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Body fluid compartments
Movement of water between body compartments
Acid-base disturbances: Pathology review
Diabetes insipidus and SIADH: Pathology review
Electrolyte disturbances: Pathology review
Renal failure: Pathology review
Acyanotic congenital heart defects: Pathology review
Adrenal masses: Pathology review
Bacterial and viral skin infections: Pathology review
Bone tumors: Pathology review
Coagulation disorders: Pathology review
Congenital neurological disorders: Pathology review
Cyanotic congenital heart defects: Pathology review
Extrinsic hemolytic normocytic anemia: Pathology review
Eye conditions: Inflammation, infections and trauma: Pathology review
Eye conditions: Refractive errors, lens disorders and glaucoma: Pathology review
Headaches: Pathology review
Intrinsic hemolytic normocytic anemia: Pathology review
Leukemias: Pathology review
Lymphomas: Pathology review
Macrocytic anemia: Pathology review
Microcytic anemia: Pathology review
Mixed platelet and coagulation disorders: Pathology review
Nasal, oral and pharyngeal diseases: Pathology review
Nephritic syndromes: Pathology review
Nephrotic syndromes: Pathology review
Non-hemolytic normocytic anemia: Pathology review
Pediatric brain tumors: Pathology review
Pediatric musculoskeletal disorders: Pathology review
Platelet disorders: Pathology review
Renal and urinary tract masses: Pathology review
Seizures: Pathology review
Viral exanthems of childhood: Pathology review
Adrenal insufficiency: Pathology review
Central nervous system infections: Pathology review
Childhood and early-onset psychological disorders: Pathology review
Congenital gastrointestinal disorders: Pathology review
Diabetes mellitus: Pathology review
Environmental and chemical toxicities: Pathology review
Gastrointestinal bleeding: Pathology review
GERD, peptic ulcers, gastritis, and stomach cancer: Pathology review
Inflammatory bowel disease: Pathology review
Medication overdoses and toxicities: Pathology review
Obstructive lung diseases: Pathology review
Pneumonia: Pathology review
Psychiatric emergencies: Pathology review
Shock: Pathology review
Supraventricular arrhythmias: Pathology review
Traumatic brain injury: Pathology review
Ventricular arrhythmias: Pathology review
Congenital TORCH infections: Pathology review
Jaundice: Pathology review
Respiratory distress syndrome: Pathology review
Autosomal trisomies: Pathology review
Cystic fibrosis: Pathology review
Disorders of sex chromosomes: Pathology review
HIV and AIDS: Pathology review
Miscellaneous genetic disorders: Pathology review
Papulosquamous and inflammatory skin disorders: Pathology review
Anxiety disorders, phobias and stress-related disorders: Pathology Review
Developmental and learning disorders: Pathology review
Eating disorders: Pathology review
Mood disorders: Pathology review
Pharmacodynamics: Agonist, partial agonist and antagonist
Pharmacodynamics: Desensitization and tolerance
Pharmacodynamics: Drug-receptor interactions
Pharmacokinetics: Drug absorption and distribution
Pharmacokinetics: Drug elimination and clearance
Pharmacokinetics: Drug metabolism
Androgens and antiandrogens
Estrogens and antiestrogens
Miscellaneous cell wall synthesis inhibitors
Protein synthesis inhibitors: Tetracyclines
Cell wall synthesis inhibitors: Penicillins
Antihistamines for allergies
Non-steroidal anti-inflammatory drugs
Antimetabolites: Sulfonamides and trimethoprim
Cell wall synthesis inhibitors: Cephalosporins
DNA synthesis inhibitors: Fluoroquinolones
DNA synthesis inhibitors: Metronidazole
Miscellaneous protein synthesis inhibitors
Protein synthesis inhibitors: Aminoglycosides
Bronchodilators: Beta 2-agonists and muscarinic antagonists
Bronchodilators: Leukotriene antagonists and methylxanthines
Pulmonary corticosteroids and mast cell inhibitors
Anticonvulsants and anxiolytics: Barbiturates
Anticonvulsants and anxiolytics: Benzodiazepines
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Water is the key to life - It has very unique properties like being an amazing solvent, which means that it’s easy for solutes to dissolve into water.
As a result, water can carry essential nutrients to our cells as well as toxins or waste products away from our cells to be excreted out of our system.
Total body water can be subdivided into two major compartments, intracellular fluid (ICF) and extracellular fluid (ECF).
On average total body water in a person is about 60% of their body weight.
From the total body water, 2/3 of that, or 40% of body weight is intracellular fluid. The other 1/3 or 20% of body weight is extracellular fluid. This is also known as the 60-40-20 rule.
Intracellular fluid is the fluid which is inside the cell and extracellular fluid is the fluid outside of the cell.
Extracellular fluid can be further subdivided into interstitial fluid, which is the fluid surrounding the cell and plasma which is the fluid that circulates within blood vessels.
Extracellular fluid is the first to be lost and makes up fluids like gut fluids, sweat and other secretions.
The extracellular fluid is made up of different solutes, the major cation being sodium (Na+) and the major anions being chloride (Cl-) and bicarbonate (HCO3-).
Each compartment has a specific solute concentration measured in mOsm/L or osmolarity, which is the number of osmoles within a liter of solution.
Now remember that an osmole refers to the individual ions within a solution. So for example, NaCl splits apart in water to become Na+ and Cl-, so a solution of 1 mmol/L of NaCl is actually 2 mOsm/L. Normally, osmolarity in the intracellular fluid and extracellular fluid is equal.
If either side ever has a few more solutes, than water will flow in that direction to lower the concentration slightly and maintain the balance. This process is called osmosis.
Now, some solutes like NaHCO3 (sodium bicarbonate) as well as large sugars like mannitol, are too large to cross cellular membranes and they’re basically trapped in the extracellular fluid.
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