Medicine, one step at a time · since October 2026
The Lab
A course in core medicine, taught one picture at a time. Each lesson takes a single idea, starting with how the heart fills and empties, builds it step by step in plain language with animated visuals, then shows how disease and common drug classes change the picture. New lessons are added in order.
Every lesson has a Clinical values tab: typical adult reference ranges from standard physiology textbooks and major guidelines, each one cited, drawn against the lesson as it runs. The lessons are educational only and not for clinical use; they give no drug doses. Everything runs in your browser, with no accounts and no trackers, and works on a phone and with a keyboard.
22 of 22 lessons readyLatest: Nov 7, 2026
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The Pressure–Volume Loop
How one heartbeat fills and empties the left ventricle, drawn as a loop, and how fluids, blood pressure and heart drugs reshape it.
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The Nephron and Diuretics
Follow salt and water along a nephron, segment by segment, and see where each diuretic blocks salt reabsorption and how much water follows it out.
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Frank–Starling and Cardiac Output
Why a fuller heart pumps harder, and how filling, heart rate and contraction strength add up to cardiac output.
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Blood Pressure Regulation
Blood pressure as flow times resistance, and how the baroreflex keeps it steady from one moment to the next.
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The Renin–Angiotensin–Aldosterone System
The hormone chain the kidney uses to raise blood pressure and hold on to salt, and the drugs that cut it at each link.
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The Autonomic Synapse
How sympathetic and parasympathetic nerves talk to organs through receptors, and how drugs mimic or block that signal.
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The Cardiac Action Potential
The ion currents behind each heartbeat, in pacemaker and muscle cells, and how antiarrhythmic drugs change their shape.
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The Neuromuscular Junction
How a nerve signal becomes a muscle contraction, and how paralytic and reversal drugs act at the junction.
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Oxygen and Hemoglobin
Why hemoglobin grabs oxygen in the lungs and lets go in the tissues, drawn as the dissociation curve, and what shifts it.
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Ventilation, Perfusion and the Alveolus
How air and blood meet in the lung, and what happens to oxygen when the two are mismatched.
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Acid–Base Balance
The bicarbonate buffer, the lungs and the kidneys working together to hold blood pH steady, and the four ways it goes wrong.
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The Coagulation Cascade
How a clot is built, from platelet plug to fibrin mesh, and where each anticoagulant and clot-busting drug acts.
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Insulin and Glucose
How insulin moves glucose out of the blood after a meal, what fails in diabetes, and how each diabetes drug helps.
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The Thyroid Axis
The brain-to-thyroid feedback loop that sets the body's metabolic pace, and the drugs that replace or suppress thyroid hormone.
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The HPA Axis and Steroids
How the brain and adrenal glands control cortisol through feedback, and why steroid drugs switch the axis off.
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Stomach Acid and the Parietal Cell
How one stomach cell pumps acid on command, and how acid-reducing drugs turn it down at different steps.
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Pharmacokinetics: Drug Levels Over Time
How a drug's level rises, plateaus and falls in the blood: absorption, distribution, half-life and steady state, drawn as curves.
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Inflammation and the Arachidonic Acid Pathway
How injured cells make prostaglandins and leukotrienes, and where anti-inflammatory drugs block the pathway.
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The Bacterial Cell and Antibiotic Targets
A tour of a bacterium's wall, ribosomes and DNA machinery, and the antibiotic families that attack each one.
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The Immune Response
How the body recognises an invader, from the first innate response to antibodies and memory, and how immune drugs steer it.
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The Cell Cycle and Chemotherapy
How a cell copies itself, phase by phase, and which chemotherapy drugs strike at which phase.
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ADH and Water Balance
Watch the brain sense blood saltiness, release ADH and open water channels in the kidney, then see urine change in DI, SIADH and polydipsia.