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:

HomeostasisThe ability of the body to

survive in a challenging and changing environment by keeping the internal environment relatively stable

“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.