Chapter 1 Lecture 3 - Characteristics of Life, Homeostasis, Feedback, and Gradients Flashcards
Stimulus
Change to activate reaction
What does the stimulus activate
Afferent signal
Controller
Typically the brain, processes info and sends output
What does the controller send
Efferent signal
Gradient Flow
Movement of things from high to low
Characteristics of Life
- Organization
- Metabolism
- Responsiveness
- Homeostasis
- Development
- Reproduction
- Evolution
Organization
Specific relationships and functions within the body
Metabolism
Chemical reactions
Responsiveness
Ability to sense and react to changes
Homeostasis
Stability
Development
Changes over time
Growth
Change in size and/or number of cells
Differentiation
Change of cells from general to specialized
Reproduction
New cells / organisms
Evolution
Change over time due to genetic mutations
Set Point
Ideal normal values of a variable
Normal Range
Values of a variable in which it is in normal function, as it fluctuates around set point
Equilibrium
Dynamic state of balance achieved by maintaining homeostasis
What feedback loops oppose change
Negative
What feedback loops amplify change
Positive
Stimulus in terms of set point
Deviates set point
Receptor
Monitors value of a variable
Control Center in terms of Set Point
Establishes set point
Effector
Drives response, and changes value of a variable
Response
Produced by effector as a reaction to a deviation from the set point
Steps to feedback systems
- Stimulus produces change
- Receptor detects change
- Afferent signal sent through afferent pathway to control center
- Control center sends info through efferent pathway to the effector
- Effector reduces effect of stimulus to return to the set point through a response
Positive feedback loop
System that when stimulus happens, a greater change occurs, climatic event with rapid change, leads away from homeostasis
Gradient
Difference between two points
Example of Gradient
- Sodium levels in vs out of cell
2. Oxygen levels in lung vs blood
Types of gradients
- Pressure
- Concentration
- Electrical
- Thermal
Why does flow typically move from high to low?
It is easier because it is a passive process. It does not require any energy input.
