This lesson describes the principles of homeostasis and the differences between negative feedback and positive feedback. The PowerPoint and accompanying resources have been designed to cover point 5.1.1 [c] of the OCR A-level Biology A specification and explains how this feedback control maintains systems within narrow limits but has also been planned to provide important details for upcoming topics such as osmoregulation, thermoregulation and the depolarisation of a neurone.
The normal ranges for blood glucose concentration, blood pH and body temperature are introduced at the start of the lesson to allow students to recognise that these aspects have to be maintained within narrow limits. A series of exam-style questions then challenge their recall of knowledge from topics 1-8 to explain why it’s important that each of these aspects is maintained within these limits. The students were introduced to homeostasis at GCSE, so this process is revisited and discussed, to ensure that students are able to recall that this is the maintenance of a state of dynamic equilibrium. A quick quiz competition is used to reveal negative feedback as a key term and students will learn how this form of control reverses the original change and biological examples are used to emphasise the importance of this system for restoring levels to the limits (and the optimum). The remainder of the lesson explains how positive feedback differs from negative feedback as it increases the original change and the role of oxytocin in birth and the movement of sodium ions into a neurone are used to exemplify the action of this control system.
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Homeostasis, Excretion, Neuronal and Hormonal communication (OCR A-level Biology A)
This bundle of 20 lessons covers the majority of the content that's included in modules 5.1.1 - 5.1.4 of the OCR A-level Biology A specification. All of the lessons are highly detailed and have been planned at length to ensure that they are filled with a wide range of tasks to engage and motivate the students whilst checking on their understanding. The following specification points are covered by the lessons in this bundle: 5.1.1: Communication and homeostasis * The communication between cells by cell signalling * The principle of homeostasis * The physiological and behavioural responses involved in temperature control in endotherms and ectotherms 5.1.2: Excretion as an example of homeostatic control * The functions of the mammalian liver * The gross structure and histology of the kidney * The processes of ultrafiltration and selective reabsorption * The control of the water potential of the blood * The effects of kidney failure and its potential treatments 5.1.3: Neuronal communication * The roles of mammalian sensory receptors in converting stimuli into nerve impulses * The structure and functions of sensory, relay and motor neurones * The generation and transmission of nerve impulses in mammals * The structures and roles of synapses in transmission 5.1.4: Hormonal communication * Endocrine communication by hormones * The structure and functions of the adrenal glands * The structure of the pancreas * The regulation of blood glucose concentration * The difference between diabetes mellitus type I and II * The potential treatments for diabetes mellitus It is estimated that it will take in excess of 2 months of allocated A-level teaching time to cover the detail included in these lessons If you would like to sample the quality of the lessons in this bundle, then download the following lessons as they have been shared for free: * The principles of homeostasis * Temperature control in ectotherms * The functions of the liver * The structure of the kidney * The generation and transmission of nerve impulses * Endocrine communication
Module 5.1.1: Communication and homeostasis (OCR A-level Biology A)
This bundle of 4 lessons covers the content of module 5.1.1 of the OCR A-level Biology A specification, titled communication and homeostasis. As this module tends to be one of the first to be taught in the second year of the course, it's extremely important that links are made to upcoming topics as well as challenging the students on their prior knowledge of modules 2 - 4. This is achieved through a wide range of tasks, that include exam-style questions, differentiated tasks and guided discussion periods. Quick quiz competitions are also used to introduce key terms and values in a fun and memorable way. The following specification points are covered by the 4 lesson PowerPoints and accompanying resources included in this bundle: * The communication between cells by cell signalling * The principles of homeostasis * The differences between negative and positive feedback * The physiological and behavioural responses involved in temperature control in endotherms and ectotherms As detailed above, these lessons have been specifically planned to tie in with the other parts of module 5, including neuronal communication, hormonal communication and animal and plant responses. If you would like to sample the quality of the lessons in this bundle, then download the principles of homeostasis and temperature control in ectotherms lessons as these have been uploaded for free
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Really good way to introduce and teach this topic. Easily modifiable to suit different exam boards (CiE for myself). Good resources too, enjoyed by students.
A really useful introduction to homeostasis, and some great quizzes. Particularly good for online lessons at the moment. Thanks for sharing.
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