Task 4
- 1. Task 4 Homeostatic Mechanisms and the Maintenance of an Internal Environment. Homeostasis and how the body responds to exercise (P5, M2, D2) To secure knowledge by explaining the concept of homeostasis To further develop knowledge by discussing the probable homeostatic responses to changes in the internal environment during exercise To show excellence by evaluating the importance of homeostasis in maintaining the healthy functioning of the body.
- 2. Task ref. Evidence submitted Page numbers or description P5 explain the concept of homeostasis M2 discuss the probable homeostatic responses to changes in the internal environment during exercise D2 evaluate the importance of homeostasis in maintaining the healthy functioning of the body. Additional comments to the Assessor:
- 3. Homeostatic Mechanisms and the Maintenance of an Internal Environment. Homeostasis is the process of maintaining a constant internal environment despite external changes. For this task you need to; (a) Describe the homeostatic mechanisms that regulate; • heart rate • breathing rate • body temperature • blood glucose levels. Include annotated diagrams with supporting descriptions. (b) Explain how these homeostatic responses change in the internal environment during exercise. Use the scenario given and show how the body works to maintain homeostasis. (c ) Explain the importance of homeostasis in maintaining the healthy functioning of the body. What would happen if homeostasis did not occur? How would the body cope?
- 4. Range of Content: 3 Understand how homeostatic mechanisms operate in the maintenance of an internal environment • Homeostasis: definition of homeostasis, internal environment, concept of negative feedback as a regulatory mechanism • Homeostatic mechanisms for regulation of: heart rate: roles of internal receptors, autonomic nervous system-sympathetic and parasympathetic nerve supply, cardiac centre, sinoatrial node; effects of increased body temperature and adrenaline on • heart rate breathing rate: roles of internal receptors, autonomic nervous system – sympathetic and parasympathetic nerve supply, respiratory centre, diaphragm and intercostal muscles body temperature: production of heat by the body, e.g. through metabolic processes; loss of heat by the body – radiation, conduction, convection, evaporation; roles of hypothalamus, autonomic nervous system – sympathetic and parasympathetic, skin – role of arterioles and sweat glands; effects of shivering; implications of surface area to volume ratios, e.g. in the care of babies; fever blood glucose levels: roles of pancreas, liver, insulin, glucagon
- 5. a)Homeostasis is….. the process of maintaining a constant internal environment despite external changes. • Heart rate • Role of internal receptors • Role of autonomic nervous system • Effects of body temperature • Effects of adrenaline • Breathing rate • Role of internal receptors • Role of autonomic nervous system • Role of diaphragm and intercostal muscles • Effects of adrenaline • Body temperature • Effect of metabolic processes • Role of the skin • How heat is lost • Role of autonomic nervous system • Blood glucose • Role of pancreas • Role of liver • Effects of insulin • Effects of glucagon Watch the following video http://study.com/academy/lesson/what-is-homeostasis- definition-examples-quiz.html
- 6. Heart rate Explain how each of the following is involved within homeostasis • Role of internal receptors • What are they? How do they work? • https://www.boundless.com/physi ology/textbooks/boundless- anatomy-and-physiology- textbook/introduction-to-human- anatomy-and-physiology- 1/homeostasis-32/homeostatic- control-284-3141/ • http://www.ncbi.nlm.nih.gov/pub med/15255616 • http://www.nursingtimes.net/clinic al- subjects/respiratory/homeostasis- part-1-anatomy-and- physiology/203292.fullarticle
- 7. Heart rate • Role of autonomic nervous system • What is it? • http://www.s- cool.co.uk/gcse/pe/how-the- body-is-controlled/revise-it/the- autonomic-nervous-system
- 8. Heart Rate explain how the heart rate affects each. • Effects of body temperature Blood Pressure The human body uses homeostasis to regulate itself internally, despite whatever activity the person is engaged in or environmental issues he is encountering. Blood pressure regulation is part of homeostasis. A normal blood pressure should be approximately 120 over 80, according to Creighton University Medical Center. Depending on the outside temperature, blood vessels will either dilate or contract. A dilation of the blood vessels will cause a drop in blood pressure, and this lowers body temperature. Contracting vessels increase blood pressure, resulting in increasing core temperature. • http://www.livestrong.com/article/228784- the-effects-of-body-temperature-on-heart- rate/ • Effects of adrenaline Adrenaline, also called epinephrine, is a hormone secreted by your adrenal glands, which sit on top of each of your kidneys. Once released by these glands, adrenaline produces a variety of effects on your body, including increases in your heart rate. These effects are triggered through interactions with certain portals on the surfaces of your cells called adrenergic receptors. • http://www.livestrong.com/article/355672- why-adrenaline-speeds-up-heart-rate/
- 9. Breathing rate Explain each of the following; • Role of internal receptors • Role of autonomic nervous system • Role of diaphragm and intercostal muscles • Effects of adrenaline
- 10. What is happening in this image? http://www.livestrong.c om/article/30209- breathing-regulated/
- 11. Body temperature http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_pre_2011/h omeostasis/bodytemprev1.shtml • Effect of metabolic processes • Role of the skin • How heat is lost • Role of autonomic nervous system • The human body is designed to function most efficiently at 37ºC. This is controlled to maintain the temperature at which the body’s enzymes work best. • If you become too hot or too cold, there are ways in which your body temperature can be controlled. Too hot When we get too hot: • Sweat glands in the skin release more sweat. The sweat evaporates, removing heat energy from the skin. • Blood vessels leading to the skin capillaries become wider - they dilate - allowing more blood to flow through the skin, and more heat to be lost. Too cold When we get too cold: • Muscles contract rapidly - we shiver. These contractions need energy from respiration, and some of this is released as heat. • Blood vessels leading to the skin capillaries become narrower - they constrict - letting less blood flow through the skin and conserving heat in the body. • The skin • The hairs on the skin also help to control body temperature. They lie flat when we are warm, and rise when we are cold. The hairs trap a layer of air above the skin, which helps to insulate the skin against heat loss. • The hypothalamus is the part of the brain which monitors the body's temperature. It receives information from temperature-sensitive receptors in the skin and circulatory system. • The hypothalamus responds to this information by sending nerve impulses to effectors to maintain body temperature.
- 12. Watch the video • http://study.com/academy/lesso n/homeostasis-and- temperature-regulation-in- humans.html
- 13. For example, if we become too cold, the hair erector muscles contract. This raises the skin hairs and traps a layer of air next to the skin. Skin hairs lie flat when we are hot and stand upright when we are cold
- 14. Negative feedback mechanisms control body temperature. They include the amount of: •shivering (rapid muscle contractions release heat) •sweating (evaporation of water in sweat causes cooling) •blood flowing in the skin capillaries
- 15. Too cold Too hot Process Vasoconstriction Vasodilation Arterioles Get narrower Get wider Blood flow in skin capillaries Decreases Increases Heat loss from skin Decreases Increases Vasoconstriction and vasodilation The amount of blood flowing through the skin capillaries is altered by vasoconstriction and vasodilation.
- 16. Blood glucose • Glucose is needed by cells for respiration. It is important that the concentration of glucose in the blood is maintained at a constant level. Insulin is a hormone - produced by the pancreas - that regulates glucose levels in the blood. • Blood sugar level • This is controlled to provide cells with a constant supply of glucose for respiration. It is controlled by the release and storage of glucose, which is in turn controlled by insulin. Low glucose High glucose Effect on pancreas Insulin not secreted into the blood Insulin secreted into the blood Effect on liver Does not convert glucose into glycogen Converts glucose into glycogen Effect on blood glucose level Increases Decreases Action of insulin
- 18. Diabetes Diabetes is a condition in which the blood glucose levels remain too high. It can be treated by injecting insulin. The extra insulin causes the liver to convert glucose into glycogen, which reduces the blood glucose level. There are two types of diabetes - Type 1 and Type 2. Type 1 diabetes Type 1 diabetes is caused by a lack of insulin. It can be controlled by: •monitoring the diet •injecting insulin People with Type 1 diabetes have to monitor their blood sugar levels throughout the day. Their levels of physical activity and their diet affect the amount of insulin needed. They can help to control their blood glucose level by being careful with their diet (eating foods that will not cause big spikes in their blood sugar level) and by exercising (which can lower blood glucose levels due to increased respiration in the muscles).
- 19. Type 2 diabetes Type 2 diabetes is caused by a person’s body becoming resistant to insulin. It can be controlled by diet and exercise. There is a link between rising levels of obesity and increasing levels of Type 2 diabetes. Changes in obesity and Type 2 diabetes Watch the video http://study.com/academy/lesson/homeostasis-glucose-levels- and-osmolarity-hormonal-control.html
- 20. Water content • This is controlled to protect cells by stopping too much water from entering or leaving them. Water content is controlled by water loss from: • the lungs - when we exhale • the skin - by sweating • the body - in urine produced by the kidneys • http://www.bbc.co.uk/schools/g csebitesize/science/add_ocr_pre _2011/homeostasis/waterbalrev 1.shtml • Explain what is happening in each organ.
- 21. Negative feedback Homeostatic control is achieved using negative feedback mechanisms: •if the level of something rises, control systems reduce it again •if the level of something falls, control systems raise it again
- 22. Additional Resources • http://www.bbc.co.uk/educatio n/guides/z4khvcw/revision • http://www.s- cool.co.uk/gcse/biology/homeos tasis/revise-it/what-is- homeostasis • http://www.abpischools.org.uk/ page/modules/homeostasis_kid neys/index.cfm?coSiteNavigatio n_allTopic=1 • http://www.bbc.co.uk/bitesize/h igher/biology/control_regulation /homeostatic_control/revision/1 / • https://www.youtube.com/watc h?v=vB7tSHqR1eY
- 23. b)How and why do homeostatic responses change in the internal environment during exercise. Use the scenario given and show how the body works to maintain homeostasis. • When you sweat, breathe heavily and feel your heart pounding, it doesn’t just mean you are having a good workout. These physiological factors are also vital to your body maintaining a state of homeostasis. Homeostasis is defined as a constant, steady environment despite external changes, such as exercise. Exercise affects your body temperature, blood oxygen levels, sugar levels and hydration – all properties necessary for your survival. Your body uses an automatic feedback system to preserve normal temperature and water levels, so you can keep exercising. Eat properly and drink plenty of fluids to help your body maintain homeostasis. Find out more at http://www.livestrong.com/article/369714-how-does-the- body-maintain-homeostasis-in-response-to-exercise/
- 24. c) Explain the importance of homeostasis in maintaining the healthy functioning of the body. What would happen if homeostasis did not occur? How would the body cope? Body system How does Homeostasis help maintain the system? What would happen if homeostasis did not occur? What would go wrong? How would the body cope? What changes would occur? Cardiovascular Respiratory Digestive Renal Nervous Muscular-skeletal Immune/Lymph/ Endocrine Reproductive