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Questions and Answers
What is one of the indicators of allostatic overload?
What is one of the indicators of allostatic overload?
Which type of allostatic overload occurs when an individual fails to inhibit allostatic responses when they are not needed?
Which type of allostatic overload occurs when an individual fails to inhibit allostatic responses when they are not needed?
What is an example of adaptation to climatic changes?
What is an example of adaptation to climatic changes?
What is the result of a 25-50% loss in BMR in cold climate adaptation?
What is the result of a 25-50% loss in BMR in cold climate adaptation?
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What is the concept of heterostasis?
What is the concept of heterostasis?
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What is the result of a reduction in thermal conductivity in cold climate adaptation?
What is the result of a reduction in thermal conductivity in cold climate adaptation?
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What is an example of a physiological adaptation to high-altitude environments?
What is an example of a physiological adaptation to high-altitude environments?
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What is the result of a 15-12°C decrease in average skin temperature in cold climate adaptation?
What is the result of a 15-12°C decrease in average skin temperature in cold climate adaptation?
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What is the primary characteristic of an open loop system?
What is the primary characteristic of an open loop system?
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Which of the following is an example of a closed loop system?
Which of the following is an example of a closed loop system?
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What is the term for the process by which the body maintains a stable internal environment?
What is the term for the process by which the body maintains a stable internal environment?
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What is the term for the ability of the body to adapt to changes in the environment?
What is the term for the ability of the body to adapt to changes in the environment?
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Which of the following is NOT an example of a closed loop system?
Which of the following is NOT an example of a closed loop system?
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What is the primary function of a detector in a closed loop system?
What is the primary function of a detector in a closed loop system?
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What is the term for the process by which the body responds to changes in the environment by changing its internal environment?
What is the term for the process by which the body responds to changes in the environment by changing its internal environment?
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What is the term for the ability of the body to maintain a stable internal environment despite changes in the external environment?
What is the term for the ability of the body to maintain a stable internal environment despite changes in the external environment?
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What does the term allostasis describe?
What does the term allostasis describe?
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What is the role of catecholamines and cortisol in the process of allostasis?
What is the role of catecholamines and cortisol in the process of allostasis?
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What is the result of repeated cycles of allostasis and inefficient turning-on or shutting off of responses?
What is the result of repeated cycles of allostasis and inefficient turning-on or shutting off of responses?
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What is an example of a manifestation of allostatic load?
What is an example of a manifestation of allostatic load?
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What is the relationship between primary stress mediators and cardiovascular disease?
What is the relationship between primary stress mediators and cardiovascular disease?
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What is the result of persistent activation of blood pressure elevation in dominant male cynomologus monkeys?
What is the result of persistent activation of blood pressure elevation in dominant male cynomologus monkeys?
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What accompanies social confrontations and leads to atherosclerosis?
What accompanies social confrontations and leads to atherosclerosis?
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What is the main difference between allostasis and homeostasis?
What is the main difference between allostasis and homeostasis?
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Study Notes
Types of Allostatic Overload
- Overstimulation by frequent stress, resulting in excessive stress hormone exposure
- Failure to inhibit allostatic responses when they are not needed or inability to habituate to the same stressor, resulting in overexposure to stress hormones
- Inability to stimulate allostatic responses when needed, leading to hyperactive inflammatory cytokines and other types of wear and tear
Indicators of Allostatic Overload
- Cardiovascular pathology
- Metabolic deterioration
- Brain atrophy
- Immune dysfunction and vulnerability to viral impact
- Bone demineralization
- Vulnerability to preterm delivery
- Changes in the sensitization processes
The Concept of Adaptation (Heterostasis)
- Adaptation is a bilateral process in which the organism adapts to the environment and the environment is modified
- Examples: grazing animals vs. herbs, trees vs. soil, and birds adapting to high altitudes
Adaptation to Climatic Changes
- Long-term adaptation to cold
- Physiological adaptation: tribes adapted to freezing cold temperatures (e.g. Gauchos of S. America, Aborigines of Australia)
- In cold climate: 25-50% loss in BMR, cooling of peripheral and deep lying tissues, reduced average skin temperature, and reduced heat loss
The Concept of Allostasis
- Allostasis refers to the adjustment of the cardiovascular system to resting and active states of the body
- It is the process of maintaining stability through acute change
- Allostasis addresses basic regulatory systems and examines the behavior of bodily regulation under constraint
Allostatic Load
- Repeated cycles of allostasis and inefficient turning-on or shutting off of responses lead to wear and tear (allostatic load) of the body
- Allostatic load refers to the cost of adaptation to a stressful environment eliciting repeated and sometimes prolonged adaptive responses
- Manifestations of allostatic load include: decreased cognitive function during aging, abdominal obesity, increased risk for hypertension, cardiovascular disease, insulin-dependent diabetes, and decreased immune responses
Loop Systems
- Open loop system: control is highly dependent on precise knowledge of disturbances, and input is not affected by output
- Closed loop system (feedback loop): communication occurs between biological components, and input is affected by output, favoring stability
Examples of Closed Loop Systems
- Temperature regulation
- PaCO2 regulation
- Blood pressure regulation
- Regulation of plasma volume
- Regulation of acute haemorrhage
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Description
Learn about allostasis, a concept introduced by Sterling and Eyer in 1988, which describes the body's adjustment to different states and its impact on cardiovascular system regulation.
