This lesson describes how the action of the radial and circular muscles of the iris causes the pupil to dilate or contract. The PowerPoint has been designed to cover point 8.6 (ii) of the Edexcel International A-level Biology specification and includes key details such as the innervation of the smooth muscles by divisions of the autonomic nervous system.
Students will learn how:
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the contraction of the radial muscles pulls the iris radially and enlarges the pupil, allowing more light to enter when an individual is in a room with dim light and that this contraction is the result of the conduction of an electrical impulse along a sympathetic motor neurone.
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the contraction of the circular muscles constricts the pupil to reduce the light that enters the eye, in order to prevent damage to the photosensitive cells in the retina. This is the result of innervation by an impulse conducted along a parasympathetic neurone
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Topic 8: Coordination, Response and Gene Technology (Edexcel Int. A-level biology)
Topic 8 of the Edexcel International A-level biology specification is content heavy and therefore all 11 lessons included in this bundle have been planned to cover this content in an engaging and memorable way. The lessons are filled with a wide variety of tasks, including understanding and prior knowledge checks, guided discussion periods and quick quiz competitions. Answers to all of the knowledge checks are embedded into the PowerPoints to allow the students to assess their progress. The following specification points are covered by this bundle: 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.8, 8.10, 8.13, 8.14, 8.18, 8.19, 8.20 If you would like to get a sense for the quality of the lessons in this bundle, then download the nervous and hormonal control, saltatory conduction and pupil reflex lessons as these have been shared for free.
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Topic 8: Coordination, Response and Gene Technology (Edexcel Int. A-level Biology)
This bundle contains 8 fully-resourced lessons which have been designed to cover the following content in topic 8 of the Edexcel International A-level Biology specification: 8.1: Know the structure and function of sensory, relay and motor neurones 8.2: Understand how the nervous system of organisms can cause effectors to respond to a stimulus 8.4: Understand how a nerve impulse is conducted along an axon 8.5: Understand the role of myelination in saltatory conduction 8.6 (i): Know the structure and function of synapses in nerve impulse transmission 8.6 (ii): Understand how the pupil dilates and contracts 8.8: Understand how the nervous system of organisms can detect stimuli with reference to rods in the retina of mammals 8.10: Know that the mammalian nervous system consists of the central and peripheral nervous systems 8.13: Understand how coordination in animals is brought about through nervous and hormonal control 8.18: Understand how recombinant DNA can be produced 8.19: Understand how recombinant DNA can be inserted into other cells Each of the lessons contains a wide range of activities, which include exam-style questions, guided discussion periods and quick quiz competitions, and these will motivate the students whilst the difficult A-level content is covered If you would like to see the quality of lessons included in this bundle then download the pupil reflex, saltatory conduction and nervous and hormonal control lessons as these have been uploaded for free
£10.00
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