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What is the primary function of effectors in homeostasis?
What is the primary function of effectors in homeostasis?
Negative feedback is the least common mechanism in homeostatic processes.
Negative feedback is the least common mechanism in homeostatic processes.
False
What are the two main processes that control homeostatic mechanisms?
What are the two main processes that control homeostatic mechanisms?
Negative Feedback and Positive Feedback
When the body temperature is too high, the control centre stimulates the __________ to initiate a cooling response.
When the body temperature is too high, the control centre stimulates the __________ to initiate a cooling response.
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Match the following terms to their correct descriptions:
Match the following terms to their correct descriptions:
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Who first recognized the concept of homeostasis?
Who first recognized the concept of homeostasis?
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Homeostasis refers to the body's ability to maintain a constant internal environment despite external changes.
Homeostasis refers to the body's ability to maintain a constant internal environment despite external changes.
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What is the significance of homeostasis in human health?
What is the significance of homeostasis in human health?
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The concept of homeostasis was introduced in ______ by Walter Cannon.
The concept of homeostasis was introduced in ______ by Walter Cannon.
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Which physiological factor is NOT typically regulated by homeostasis?
Which physiological factor is NOT typically regulated by homeostasis?
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Homeostasis does not require the expenditure of metabolic energy.
Homeostasis does not require the expenditure of metabolic energy.
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Name two ways the body maintains homeostasis.
Name two ways the body maintains homeostasis.
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Match the following physiological factors with their description:
Match the following physiological factors with their description:
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What is the primary function of homeostatic control mechanisms?
What is the primary function of homeostatic control mechanisms?
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Oxygen is an example of a therapeutic drug that helps maintain blood oxygen levels.
Oxygen is an example of a therapeutic drug that helps maintain blood oxygen levels.
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What is the normal body temperature in degrees Celsius that serves as a set point for humans?
What is the normal body temperature in degrees Celsius that serves as a set point for humans?
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The three main components of homeostatic mechanisms are receptors, ___, and effectors.
The three main components of homeostatic mechanisms are receptors, ___, and effectors.
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Which receptor type detects changes in temperature?
Which receptor type detects changes in temperature?
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Match the following therapeutic drugs with their functions:
Match the following therapeutic drugs with their functions:
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Homeostatic mechanisms are only present in humans.
Homeostatic mechanisms are only present in humans.
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What do control centres process information from to indicate change?
What do control centres process information from to indicate change?
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What is the primary function of thermoreceptors in the body's response to cold temperatures?
What is the primary function of thermoreceptors in the body's response to cold temperatures?
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Vasodilation occurs when body temperature rises.
Vasodilation occurs when body temperature rises.
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What physiological response occurs in the body when the temperature is too cold?
What physiological response occurs in the body when the temperature is too cold?
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The process of __________ leads to the narrowing of blood vessels to conserve heat.
The process of __________ leads to the narrowing of blood vessels to conserve heat.
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Match the following responses to their respective temperature changes:
Match the following responses to their respective temperature changes:
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What is the effect of insulin on blood glucose levels?
What is the effect of insulin on blood glucose levels?
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Positive feedback mechanisms help to stabilize physiological changes in the body.
Positive feedback mechanisms help to stabilize physiological changes in the body.
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Which of the following is an example of a positive feedback loop?
Which of the following is an example of a positive feedback loop?
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What happens to blood flow in skin capillaries during vasodilation?
What happens to blood flow in skin capillaries during vasodilation?
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Positive feedback mechanisms help maintain homeostasis by returning variables to normal.
Positive feedback mechanisms help maintain homeostasis by returning variables to normal.
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What hormone is released during childbirth to promote stronger uterine contractions?
What hormone is released during childbirth to promote stronger uterine contractions?
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The autonomic nervous system is concerned with _____ changes in the body.
The autonomic nervous system is concerned with _____ changes in the body.
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Match the following examples with their feedback type:
Match the following examples with their feedback type:
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What is the primary role of the endocrine system in homeostasis?
What is the primary role of the endocrine system in homeostasis?
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List one condition that can be regulated by negative feedback mechanisms.
List one condition that can be regulated by negative feedback mechanisms.
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Positive feedback loops are more common in the body than negative feedback loops.
Positive feedback loops are more common in the body than negative feedback loops.
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Study Notes
Homeostasis
- Homeostasis is the body's ability to maintain a stable internal environment.
- This involves adjusting internal factors in response to external changes.
- Maintaining stable conditions is crucial for cell, tissue, and organ function.
Learning Objectives
- Understand the importance of homeostasis in the human body.
- Recognize two methods the body uses to maintain homeostasis.
- Define a negative feedback loop within homeostasis.
Origins
- Claude Bernard (1813-1878), a French physiologist, was the first to recognize the concept.
- Walter Cannon (1871-1945), an American scientist, introduced the term "homeostasis" in 1926.
- Homoios (Greek) - similar
- Stasis (Greek) - to stand still
What is homeostasis?
- The internal environment in the body needs to stay relatively stable in order for the body to properly function.
- This includes the levels of nutrients, fluids, pressure and gasses within the body.
Group Exercise
- List physiological factors within the body needing fine balance.
Examples of Physiological Factors
- Temperature
- Waste product concentration
- Gas exchange
- Volume/pressure
- pH
- Water/Ion balance
- Energy requirements
Why is Homeostasis Important?
- Body cells, tissues, and organs function best within specific parameters of temperature, pH, nutrient levels.
- Extracellular fluid consists of water and dissolved substances surrounding cells. The intracellular fluid is contained inside of cells. It is separated from the extracellular fluid by the cell membrane.
- Maintaining homeostasis requires substantial amounts of metabolic energy.
- The stability of the internal environment is essential to cell, tissue, and organ health.
How are these Regulated?
- Shivering
- Kidney function
- Breathing
- Sugar levels
- Calcium levels in bone
- Lymphatic system (fighting infection)
Relevance to Clinicians
- Homeostasis underlies every physiological process in the body, including sensations like thirst, hunger, and pain.
- Understanding homeostasis and its control mechanisms is vital for diagnosing, treating, and comprehending the consequences of common diseases and trauma.
Examples of Therapeutic Drugs
- Oxygen
- Sodium chloride 0.9% fluid
- Aspirin
- Glucose
- Salbutamol
- These drugs maintain needed blood levels for optimum function.
How is Balance Achieved?
- Homeostasis requires specific control mechanisms to maintain balance.
- Processes regulate the body's internal environment.
Homeostatic Control Mechanisms
- Self-regulating systems that maintain homeostasis.
- The body maintains levels within a normal range, but normal ranges may vary between individuals.
- Body temperature regulation is analogous to a home thermostat.
- Blood pressure regulation relies on pressure-sensitive receptors and muscle cells in blood vessels.
Homeostatic Mechanisms - 3 Main Components
- Receptors for detection of internal environmental changes.
- Control centers that contain a set point and process information.
- Effectors that respond to stimuli to return conditions to normal.
Receptors
- Detect changes in the internal environment.
- These can be cells, proteins, or channels within cell walls.
- Types include chemoreceptors, thermoreceptors, and baroreceptors.
- Receptors initiate responses that are sent to control centers.
Set point and Control Centre
- The physiological value required for cells to function optimally.
- It's the center around which normal ranges fluctuate. Body temperature (37 degrees C) would be an example.
- Located in the brain and other parts of the body.
- They process information from stimuli, detecting internal changes.
- If changes exceed the set point, the control center activates effectors.
Effectors
- Muscles or glands that receive stimuli from the control center.
- They respond by contracting, relaxing, or releasing hormones to return conditions to the set point.
- This aims to achieve homeostasis.
Components of Homeostatic Mechanisms (Diagram)
- Receptors detect a stimulus (a change in the internal environment).
- The stimulus is sent to the control center (set point).
- The change is compared to the set point.
- The control center sends signals to effectors.
- Effectors respond to return the internal environment to the set point.
Homeostatic Mechanisms How They Work
- Two main processes control how homeostatic mechanisms function.
- Negative Feedback
- Positive Feedback
Negative Feedback
- Mechanisms correct deviations from set points.
- Negative feedback is the most common homeostatic mechanism.
- Receptors and control centers initiate responses to return conditions to normal ranges.
- As the variable reaches the set point, stimulation of effectors by the control center decreases to prevent over-correction. (For example body temperature regulation).
A Thermostat as an Example of Negative Feedback
- Diagram illustrating how a thermostat works to regulate temperature.
- Illustrates negative feedback loop
Which Systems Contribute to Homeostatic Temperature Control?
- This requires a short-term think time to complete.
The Body's Response to Change
- The body detects a change outside of normal limits
- Now what?
Negative Feedback Loop (Diagram)
- Illustration of a negative feedback loop as it relates to body temperature.
- The loop includes a stimulus that causes a response that brings the body back to homeostasis.
Homeostatic Temperature Control: Responses to Cold
- Thermoreceptors detect a drop in body temperature.
- Signals are sent to the brain.
- Blood vessels in the skin constrict to conserve heat.
- Muscles contract involuntarily. (Shivering)
Homeostatic Temperature Control: Responses to Warm
- Thermoreceptors detect rising body temperature.
- Signals are sent to the brain.
- Sweat glands are activated.
- Blood vessels in the skin dilate to release heat.
Blood Flow in Skin Capillaries (Tables and Images)
- Vasoconstriction during cold and vasodilation during heat.
- Tables summarizing the responses of blood vessels in the skin to changes in temperature.
Further Examples of Negative Feedback
- Blood pressure control
- Metabolism
- Blood Glucose levels
- Red blood cell production
Regulation of Blood Glucose
- Diagram showing the negative feedback loop in the regulation of blood glucose.
- Illustration details the involvement of pancreatic cells, insulin, glucagon, liver cells, etc in maintaining blood glucose levels.
Positive Feedback
- Feedback loop intensifies a change in body condition.
- A deviation from normal range results in continued activity.
- Usually creates unstable states.
Positive Feedback Loops
- Rare examples include:
- Blood clotting
- Uterine contractions during labor (childbirth)
Examples
- Blood clotting
- Childbirth
Positive Feedback Loops (Details)
- Blood clotting: Increased blood clotting stops bleeding.
- Childbirth: Uterine contractions become stronger with the release of oxytocin.
Childbirth (Diagram)
- Illustration of the positive feedback loop in childbirth, showing nerve impulses, oxytocin, uterine contractions, etc
Key Points
- Negative feedback mechanism returns the body to a normal state.
- Positive feedback mechanism drives the body away from a normal state. Such mechanisms are shorter and have a specific function that helps the body to get back to homeostasis.
Nervous and Endocrine System
- Homeostasis is maintained by two systems.
- Autonomic nervous system - controls rapid changes.
- Endocrine system - controls hormonal changes, slower but precise changes.
To be completed by next week
- Complete additional resources for the week.
- Complete the weekly quiz.
- Complete the self-study in your anatomy/physiology book.
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Description
Test your understanding of homeostasis, its significance in human health, and the processes involved in maintaining internal stability. This quiz covers key concepts, definitions, and the historical background related to homeostasis. Dive into the mechanisms that keep our bodies functioning smoothly despite external changes.
