Regulatory Mechanisms Review (1/2) Flashcards
State what cells are constantly experiencing
Changes in their environment (both internal and external)
State where the internal environment must always remain
Within tolerable limits
Describe homeostasis
Maintenance of a constant internal environment
State what allows for the achievement of homeostasis within organisms
Negative feedback loops
Describe negative feedback loops
Receptors detect a change in the internal environment and receptors work to reverse the direction of the change to achieve equilibrium
State the 2 main systems involved in the maintenance of homeostasis
- endocrine system
2. nervous system
State what both the nervous and endocrine system have in common
Rely on chemical communication
State what negative feedback loops promote within the internal environment
Stability
Provide 1 example of a negative feedback loop in action
Regulation of blood sugar levels by insulin
State the 5 steps involved in a negative feedback loop
- stimulus
- receptor
- control center
- effector
- response
State what occurs in the control center
Information from a sensory receptor is received and compared with a set-point and an appropriate response is initiated
State what the fluctuations surrounding the variable set point are determined by
- receptor sensitivity
- tolerance of control center
- effector efficiency
State the 2 types of feedback loops
- positive
2. negative
Describe positive feedback loops
Force an organism out of homeostasis by maintaining the direction of the stimulus
Provide 1 example of a positive feedback loop in action
Childbirth (hormone oxytocin stimulates the uterus to contract - contractions strengthn due to strengthened stimulation)
