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Unit 4 · 7 lessons

Homeostasis

How the nervous, endocrine and excretory systems use feedback loops to hold body temperature, blood glucose, pH, water and salt within narrow limits, and what happens when drugs, disease or the environment push those systems off balance.

  • 76 practice questions
  • 67 flashcards
  • 1 interactive lesson
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Lessons

  1. 1Homeostasis, Feedback and ThermoregulationThe internal environment as a dynamic equilibrium, the stimulus–receptor–control centre–effector–response loop, negative versus positive feedback, how the hypothalamus controls body temperature, how the bicarbonate buffer, lungs and kidneys hold blood pH, and how to design an invertebrate choice-chamber investigation.10 questions
  2. 2The Nervous SystemHow the nervous system is organized, how neurons are built, how the Na+/K+ pump and ion channels create the resting potential and the action potential, how signals jump along myelinated axons and cross synapses, and how common drugs and medications act at the synapse.Interactive12 questions
  3. 3The Brain, Spinal Cord and ReflexesHow the meninges and cerebrospinal fluid protect the central nervous system, what each brain region and lobe does, how grey and white matter are arranged in the spinal cord, how reflex arcs and autonomic pathways are wired, how fMRI and EEG let us watch the brain work, and what goes wrong in concussion, Alzheimer's, Parkinson's and multiple sclerosis.11 questions
  4. 4The Endocrine SystemHow hormones reach and act on target cells, steroid versus peptide hormones, the hypothalamus–pituitary axis and thyroxine feedback, blood glucose control by insulin and glucagon and the Canadian discovery of insulin, the stress response, reproductive hormones and the menstrual cycle, and how steroids, endocrine disruptors and medical treatments affect homeostasis.11 questions
  5. 5The Excretory System and Water BalanceWhy animals make ammonia, urea or uric acid, the anatomy of the urinary system and the nephron, filtration, reabsorption and secretion, how the loop of Henle and ADH concentrate urine, aldosterone and the renin–angiotensin system, the kidneys' role in pH, diuretics, kidney disorders, dialysis and transplants.11 questions
  6. 6Supplements, Drugs and PerformanceHow vitamin megadoses, protein and creatine supplements, EPO and blood doping, anabolic steroids, stimulants, alcohol and stress-axis substances push the body's feedback systems off balance, and a step-by-step framework for evaluating any supplement or drug case study.11 questions
  7. 7Systems Working TogetherThree integrated cases (a marathon in the heat, diabetic ketoacidosis and the fight-or-flight response) showing how the nervous, endocrine, excretory, circulatory and respiratory systems cooperate and compete, plus how to build feedback flowcharts and design a safe feedback investigation.10 questions