Presentation on theme: "Sponge (Pg. 36) Hypothesize how these climbers hang on to their body temperature."— Presentation transcript:
1 Sponge (Pg. 36)Hypothesize how these climbers hang on to their body temperature.
2 Hypothesize how these climbers hang on to their body temperature. His body is working inside to provide energy and to maintain a stable body temperature.
3 28.2 Mechanisms of Homeostasis Set up Cornell Notes on pg. 37Topic: 28.2 Mechanisms of HomeostasisEssential Question(s):On the top ½ of pg. 36 please create a double-bubble comparing and contrasting Negative and Positive feedbackOn the bottom ½ of pg. 36 please draw your own negative feedback loop with a real example NOT used in class28.2 Mechanisms of Homeostasis2.1 Atoms, Ions, and Molecules
4 KEY CONCEPT Homeostasis is the regulation and maintenance of the internal environment.
5 Homeostasis is the regulation and maintenance of the internal environment within the narrow ranges that support human life. It is a delicate balance.TemperatureFluidsSaltspHnutrients
6 Conditions within the body MUST remain within a narrow range. Homeostasis involves keeping the internal environment within set ranges.
7 Human Internal Environment Protects our cells from external changesIs relatively constant, despite an ever-changing outside environment (98.6 degrees)
8 activated by an imbalance Negative Feedback: The control system (brain) sends signals/instructions to effectors (muscles and glands) to stabilize the bodyactivated by an imbalancecorrects an imbalance, brings body back to HomeostasisPancreas receptors detect high blood sugarStimulus: rising blood sugarThe control center signals the pancreas to secrete insulinEffector: Insulin causes liver cells to take up sugar in the bloodResponse: blood sugar returns to normal= homeostasis
9 How does a thermostat work? Your control center (brain) is like a thermostatHas a set temperature (98.6)If it is too hot- sends signals to effectors (sweat glands) to lower body temp (ex: sweat)If too cold- sends signals to effectors to raise body temp (ex: shiver)How does a thermostat work?Air conditionerHeater
10 100*Change occurs in internal or external environment
11 ReceptorsSensors: Gather data, and Send signals to the control center
12 The brain receives data, and compares it with “set point”, sends messages to effectors
13 Work to return the body to balanced levels- delivers messages to target organs/glands
14 Targets respond to change, and body returns to homeostasis
15 Real life example:100*Body temperature rises above set point due to the environment
19 You sweat, body temperature lowers to normal (98.6)
20 How are negative feedback loops necessary for homeostasis? Feedback compares current conditions to set ranges.Negative feedback counteracts changeKeeps environment stableNegative Feedback LoopHolding breath, CO2 levels rise,O2 / CO2 level returns to normalControl system forces exhale, inhale
21 Positive Feedback: Process by which changes cause additional similar changes, producing unstable conditions- pushes away from homeostasis
22 Positive feedback increases change Important when rapid change is neededplateletsfibrinwhite blood cellred blood cellblood vesselclotEX: Torn vessel stimulates release of clotting factors
23 At your table, please explain the difference between a negative feedback loop and positive feedback loop?Negative feedback loop counteracts change away from set points. Positive feedback loops increases change away from set points.
24 Homeostasis is the regulation and maintenance of the internal environment within the narrow ranges that support human life.Body temperature is normalNormal amounts of blood and other bodily fluidsWith your neighbor, please make a list of external or internal factors that would affect your body’s homeostasis.
25 Lifestyle (drinking, smoking, diet) Injury Illness (fever, infection) Please make a list of external or internal factors that would affect your body’s homeostasis.DiseaseStressRestLifestyle (drinking, smoking, diet)InjuryIllness (fever, infection)Dehydration/Starvation
26 A disruption of homeostasis can be harmful Sensors fail to detect changesWrong messages sentMessages fail to reach their targetsSerious injuries overwhelm the bodyViruses or bacteria change the body’s internal chemistry
27 Short term effectsLast a few days or weeksEx: A cold virus enters your bodyWithin a few days your immune system begins to kill the virus
28 Long term effectsCauses long term damage to the bodyEx: diabetes
29 HomeworkOn the top ½ of pg. 37 draw a double-bubble map, comparing and contrasting negative and positive feedback. Make sure you give examples of each.
30 Causes additional changes stimuli Corrects an imbalanceCauses additional changesstimuliNegativeFeedbackreceptorsPositiveFeedbackEx: Contractions during childbirthEx: temperature regulationControl centerMoves body away from homeostasiseffectorsReturns body to homeostasis
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