Category
Biology & Medicine
Mechanisms of living systems and disease, currently centered on metabolism, diabetes, sleep, cell biology, and selected medical conditions.
Topics
Metabolism & DiabetesHow the body shifts among glucose, glycogen, fat, and ketones, and what happens when insulin regulation fails.12SleepHow sleep cycles through NREM and REM, what those stages do, and what apnea disrupts.3CardiovascularHow pressure, flow, vessel biology, atherosclerosis, heart attack and stroke fit into one causal cardiovascular system.7Genetics & Cell BiologyHow genetic information is stored, copied, expressed, and divided between cells.2Joints & ConditionsSpecific medical conditions and musculoskeletal problems Gavin has encountered and wants explained clearly.1
All Entries
Metabolism & Diabetes
- Metabolic Fuel Use“Carb burning” and “fat burning” are useful shorthand.
- From Food to ATP: How Cells Release EnergyFood energy does not jump directly from a molecule of fat or glucose into a moving muscle.
- Fat vs Glycogen: Energy Density and Storage TradeoffsIf biology cared only about storing the most food energy in the least mass, fat would appear to win easily.
- Fuel by Tissue: Brain, Muscle, Heart, Liver and Red Blood CellsThe bloodstream can contain glucose, fatty acids, lactate, amino acids and ketone bodies at the same time.
- Blood Glucose RegulationBlood glucose homeostasis is a control system centered on the pancreas and liver, with muscle and fat acting as major fuel users/stores.
- GluconeogenesisGluconeogenesis literally means making new glucose. It keeps glucose available when dietary carbohydrate and liver glycogen are insufficient.
- Fasting MetabolismFasting metabolism is a continuous shift in proportions, not a clock that suddenly switches from glucose to fat at hour 12.
- KetonesKetone bodies are a way for the liver to package energy derived from fat into water-soluble molecules that can circulate to tissues -- especially the brain -- when carbohydrate availability and insulin signaling are low.
- Nutritional Ketosis vs Diabetic KetoacidosisNutritional ketosis and diabetic ketoacidosis both involve ketone production, but they are different regulatory states.
- Type 1 vs Type 2 DiabetesBoth Type 1 and Type 2 diabetes can produce high blood glucose, but the failure occurs in different places.
- From ATP to Force: How Muscle Lifts a WeightSuppose you lift a 100-pound weight through one vertical metre.
- How Plants Store and Spend EnergyAnimals have an obvious energy-storage problem:
Sleep
- Sleep and Memory ConsolidationLearning does not end when practice stops. Memories continue to change after encoding, and sleep is one important environment in which this consolidation occurs.
- Sleep ApneaIn obstructive sleep apnea (OSA), the upper airway repeatedly narrows or collapses during sleep even though the chest is still trying to breathe. Each event can reduce airflow/oxygen and trigger a brief arousal, producing fragmented sleep that the sleeper may not remember.
- Sleep ArchitectureA normal night's sleep is not eight hours of one state. The brain repeatedly cycles through N1 -> N2 -> N3 -> back toward lighter NREM -> REM, with the mixture changing over the night.
Cardiovascular
- Cardiovascular System: Pressure, Flow, and Oxygen DeliveryThe cardiovascular system is often taught as a list of parts: heart, arteries, veins, capillaries.
- Blood Pressure ExplainedA blood-pressure reading such as:
- Hypertension: How High Pressure Causes DamageHypertension is not dangerous because an artery simply "cannot tolerate a big number."
- Atherosclerosis: From LDL Retention to Plaque and ThrombosisAtherosclerosis is not simply "fat clogging a pipe."
- Myocardial Infarction: What a Heart Attack Actually IsA myocardial infarction (MI) is death of heart-muscle cells caused by prolonged ischemia.
- Stroke: Ischemic and HemorrhagicA stroke is acute brain injury caused either by:
- Cardiovascular Risk: Probability, Not DestinyCardiovascular risk factors are often discussed as if each one were a verdict.
Genetics & Cell Biology
- DNA vs RNADNA and RNA are chemically close relatives used for very different jobs.
- Mitosis vs MeiosisMitosis and meiosis both start with copied chromosomes and both use chromosome-separation machinery. Their different jobs come from what pairs up and what gets separated.
Joints & Conditions
- PVNS / Tenosynovial Giant Cell TumorPVNS means pigmented villonodular synovitis, an older name for what is now generally classified within tenosynovial giant cell tumor (TGCT). It arises from synovial tissue -- the lining of joints, bursae, and tendon sheaths.