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  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 Observation (and/or study of prior knowledge)/Question Hypothesis Hypothesis Experimentation Experimentation Collection and analysis of data (can you replicate results?) Collection and analysis of data (can you replicate results?) Conclusion: reject or accept hypothesis 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 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

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.