Body Systems & Common Conditions for CNAs

The cardiovascular system includes the heart, blood vessels (arteries, veins, and capillaries), and the blood itself. The heart is a muscular pump roughly the size of a fist that moves oxygen-rich blood out to the body through arteries and pulls oxygen-poor blood back through veins to the lungs. A normal adult pulse is 60 to 100 beats per minute and a normal blood pressure is generally under 120/80 mmHg. As people age, blood vessels stiffen, the heart works harder, and circulation slows, making cardiovascular disease one of the most common reasons residents are admitted to long-term care.

Hypertension, or high blood pressure, is often called the silent killer because residents may have no symptoms while their heart and kidneys are being damaged. CNAs play a key role by taking accurate blood pressure readings, reporting values above 140/90 mmHg, and noting headaches, dizziness, or nosebleeds. Congestive heart failure (CHF) occurs when the heart cannot pump efficiently and fluid backs up in the lungs and lower extremities. Watch closely for swelling (edema) in the ankles and feet, sudden weight gain of two or more pounds in a day, shortness of breath, and a wet-sounding cough.

A heart attack (myocardial infarction) happens when blood flow to part of the heart muscle is blocked. Classic signs include crushing chest pain or pressure, pain radiating into the left arm, jaw, neck, or back, profuse sweating (diaphoresis), nausea, and shortness of breath. Women, older adults, and people with diabetes often have atypical symptoms such as fatigue, indigestion, or simply not feeling right. A stroke (cerebrovascular accident) is a brain attack caused by a blocked or ruptured vessel and requires the FAST response: Face drooping, Arm weakness, Speech difficulty, Time to call 911.

The respiratory system moves air in and out of the body, bringing oxygen to the blood and removing carbon dioxide. It includes the nose, mouth, pharynx, larynx, trachea, bronchi, and the lungs with their tiny air sacs called alveoli where gas exchange happens. A normal adult respiratory rate is 12 to 20 breaths per minute, and oxygen saturation should generally be 95% or higher. With age, lung tissue loses elasticity, the chest wall stiffens, and the cough reflex weakens, making elderly residents more vulnerable to respiratory infections and chronic lung disease.

Chronic Obstructive Pulmonary Disease (COPD) is an umbrella term that includes emphysema, in which the alveoli are damaged and air becomes trapped, and chronic bronchitis, in which the airways are chronically inflamed and produce excess mucus. Residents with COPD often breathe with pursed lips, sit leaning forward, and require low-flow oxygen. Never adjust an oxygen flow rate without nurse direction, because giving too much oxygen to a COPD patient can actually suppress their drive to breathe. Pneumonia is a lung infection that may cause fever, chills, a productive cough, chest pain, shortness of breath, and confusion in the elderly.

Asthma causes the airways to narrow and swell, producing wheezing, coughing, chest tightness, and shortness of breath, often triggered by allergens, cold air, or stress. CNAs assist by keeping the environment calm, helping the resident sit upright, and notifying the nurse immediately. Oxygen safety is critical: post No Smoking signs, remove lighters and matches, avoid petroleum-based products like Vaseline on the face, do not use electric razors near oxygen, and keep tubing free of kinks. Oxygen itself does not burn, but it makes everything else burn faster and hotter.

The musculoskeletal system gives the body shape, support, and movement. It includes 206 bones, the muscles attached to them by tendons, the ligaments that connect bone to bone, and the joints where bones meet. With age, bones lose density, muscles lose mass (sarcopenia), joints lose cartilage, and reaction time slows. These changes make older adults far more likely to fall and to break bones when they do. CNAs help prevent decline by encouraging activity, performing range-of-motion exercises, and using safe transfer techniques that protect both the resident and the caregiver.

Osteoporosis is a disease in which bones become porous and brittle, especially in postmenopausal women. A simple fall, or even a sneeze, can fracture a hip, wrist, or vertebra. Arthritis is inflammation of the joints. Osteoarthritis is wear-and-tear damage to cartilage that causes pain, stiffness, and reduced range of motion, most often in knees, hips, and hands. Rheumatoid arthritis is an autoimmune disease in which the body attacks its own joints, causing symmetrical swelling, deformity, and morning stiffness lasting more than an hour.

Hip fracture is one of the leading reasons elderly people are admitted to long-term care. After surgery, residents may have hip precautions: do not bend the hip past 90 degrees, do not cross the legs, and do not turn the toes inward. Parkinson's disease is a progressive neurological condition that affects movement, with four cardinal signs: tremor (often pill-rolling at rest), rigidity (stiff muscles), bradykinesia (slow movement), and postural instability (poor balance). Residents may have a shuffling gait, masked facial expression, and difficulty initiating movement.

The nervous system is the body's communication network. The central nervous system consists of the brain and spinal cord, while the peripheral nervous system includes all the nerves that branch out to the rest of the body. The brain controls thought, memory, movement, sensation, and vital functions like breathing and heart rate. As we age, nerve conduction slows, reflexes diminish, and the senses dull. CNAs must understand that a resident's confusion, weakness, or change in behavior is often the first sign of a serious neurological problem and never just normal aging.

Stroke, or cerebrovascular accident (CVA), occurs when blood flow to part of the brain is interrupted by a clot (ischemic) or a bleed (hemorrhagic). Brain cells die quickly without oxygen, so every minute matters. Use the FAST acronym: Face drooping, Arm weakness, Speech difficulty, Time to call 911. After a stroke, residents may have hemiparesis (one-sided weakness), aphasia (difficulty speaking or understanding language), or dysphagia (difficulty swallowing, which raises aspiration risk). A transient ischemic attack (TIA) is a mini-stroke with the same symptoms that resolve within 24 hours but still requires urgent evaluation.

Seizures are sudden bursts of abnormal electrical activity in the brain. During a seizure, protect the resident from injury by moving objects away, cushioning the head, turning them on their side if possible, and never putting anything in their mouth. Time the seizure and notify the nurse immediately. Multiple sclerosis (MS) is an autoimmune disease that damages the protective coating of nerves, leading to muscle weakness, vision problems, fatigue, balance issues, and bladder dysfunction. Symptoms often come and go in cycles called relapses and remissions.

The endocrine system is a network of glands that release hormones into the bloodstream to regulate metabolism, growth, mood, and reproduction. The pancreas is especially important to CNAs because it produces insulin, the hormone that allows glucose (sugar) to enter cells for energy. When the pancreas fails or the body becomes resistant to insulin, blood sugar rises and diabetes develops. Endocrine disorders are common in long-term care and can dramatically change a resident's mental status from one shift to the next.

Type 1 diabetes is an autoimmune disease in which the pancreas makes little or no insulin; these residents always need insulin injections. Type 2 diabetes is far more common in older adults and develops when the body becomes resistant to insulin; it is often managed with diet, oral medication, and sometimes insulin. A normal fasting blood glucose is 70 to 100 mg/dL. Diabetes is generally diagnosed when fasting glucose is 126 mg/dL or higher on more than one test. CNAs monitor intake, encourage activity, report skipped meals, and watch carefully for both low and high blood sugar.

Hypoglycemia means blood sugar below 70 mg/dL and is a true emergency. Signs include shakiness, sweating, cold and clammy skin, dizziness, irritability, confusion, blurred vision, rapid heartbeat, and eventually loss of consciousness. If the resident is awake and able to swallow safely, give 15 grams of fast sugar such as 4 ounces of juice, regular soda, or glucose tablets, then notify the nurse. Hyperglycemia means blood sugar that is too high. Signs include extreme thirst, frequent urination, blurred vision, fatigue, slow-healing wounds, and a fruity, acetone-like breath odor that signals diabetic ketoacidosis.

The genitourinary system includes the kidneys, ureters, bladder, urethra, and the reproductive organs. The kidneys filter waste from the blood and produce urine, the ureters carry urine to the bladder, the bladder stores it, and the urethra carries it out of the body. A healthy adult produces about 1,500 mL (about 30 mL per hour) of clear, pale-yellow urine each day. With age, bladder capacity shrinks, the kidneys filter less efficiently, and pelvic floor muscles weaken, which is why incontinence and urinary infections are so common in long-term care.

Urinary tract infections (UTIs) are one of the most frequent infections in elderly residents. Classic signs include burning during urination, frequency, urgency, cloudy or foul-smelling urine, and lower abdominal pain. In older adults, the only sign may be sudden confusion, agitation, falls, or a new fever. Report any of these immediately. Kidney failure can develop slowly (chronic) or suddenly (acute) and shows up as decreased urine output, swelling, fatigue, nausea, and confusion. Residents on dialysis need careful monitoring of fluids and protected access sites; never take blood pressure on a fistula arm.

Benign prostatic hyperplasia (BPH) is enlargement of the prostate gland in older men, which presses on the urethra and causes a weak stream, dribbling, frequent nighttime urination, and a sense of incomplete emptying. Severe BPH can lead to urinary retention, where the bladder cannot empty. Signs include a distended lower abdomen, restlessness, and pain. Always report. Indwelling urinary catheters should be kept below bladder level, never looped or kinked, and the bag emptied per facility policy.

The gastrointestinal (GI) system processes food, absorbs nutrients, and eliminates waste. It includes the mouth, esophagus, stomach, small intestine, large intestine (colon), rectum, and anus, plus accessory organs like the liver, gallbladder, and pancreas. With age, saliva decreases, taste dulls, peristalsis slows, and many medications cause GI side effects. Because nutrition and hydration directly affect every other body system, CNAs play a critical role by monitoring how much residents eat and drink, recording bowel movements, and reporting changes in appetite or weight.

Constipation is extremely common in long-term care due to low fluid intake, low fiber, inactivity, and medications such as opioids and iron. Signs include hard, dry stools, straining, abdominal distension, decreased appetite, and even confusion. Diarrhea is loose, watery stool occurring three or more times per day and quickly leads to dehydration, especially in elders. Always use standard precautions and report changes promptly because diarrhea in long-term care may signal C. difficile infection. Dehydration shows up as dry mouth, sunken eyes, dark concentrated urine, low blood pressure, rapid pulse, and confusion.

Gastroesophageal reflux disease (GERD) occurs when stomach acid backs up into the esophagus, causing heartburn, sour taste, and sometimes a chronic cough. Keep residents upright for at least 30 to 60 minutes after meals. An ostomy is a surgically created opening in the abdomen for the elimination of stool. A colostomy drains from the colon and produces semi-formed stool, while an ileostomy drains from the small intestine and produces liquid, very irritating output. Empty the pouch when it is one-third to one-half full, observe for skin breakdown around the stoma, and report a stoma that is not pink and moist.

The integumentary system is the body's largest organ and includes the skin, hair, nails, and sweat glands. Skin protects against infection, regulates temperature, prevents water loss, and provides sensation. With age, skin thins, loses elasticity, produces less oil, bruises more easily, and heals more slowly. These changes make older adults especially vulnerable to skin tears and pressure injuries. Because CNAs spend more time with residents than any other staff member, prevention of skin breakdown is largely your responsibility, and identifying problems early can prevent infections, hospitalizations, and even death.

A pressure injury, formerly called a pressure ulcer or bedsore, develops when sustained pressure cuts off blood flow to the skin and underlying tissue. The National Pressure Injury Advisory Panel (NPIAP) defines six categories. Stage 1 is intact skin with non-blanchable redness, often over a bony prominence. Stage 2 is partial-thickness loss of skin with exposed dermis; it looks like a shallow open ulcer or a blister. Stage 3 is full-thickness loss with visible fat but no exposed bone, tendon, or muscle. Stage 4 is full-thickness loss with exposed bone, tendon, muscle, or cartilage.

Unstageable pressure injuries are full-thickness wounds whose depth cannot be determined because slough or eschar covers the wound bed. Deep tissue injury (DTI) appears as intact or non-intact skin with a localized area of persistent non-blanchable deep red, maroon, or purple discoloration that may evolve rapidly. Major risk factors include immobility, incontinence, moisture, friction, shear, poor nutrition, dehydration, and decreased sensation. The Braden Scale is a screening tool nurses use to assess risk, but CNAs supply the daily observations that drive prevention.

Prevention is everything. Reposition residents in bed at least every two hours, shift those in chairs every 15 minutes when able, keep skin clean and dry, use pillows to offload bony prominences, never drag a resident across sheets (always lift to avoid shear), encourage fluids and protein, and inspect skin during every bath, dressing change, and brief change. Report any redness that does not fade within 30 minutes, any blister, opening, or new skin discoloration immediately.