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BELLWORK – 2/4/2014. 1. Read pages 29-31 in your review book on FEEDBACK and HOMEOSTASIS. 2. Read and discuss QUIETLY the ESSENTIAL question below with your table partner (be prepared to explain if called upon):
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BELLWORK – 2/4/2014 1. Read pages 29-31 in your review book onFEEDBACK and HOMEOSTASIS. 2. Read and discuss QUIETLY the ESSENTIAL questionbelow with your table partner (be prepared to explain if called upon): • During hot weather and vigorous exercise, people sweat. As the water on their skin evaporates, the water molecules absorb heat energy. • Explain why this process is important to the individual.
Dynamic Equilibrium Our bodies are constantly responding and adjusting to external and internal stimuli, causes small changes in our body temperature, blood sugar level, etc. We refer to these small changes as dynamic equilibrium. This allows us to maintain homeostasis (internal balance). All living things must maintain homeostasis in order to survive. EX. Human body temp is 37 C; if temp is altered, processes that keep us going will begin to fail
Dynamic Equilibrium • Constant small corrections that keep internal environment w/in stable limit AFTER MEAL BODY TEMP BLOOD SUGAR LEVEL TIME TIME
FEEDBACK MECHANISMS • Help regulate the endocrine system • Maintain homeostasis • Let’s watch: • http://www.brainpop.com/health/bodysystems/homeostasis/ • http://www.learnerstv.com/animation/animation.php?ani=241&cat=Biology
TYPES OF FEEDBACK MECHANISM 1. Negative Feedback • considered negative because the original signal is lowered or shut off.
Examples OF FEEDBACK MECHANISM Ex. Body Temperature EX:Thermostat
Example 3: Glucose levels in the blood Blood sugar regulation by insulin (secreted by pancreas) Video: Insulin, Glucose and you http://www.youtube.com/watch?v=ae_jC4FDOUc http://bcs.whfreeman.com/thelifewire/content/chp50/5002s.swf
Ex 4. Plants regulating water loss • Guard cells in plants opening and closing to prevent water loss
2. Positive Feedback Mechanism –Change in system causes greater change or response Positive Feedback