IGCSE Biology - Homeostasis (14.4)

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Cambridge IGCSE Biology (0610/0970)
Chapter 14 - Coordination and response
Topic 14.4 - Homeostasis
For exams in 2023, 2024 & 2025 (core and extended)

As always this video follows the Cambridge syllabus exactly and contains absolutely everything you need to know for your final exam!

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Timestamps:
0:00 Contents
0:35 Homeostasis
0:48 Insulin
1:05 Negative feedback (extended)
1:47 Blood glucose control (extended)
2:35 Type 1 diabetes (extended)
3:15 Temperature control (extended)

Core content:
- Describe homeostasis as the maintenance of a constant internal environment
- State that insulin decreases blood glucose concentration

Extended content:
- Explain the concept of homeostatic control by negative feedback with reference to a set point
- Describe the control of blood glucose concentration by the liver and the roles of insulin and glucagon
- Outline the treatment of Type 1 diabetes: monitoring the blood, insulin injections, healthy balanced diet (limiting refined carbohydrate and sugar) and regular exercise
- Identify in diagrams and images of the skin: hairs, hair erector muscles, sweat glands, receptors, sensory neurones, blood vessels and fatty tissue
- Describe the maintenance of a constant internal body temperature in mammals in terms of: insulation, sweating, shivering and the role of the brain
- Describe the maintenance of a constant internal body temperature in mammals in terms of vasodilation and vasoconstriction of arterioles supplying skin surface capillaries

Context:
- So far in chapter 14, we've learned about the ways in which animals coordinate responses to changes in the internal and external environment, otherwise known as stimuli. In topic 14.1 we learned how the nervous system sends electrical impulses along nerve cells called neurones, from receptors in the sense organs to effectors (muscles and glands). We also covered the anatomy of the nervous system, including; the central nervous system, peripheral nervous system, sensory, relay and motor neurones.
- In topic 14.2 we looked at sense organs in more detail, specifically the structure and function of the eye.
- In topic 14.3 we looked at the other communications system of the body, the endocrine system. We learned about the function of hormones, four specific endocrine glands and the hormones they secrete and the role of the hormone adrenaline. We also compared nervous and hormonal control.
- In our next lesson (14.5), we'll cover coordination and response in plants: Tropic responses or tropisms (e.g. gravitropism and phototropism) are the growth movements of plants in response to stimuli like light, water and gravity. Tropisms are controlled by chemicals (e.g. auxin).