Source: https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-7-2-kidneys-and-osmoregulation [Revision notes](https://senecalearning.com/en-gb/revision-notes.md) › [BTEC](https://senecalearning.com/en-gb/revision-notes/btec.md) › [Science](https://senecalearning.com/en-gb/revision-notes/btec/science.md) › [Applied Science: BTEC Level 3](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3.md) › Kidneys & Osmoregulation # Kidneys & Osmoregulation Applied Science: BTEC Level 3 National Extended Diploma, topic 4.7.2 ## Excretion and the Kidneys The kidneys work alongside the liver in the excretion of waste products. ### Kidney structure ![Kidney structure](https://image-v2.cdn.app.senecalearning.com/2018-10/e2d5d13d-79e5-4fdb-8b22-ad083fcca52c/Structure-kidney-kidneys-renal-medulla-nephron-.png) ### Kidney structure ![Kidney structure](https://image-v2.cdn.app.senecalearning.com/2018-10/e2d5d13d-79e5-4fdb-8b22-ad083fcca52c/Structure-kidney-kidneys-renal-medulla-nephron-.png) - The kidneys are surrounded by the capsule to protect the fragile structures underneath. - Nephrons extend from the cortex into the medulla and are the site of ultrafiltration, selective reabsorption and urine formation. - The renal tubule of each nephron is lined with microvilli to increase the surface area for absorption. ### Nephron structure ![Nephron structure](https://image-v2.cdn.app.senecalearning.com/2018-11/f300cacd-a852-43d9-9f6b-d5f75dd6d102/Nephron-kidney-henle-loop-homeostasis-.png) ### Ultrafiltration ![Ultrafiltration](https://image-v2.cdn.app.senecalearning.com/2018-11/f300cacd-a852-43d9-9f6b-d5f75dd6d102/Nephron-kidney-henle-loop-homeostasis-.png) - Ultrafiltration is carried out in the glomerular capsule (often called the Bowman's capsule). - Everything except larger proteins, red blood cells, and most white blood cells is forced out of the blood and into the glomerular capsule due to the high pressure caused by the difference in diameter between the afferent and efferent arterioles. - The afferent arteriole is much wider than the efferent arteriole. ### Selective reabsorption ![Selective reabsorption](https://image-v2.cdn.app.senecalearning.com/2018-09/7ab83efb-a245-4170-be86-c0f089c2f660/urine-test-sample-science-biology-.jpg) - Water, amino acids, glucose and ions are selectively reabsorbed first in the proximal convoluted tubule (PCT). - This helps to maintain electrolyte balance. - The final composition of urine produced is dependent on: - Selective reabsorption out of the nephron. - Secretion of nitrogenous waste into the nephron by surrounding capillaries. ### Loop of Henle ![Loop of Henle](https://image-v2.cdn.app.senecalearning.com/2018-11/f300cacd-a852-43d9-9f6b-d5f75dd6d102/Nephron-kidney-henle-loop-homeostasis-.png) - After the proximal convoluted tubule, water is also reabsorbed into the blood by osmosis in the descending limb of the loop of Henle. - Ions are reabsorbed in the ascending limb of the loop of Henle. - The ion concentration gradient set up in the area between the limbs drives osmosis in the descending limb. - Approximately 95% of urine is water. ### Urine excretion ![Urine excretion](https://image-v2.cdn.app.senecalearning.com/2018-11/6f605d36-61ec-4078-867e-18141c688915/urinary-tract-kidney-ureter-.png) - Urine is formed from each nephron in collecting ducts. - The collecting ducts converge in the renal pelvis to form the ureter of each kidney. - The urine passes down the ureters and into the bladder. - When the bladder is full, urine passes through the urethra and out of the body. ## Osmoregulation and the Kidneys The kidneys are vital in osmoregulation and control water balance by reabsorbing more water when the body is dehydrated. This affects blood pressure and volume and the amount of water in the tissues. ### Osmoreception ![Osmoreception](https://image-v2.cdn.app.senecalearning.com/2018-08/eab3e0d8-0985-4404-9609-a39b4f14d1a9/hypothalamus-brain.jpg) - Osmoreceptors in the hypothalamus detect water composition in the blood. - If the water level drops (due to increased sweating, decreased water intake or vomiting), the hypothalamus secretes antidiuretic hormone (ADH) and signals for the posterior pituitary gland to release it into the bloodstream. ### Antidiuretic hormone (ADH) ![Antidiuretic hormone (ADH)](https://image-v2.cdn.app.senecalearning.com/courseImages/biology/2.3.1%20-%20Blood%20vessels/bloodclot-min.jpg) - When the ADH reaches the cells in the collecting ducts, they become more permeable to water and so reabsorb more water. - This increases the concentration of the urine and it appears darker. - High concentrations of ADH constrict blood vessels, increasing blood pressure. ## Test yourself on Kidneys & Osmoregulation - Which of these is NOT selectively reabsorbed into the bloodstream from the nephron? - What is the kidney made up from? - Excretion of Urine - What does antidiuretic hormone do? - Avoiding Dehydration [Practise this topic for free](https://app.senecalearning.com/classroom/course/83e90d6d-8d3e-4e59-a2df-b5a5e1957f6c/section/a213a73e-8e59-44f7-b736-a5b8b2cfe4d4/session) - Previous topic: [4.7.1 Kidneys & Control of Water Balance](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-7-1-kidneys-and-control-of-water-balance.md) - Next topic: [4.7.3 Kidneys & Blood Pressure](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-7-3-kidneys-and-blood-pressure.md) ## Applied Science: BTEC Level 3 National Extended Diploma contents ### 1 Principles of Science I - 1.1 Structure & Bonding - [1.1.1 Atomic Model](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-1-atomic-model.md) - [1.1.2 Electron Shells, Sub-Shells & Orbitals](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-2-electron-shells-sub-shells-and-orbitals.md) - [1.1.3 Ionic Bonding](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-3-ionic-bonding.md) - [1.1.4 Representing Ionic Bonds](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-4-representing-ionic-bonds.md) - [1.1.5 Covalent Bonding](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-5-covalent-bonding.md) - [1.1.6 Representing Covalent Bonds](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-6-representing-covalent-bonds.md) - [1.1.7 Metallic Bonding](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-7-metallic-bonding.md) - [1.1.8 Intermolecular Forces](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-8-intermolecular-forces.md) - [1.1.9 Intermolecular Forces 2](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-9-intermolecular-forces-2.md) - [1.1.10 End of Topic Test - Bonding](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-10-end-of-topic-test-bonding.md) - [1.1.11 Relative Masses](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-11-relative-masses.md) - [1.1.12 The Mole](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-12-the-mole.md) - [1.1.13 Molar Calculations](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-13-molar-calculations.md) - [1.1.14 Molar Calculations 2](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-14-molar-calculations-2.md) - [1.1.15 Empirical & Molecular Formulae](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-15-empirical-and-molecular-formulae.md) - [1.1.16 Balanced Equations](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-16-balanced-equations.md) - [1.1.17 Percentage Yield](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-17-percentage-yield.md) - [1.1.18 End of Topic Test - Amount of Substance](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-1-18-end-of-topic-test-amount-of-substance.md) - 1.2 Properties of Substances - [1.2.1 The Periodic Table](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-2-1-the-periodic-table.md) - [1.2.2 Ionisation Energy](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-2-2-ionisation-energy.md) - [1.2.3 Factors Affecting Ionisation Energies](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-2-3-factors-affecting-ionisation-energies.md) - [1.2.4 Trends of Ionisation](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-2-4-trends-of-ionisation.md) - [1.2.5 Trends in the Periodic Table](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-2-5-trends-in-the-periodic-table.md) - [1.2.6 Polarity](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-2-6-polarity.md) - [1.2.7 Metals & Non-Metals](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-2-7-metals-and-non-metals.md) - [1.2.8 Alkali Metals](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-2-8-alkali-metals.md) - [1.2.9 Alkaline Earth Metals](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-2-9-alkaline-earth-metals.md) - [1.2.10 Reactivity of Alkaline Earth Metals](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-2-10-reactivity-of-alkaline-earth-metals.md) - [1.2.11 Redox](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-2-11-redox.md) - [1.2.12 Transition Metals](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-2-12-transition-metals.md) - [1.2.13 Redox Reactions of Transition Metals](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-2-13-redox-reactions-of-transition-metals.md) - 1.3 Cell Structure & Function - [1.3.1 Introduction to Cells](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-3-1-introduction-to-cells.md) - [1.3.2 Prokaryotes](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-3-2-prokaryotes.md) - [1.3.3 Organelles of Eukaryotic Cells](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-3-3-organelles-of-eukaryotic-cells.md) - [1.3.4 Organelles of Eukaryotic Cells 2](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-3-4-organelles-of-eukaryotic-cells-2.md) - [1.3.5 Organelles in Plant Cells](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-3-5-organelles-in-plant-cells.md) - [1.3.6 Microscopy](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-3-6-microscopy.md) - [1.3.7 End of Topic Test - Cell Structure](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-3-7-end-of-topic-test-cell-structure.md) - 1.4 Cell Specialisation - [1.4.1 Cell Specialisation](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-4-1-cell-specialisation.md) - [1.4.2 Blood Cells](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-4-2-blood-cells.md) - [1.4.3 Plant Cells](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-4-3-plant-cells.md) - [1.4.4 Gametes](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-4-4-gametes.md) - 1.5 Tissue Structure & Function - [1.5.1 Human Gas Exchange](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-5-1-human-gas-exchange.md) - [1.5.2 Blood Vessels](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-5-2-blood-vessels.md) - [1.5.3 Atherosclerosis](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-5-3-atherosclerosis.md) - [1.5.4 Skeletal Muscle](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-5-4-skeletal-muscle.md) - [1.5.5 Slow & Fast Twitch Fibres](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-5-5-slow-and-fast-twitch-fibres.md) - [1.5.6 Neurones](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-5-6-neurones.md) - [1.5.7 Speed of Transmission](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-5-7-speed-of-transmission.md) - [1.5.8 Action Potentials](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-5-8-action-potentials.md) - [1.5.9 End of Topic Test - Neurones & Action Potentials](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-5-9-end-of-topic-test-neurones-and-action-potentials.md) - [1.5.10 Synapses](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-5-10-synapses.md) - [1.5.11 Types of Synapse](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-5-11-types-of-synapse.md) - [1.5.12 Medical Application](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-5-12-medical-application.md) - [1.5.13 End of Topic Test - Synapses](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-5-13-end-of-topic-test-synapses.md) - [1.5.14 Chemical Brain Imbalances](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-5-14-chemical-brain-imbalances.md) - [1.5.15 Effect of Drugs on the Brain](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-5-15-effect-of-drugs-on-the-brain.md) - 1.6 Working with Waves - [1.6.1 Progressive Waves](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-6-1-progressive-waves.md) - [1.6.2 Wave Speed & Phase Difference](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-6-2-wave-speed-and-phase-difference.md) - [1.6.3 Longitudinal & Transverse Waves](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-6-3-longitudinal-and-transverse-waves.md) - [1.6.4 Stationary Waves](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-6-4-stationary-waves.md) - [1.6.5 Stationary Waves 2](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-6-5-stationary-waves-2.md) - [1.6.6 Applications of Stationary Waves](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-6-6-applications-of-stationary-waves.md) - [1.6.7 Interference](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-6-7-interference.md) - [1.6.8 Diffraction](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-6-8-diffraction.md) - [1.6.9 Diffraction Gratings](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-6-9-diffraction-gratings.md) - [1.6.10 Application of Diffraction Gratings](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-6-10-application-of-diffraction-gratings.md) - 1.7 Waves in Communication - [1.7.1 Refraction at a Plane Surface](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-7-1-refraction-at-a-plane-surface.md) - [1.7.2 Internal Reflection & Fibre Optics](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-7-2-internal-reflection-and-fibre-optics.md) - [1.7.3 Applications of Total Internal Reflection](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-7-3-applications-of-total-internal-reflection.md) - [1.7.4 Properties](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-7-4-properties.md) - [1.7.5 Gamma, X-Ray & UV Light](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-7-5-gamma-x-ray-and-uv-light.md) - [1.7.6 Visible Light](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-7-6-visible-light.md) - [1.7.7 Infrared, Microwave & Radio Waves](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-7-7-infrared-microwave-and-radio-waves.md) - [1.7.8 Intensity](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-7-8-intensity.md) - [1.7.9 Digital & Analogue Signals](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-7-9-digital-and-analogue-signals.md) - [1.7.10 Communication Channels](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/1-7-10-communication-channels.md) ### 2 Practical Scientific Procedures and Techniques - 2.1 Titration - [2.1.1 pH Curves & Titrations](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/2-1-1-ph-curves-and-titrations.md) - [2.1.2 pH Curves & Titrations 2](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/2-1-2-ph-curves-and-titrations-2.md) - [2.1.3 Buffer Solutions](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/2-1-3-buffer-solutions.md) - 2.2 Colorimetry - [2.2.1 Measuring Rates](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/2-2-1-measuring-rates.md) - [2.2.2 Beer-Lambert Law](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/2-2-2-beer-lambert-law.md) - 2.3 Chromatography - [2.3.1 Overview of Chromatography](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/2-3-1-overview-of-chromatography.md) - [2.3.2 Thin-Layer Chromatography](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/2-3-2-thin-layer-chromatography.md) - [2.3.3 Column Chromatography](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/2-3-3-column-chromatography.md) - [2.3.4 Gas Chromatography](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/2-3-4-gas-chromatography.md) ### 3 Science Investigation Skills - 3.1 Scientific Processes - [3.1.1 Aims, Hypotheses & Sampling](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-1-1-aims-hypotheses-and-sampling.md) - [3.1.2 Pilot Studies & Design](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-1-2-pilot-studies-and-design.md) - [3.1.3 Ethics](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-1-3-ethics.md) - [3.1.4 Variables & Control](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-1-4-variables-and-control.md) - [3.1.5 Demand Characteristics & Investigator Effects](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-1-5-demand-characteristics-and-investigator-effects.md) - [3.1.6 Features of Science](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-1-6-features-of-science.md) - [3.1.7 Scientific Report](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-1-7-scientific-report.md) - [3.1.8 Scientific Report 2](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-1-8-scientific-report-2.md) - 3.2 Data Handling & Analysis - [3.2.1 Types of Data](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-2-1-types-of-data.md) - [3.2.2 Descriptive Statistics](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-2-2-descriptive-statistics.md) - [3.2.3 Presentation & Display of Data](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-2-3-presentation-and-display-of-data.md) - 3.3 Enzymes in Action - [3.3.1 Overview of Protein Structure](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-3-1-overview-of-protein-structure.md) - [3.3.2 Enzymes](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-3-2-enzymes.md) - [3.3.3 Factors Affecting Enzyme Activity](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-3-3-factors-affecting-enzyme-activity.md) - [3.3.4 Enzyme-Controlled Reactions](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-3-4-enzyme-controlled-reactions.md) - 3.4 Diffusion - [3.4.1 Diffusion](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-4-1-diffusion.md) - 3.5 Plants & Their Environment - [3.5.1 Factors Affecting Plant Growth](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-5-1-factors-affecting-plant-growth.md) - [3.5.2 Measuring Number & Distribution of Species](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-5-2-measuring-number-and-distribution-of-species.md) - 3.6 Energy Content in Fuels - [3.6.1 Fractions](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-6-1-fractions.md) - [3.6.2 Burning Hydrocarbons](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-6-2-burning-hydrocarbons.md) - [3.6.3 Combustion](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-6-3-combustion.md) - [3.6.4 Energy](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-6-4-energy.md) - [3.6.5 Energy at Home](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-6-5-energy-at-home.md) - [3.6.6 Calorimetry](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-6-6-calorimetry.md) - 3.7 Electrical Circuits - [3.7.1 Circuit Diagrams & Components](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-7-1-circuit-diagrams-and-components.md) - [3.7.2 Diodes, LDRs & Thermistors](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-7-2-diodes-ldrs-and-thermistors.md) - [3.7.3 Resistance](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-7-3-resistance.md) - [3.7.4 Electrical Work](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-7-4-electrical-work.md) - [3.7.5 Ohm's Law](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-7-5-ohms-law.md) - [3.7.6 Domestic Uses of Electricity](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-7-6-domestic-uses-of-electricity.md) - [3.7.7 Fuses](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/3-7-7-fuses.md) ### 4 Principles of Science II - 4.1 Extracting Elements - [4.1.1 Atom Economy](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-1-1-atom-economy.md) - 4.2 Relating Properties to use of Substances - [4.2.1 Group 2 Chemistry](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-2-1-group-2-chemistry.md) - [4.2.2 End of Topic Test - Group 2](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-2-2-end-of-topic-test-group-2.md) - [4.2.3 Electrolysis](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-2-3-electrolysis.md) - [4.2.4 Electrolysis Examples](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-2-4-electrolysis-examples.md) - [4.2.5 Extracting Metals](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-2-5-extracting-metals.md) - [4.2.6 Transition Metals](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-2-6-transition-metals.md) - [4.2.7 Variable Oxidation States](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-2-7-variable-oxidation-states.md) - [4.2.8 Heterogeneous Catalysts](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-2-8-heterogeneous-catalysts.md) - [4.2.9 Homogeneous Catalysts](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-2-9-homogeneous-catalysts.md) - 4.3 Organic Chemistry - [4.3.1 Naming Compounds](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-3-1-naming-compounds.md) - [4.3.2 Functional Groups](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-3-2-functional-groups.md) - [4.3.3 Isomerism](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-3-3-isomerism.md) - [4.3.4 Hydrocarbons](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-3-4-hydrocarbons.md) - [4.3.5 Structure of Alkanes](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-3-5-structure-of-alkanes.md) - [4.3.6 Boiling Points of Alkanes](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-3-6-boiling-points-of-alkanes.md) - [4.3.7 Alkenes](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-3-7-alkenes.md) - [4.3.8 Curly Arrows & Mechanisms](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-3-8-curly-arrows-and-mechanisms.md) - [4.3.9 Cracking](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-3-9-cracking.md) - [4.3.10 Combustion](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-3-10-combustion.md) - [4.3.11 Free Radical Substitution of Alkanes](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-3-11-free-radical-substitution-of-alkanes.md) - [4.3.12 Electrophilic Addition of Alkenes](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-3-12-electrophilic-addition-of-alkenes.md) - 4.4 Energy Changes in Industry - [4.4.1 The Kelvin Scale](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-4-1-the-kelvin-scale.md) - [4.4.2 Enthalpy Changes](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-4-2-enthalpy-changes.md) - [4.4.3 Calorimetry](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-4-3-calorimetry.md) - [4.4.4 Bond Enthalpies](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-4-4-bond-enthalpies.md) - [4.4.5 Hess' Law](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-4-5-hess-law.md) - 4.5 The Circulatory System - [4.5.1 The Circulatory System](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-5-1-the-circulatory-system.md) - [4.5.2 Blood Vessels](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-5-2-blood-vessels.md) - [4.5.3 Blood Transfusion & the ABO Rhesus System](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-5-3-blood-transfusion-and-the-abo-rhesus-system.md) - [4.5.4 The Heart](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-5-4-the-heart.md) - [4.5.5 The Cardiac Cycle](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-5-5-the-cardiac-cycle.md) - [4.5.6 Cardiac Output](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-5-6-cardiac-output.md) - [4.5.7 Coordination of Heart Action](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-5-7-coordination-of-heart-action.md) - [4.5.8 Heart Dissection](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-5-8-heart-dissection.md) - [4.5.9 Controlling Heart Rate](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-5-9-controlling-heart-rate.md) - [4.5.10 Electrocardiograms](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-5-10-electrocardiograms.md) - [4.5.11 Cardiovascular Disease](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-5-11-cardiovascular-disease.md) - [4.5.12 Investigating Heart Rates](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-5-12-investigating-heart-rates.md) - 4.6 Ventilation & Gas Exchange - [4.6.1 Human Gas Exchange](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-6-1-human-gas-exchange.md) - [4.6.2 Ventilation](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-6-2-ventilation.md) - [4.6.3 Measuring Gas Exchange](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-6-3-measuring-gas-exchange.md) - [4.6.4 Controlling Ventilation Rate](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-6-4-controlling-ventilation-rate.md) - [4.6.5 Lung Disease](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-6-5-lung-disease.md) - [4.6.6 Lung Disease Data](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-6-6-lung-disease-data.md) - 4.7 Urinary System - [4.7.1 Kidneys & Control of Water Balance](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-7-1-kidneys-and-control-of-water-balance.md) - [4.7.2 Kidneys & Osmoregulation](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-7-2-kidneys-and-osmoregulation.md) - [4.7.3 Kidneys & Blood Pressure](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-7-3-kidneys-and-blood-pressure.md) - [4.7.4 Urine](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-7-4-urine.md) - [4.7.5 Kidney Failure & Urinalysis](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-7-5-kidney-failure-and-urinalysis.md) - [4.7.6 Dialysis](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-7-6-dialysis.md) - [4.7.7 Transplants](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-7-7-transplants.md) - 4.8 Cell Transport - [4.8.1 Cell Membrane Structure](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-8-1-cell-membrane-structure.md) - [4.8.2 Diffusion](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-8-2-diffusion.md) - [4.8.3 Osmosis](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-8-3-osmosis.md) - [4.8.4 Active Transport](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-8-4-active-transport.md) - 4.9 Thermal Physics - [4.9.1 Power & Efficiency](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-9-1-power-and-efficiency.md) - [4.9.2 Work & Energy](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-9-2-work-and-energy.md) - [4.9.3 Conservation of Energy](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-9-3-conservation-of-energy.md) - [4.9.4 Pressure](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-9-4-pressure.md) - [4.9.5 First Law of Thermodynamics](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-9-5-first-law-of-thermodynamics.md) - [4.9.6 Second Law of Thermodynamics](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-9-6-second-law-of-thermodynamics.md) - [4.9.7 Heat Engines, Heat Pumps & Refrigerators](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-9-7-heat-engines-heat-pumps-and-refrigerators.md) - [4.9.8 Non-Flow Processes](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-9-8-non-flow-processes.md) - [4.9.9 p-V Diagrams](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-9-9-p-v-diagrams.md) - [4.9.10 Ideal Gases](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-9-10-ideal-gases.md) - [4.9.11 Ideal Gases 2](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-9-11-ideal-gases-2.md) - [4.9.12 Thermal Energy Transfer](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-9-12-thermal-energy-transfer.md) - [4.9.13 Thermal Energy Transfer Experiments](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-9-13-thermal-energy-transfer-experiments.md) - 4.10 Materials - [4.10.1 Density](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-10-1-density.md) - [4.10.2 Stress & Strain](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-10-2-stress-and-strain.md) - [4.10.3 Properties of Materials](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-10-3-properties-of-materials.md) - [4.10.4 Elasticity](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-10-4-elasticity.md) - [4.10.5 Plasticity](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-10-5-plasticity.md) - [4.10.6 Energy in Materials](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-10-6-energy-in-materials.md) - [4.10.7 Young Modulus](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-10-7-young-modulus.md) - 4.11 Fluids - [4.11.1 Fluid Flow](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-11-1-fluid-flow.md) - [4.11.2 Viscosity](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-11-2-viscosity.md) - [4.11.3 Density](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-11-3-density.md) - [4.11.4 Continuity Equation](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-11-4-continuity-equation.md) - [4.11.5 Bernoulli's Equation](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-11-5-bernoullis-equation.md) - [4.11.6 Non-Newtonian Fluids](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/4-11-6-non-newtonian-fluids.md) ### 5 Contemporary Issues in Science - 5.1 Contemporary Issues in Science - [5.1.1 Sustainability](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/5-1-1-sustainability.md) - [5.1.2 Genetic Engineering](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/5-1-2-genetic-engineering.md) - [5.1.3 Uses of Genetic Modification](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/5-1-3-uses-of-genetic-modification.md) - [5.1.4 Stem Cell Therapy](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/5-1-4-stem-cell-therapy.md) - [5.1.5 Cloning](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/5-1-5-cloning.md) - [5.1.6 Cloning 2](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/5-1-6-cloning-2.md) - [5.1.7 Nanotechnology](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/5-1-7-nanotechnology.md) - [5.1.8 Ecosystems](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/5-1-8-ecosystems.md) - 5.2 Analysing Scientific Information - [5.2.1 Validity](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/5-2-1-validity.md) - [5.2.2 Peer Review](https://senecalearning.com/en-gb/revision-notes/btec/science/applied-science-btec-level-3/5-2-2-peer-review.md)