

  • Fewer neuroreceptors: Affecting neurotransmission.

  • Decrease in peripheral nerve function: Slower reaction times.

Common Disorders Seen with Aging

  • Parkinson disease: Movement disorder due to dopamine loss.

  • Dementia: Decline in cognitive function.

  • Alzheimer dementia: The most prevalent form of dementia.

  • Transient ischemic attack: Temporary stroke symptoms due to reduced blood flow.

  • Stroke: Can be ischemic (blockage) or hemorrhagic (bleeding).

The Special Senses

The Eyes

  • Composed of three layers:

    • Sclera

    • Choroid

    • Retina

  • The majority of eye mass consists of anterior and posterior fluid-filled cavities; protective structures include eyelids and tear glands.

Expected Age-Related Changes (Eyes)

  • Fewer eyelashes and decrease in tear production: Leading to dry eyes.

  • Greater discoloration of lens: Impairing vision quality.

  • Decrease in tissue elasticity and muscle tone: Affecting accommodation and focus (presbyopia).

Common Disorders Seen with Aging (Eyes)

  • Blepharitis: Inflammation of eyelid margins.

  • Diplopia: Double vision.

  • Cataracts: Clouding of the lens.

  • Glaucoma: Increased pressure leading to nerve damage.

  • Age-related macular degeneration and retinal detachment: Affecting central vision.

The Ears

  • Composed of three distinct portions:

    • Outer ear

    • Middle ear

    • Inner ear

  • Functions include sound detection and balance maintenance.

Expected Age-Related Changes (Ears)

  • Decreased tissue elasticity: Affecting sound transmission.

  • Decreased joint mobility: Impeding muscle function.

  • Decreased ceruminous cells in the external ear canal: Affecting earwax production.

  • Atrophy of vestibular structures: Leading to balance issues.

  • Presbycusis: Age-related hearing loss.

Common Disorders Seen with Aging (Ears)

  • Otosclerosis: Abnormal bone growth in the ear.

  • Tinnitus: Ringing in the ears.

  • Deafness: Progressive hearing loss.

  • Ménière's disease: Inner ear disorder affecting balance and hearing.

The Special Senses: Taste and Smell

  • Taste receptors located in taste buds on the tongue respond to chemical stimuli; stimulated by olfactory senses.

Expected Age-Related Changes (Taste and Smell)

  • Fewer papillae on the tongue decrease taste sensations; fewer nasal sensory receptors also impact the sense of smell.

The Endocrine System

Pituitary Gland

  • Known as the master gland; regulates many body functions via hormonal signaling.

  • Features two segments:

    • Anterior pituitary

    • Posterior pituitary (connects nervous system to endocrine system).

Thyroid Gland

  • Surrounds the trachea, located below the larynx; major hormones include:

    • Thyroxin

    • Triiodothyronine

    • Calcitonin

Parathyroid Glands

  • Located posterior to the thyroid; secrete parathyroid hormone, which increases calcium and phosphorus in the blood.

Pancreas

  • Functions as both an exocrine (digestive) and endocrine (hormonal) gland:

    • α cells produce glucagon to raise blood sugar levels.

    • β cells produce insulin to lower blood sugar and assist cellular uptake of glucose.

Adrenal Glands

  • Located atop each kidney:

    • Adrenal medulla: Secretes epinephrine and norepinephrine.

    • Adrenal cortex: Releases various hormones, including mineralocorticoids and glucocorticoids.

Ovaries and Testes

  • Secrete hormones involved in sexual maturation and functioning:

    • Ovaries: Estrogen and progesterone.

    • Testes: Testosterone for sperm maturation and male characteristics.

Expected Age-Related Changes

  • Decrease in pituitary secretions (including growth hormone).

  • Decrease in thyroid-stimulating hormone leading to metabolic changes.

  • Decrease in insulin production or increased insulin resistance.

  • Decrease in parathyroid hormone production affecting calcium metabolism.

Common Disorders Seen with Aging

  • Diabetes mellitus: Type 1 is not age-related; Type 2 incidence increases with age.

  • Hypoglycemia: Low blood sugar risks.

  • Hypothyroidism: Reduced thyroid function.

Audience Response Systems

  • Question 1: Which is the body’s natural pacemaker?

    • -ä Atrioventricular node

    • -ä Purkinje fibers

    • -ä Sinoatrial node (Correct Answer)

    • -ä Bundle of His

  • Question 2: Which of the following is a result of aging?

    • -ä Smaller urinary bladder size (Correct Answer)

    • -ä Larger urinary bladder size

    • -ä Greater muscle tone in the bladder

    • -ä Less nocturnal urine production

  • Question 3: What is the most common form of dementia?

    • -ä Alzheimer disease (Correct Answer)

    • -ä Vascular dementia

    • -ä Dementia with Lewy bodies

    • -ä Frontotemporal dementia

  • Question 4: Which organ produces calcitonin?

    • -ä Parathyroid

    • -ä Pituitary

    • -ä Adrenal

    • -ä Thyroid (Correct Answer)

  • Question 5: According to the CDC, the number of older adults with diabetes is how many times higher than adults aged 18 to 44?

    • -ä 10

    • -ä 100

    • -ä 2.5 (Correct Answer)

    • -ä 7.5

The Reproductive and Genitourinary Systems

Female Reproductive Organs

  • Include ovaries, fallopian tubes, uterus, and vagina, located in the pelvic cavity.

  • Hormonal function typically ceases after menopause (ages 45-60).

Male Reproductive Organs

  • Include testes and penis; testes are located in the scrotum below the urinary bladder.

Expected Age-Related Changes

  • Changes in women:

    • Decrease in estrogen levels leading to vaginal dryness.

    • Decrease in tissue elasticity and greater vaginal alkalinity.

  • Changes in men:

    • Decrease in testosterone levels decreasing libido and function.

    • Decrease in circulation impacting reproductive health.

Common Disorders Seen with Aging

  • Uterine prolapse: The uterus descends into the vaginal canal.

  • Vaginal infections: Due to changes in flora.

  • Breast cancer: Increased risk with age.

  • Prostate cancer: A common cancer in older men.

Conclusion

  • Understanding age-related changes through various body systems is critical for improving older adults' self-image, wellbeing, and nursing care tailored to their specific needs.