Chapter One: The Study of Body Function
Chapter Outline (Notes and figures adopted from Human Physiology 13th Edition by Stuart Ira Fox)
1.1 Introduction to Physiology
1.2 Homeostasis and Feedback Control
1.3 The Primary Tissue
1.4 Organs and Systems
1.1 Introduction to Physiology
• Physio...
Chapter Outline (Notes and figures adopted from Human Physiology 13th Edition by Stuart Ira Fox)
1.1 Introduction to Physiology
1.2 Homeostasis and Feedback Control
1.3 The Primary Tissue
1.4 Organs and Systems
1.1 Introduction to Physiology
• Physiology is the study of biological function; of how the body works.
– Concerned with the normal function of cells
– It emphasizes mechanisms – how it works.
– It explains mechanisms using cause and effect sequences.
– Data explaining these cause and effect sequences are derived from scientific experiments.
• ______________ is concerned with how physiological processes are altered in disease or injury.
– Aids understanding of normal processes
• Comparative physiology is the study of the differences and similarities in the functions of
invertebrates and vertebrates.
– It has benefited the study of human physiology and has aided in the development of
pharmaceutical drugs.
The Scientific Method
• All that we know about physiology has been gained by application of the scientific method.
– Making observations; forming testable hypotheses; designing and conducting experiments
or making more observations; analyzing the data; replicating results many times before a
conclusion is accepted.
– Several verified hypotheses may become a general theory.
Measurements, Controls, and Statistics
• Good physiological research requires:
– Quantifiable measurements.
– An experimental group and a _____________________.
– Statistical analysis
– Review and publication by a peer-reviewed journal.
Developing Pharmaceuticals
• The development of new pharmaceutical drugs can serve as an example of how scientific method is
used in physiology and its health applications.
• Research often begins by studying the effects of a chemical on cells in vitro (in a culture dish).
• Next, studies are done in animals to see if the same effects occur in vivo (in a living creature) and if
there are any toxic side effects.
– Animal trials may take several years.
• Clinical trials in humans follow successful safety and efficacy studies in animals.
1
This study source was downloaded by 100000850647391 from CourseHero.com on 08-24-2022 00:50:08 GMT -05:00
, • Phase I clinical trials test the drug on healthy human volunteers to test for safety and metabolism.
• Next the drug goes into phase II clinical trials to test its effectiveness on people with the particular
disease.
• Phase III clinical trials are conducted on a large number of people to include both sexes, many age
groups and ethnicities, and people with more than the one health condition. From here the FDA can
approve the drug for sale.
• Phase IV trials test other applications for the drug.
1.2 Homeostasis and Feedback Control
• Homeostasis is the maintenance of constancy of the internal environment.
• The main purpose of our physiological mechanisms is to maintain homeostasis.
• Significant deviations from homeostasis indicate disease.
• The components of the internal environment that are regulated:
– Composition (oxygen, carbon dioxide, sodium, potassium, calcium…)
– Temperature
– Volume
Homeostasis: Terms
• Regulated variable - that aspect which is maintained (composition, temperature, volume).
– Examples: Speed of a car, blood glucose concentration, blood pH, plasma levels of sodium
• Negative feedback – if a regulated variable increases, the system responds by making it decrease; if a
regulated variable decreases, the system responds by making it increase.
• ______________ – the normal “desired” value of a regulated variable.
• Error signal – the difference between the actual value and the set point.
Homeostasis: Components
• Sensors – cells (usually neurons) that are sensitive
to the variable in question.
• Integrating center – receives signals (input) from
sensors and compares the regulated variable to
the set point and relays signals (output) to the
effectors.
• ______________ – cells, tissues, or organs that
bring about the final response (muscles or glands).
Mechanism of Negative Feedback Loops
• Homeostasis is accomplished most often by negative feedback loops.
• The regulation moves in the opposite direction from the change.
• It makes the error signal smaller.
• This is a continuous process, always making fine adjustments to stay in homeostasis.
2
This study source was downloaded by 100000850647391 from CourseHero.com on 08-24-2022 00:50:08 GMT -05:00
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller YANCHY. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $9.49. You're not tied to anything after your purchase.
