Organ Systems
Cardiovascular, respiratory, renal, digestive, endocrine, and nervous systems
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Organ Systems for the MCAT
Cardiovascular
- 4 chambers: right side → lungs (pulmonary), left side → body (systemic)
- SA node pacemaker → atrial contraction → AV node → ventricular contraction
- Hemoglobin: cooperative binding, Bohr effect (low pH → right shift → O₂ release)
Respiratory
- Negative pressure breathing (diaphragm contraction)
- Gas exchange in alveoli via partial pressure gradients
Renal
- Nephron: glomerulus → PCT → Loop of Henle → DCT → Collecting duct
- ADH: increases water reabsorption
- Aldosterone: increases Na⁺ reabsorption (RAAS)
Digestive
- Stomach: HCl, pepsin (protein digestion)
- Small intestine: pancreatic enzymes + bile salts
- Absorption via villi
Endocrine
- Hypothalamus → Pituitary → Target organs
- Insulin (↓glucose) vs. Glucagon (↑glucose)
- Thyroid (T3/T4: ↑metabolism), PTH (↑Ca²⁺)
Nervous
- CNS (brain + spinal cord) + PNS (somatic + autonomic)
- Sympathetic (fight/flight) vs. Parasympathetic (rest/digest)
- Action potential: resting (−70mV) → depolarization (Na⁺ in) → repolarization (K⁺ out)
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❓ Frequently Asked Questions
What is Organ Systems?▾
Cardiovascular, respiratory, renal, digestive, endocrine, and nervous systems
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Start by reading the study notes and working through the examples on this page. Then use the flashcards to test your recall. Regular review and active practice are key to retention.
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What course covers Organ Systems?▾
Organ Systems is part of the MCAT Prep course on Study Mondo, specifically in the Biological & Biochemical Foundations section. You can explore the full course for more related topics and practice resources.