Human Physiology I

The route

Lessons are in the order that makes each one easier than the last. Each unit ends with a short quiz.

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   Unit 1

   Homeostasis and Feedback Control

   Harmattan mornings, hot afternoons, a skipped lunch, and your body still holds steady. How?
   1. Introduction to PhysiologyFree Anatomy tells you where the engine parts sit. Physiology tells you why the engine runs. 8 min
   3. The Internal Environment and Homeostasis Your cells live in a private ocean, and the whole body works to keep that ocean calm. 9 min
   4. Negative Feedback Mechanisms Most of your body's control systems work by undoing whatever change set them off. 10 min
   5. Positive Feedback and Homeostatic Imbalance Sometimes the body needs to finish a job fast, so it presses the accelerator instead of the brake. 9 min
   6. Unit 1 quiz7 questions on this unit 9 min
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   Unit 2 Full plan

   Cell Physiology and Membrane Transport

   Water, salt, sugar and oxygen cross every cell's border all day long. Some roll downhill; some must be pumped.
   1. Biologically Important Molecules Six kinds of molecule do almost all the work in your body, and each has a job description. 9 min
   2. Passive Transport: Diffusion, Osmosis and Filtration Most things cross the cell membrane for free, simply by rolling down a concentration hill. 10 min
   3. Tonicity and Its Effects on Red Blood Cells Put a red cell in the wrong fluid and it either bursts or shrivels. Here is why. 9 min
   4. Active Transport and Vesicular Transport When a cell needs something to go the wrong way, or needs to move a big parcel, it pays in ATP. 10 min
   5. Protein Synthesis Your DNA is a recipe book that never leaves the kitchen office. Here is how the recipes reach the cooks. 10 min
   6. Unit 2 quiz8 questions on this unit 10 min
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   Unit 3 Full plan

   Body Fluids and Electrolytes

   Where 42 litres of water live inside you, what is dissolved in them, and how the body keeps the amount just right.
   1. Body Fluid Compartments A 70 kg man carries about 42 litres of water, and every litre has an address. 10 min
   2. Electrolytes Sodium rules outside the cell, potassium rules inside, and the difference keeps you alive. 9 min
   3. Water Balance and Its Regulation Every day about two and a half litres come in and the same leave, and three hormones keep the books balanced. 10 min
   4. Capillary Exchange and Oedema Two pressures fight over every drop of fluid in your tissues. When one wins too often, ankles swell. 10 min
   5. Acid–Base Balance Your blood lives on a knife-edge between 7.35 and 7.45, guarded by three lines of defence. 10 min
   6. Unit 3 quiz7 questions on this unit 9 min
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   Unit 4 Full plan

   Physiology of Blood

   Red cells and genotypes, white cells and defence, clotting, and the blood groups that make transfusion safe.
   1. Composition and Functions of Blood Spin a tube of blood and it separates into layers, each with its own story. 10 min
   2. Erythrocytes, Haemoglobin and Erythropoiesis A cell with no nucleus, a 120-day life and one job, carried out about twenty-five trillion times over. 12 min
   3. Leucocytes and Body Defence Five kinds of white cell, two lines of defence, and a memory that lasts for years. 11 min
   4. Haemostasis and Blood Coagulation A cut finger triggers a three-stage emergency response that ends in a mesh of fibrin threads. 10 min
   5. Blood Groups and Blood Transfusion Why some blood can save a life and the wrong blood can end one. 12 min
   6. Unit 4 quiz9 questions on this unit 11 min
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   Unit 5 Full plan

   Nerve Physiology

   How a nerve cell charges itself, fires in a millisecond, and passes its message on.
   1. The Resting Membrane Potential Every neuron sits at minus seventy millivolts, charged and waiting. Here is how it holds that charge. 9 min
   2. The Action Potential Sodium rushes in, potassium rushes out, and a message is born in about a thousandth of a second. 11 min
   3. Nerve Impulse Conduction and Synaptic Transmission Myelin lets impulses leap along a nerve, and at the end of the line a chemical carries the message across. 12 min
   4. Unit 5 quiz5 questions on this unit 6 min
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   Unit 6 Full plan

   Muscle Physiology

   From a puff of acetylcholine to filaments sliding past each other, the chain of events behind every movement.
   1. The Neuromuscular Junction and the Motor Unit A single puff of acetylcholine turns a nerve's message into a muscle's movement. 10 min
   2. Sliding Filament Theory Muscles shorten without a single filament getting shorter. The trick is sliding. 12 min
   3. Mechanics and Energetics of Muscle Contraction How a muscle grades its strength, where it gets its energy, and why the heart can never cramp up. 12 min
   4. Unit 6 quiz6 questions on this unit 8 min

Practise and remember