Cellular Physiology, Pathophysiology & Fluid-Electrolyte Basics

Comprehensive vocabulary flashcards covering membrane transport, cell adaptation, fluid-electrolyte concepts, hormones, and related pathophysiology from the lecture transcript.

Passive Transport

Movement of substances across a membrane without ATP; includes diffusion and osmosis.

Diffusion

Passive movement of solute particles from high to low concentration.

Osmosis

Passive movement of water across a semipermeable membrane from high to low water concentration.

Facilitated Transport

Passive movement of large/charged molecules via membrane channels or carriers.

Active Transport

Energy-requiring movement of substances against a concentration gradient using ATP.

ATP (Adenosine Triphosphate)

Cellular energy currency produced mainly by mitochondria.

Mitochondria

Organelle that generates ATP; the cell’s “powerhouse.”

Sodium-Potassium Pump

ATP-driven transporter that moves 3 Na⁺ out and 2 K⁺ into the cell.

Phagocytosis

Cellular “eating” of large solid particles such as bacteria.

Pinocytosis

Cellular “drinking” of fluid-filled vesicles; endocytosis of liquids.

Receptor-Mediated Endocytosis

Selective uptake of molecules after receptor binding.

Exocytosis (Secretion)

Vesicular release of cellular products or waste to the exterior.

Aerobic Respiration

ATP production pathway that requires oxygen.

Anaerobic Respiration

Energy production without oxygen; less efficient than aerobic.

Mitosis

Somatic cell division producing two genetically identical daughter cells.

Meiosis

Gamete cell division generating haploid sperm or ova.

Cellular Differentiation

Process by which daughter cells become specialized in form or function.

Atrophy

Decrease in cell size and number leading to tissue shrinkage.

Hypertrophy

Increase in individual cell size causing tissue enlargement.

Hyperplasia

Increase in the number of cells within a tissue or organ.

Metaplasia

Reversible substitution of one differentiated cell type for another.

Dysplasia

Abnormal, disordered cell growth and organization; precancerous.

Apoptosis

Programmed, regulated cell death beneficial for tissue homeostasis.

Necrosis

Uncontrolled cell and tissue death due to injury or ischemia.

Cerebral Atrophy

Loss of brain tissue volume seen in dementia and TBI.

Cardiac Hypertrophy

Enlargement of heart muscle cells, often from hypertension.

Acromegaly

Post-epiphyseal hyperplasia causing enlarged bones and soft tissues from excess growth hormone.

Cervical Metaplasia

Reversible change of cervical cell type, often due to HPV.

Cervical Dysplasia

Precancerous abnormal cervical cell growth following continued injury.

ADH (Antidiuretic Hormone)

Posterior pituitary hormone that promotes kidney water reabsorption.

Aldosterone

Adrenal cortex hormone that increases renal sodium and water reabsorption.

Renin-Angiotensin System (RAS)

Hormonal cascade that raises blood pressure via vasoconstriction and aldosterone release.

Osmotic Pressure

Force created by solute concentration differences driving water movement.

Hydrostatic Force

Pressure exerted by fluid to push it through or against membranes.

Tonicity

Relative solute concentration of a fluid compared with cytoplasm; affects cell volume.

Isotonic Solution

Fluid with equal solute concentration to cell interior; no net water shift.

Hypotonic Solution

Lower solute concentration; water flows into cells causing swelling.

Hypertonic Solution

Higher solute concentration; water leaves cells causing shrinkage.

Intracellular Fluid (ICF)

Fluid contained within cells (~40 % body weight).

Extracellular Fluid (ECF)

Fluid outside cells, including interstitial, intravascular, and transcellular compartments.

Transcellular Fluid

ECF sequestered in cavities (CSF, pleural, ascitic); formerly “third spacing.”

Fluid Volume Deficit (Hypovolemia)

Insufficient intravascular fluid leading to hypotension and dehydration signs.

Fluid Volume Excess

Excess body water/Na⁺ causing edema, weight gain, crackles, JVD.

Polydipsia

Excessive thirst and fluid intake.

Polyuria

Excessive urine output.

Jugular Vein Distension (JVD)

Visible bulging neck veins indicating elevated venous pressure.

Ascites

Abnormal fluid accumulation within the peritoneal cavity.

Osmolality

Concentration of solutes per kilogram of solvent in plasma.

Sodium (Na⁺)

Major ECF cation; normal 135-145 mEq/L; key for neuro function & water balance.

Chloride (Cl⁻)

Primary ECF anion that follows sodium; normal 98-108 mEq/L.

Potassium (K⁺)

Main ICF cation; normal 3.5-5 mEq/L; critical for cardiac rhythm.

Calcium (Ca²⁺)

Mineral for bones, muscle contraction, nerve impulse; 8.5-10 mg/dL.

Magnesium (Mg²⁺)

Cation stored in bone/muscle; supports enzyme and nerve function; 1.5-2.5 mEq/L.

Phosphorus (PO₄³⁻)

Bone & energy metabolism anion; inversely related to calcium.

Ischemia

Insufficient blood supply to tissues causing injury or necrosis.

Free Radicals

Highly reactive molecules that damage DNA, proteins, and membranes.

Fontanelle

Soft membrane-covered gap between infant skull bones; bulges with fluid excess, sinks with dehydration.

Homeostasis

Dynamic physiological equilibrium maintained through feedback mechanisms.

Negative Feedback Loop

Regulatory mechanism that negates deviations to restore balance (e.g., sweating when hot).

Positive Feedback Loop

Mechanism that amplifies changes (e.g., oxytocin-driven uterine contractions).

Oxytocin

Posterior pituitary hormone triggering labor contractions and milk ejection.

Prolactin

Anterior pituitary hormone stimulating breast milk production.

Pituitary Gland

Master endocrine gland directing other glands via tropic hormones.

Hypothalamus

Brain region regulating pituitary function and autonomic responses.

General Adaptation Syndrome (GAS)

Selye’s three-stage stress response: alarm, resistance, exhaustion.