Human Biology
Welcome To Your First Day of Class
Anatomy
 The study of form
Physiology is…
¤ The study of the function of all plants
and animals in their normal state.
¤ An integrative science
Key Themes in Physiology:
Homeostasis
“The Wisdom of the Body”
Homeostasis
 Negative Feedback Loops are Homeostatic
 Negative feedback loops can restore the normal state
but can’t prevent the initial disturbance.
Negative Feedback
 The body maintains a set point until there is a
perturbation.
 The change in the environment signals a response by
the body
 The response is to bring the body back to homeostasis
 If possible!
Positive Feedback
 Positive Feedback is NOT homeostatic
 Positive Feedback reinforces the initial stimulus
rather than decreasing or removing it.
 The response sends the variable being regulated
even farther from its normal value
 This triggers a vicious cycle of ever-increasing
response sending the system out of control
temporarily
 Must have a “shut off” switch or it becomes
pathological.
Flow Diagram of the
Scientific Method (know for test)
Basic Steps of Scientific Method:
Observation (and/or study of prior
knowledge)/Question
Hypothesis
Experimentation
Collection and analysis of data (can you
replicate results?)
Conclusion: reject or accept hypothesis
theory
Scientific Theory
 A scientific theory is a concept supported by a broad
range of observations, experiments, and conclusions.
Example:
What makes up human scent
Prior knowledge:
Mice smell each other using urine MHC
Hypothesis: ?
Experiments: ?
Collect and analyze data
Conclusion
The Process of Science
A Controlled Study
 Experiments in controlled studies have two types of
groups:
 Control Group (for comparison)
 Experimental Group ( 1 variable
manipulated)
The Process of Science
A Controlled Study
 Variables
 The experimental
variable
(independent variable) is manipulated
by the investigator. All other factors
remain identical.
The Process of Science
A Controlled Study
 Variables
 The experimental variable (independent variable) is
manipulated by the investigator. All other factors
remain identical.
 The
response variable (dependent variable)
represents the result of the manipulation of the
experimental variable. (what we are testing for and
hope to “quantify” mathematically)
An Experiment
 HYPOTHESIS: Bloodhounds are able to trail
people because of their unique smell, which is
genetically controlled.
An Experiment
 HYPOTHESIS: Bloodhounds are able to trail
people because of their unique smell, which is
genetically controlled.
 PREDICTION: Bloodhounds will be able to
trail identical twins, but the dog will not be
able to tell the difference between the twins.
An Experiment
 Conclusion: The hypothesis was supported. When
scent was taken from one twin the bloodhounds were
able to trail the twins, but could not tell the difference
between the genetically identical twins.
Animal vs. Human Experimentation

In Physiology most knowledge is derived from
_______ experimentation.

Sometime human experimentation is necessary.

Difficulties of Human Experimentation:
 Very
dissimilar test subjects
 Psychological aspects (placebo and nocebo effects)
 Ethical questions (is it ok to withhold potential drug from
seriously ill?)
Animal Research
Science and Social
Responsibility
Science and Social
Responsibility
• Technology is the application of knowledge
for a practical purpose.
Science and Social
Responsibility
• Technology is the application of
knowledge for a practical purpose.
•
Technology has both benefits and drawbacks.
Science and Social
Responsibility
• Technology is the application of
knowledge for a practical purpose.
•
Technology has both benefits and drawbacks.
•
Ethical and moral issues surrounding the use
of technology must be decided by everyone.