Ch 2 - Homeostasis Flashcards
What are 3 levels of Homeostatic Control
- Intracellular
- Intrinsic
- Extrinsic
Intracellular Control
Operates at cell level.
Regulates functions within the cell by way of genes and enzymes.
Intrinsic Control
Operates at tissue & organ level.
Auto regulation
I.e. Heart- when it’s stretched, the muscle automatically contacts with more force.
Extrinsic Control
Operates at system & organism level Operates outside the controlled organ.
Organ to organ
Involves nerves & hormones
Homeostasis
Standing or staying the same.
Bodies ability to maintain constant conditions inside the body, despite external changes.
Set Point
Range of normalcy
4 Basic components of control in every feedback loop
- Sensor mechanism
- Integrator or control center
- Effector mechanism
- Feedback
Sensor mechanism
When deviate from set point, sensors generate a signal (nerve impulse or release of hormone) to integrator.
Sensory nerves or endocrine glands.
Integrator
Control center
Receives input from sensor.
Analyzes the info and sends approp signal to effector mechanism.
Compares variable to normal set points for homeostasis.
i.e medulla, hypothalamus
Effectors
Organs such as muscles or glands that directly influence or control physiological variables.
Action that increases or decreases variables like temp, HR, BP to keep in normal range.
Feedback
Effector activity to the sensory mechanism then completes the loop.
Gives information back. Reports.
Only happens at extrinsic control.
Positive feedback Loop
Adds to or reinforces the change that is occurring.
Can be harmful.
Disrupts homeostasis.
Amplifies the change.
Negative Feedback Loop
Produces and action opposite to the change that is activated by the system.
Maintains homeostasis
Feed Forward Loop
Changes triggered by anticipation.
Digestive system prepares when you smell food.
