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What does the term homeostasis refer to?
The maintenance of an organisms internal environment within set parameters.
How can the body maintain homeostasis?
The body uses regulatory systems to keep the factors of its internal environment in check. The nervous and endocrine systems involved in creating feedback loops to detect and take action in response to changes within the organism.
What are the three basic components of a feedback loop?
- 1. Receptor.
- 2. Control centre.
- 3. Effector.
What is a negative feedback loop? How does it work?
A negative feedback loop attempts to counter a deviation from a set parameter when it occurs.
The receptor detects a deviation from the parameters and notifies the control centre which creates a response by activating an effector. The effector takes an action that will counter the deviation.
Eg. When your body is hot skin receptors detect the deviation in temperature, they signal the hypothalamus which may activate sweat glands to cool the body.
What is a positive feedback loop? How does it work?
A positive feedback loop attempts to increase a deviation from a set parameter when it occurs.
A receptor detects the deviation and notifies a control centre, which creates a response activating an effector. The effect takes an action that will intensify the deviation. A limiting factor will eventually cease the loop or the system will collapse.
Eg. When the skin is cut, chemicals are released that activate platelets. The platelets begin to clot the wound, releasing chemicals when they activate, this is the start of the positive feedback loop. These chemicals stimulate more platelets, which release more chemical when activated, creating a cycle. The cycle stops when the bleeding stops and the platelets cannot activate (limiting factor).
Other examples: Breastfeeding, giving birth.
What is a homeostatic imbalance? What can it cause?
A homeostatic imbalance occurs when one or more regulatory systems fails to maintain the internal environment within set parameters.
This can lead to disease, disorder and eventually death.
What is a disorder?
An abnormality in a structure or function.
What is a disease?
A disease alters the structure and/or function of body components in a specific way that results in a set of signs/symptoms.
What is the difference between local and system diseases?
A local disease only effects on part of the body, a system disease affects multiple body parts.
- Eg. Skin infection: Local
What is a sign?
- A sign is an objective, measurable observational change that can indicate disorder or disease.
- Eg. Blood pressure, elevated heart rate, visible swelling.
What is a symptom?
A symptom is a subjective experience that indicates the presence of a disorder or a disease.
Eg. Pain, nausea, headache, anxiety.