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Homeostasis and Feedback in the Body

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Presentation on theme: "Homeostasis and Feedback in the Body"— Presentation transcript:

1 Homeostasis and Feedback in the Body
Colorado Life Science 2.6: Cells, tissues, organs, and organ systems maintain relatively stable internal environments, even in the face of changing external environments

2 What is homeostasis? Process that occurs in all living things
All organ systems work together to achieve ___________. Ability of an organism to maintain its internal environment, despite changes to its internal or ________ environment! all images generated by Microsoft Clip Art Gallery

3 How does homeostasis work?
pathways A cellular relay race! Specific organs and structures must communicate with each other in response to changes in the body Keeps levels of certain processes within a normal all images generated by Microsoft Clip Art Gallery

4 What things in your body need to be kept within a range?
Body Temperature Blood pressure Blood pH O2 and CO2 concentration Osmoregulation-Water balance Blood glucose all images generated by Microsoft Clip Art Gallery

5 How Does it Work? Stimulus Receptor Integrating center Effector
Response Reverses the stimulus all images generated by Microsoft Clip Art Gallery

6 Example: Consider temperature in your home….
Stimulus- low thermal energy in the room (it’s cold) Receptor- sensor in thermostat Integrating center- thermostat Effector- Heater Response- increased thermal energy (it’s warmer)

7 Negative Feedback Also called feedback Way in which MOST homeostatic mechanisms work Stimulus produces a response that opposes or the original stimulus In other words, the product of a negative feedback pathway inhibits or shuts down the original signal.

8 Negative Feedback Stimulus

9 Negative Feedback Living Example

10 You can think of negative feedback like dueling mechanisms- What goes up, must come down!
_______________________ Sweating (cooling) vs. shivering (warming) Blood Pressure Vasconstriction vs. vasodilation Osmoregulation Hypotonic vs. hypertonic all images generated by Microsoft Clip Art Gallery

11 Positive Feedback A B Takes body out of homeostasis (which can be necessary in certain circumstances) Stimulus causes a _________ that causes more of the stimulus

12 Positive Feedback Examples
Increase in births increases population which increases births – and so on.

13 Positive Feedback Examples in Our Body Blood clotting ______________
Injured tissue signals platelets to be activated, activated platelets produce chemical signal that activates more platelets ______________ The hormone oxytocin signals a contraction, which signals they brain to produce more oxytocin

14 Additional Examples… Identify the following as examples of positive or negative feedback loops within the body?

15 Homeostasis & the Integumentary System
Functions of Integumentary System: Protection Body Temperature Regulation Excretion Information Gathering Vitamin D Production

16 Homeostasis: Body Temperature Regulation
If cold, ___________ generates heat and goose bumps and constricted blood vessels help decrease the heat loss from skin If hot, __________ blood vessels allows excess heat released from skin and sweating allows energy to leave the body

17 Body Temperature & Feedback


19 Positive or Negative?

20 Homeostasis & the Circulatory System
Function of Circulatory System Transport Oxygen, CO2, nutrients and waste to and from cells, as needed

21 How the Heart Works _________ are exchanged in the lungs (Oxygen in and Carbon Dioxide out) Heart pumps blood from the body to the lungs and then to the rest of the body

22 Homeostasis: Blood pH Buffering System
Blood has pH of 7.4 ( ) Below 6.8 or above ______ cells stop functioning

23 Homeostasis: Blood pH & Bicarbonate Buffering System

24 Positive or Negative?

25 Lack of Sleep & Stress Levels

26 Positive or Negative?

27 Homeostasis- The Digestive & Circulatory & Endocrine Systems!
Blood Sugar Regulation!

28 Processes of the Digestive System
_________ – food into mouth Digestion – mechanical and chemical break down – starts in mouth, continues to break down in stomach and small intestine ___________ – bloodstream absorbs nutrients in small intestine and absorbs water in large intestine Elimination – Waste eliminated through anus

29 Homeostasis- The Digestive & Circulatory & Endocrine Systems- Blood Sugar Regulation!
Glycogen- Stored glucose (polysaccharide of glucose) Glucagon- Hormone secreted by pancreas that _________ blood sugar (break down glycogen into glucose) Produced by alpha-cells of the pancreas Released into the circulatory system when blood glucose is low Signals the liver to break down glycogen into simple glucose Insulin- Hormone secreted by the pancreas that _________ blood sugar (glucose to glycogen) Produced by beta-cells of the pancreas Released into circulatory system when blood glucose is high Facilitates the transport of glucose into target cells

30 Homeostasis & the Digestive System
Blood sugar regulation:

31 Homeostasis & the Digestive System

32 Positive or Negative?

33 Food for thought… On average, how many organ systems are involved in each of the processes we’ve explored? Are there any organ systems that you see in all of these processes? What might happen to these pathways if just one system was not functioning properly? all images generated by Microsoft Clip Art Gallery

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