Lesson 2: Homeostasis: Negative & Positive Feedback Flashcards
What is homeostasis?
The ability to maintain a constant internal environment in response to environmental changes.
What is the physiological constancy of the body despite external fluctuations called?
Homeostasis.
What are examples of homeostasis?
- Blood pH (7.35 to 7.45)
- Body Temperature (36.4°C - 37.6°C)
- Blood Pressure (120/80)
- Blood Glucose (70-100 mg/dL)
What are the three functional components of homeostatic control systems?
- Receptor
- Control Center
- Effector
What role does the receptor play in a homeostatic control system?
Detects change (detecting the stimulus).
What is the function of the control center in homeostasis?
Processes information from the receptor.
What is the role of the effector in homeostasis?
Produces an appropriate response, sometimes referred to as the adaptive response.
How is homeostasis controlled?
It relies on feedback mechanisms.
What is negative feedback?
A mechanism that diminishes or counteracts the stimulus to re-establish homeostasis.
What happens once the normal state is regained in negative feedback?
The receptor stops signaling the control center.
In a negative feedback system, what is an example of a controlled condition?
Blood pH, temperature, or glucose levels.
What is positive feedback?
A mechanism where the stimulus causes an increase, leading to a greater adaptive response.
What are some examples of positive feedback?
- Breastfeeding (lactation)
- Childbirth
- Blood clotting
What hormone is involved in the positive feedback loop during childbirth?
Oxytocin.
What triggers the release of oxytocin during childbirth?
Pressure from the baby’s head against the cervix.
What is the main control center involved in childbirth?
Hypothalamus and pituitary gland.
What happens in stage II shock?
There is a 15-30% loss of blood volume causing a positive feedback loop that reduces blood pressure.
What is the response of the vasomotor center during shock?
Decreased activity, leading to decreased vasoconstriction and further decreased blood pressure.
True or False: Positive feedback systems are more common in the body than negative feedback systems.
False.
Fill in the blank: The _______ is responsible for monitoring and controlling body conditions in negative feedback.
Control center.
What is the name of the part of the brain that controls our body?
Hypothalamus
