Introduction to Physiology and Homeostasis Flashcards
Physiology
The study of the normal functioning of a living organism and its component parts, including all its chemical and physical processes
Cells
Smallest unit of structure capable of carrying out life processes
Tissue
Collection of cells carrying out related functions
Organ
Formation of tissues into a structural and functional unit
Organ System
integrated groups of organs
Emergent Properties
Properties of a complex system that cannot be explained by a knowledge of a systems individual components
Examples of Emergent Properties
Emotion or intelligence in humans cannot be predicted from knowing the individual properties of nerve cells
Teleological Approach
Function or “Why”
Example of a Teleological Approach
Why do red blood cells transport oxygen?
Mechanistic Approach
Mechanism or “How”
Example of mechanistic approach
How do red blood cells transport oxygen?
Physiology focuses on
Mechanistic Approach
Homeostasis
The ability to maintain a relatively stable internal environment despite exposure of external variability
Two main principles of physiology
Homeostasis and regulation of the internal environment are key principles in physiology
homeo
like or similar
homo
same
Stasis
condition(not a static state)
What is considered as the internal environment of the body
Extracellular Fluid (ECF)
Extracellular Fluid (ECF)
Surrounding cells is a buffer between cells and the external environment
Dynamic Steady State
Materials constantly moving back and forth
Law of mass balance
If the amount of s substance in the body is to the remain constant, any gain must be offset by an equal loss
Two types of control systems for Homeostasis
Local
Reflex
Steps for a control system
Input signal - Integrating Center - Output Signal - Response
Local Control
Restricted to tissues or cells involved - Distinct to a small area
Example of local control
Key: Very Picky and localized
Active cells - Reduced O2 Levels
Endothelial cells send local signals
O2 levels in tissue restored
Reflex Control
Uses long distance signalling
Changes widespread throughout the body (systemic) use more complex control systems to maintain homeostasis
Two parts of Reflex control
Response loop
Feedback loop
What parts does the Reflex control system use
Response loop
Feedback loop
Which systems does the reflex control use
Nervous and Endocrine as they are long distance systems
Response loop
Stimulus - Response
Feedback loop
Modulates the response loop
Feeds back to ultimately influence the input ; so changes the stimulus
Types of Feedback loop
Negative feedback
Positive feedback
Feedforward control
Negative Feedback Loops
A pathway in which the response opposes or removes the stimulus signal is known as negative feedback
Stabilizes a system
Homeostatic
Can restore the initial state but cannot prevent the initial disturbance
Positive Feedback loops
Are not homeostatic
Increases the stimulus through the response
Example: Cervical stretch
