Transcript 1 introduction - bloodhounds Incorporated

Human Physiology
Welcome to your first day of class!!
You Can Contact Me
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[email protected]
760-245-4271, ext. 2658
Physiology is…
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The study of the function of all plants
and animals in their normal state.
An integrative science
Function and Process:
Teleological vs. Mechanistic
Approach to Science
What is the purpose or function?
Why does something exist?
Why does it need to be done?
What are the processes involved?
How does something work?
Distinguish between
Process & Function
How do we breathe?
Why do we breathe?
How does blood
flow?
Why does blood
flow?
How do RBCs
transport O2?
Why do RBC
transport O2?
Integrate both for complete picture!
Key Concept in Physiology:
Homeostasis
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Homeostasis refers to
maintaining relative
constancy in a system.
The
ability of the body to
survive in a challenging and
changing environment by
keeping the internal
environment relatively stable
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The change in the
environment signals a
response by the body
The response is to
bring the body back
to homeostasis
–
If possible!
Homeostasis

A given system tends
to stay in equilibrium
or balance despite
influences that cause
disequilibrium.
Negative Feedback
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Negative Feedback Loops are Homeostatic
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Negative feedback loops can restore the normal
state but can’t prevent the initial disturbance.
Negative Feedback
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Refers to the corrective effect produced by the
feedback signal. The effect must be to
REDUCE the DIFFERENCE BETWEEN the
SET POINT and the CONTROLLED
VARIABLE
Negative Feedback
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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
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If possible!
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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
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Must have a
switch
or it becomes
pathological.
Positive Feedback
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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.
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http://www.youtube.com/watch?v=Vae5CcaP
N_8&feature=related
The Science of Physiology
is
based on the Scientific Method
Review
1.
2.
3.
Basic steps of scientific method
Parameters to consider
Experimental design
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
Example:
Company has found new artificial
sweetener (S)
Prior knowledge:
Some food additives are not safe.
Hypothesis: ?
Experiments: ?
Collect and analyze data
Conclusion
Animal vs. Human Experimentation
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In Physiology most knowledge is derived from _______
experimentation.
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Sometime human experimentation is necessary.
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Difficulties of Human Experimentation:
 Very
dissimilar test subjects
 Psychological aspects (placebo and nocebo effects)
 Ethical questions (is it o.k. to withhold potential drug from
seriously ill?)
Focus on . . . . (Concept)
Mapping
1.
Structure – function maps
2.
Process maps or Flow charts
Follow process in sequence