cellular adaptation + electrolytes/fluids

Atrophy-

A decrease in cell size leading to a decrease in organ size

Causes/Triggers atrophy

- Reduced workload/function, disuse, denervation, reduced blood supply, inadequate nutrition, or loss of hormonal/nervous stimulation

Hypertrophy-

An increase in cell size (without cell division/mitosis), resulting in an enlarged organ, Can be physiologic (e.g., striated muscle exercise) or pathologic (e.g., cardiac hypertrophy from hypertension)

Causes/Triggers hypertrophy-

Increased functional demand, metabolic demand, stretch, growth factors, or hormonal stimulation

Hyperplasia-

An increase in the number of cells due to an increased rate of cell division (requires cells capable of mitosis)3.

Causes/Triggers hyperplasia-

Injury response (loss of epithelial, liver, or kidney cells), normal compensatory/hormonal processes, or pathologic cell proliferation (e.g., endometrial hyperplasia caused by an estrogen-progesterone imbalance leading to excessive uterine bleeding)

Hypoxic / Ischemic Injury-

Occurs when cells receive inadequate oxygen, Tissue oxygenation depends on oxygen content, hemoglobin levels, and cardiac output

Pathophysiology typoxic/ishemic injury-

Cells switch to anaerobic metabolism pH drops lactic acid accumulates (lactic acidosis) cell injury or death

Ischemia

Ischemia is reduced blood flow/oxygen. Prolonged ischemia causes infarction

necrosis-

irreversible cell death characterized by swelling, cell bursting, and inflammation). Dead tissue creates a breeding ground for bacteria

Dry Gangrene-

Tissue appears dry, wrinkled, and blackened3.

Wet Gangrene-

Involves liquefaction, a foul odor, and rapid spread; can become systemic

Gas Gangrene-

Caused by Clostridium perfringens infection; characterized by gaseous bubbles in the tissue

Total Body Water

is 60% of body weight

Intracellular Fluid (ICF)-

66% of body water (inside cells)

Extracellular Fluid (ECF)-

33% of body water (25% interstitial fluid, 8% blood plasma)

Hydrostatic Pressure-

Water "pushing" pressure

Osmotic / Oncotic Pressure-

Water "pulling" pressure exerted by solutes/proteins

Isotonic-

Equal concentration to plasma (e.g., 0.9% Normal Saline, Lactated Ringer's, D5W), Cells remain the same size

Hypotonic

Lower concentration than plasma (e.g., 0.45% Normal Saline)23. Fluid moves out of vascular space into cells, causing cells to swell/engorge

Hypertonic-

Higher concentration than plasma (e.g., 3% Saline, D5W + 0.9% Saline), Fluid moves out of cells into the vascular space, causing cells to shrink

Isotonic Hypovolemia-

Proportional loss of sodium and water caused by emesis, gastric drainage, diarrhea, burns, hemorrhage, or diaphoresis

Third-Spacing-

Abnormal accumulation of fluid in transcellular or interstitial spaces (e.g., ascites, edema, pleural effusion) where it is physiologically unavailable

Hypernatremia-

high sodium

Manifestations of hypernatremia-

Thirst, dry mucous membranes, oliguria, and neurological changes (confusion, lethargy, seizures, coma)26.

Hypokalemia-

low potassium

Causes hypokalemia-

GI loss (diarrhea), renal loss/diuresis, inadequate intake, or alkalosis (as H+ shifts out of cells to fix pH, K+ shifts into cells)

Manifestations hypokalemia-

Muscle weakness, fatigue, lethargy, confusion, shallow respirations, arrhythmias (tachycardia/bradycardia), thready pulse, decreased GI motility (nausea, vomiting, ileus), and alkalosis

Treatment hypokalemia-

Oral KCl: Take with plenty of water/food to prevent severe GI distress/bleeding; hold if NPO for surgery, IV KCl: Dilute and infuse slowly (10mEq/hr max via peripheral IV, 20mEq/hr max via central line), NEVER give IV push

Hypocalcemia-

Low calcium level (inversely related to phosphorus)30.

Manifestations hypocalcemia-

Increased cell membrane excitability, tremors, muscle spasms, seizures, dysrhythmias, hyperreflexia, and decreased bone density

Trousseau's Sign-

Carpal spasm induced by inflating a BP cuff on the upper arm for 3 minutes30.

Chvostek's Sign-

Tapping the facial nerve in front of the ear elicits facial muscle twitching (nose, mouth, eye