Homeostasis
Overview
Whether you are sunbathing or shivering in the snow, your core body temperature stays close to 37 degrees Celsius. Whether you have just eaten a sugary meal or skipped breakfast, your blood glucose stays within narrow limits. This steady internal world is called homeostasis, and your body works constantly to maintain it.
In this lesson you will learn what homeostasis is, how negative feedback keeps conditions near a set point, how insulin and glucagon control blood glucose, how Type 1 diabetes is treated, and how the skin keeps your temperature constant through sweating, shivering, vasodilation and vasoconstriction.
Objectives
- Describe homeostasis as the maintenance of a constant internal environment
- State that insulin decreases blood glucose concentration
- [Supplement] Explain the concept of homeostatic control by negative feedback with reference to a set point
- [Supplement] Describe the control of blood glucose concentration by the liver and the roles of insulin and glucagon
- [Supplement] Outline the treatment of Type 1 diabetes
- [Supplement] Identify in diagrams and images of the skin: hairs, hair erector muscles, sweat glands, receptors, sensory neurones, blood vessels and fatty tissue
- [Supplement] Describe the maintenance of a constant internal body temperature in mammals in terms of: insulation, sweating, shivering and the role of the brain
- [Supplement] Describe the maintenance of a constant internal body temperature in mammals in terms of vasodilation and vasoconstriction of arterioles supplying skin surface capillaries
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Lesson Evaluation
Congratulations on completing the lesson on Homeostasis. Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Homeostasis is the maintenance of a constant: A. external environment B. internal environment C. body mass D. heart rate Answer: B
- After a sugary meal the blood glucose level rises, and the pancreas releases a hormone that brings it back down. Which hormone is this? A. glucagon B. insulin C. adrenaline D. testosterone Answer: B
- When the body is too hot, the skin arterioles: A. narrow (vasoconstriction) B. widen (vasodilation) C. disappear D. stop carrying blood Answer: B
- Shivering helps to warm the body because muscle contraction releases heat from: A. evaporation B. respiration C. digestion D. excretion Answer: B
- Type 1 diabetes is treated mainly with regular: A. glucagon tablets B. insulin injections C. adrenaline injections D. extra sugar Answer: B
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