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Homeostasis Presentation. What must we do to maintain life?. 1. Maintain Boundaries Skin covers us and protects us from the external environments that we live in 2. Movement Skeletal muscle allows us to move and if necessary protect ourselves 3. Responsiveness –
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What must we do to maintain life? • 1. Maintain Boundaries • Skin covers us and protects us from the external environments that we live in • 2. Movement • Skeletal muscle allows us to move and if necessary protect ourselves • 3. Responsiveness – • Ability to detect changes and make proper adjustments • 4. Digestion • Breakdown foods to get nutrients for growth, development, and homeostasis
Maintain Continued • 5. Metabolism • Ability to take nutrients and use them to build, and energize the body • 6. Excretion • Removal of wastes • 7. Reproduction • Pass on good genes to future generations • 8. Growth • Increase in size
What things do we need to survive? • 1. Nutrients • 2. Water • 3. Oxygen • 4. Stable temperature • 5. Environment that is at 1 ATM of pressure
Homeostatic Control Mechanisms Consist of 3 key parts • Receptor Stimulated by a change in the environment Carries impulses to the CNS via afferent pathways 2. Control Center Needs to determine what to do when it gets the impulse 3. Effector Responds to the original stimulus Receives direction from the control center Uses an efferent pathway
Negative Feedback • Most homeostatic control mechanisms fall under this category • Effect of the response is to shut off the stimulus, or to reduce its intensity • Insulin control of blood sugar is a good example • After a meal blood sugar rises, and so insulin is released by the pancreas • This allows us to move glucose into cells • As the level of glucose drops, so does the level of insulin • This repeats each time we eat
Positive Feedback • Rare in the body • Here the response intensifies the original stimulus • Usually these responses lead to a major event for the person • Examples are blood clotting, and childbirth