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Introduction to Anatomy and Physiology

Science and Homeostasis

I.  What is Science?

It is a process of observing and studying things in our world.

A).  Levels of Science

1). Scientific Law:

2). Theory:

It is not a guess and it does not mean "I think"

3). Hypothesis:


4).  Observation


B.  Scientific Method

Step 1: Observation

Step 2: Make a hypothesis.

Step 3: Design a controlled experiment.



Step 4: Repeat the experiment.

Step 5: Analyze the results.

Step 6: Draw conclusions

Step 7: Report the results in a peer review journal


scientific method

C.  Science vs. Pseudo-Science

Pseudo-Science takes on the appearance of science but the purpose is to mislead.

Characteristics of Accepted Science

Characteristics of "Shoddy" Science or Pseudo-Science

Uses hypothesis that can be tested using the scientific method

Hypothesis can not be tested using the scientific method

Stated conclusions based on supporting evidence and numerous studies

Easy acceptance of strongly stated opinions

Careful attention to detail


Peer review of conclusions

Conclusions that ignore peer review

Strong basis in ethics

Shoddy science, falsified data, plagiarized data.

Depend on peer review journals for the acceptance of ideas

Depend on popular media for the acceptance of ideas

Continually tests principals and assumptions

Does not test assumptions

Purpose is to clarify

Purpose is to mislead or confuse


D). How to Identify Pseudo-Science

1).  Doubt everything

2).  Anecdotes arenít data

3).  Demand definitions.

4).  Know the source of your information 

5).  Statistics donít prove cause or effect.

6).  Statistics arenít science. 

7).  The burden of proof is on the person trying to prove a point

8).  Speculation isnít science.


II.  Anatomy & Physiology





III). Hierarchy of Life


Chemical level:

down arrow

Cellular level:

diwb arrow

Tissue level:

Down Arrow

Organ levels:

Down Arrow

Organ system level:

Down Arrow




Hierarchy of Life

IV). Maintenance of life

A). Maintain Boundaries

B). Movement

C). Responsiveness

D). Digestion

E). Metabolism

F). Excretion

G). Reproduction

H). Growth

I).  DNA


V). Survival Needs

A). Nutrients

B). Oxygen

C). Water

D). Body Temperature

E). Atmospheric Pressure

F). pH


VI). Maintaining Homeostasis

A). Definition

Homeostasis :

B). Homeostatic Control Mechanisms

 receptor sensor (affector) > control center    >  stimulus response  (output) --->output eventually is recorded as input

1). Receptor

2).  Control Center

3). Effector

causes a response or an output

C). Types of Control

1). Negative Feedback

When the output increases  it feedbacks into the system and inhibits input  . Thus lowering the output.

negative feedback


2). Positive Feedback

An increase output results in the input increasing which increases the output.