Pathophysiology Exam 2 Review: Fluid, Electrolyte, Acid-Base, and Endocrine Disorders

Comprehensive vocabulary flashcards covering fluid and electrolyte balance, acid-base homeostasis, endocrine regulation (pituitary, thyroid, adrenal), and diabetes mellitus from the Pathophysiology Exam 2 mock exam review.

Intracellular Fluid Electrolyte Distribution

Potassium ($K^+$) is the electrolyte with the greatest concentration within the intracellular fluid compartment ($140\text{--}150\,\text{mEq/dL}$).

Extracellular Fluid Electrolyte Distribution

Sodium ($\text{Na}^+$) and chloride ($\text{Cl}^-$) are the electrolytes with the highest concentration in the extracellular fluid compartment.

Extracellular Calcium Concentration

The normal physiological extracellular concentration of calcium is $8.5\text{--}10.5\,\text{mg/dL}$.

Extracellular Potassium Concentration

The normal physiological extracellular concentration of potassium is $3.5\text{--}5.0\,\text{mEq/L}$.

Extracellular Sodium Concentration

The normal physiological extracellular concentration of sodium is $135\text{--}145\,\text{mEq/L}$.

Extracellular Magnesium Concentration

The normal physiological extracellular concentration of magnesium is $1.8\text{--}3.0\,\text{mg/dL}$.

Intracellular Potassium Concentration

The normal intracellular concentration of potassium is $140\text{--}150\,\text{mEq/dL}$.

Hyponatremia

An electrolyte disorder characterized clinically by headache, oliguria ($350\,\text{mL}$ in $24\,\text{hours}$), hypotension, confusion, extremity weakness, and seizures.

Hypokalemia

An electrolyte deficiency characterized by cardiac arrhythmias, shallow respirations, decreased deep tendon reflexes, and leg cramps.

Hypomagnesemia

An electrolyte deficiency characterized by seizures, cardiac arrhythmias, muscle tremors, weakness, and depressed mood.

Hypocalcemia

An electrolyte deficiency manifesting with muscle twitching, muscle cramps, hyperactive reflexes, and abnormal blood clotting.

Hypernatremia

An electrolyte excess presenting with acute headache, extreme thirst, tachycardia, dry skin, dry mucous membranes, and lethargy.

Hyperkalemia

An electrolyte excess presenting with nausea, diarrhea, muscle weakness, and a high risk of lethal cardiac arrest.

Hypermagnesemia

An electrolyte excess presenting primarily with generalized muscle weakness and diminished deep tendon reflexes with otherwise stable vitals.

Hypercalcemia

An electrolyte excess presenting with severe constipation, abdominal cramps, muscle weakness, and confusion.

Baroreceptors

Vascular wall sensory receptors that regulate effective fluid volume by sensing changes in vessel wall tension and triggering thirst sensations.

Osmoreceptors

Sensory receptors located within the hypothalamic thirst center that promote thirst in response to changes in solute concentration.

Antidiuretic Hormone (ADH)

A hormone that controls the excretion of total body fluid by acting directly on the kidneys to promote water reabsorption.

Aldosterone

A mineralocorticoid hormone that acts on the kidneys to stimulate the reabsorption of sodium and water while increasing potassium excretion.

Renin-Angiotensin-Aldosterone System (RAAS)

The sequential hormonal cascade wherein: 1. Liver produces angiotensinogen; 2. Kidneys secrete renin to convert it to angiotensin I; 3. Lungs secrete ACE to convert it to angiotensin II; 4. Angiotensin II triggers aldosterone release and vasoconstriction; 5. Aldosterone promotes sodium and water reabsorption.

Potassium-Sparing Diuretics

A class of diuretics that promotes sodium and water excretion from the late distal tubule to the collecting duct while retaining potassium.

Thiazide Diuretics

A class of diuretics that promotes fluid excretion by increasing the excretion of sodium and water in the distal tubule.

Loop Diuretics

A class of diuretics that decreases the reabsorption of $\text{NaCl}$ in the thick ascending limb of the loop of Henle.

Hypertonic Solution

An intravenous solution with a higher solute osmolarity than intracellular fluid, causing water to shift out of cells and resulting in cellular shrinkage.

Hypotonic Solution

An intravenous solution with a lower solute osmolarity than intracellular fluid, causing water to enter cells and resulting in cellular swelling.

Physiological Routes of Fluid Loss

Routes by which total body water is excreted: the kidneys ($1\,\text{mL/kg/hr}$ urine output), the lungs ($300\,\text{mL}$ per day via exhalation), the skin ($150\,\text{mL}$ through sweat), and the GI tract.

Hypervolemia

Fluid volume excess manifested by acute weight gain, generalized edema, bounding pulse, jugular venous distension, dyspnea, and pulmonary crackles.

Hypovolemia

Fluid volume deficit characterized by acute weight loss, hypotension, tachycardia, weak pulse, hypothermia, flattened neck veins, dry mucous membranes, and delayed capillary refill.

Pathophysiological Factors of Edema Formation

The microvascular alterations that produce interstitial swelling: increased capillary filtration pressure, decreased capillary colloidal osmotic pressure, and increased capillary permeability.

Cirrhosis

A chronic liver disease characterized by hepatocyte damage and interference of local hepatic blood flow, frequently caused by alcohol abuse and hepatitis, resulting in impaired albumin synthesis, portal hypertension, ascites, and edema.

Albumin

The primary intravascular plasma protein synthesized by the liver that generates colloidal osmotic pressure to keep fluid within the vascular compartment.

Dehydration

A clinical fluid deficit presenting with altered mental status, tachypnea ($24/\text{min}$), tachycardia ($122\,\text{bpm}$), hypotension ($90/56\,\text{mmHg}$), weak pulse, capillary refill $> 3\,\text{seconds}$, dry mucous membranes, and concentrated urine (specific gravity $1.028$).

Acids

Chemical substances that donate hydrogen ions ($\text{H}^+$) to a solution.

Bases

Chemical substances that accept hydrogen ions ($\text{H}^+$) from a solution.

Normal Blood pH

The ideal arterial physiological range of hydrogen ion concentration in human blood, defined as $7.35\text{--}7.45$.

pH Regulatory Systems Hierarchy

The physiological systems controlling pH, ordered from fastest-acting to slowest-acting: plasma chemical buffers (immediate), respiratory system (minutes to hours), and renal system (hours to days).

Potassium-Hydrogen Ion Exchange

A cellular buffering mechanism wherein an influx of potassium ($\text{K}^+$) into the intracellular compartment causes an efflux of hydrogen ($\text{H}^+$) into the extracellular fluid, and vice versa.

Metabolic Acidosis

An acid-base imbalance characterized by low pH and low plasma bicarbonate ($\text{HCO}_3^-$), caused by excess metabolic acids or loss of bicarbonate; associated with hyperkalemia, Kussmaul respirations, lethargy, bradycardia, and hypotension.

Metabolic Alkalosis

An acid-base imbalance characterized by high pH and high plasma bicarbonate ($\text{HCO}_3^-$), caused by hydrogen ion loss or excess bicarbonate intake; associated with hypokalemia, hypoventilation, arrhythmias, and convulsions.

Respiratory Acidosis

An acid-base disturbance characterized by low pH and elevated carbon dioxide ($\text{CO}_2$), caused by hypoventilation, respiratory depression, or obstructive pulmonary diseases (COPD, asthma); presents with headache, weakness, confusion, and hallucinations.

Respiratory Alkalosis

An acid-base disturbance characterized by high pH and low carbon dioxide ($\text{CO}_2$), caused by hyperventilation or mechanical over-ventilation; presents with lightheadedness, dizziness, and peripheral paresthesias.

Hypothalamus

The central neural structure that serves as the coordinating center of both the endocrine and autonomic nervous systems.

Anterior Pituitary Gland

An endocrine gland stimulated by hypothalamic releasing hormones to synthesize and secrete ACTH, TSH, LH, FSH, GH, and prolactin.

Posterior Pituitary Gland

An anatomical extension of the hypothalamus that stores and releases hormones synthesized in the hypothalamus, specifically antidiuretic hormone (ADH) and oxytocin.

Endocrine Pathway

A hormonal signaling pathway wherein hormones are released into the systemic blood circulation to act on distant target organs.

Paracrine Pathway

A hormonal signaling pathway wherein secreted chemical messengers act locally on neighboring cells in the immediate vicinity of their release.

Autocrine Pathway

A hormonal signaling pathway wherein secreted hormones act directly upon receptors on the exact same cell that released them.

Primary Endocrine Disorder

An endocrine dysfunction originating directly within the target gland responsible for synthesizing the ultimate effector hormone.

Secondary Endocrine Disorder

An endocrine dysfunction wherein the target gland is structurally normal but its function is impaired due to defective secretion of stimulating hormones or releasing factors from the pituitary system.

Tertiary Endocrine Disorder

An endocrine dysfunction originating from hypothalamic dysfunction, resulting in understimulation of both the pituitary gland and the downstream target organ.

Thyroid Hormone Release Cascade

The tripartite hormonal pathway: 1. Hypothalamus releases thyrotropin-releasing hormone (TRH); 2. Pituitary gland releases thyroid-stimulating hormone (TSH); 3. Thyroid gland synthesizes and secretes $T_3$ and $T_4$.

Hypothyroidism

A hypometabolic endocrine condition caused by Hashimoto's thyroiditis, thyroid ablation, or iodine deficiency; manifests with cold intolerance, weight gain, fatigue, bradycardia ($38\,\text{bpm}$), coarse dry skin/hair, and risk of myxedema.

Hyperthyroidism

A hypermetabolic endocrine condition presenting with increased oxygen consumption, heat intolerance, diaphoresis, weight loss, diarrhea, fine silky skin, insomnia, tachycardia ($131\,\text{bpm}$), and arrhythmias.

Grave's Disease

An autoimmune disorder caused by thyroid-stimulating antibodies that bind to and activate TSH receptors, characterized by a triad of hyperthyroidism, diffuse goiter, and exophthalmos.

Thyroid Storm

An acute, life-threatening exacerbation of hyperthyroidism characterized by extreme hyperpyrexia, profound tachycardia ($174\,\text{bpm}$), delirium, agitation, seizures, and angina.

Syndrome of Inappropriate Antidiuretic Hormone (SIADH)

A disorder of autonomous, excessive ADH release (frequently ectopic from tumors or secondary to CNS injury/drugs), leading to water intoxication, concentrated urine, and dilutional hyponatremia ($<110\text{--}120\,\text{mEq/L}$).

Diabetes Insipidus

A disorder caused by insufficient ADH synthesis or renal unresponsiveness to ADH, presenting with copious polyuria, intense polydipsia, skin tenting, hypotension ($80/54\,\text{mmHg}$), and dilute urine.

Addison's Disease (Adrenal Insufficiency)

Primary hypoadrenocorticism characterized by autoimmune destruction of the adrenal cortex, causing deficiencies in cortisol and aldosterone that produce skin hyperpigmentation, hyponatremia ($115\,\text{mEq/L}$), hyperkalemia ($7.7\,\text{mEq/L}$), hypoglycemia ($52\,\text{mg/dL}$), and orthostatic hypotension.

Glucocorticoid Hormone Excess

A hypercortisolemic condition (Cushing's syndrome) caused by long-term corticosteroid therapy or ACTH/cortisol-secreting tumors; presents with truncal obesity, moon face, buffalo hump, purple striae, hirsutism, osteoporosis, hyperglycemia ($190\,\text{mg/dL}$), hypernatremia ($164\,\text{mEq/L}$), and hypokalemia ($2.0\,\text{mEq/L}$).

Beta Cells

Endocrine cells located in the pancreatic islets of Langerhans that synthesize and secrete insulin to facilitate cellular glucose uptake and utilization.

Alpha Cells

Endocrine cells of the pancreatic islets that secrete glucagon to mobilize glucose from hepatic glycogen stores and suppress insulin secretion.

Delta Cells

Pancreatic islet cells responsible for secreting somatostatin, which regulates both alpha and beta cell secretory function.

Type 1 Diabetes Mellitus

An autoimmune metabolic disorder characterized by cell-mediated destruction of pancreatic beta cells causing absolute insulin deficiency; manifests with hyperglycemia, osmotic diuresis, and acute vulnerability to diabetic ketoacidosis (DKA).

Type 2 Diabetes Mellitus

A metabolic disorder characterized by peripheral insulin resistance paired with progressive secretory failure of beta cells, strongly associated with central obesity, age $>30\,\text{years}$, and hyperosmolar hyperglycemic state (HHNK/HHS).

Hemoglobin A1C

A diagnostic blood test measuring the percentage of glycated hemoglobin to evaluate average glycemic control over the approximate $120\text{-day}$ lifespan of red blood cells.

Basal Rate Insulin

A long-acting exogenous insulin formulation with a slow onset designed to supply continuous baseline glycemic suppression throughout the day and night.

Bolus Rate Insulin

A rapid-onset, short-acting regular insulin formulation administered in discrete doses to control prandial post-meal glycemic spikes.

Metformin

An oral antihyperglycemic biguanide medication commonly utilized as standard pharmacological therapy for type 2 diabetes mellitus.

Hypoglycemia Manifestations

Signs of dangerously low blood glucose ($<60\,\text{mg/dL}$): tremors, diaphoresis, headache, confusion, anxiety, slurred speech, palpitations, seizures, coma, and potential death.

Somogyi Effect

An acute diabetic phenomenon involving rebound morning hyperglycemia caused by counter-regulatory hormone release following an undetected nocturnal hypoglycemic episode, usually triggered by ill-timed insulin or missed meals.

Dawn Phenomenon

An early-morning elevation in blood glucose occurring without prior nocturnal hypoglycemia, driven by normal circadian surges of cortisol and glucagon.

Microvascular Complications of Diabetes

Chronic structural damage to small blood vessels from persistent hyperglycemia and hypertension, specifically leading to diabetic retinopathy (and cataracts/glaucoma), nephropathy, and peripheral neuropathy.

Macrovascular Complications of Diabetes

Chronic atherosclerotic damage to large vessels induced by hyperglycemia, hypertension, and insulin resistance, manifesting as coronary artery disease, cerebrovascular disease (stroke, TIA), and peripheral vascular disease.