Philippines PLE cheat sheet

Cardiac output = heart rate × stroke volume; Fick principle: CO = O2 consumption ÷ arteriovenous O2 difference.

Frank–Starling law: increased end-diastolic volume raises stroke volume up to a physiologic limit; excessive stretch reduces it.

Right lung has 3 lobes and 10 segments; left lung has 2 lobes and 8–10 segments (lingula replaces middle lobe).

Coronary arteries arise from the aortic sinuses: left main divides into LAD and circumflex; right coronary supplies the SA node in ~60% of people.

Glomerular filtration rate ≈ 125 mL/min; filtration fraction = GFR ÷ renal plasma flow, normally ~0.20.

Nephron segments: proximal tubule reabsorbs ~65% of filtered Na+ and water; thick ascending limb is impermeable to water (diluting segment).

Cranial nerves with parasympathetic outflow: III (Edinger–Westphal), VII (lacrimal, submandibular), IX (parotid), X (visceral).

Brachial plexus roots C5–T1 form trunks (upper C5–C6, middle C7, lower C8–T1); Erb palsy affects C5–C6.

Oxygen–hemoglobin dissociation curve shifts right (↓affinity) with ↑CO2, ↑H+, ↑temperature, ↑2,3-BPG.

Glycolysis nets 2 ATP and 2 NADH per glucose; anaerobic conversion of pyruvate to lactate regenerates NAD+.

Pyruvate dehydrogenase converts pyruvate to acetyl-CoA, requiring thiamine (TPP), lipoic acid, CoA, FAD, NAD+; deficiency causes beriberi.

Krebs cycle per acetyl-CoA yields 3 NADH, 1 FADH2, 1 GTP; oxidative phosphorylation gives ~2.5 ATP/NADH and ~1.5 ATP/FADH2.

Rate-limiting enzymes: glycolysis phosphofructokinase-1; gluconeogenesis fructose-1,6-bisphosphatase; glycogenolysis glycogen phosphorylase; fatty acid synthesis acetyl-CoA carboxylase.

Urea cycle: carbamoyl phosphate synthetase I (mitochondria) is rate-limiting; ammonia is delivered as alanine and glutamine.

Heme synthesis: ALA synthase (rate-limiting, requires pyridoxine) in mitochondria; lead inhibits ALA dehydratase and ferrochelatase.

Essential amino acids (9): histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine.

Energy values: carbohydrate 4 kcal/g, protein 4 kcal/g, fat 9 kcal/g, alcohol 7 kcal/g.

Phenylketonuria: phenylalanine hydroxylase or tetrahydrobiopterin defect; treatment is dietary phenylalanine restriction plus tyrosine supplementation.

Gram-positive cell wall: thick peptidoglycan with teichoic acid; Gram-negative: thin peptidoglycan plus outer membrane with lipopolysaccharide (endotoxin).

Catalase-positive, coagulase-positive gram-positive cocci in clusters = Staphylococcus aureus; coagulase-negative = Staphylococcus epidermidis.

Streptococcus classification: bacitracin-sensitive, optochin-sensitive = S. pneumoniae; bacitracin-sensitive, bile-esculin positive = group D enterococcus.

Oxidase-positive, non-lactose-fermenting gram-negative rods: Pseudomonas aeruginosa (grape-like odor, blue-green pigment).

Mycobacterium tuberculosis is acid-fast (mycolic acid), grows on Löwenstein–Jensen medium; Ziehl–Neelsen stain.

Hepatitis B serology: HBsAg = infection; anti-HBs = immunity; HBeAg = high infectivity; anti-HBc IgM = acute or window period.

Malaria: Plasmodium falciparum causes severe disease (banana-shaped gametocytes); diagnosis by thick and thin Giemsa smears.

Ascaris lumbricoides: largest intestinal nematode; eggs passed in stool; complications include biliary obstruction and Loeffler syndrome.

Dengue: Aedes aegypti daytime biter; NS1 antigen positive in first 5 days; thrombocytopenia with hemoconcentration signals warning signs.

Cell injury: reversible injury shows swelling and fatty change; irreversible injury shows membrane rupture, mitochondrial damage, and nuclear dissolution (karyolysis, pyknosis, karyorrhexis).

Necrosis types: coagulative (ischemia, architecture preserved), liquefactive (brain, abscess), caseous (TB), fat (pancreatitis), fibrinoid (vasculitis).

Apoptosis is energy-dependent, caspase-mediated, without inflammation; mediated by Bcl-2 family and cytochrome c release.

Acute inflammation: vasodilation, increased permeability, neutrophil emigration (margination, rolling via selectins, adhesion via integrins, transmigration).

Granuloma: collection of activated macrophages (epithelioid cells) with giant cells; seen in TB, sarcoidosis, leprosy, fungal infection.

Neoplasia: benign tumors are well circumscribed and non-metastatic; malignant tumors show invasion, metastasis, anaplasia, and increased nuclear-to-cytoplasmic ratio.

Tumor suppressor genes: RB (retinoblastoma), TP53 (Li–Fraumeni), APC (familial adenomatous polyposis), BRCA1/2 (breast and ovarian cancer).

Shock: hypovolemic, cardiogenic, distributive (septic, anaphylactic, neurogenic), obstructive; septic shock is distributive with warm skin early.

Thrombosis triad (Virchow): endothelial injury, stasis or turbulent flow, hypercoagulability.

First-order kinetics: constant fraction eliminated per unit time; zero-order: constant amount eliminated (phenytoin, ethanol, aspirin at high dose).

Volume of distribution = dose ÷ plasma concentration; clearance = rate of elimination ÷ plasma concentration; half-life ≈ 0.693 × Vd ÷ clearance.

Loading dose = Vd × target concentration ÷ bioavailability; maintenance dose rate = clearance × target concentration ÷ bioavailability.

Cytochrome P450: inducers include rifampicin, carbamazepine, phenytoin, and St John's wort; inhibitors include ketoconazole, erythromycin, cimetidine, and grapefruit.

Beta-blocker selectivity: cardioselective agents (metoprolol, atenolol) are safer in asthma; propranolol is nonselective.

ACE inhibitors cause cough (bradykinin accumulation) and hyperkalemia; contraindicated in pregnancy and bilateral renal artery stenosis.

Aminoglycosides are bactericidal, concentration-dependent, and nephrotoxic/ototoxic; monitor levels and avoid in myasthenia gravis.

Warfarin inhibits vitamin K epoxide reductase; monitored by INR; reversal with vitamin K and fresh frozen plasma or prothrombin complex.

Paracetamol overdose: N-acetylcysteine replenishes glutathione; hepatotoxicity risk increased by alcohol-induced CYP2E1 induction.

Informed consent requires capacity, adequate disclosure, comprehension, and voluntariness; documentation in the chart is essential.

Philippine Medical Act (RA 2382) governs licensure; the Professional Regulation Commission issues the physician license.

Patient record confidentiality is protected; disclosure without consent is permitted for reportable diseases, court orders, and imminent harm to others.

Medical negligence requires duty, breach, causation, and damages; res ipsa loquitur may shift the burden of proof.

Good Samaritan protection applies to emergency care rendered without expectation of remuneration.

Reportable conditions include notifiable infectious diseases; the physician must report to the local health authority.

Physician-assisted suicide and active euthanasia are not legal in the Philippines; withholding futile treatment with consent is distinct.

Conflict of interest must be disclosed; referral fees and fee-splitting are prohibited by medical ethics rules.