Medicine

142 ideas, each explained on one page with a 60-second lesson you can play right there.

5-HT2A receptor The 5-HT2A receptor is the primary excitatory serotonin receptor in the brain and the main docking target for psychedelic drugs like LSD.
Action Potential An action potential is a fast electrical spike across a cell membrane that lets neurons, muscles, and endocrine cells send signals.
Adaptive immune system The adaptive immune system is the specialized part of your body's defenses that learns to recognize and destroy specific pathogens.
Adrenal Glands Learn how the adrenal cortex and medulla produce hormones like cortisol and adrenaline to manage metabolism, blood pressure, and stress.
Adrenaline Adrenaline is a hormone produced by the adrenal glands that prepares your body to react to danger or stress.
Allostatic load Allostatic load is the cumulative physical wear and tear on your body caused by chronic or repeated stress.
AMP-activated protein kinase AMP-activated protein kinase (AMPK) is an enzyme inside cells that acts as a low-energy sensor.
Amyloid beta Amyloid beta is a small protein fragment naturally produced and released by brain cells every day.
Angiogenesis Angiogenesis is the growth of new blood vessels from pre-existing ones.
Antibody An antibody is a specialized protein produced by immune cells to identify and latch onto foreign invaders like viruses and bacteria.
Antibody-dependent cellular cytotoxicity Antibody-dependent cellular cytotoxicity uses antibodies to guide immune cells like natural killer cells to destroy infected or cancerous cells.
Antigen An antigen is any molecule that can latch onto a specific immune receptor or antibody, acting like a chemical identifier.
Apoptosis Apoptosis is programmed cell death, a built-in biological routine where an unneeded or damaged cell systematically destroys itself.
Assay An assay is a laboratory test that detects or measures a specific target substance, called an analyte, in a sample.
Autoimmunity Autoimmunity is a state where an organism's immune defenses mistakenly target and attack its own healthy cells and tissues.
Autophagy Autophagy is the cell's waste recycling system.
Avoidant coping Avoidant coping reduces stress by evading a problem rather than fixing it, bringing immediate relief at the cost of compounding future damage.
Basal ganglia The basal ganglia are a group of interconnected structures deep beneath the cerebral cortex.
Behavioral activation Behavioral activation is a form of psychotherapy that treats depression by scheduling specific, rewarding activities into a person's routine.
Behavioral addiction Behavioral addiction is a compulsion to repeat a rewarding action despite real harm, sharing the same brain adaptations as drug addiction.
Beta Endorphins Beta endorphins are peptide molecules, chains of amino acids made in the brain, that act as the body's natural painkillers.
Blood Sugar Levels Blood sugar level is the concentration of glucose, a simple sugar used for energy, dissolved in your bloodstream.
Burnout (psychology) Occupational burnout stems from unmanaged workplace stress.
Caffeine Caffeine is a central nervous system stimulant, a chemical that speeds up messaging between your brain and body.
Calorie restriction Calorie restriction lowers energy intake while maintaining essential nutrients, shifting cellular resources toward repair and metabolic health.
CAR T cell A CAR T cell is a patient's own white blood cell that has been genetically modified in a laboratory to hunt and destroy cancer cells.
Cell Culture Cell culture is the process of growing living cells outside their natural organism inside controlled laboratory vessels.
Checkpoint inhibitor Cancer drugs called checkpoint inhibitors block off-switches on T cells, freeing the immune system to attack tumors.
Chemotherapy Chemotherapy is a systemic cancer treatment that uses drugs to disrupt cell division and trigger cell death.
Chronotype A chronotype is a person's natural biological tendency to sleep and be active at specific times during a 24-hour day.
Circadian Rhythm Circadian rhythms are roughly 24-hour internal biological cycles.
Cognitive Behavioral Therapy (CBT) Cognitive behavioral therapy treats automatic negative thoughts as unverified hypotheses, combining cognitive reframing with new behavioral habits.
Cognitive behavioral therapy for insomnia Cognitive behavioral therapy for insomnia is the first-line treatment for chronic insomnia, relying on sleep restriction and stimulus control.
Cognitive Distortions A cognitive distortion is an exaggerated or irrational thought pattern that causes you to perceive reality inaccurately.
Cognitive reframing Cognitive reframing is a technique where you identify and change the way you view situations, thoughts, or emotions.
Complement System The complement system is a network of about 50 blood proteins that automatically attack foreign invaders and clear damaged cells.
Cortisol Cortisol is a steroid hormone produced by your adrenal glands that mobilizes energy and helps regulate the immune system.
Creatine Creatine is an organic compound that your body uses to rapidly recycle ATP, the molecule cells consume for energy.
CRISPR CRISPR is a microbial defense mechanism that stores virus DNA fragments and guides Cas enzymes to cut matching genetic sequences.
Cytotoxicity Cytotoxicity is the ability of a substance to damage or kill living cells.
Defence mechanism Defence mechanisms are unconscious psychological tactics that protect the mind from anxiety and maintain emotional homeostasis.
Dementia Dementia is an umbrella term for a progressive decline in mental abilities caused by physical damage to the brain, which interferes with daily life.
Dietary fiber Dietary fiber is the part of plant food that your digestive enzymes cannot break down.
DNA profiling DNA profiling is a laboratory technique that determines an individual's unique genetic characteristics.
DNA Sequencing DNA sequencing determines the precise order of bases in genetic material, shrinking full-genome reads from thirteen years to under a day.
Dopamine Dopamine is a chemical messenger that nerve cells use to communicate with one another.
Doppler Effect The Doppler effect changes the observed pitch or frequency of waves when a source and observer move relative to each other.
Dose–response relationship A dose–response relationship is the pattern showing how a living system reacts to different amounts of a substance or stressor over time.
Enteric nervous system The enteric nervous system is a mesh of 500 million neurons lining your digestive tract that runs your digestion.
Enteroendocrine cell Enteroendocrine cells are hormone-producing cells scattered throughout the lining of the stomach, intestines, and pancreas.
Ergotism Ergotism is toxic poisoning caused by eating fungus-infected rye or grain.
Essential amino acid Humans cannot synthesize nine of the amino acids used to build proteins, meaning they must be supplied entirely by the foods in your diet.
Exposure therapy Exposure therapy treats anxiety by confronting fear triggers without escaping, helping the brain learn that the feared outcome will not occur.
Fever A fever is a temporary rise in body temperature caused by the brain resetting its internal thermostat to a higher target.
Food additive A food additive is any substance added to food to preserve it or enhance its flavor, appearance, or texture.
Gamma-Aminobutyric acid Gamma-Aminobutyric acid, or GABA, is the main chemical messenger that dampens nerve cell activity in the adult mammalian nervous system.
Gene Therapy Gene therapy is a medical technique that treats disease by directly altering the genetic material inside a patient's living cells.
Ghrelin Ghrelin is a hormone made mainly by cells in the stomach that travels to the brain to trigger hunger.
Glial cell Glial cells are non-neuronal cells in the nervous system that support, protect, and insulate neurons instead of firing electrical impulses.
Glycogen Glycogen is a branched chain of glucose sugar molecules packed together for quick energy storage in animals, fungi, and bacteria.
Gut Microbiome The gut microbiome contains 10 to 100 trillion microbes that ferment fiber, make vitamins, and influence mood via the gut-brain axis.
Habit reversal training Habit reversal training treats tics, hair pulling, and nail biting by teaching a physical action that blocks the repetitive urge.
Hippocampus The hippocampus is a curved structure tucked inside each side of the brain that turns new experiences into long-term memories.
Hyperpalatable food Hyperpalatable foods combine specific ratios of fat, sugar, salt, and carbs to overstimulate brain reward circuits and bypass fullness cues.
Hypothalamus The hypothalamus is an almond-sized brain structure located below the thalamus that connects your nervous system to your hormone system.
IC50 IC50 measures how much of a drug is needed to inhibit a biological target by 50 percent, acting as a core metric for inhibitor potency.
Immune Memory How specialized memory B and T cells recognize returning pathogens to eliminate them before they can cause illness.
Immunology Immunology is the branch of biology and medicine that studies how immune systems protect organisms from disease.
Inflammation Inflammation is your body's emergency biological defense against injuries, infections, and damaged tissue.
Insomnia Insomnia is a sleep disorder where a person struggles to fall asleep or stay asleep for as long as needed.
Insulin Insulin is a hormone produced in the pancreas that signals cells to absorb glucose from the bloodstream.
Intestinal villus An intestinal villus is a tiny, finger-like projection lining the inside wall of the small intestine.
Iodised salt Iodised salt is common table salt mixed with tiny amounts of chemical iodine compounds.
Joint Cavitation Joint cavitation is the formation of gas bubbles inside the lubricating fluid of a joint when its surfaces are pulled apart.
Killer T Cells Killer T cells are white blood cells that hunt and destroy infected or cancerous cells by recognizing antigens displayed on MHC molecules.
Lactate dehydrogenase Lactate dehydrogenase is an enzyme found in almost all living cells that converts pyruvate into lactate and back again.
Leptin Leptin is a protein hormone made by fat cells that tells your brain how much energy your body has stored.
Lipoproteins Lipoproteins are microscopic carrier particles made of fats and proteins that transport greasy molecules through watery fluids like blood plasma.
Loneliness Loneliness is an unpleasant emotional reaction to perceived or actual social isolation.
LSD LSD is a powerful semisynthetic psychedelic drug derived from ergot, a fungus that grows on rye.
Major histocompatibility complex Learn how the Major Histocompatibility Complex (MHC) presents protein fragments on cell surfaces to help T cells detect viruses and cancers.
Mast cell Mast cells are resident white blood cells packed with histamine granules, defending against pathogens while driving allergic reactions.
Melatonin Melatonin is a hormone produced in the brain that tells the body when it is dark outside.
Memory B cell A memory B cell is a long-lived white blood cell that remembers the exact molecular shape of an invader you have fought before.
Metastasis Metastasis is the spread of cancer cells from a primary tumor to distant organs through the bloodstream or lymphatic system.
Metformin Metformin is a medication taken by mouth to lower blood sugar in people with type 2 diabetes.
mTOR mTOR, or mechanistic target of rapamycin, is an enzyme inside your cells that acts as a master growth switch.
Muscle Hypertrophy Muscle hypertrophy is the enlargement of skeletal muscle caused by individual muscle cells growing thicker rather than multiplying.
Muscle Soreness Delayed onset muscle soreness comes from lengthening muscles under load, not lactic acid.
Myelin Myelin is a fatty coating that wraps around nerve fibers to insulate them and speed up electrical signals.
Myenteric plexus The myenteric plexus is a mesh-like network of nerve cells embedded between the muscle layers of your digestive tract.
Myosatellite cell A myosatellite cell is a dormant stem cell nestled against the outer edge of a skeletal muscle fiber.
Narcissistic personality disorder Narcissistic personality disorder is a psychiatric condition defined by grandiosity, low empathy, and impaired relationships across 256 trait combinations.
Nasal cycle The nasal cycle is the subconscious process where your body alternates airflow between your left and right nostrils throughout the day.
Natural killer cell Natural killer cells are white blood cells that destroy tumor and virus-infected cells lacking normal MHC class I identity markers.
Necrosis Necrosis is the premature, violent death of cells from trauma or infection.
Neurogenesis Neurogenesis is the biological process where neural stem cells divide and create new neurons, the signaling cells of the nervous system.
Neuroscience Neuroscience is the scientific study of the nervous system, including the brain, spinal cord, and peripheral nerves.
Neurotransmitters A neurotransmitter is a chemical messenger released by a nerve cell to send a signal across a microscopic gap to another cell.
Noradrenaline Noradrenaline is a chemical messenger in your body and brain that acts as both a hormone and a neurotransmitter.
Nutrition Nutrition is the biological process where an organism takes in food and water to create energy and build living tissue.
Oncogene An oncogene is a mutated or overactive gene that has the potential to cause cancer.
Oxytocin Oxytocin is a peptide hormone, a small chemical messenger made of amino acids, produced in the brain's hypothalamus.
P53 P53 is a protein that acts as a quality control inspector inside your cells, binding to DNA to control which genes get turned on.
Piperine Piperine is a plant compound known as an alkaloid that gives black and long pepper their pungent bite.
Pituitary Gland The pituitary gland is a tiny hormone-secreting organ at the base of the brain that directs the rest of the endocrine system.
Polymerase Chain Reaction Polymerase Chain Reaction (PCR) is a laboratory method that rapidly makes billions of copies of a specific piece of DNA.
Portal vein The portal vein is a large blood vessel in the abdomen that carries blood from the digestive organs and spleen straight to the liver.
Prion A prion is an infectious misfolded protein that forces healthy proteins of the same type to fold into its own abnormal shape.
Probiotics Probiotics are live microorganisms that benefit their host.
Progressive overload Progressive overload is the training principle of gradually increasing the stress placed on your muscles and nervous system.
Proteostasis Proteostasis is the cell's system for balancing the creation, folding, and destruction of all its proteins.
Psychoanalysis Psychoanalysis is Freud's theory of mind and talk therapy for uncovering unconscious drives.
Psychological stress Psychological stress is a reaction to perceived demands.
Psychotherapy Psychotherapy uses psychological methods to improve mental health.
Rapamycin Rapamycin is a bacterial compound that inhibits mTOR, halts cell division, stops transplant rejection, and is studied for extending lifespan.
Sarcopenia Sarcopenia is the progressive loss of skeletal muscle mass, strength, and function that happens with aging or prolonged immobility.
Serotonin Serotonin is a chemical messenger that nerve cells use to communicate with each other and with the rest of the body.
Short-chain fatty acid Short-chain fatty acids are energy-rich molecules made by gut bacteria fermenting dietary fiber, powering the cells lining your colon.
Sigmund Freud Sigmund Freud founded psychoanalysis, explaining how unconscious desires, dreams, and slips of the tongue shape human behavior.
Single-chain variable fragment A single-chain variable fragment is an engineered fusion protein that links the binding tips of an antibody into a compact sensor.
Sleep Sleep is a reversible state of reduced consciousness and physical activity where the body rests and sensory responses drop.
Sleep debt Sleep debt is the cumulative effect of not getting enough sleep over days or weeks.
Sleep Deprivation Sleep deprivation is the condition of not getting enough sleep duration or quality to keep your body and mind working properly.
Slow-Wave Sleep Slow-wave sleep is the deepest stage of non-REM sleep, defined by large delta waves that help the brain consolidate declarative memories.
Sports science Sports science is the study of how the healthy human body responds and adapts to physical exercise.
Stress Hormone A stress hormone is a chemical signal released by endocrine glands to adjust your body during times of threat.
Stress Management Stress management uses psychological techniques and physical interventions to reduce chronic stress and prevent health decline.
Synapse A synapse is the microscopic junction where a nerve cell passes signals to another cell.
T cell Learn what T cells are, how they develop in the thymus, and how killer and helper T cells coordinate specific immune defenses.
Tau protein Tau protein stabilizes the internal skeleton of nerve cells, but clumps into neurofibrillary tangles during dementia and Alzheimer's disease.
Therapeutic Window The therapeutic window is the specific range of drug doses that effectively treats an illness without causing dangerous toxic side effects.
Thermic effect of food The thermic effect of food is the amount of energy your body burns above resting levels to process, absorb, and store nutrients from a meal.
Thyroid gland The thyroid gland is a butterfly-shaped endocrine organ in your neck, sitting just below the Adam's apple.
Transference Transference happens when a person unconsciously redirects feelings, expectations, or desires from past relationships onto someone in the present.
TRPV1 Receptors TRPV1 receptors are ion channels in sensory nerve cells that detect scalding heat, acids, and pungent chemicals like capsaicin.
Tumor suppressor gene A tumor suppressor gene is a stretch of DNA that produces proteins to control cell division and stop abnormal cell growth.
Ultra-processed food Ultra-processed foods are industrial formulations made with additives and modified ingredients that bypass standard digestion and satiety.
Vaccination Vaccines train the immune system with weakened pathogens or proteins to build lasting defense against deadly infectious diseases.
Vagus nerve The vagus nerve is the longest cranial nerve in your body, running from your brainstem down into your chest and abdomen.
Viral vector A viral vector is a modified virus stripped of its disease-causing parts and used to deliver genetic material into living cells.
Work–life balance Work–life balance is the equilibrium between a person's job and their personal life, including family, leisure, and health.