Chapter 1 & 2

BIOL 3320
Principle of Animal Physiology
• Instructor: Yong Zhu
• Textbook: Sherwood, Klandorf, Yancey “Animal Physiology”
• References:
– Eckert Animal Physiology (2002) 5th
Course Introduction
• What is Principle of Animal Physiology
– studies functions of organ systems, tissues and
molecules in multicellular animals.
– deals physiological functions of animals and
adaptation to various physiological and
environmental conditions.
Course Introduction
• What is Principle of Animal Physiology
– Studies various organ systems such as nervous
system, endocrine system, circulation system,
respiratory system, muscle movement,
osmoregulation, metabolism, growth, aging and
– will be discussed from homeostatic, comparative, and
adaptive aspects.
Course Introduction
• Course Objectives:
– structures and functions of vertebrate organ
– physiological processes and molecular
– regulation, adaptation, signaling pathways etc
Course Introduction
• 5 Test periods, 100 points for each test periods
(exam 70, quiz 10, attendance 20) ,
attendance 20)
• Final exam 300 points
• Total points
800 points
Course Introduction
• Keys to success
– Come to Class
– Keep up with the readings
– talk to the professor
If you find you are having difficulty with the materials, DO NOT
WAIT until you have problems with an exam before coming in for help
• Contact
– email: [email protected]
– tel: 328-6504
• office hour:
– Tuesday/Thursday 2-3 PM or By appointment
Fig. 1-11, p.18
Why study animal physiology?
•Scientific curiosity
•Commercial and agricultural application
•Insights into human physiology
Function depends on structure
•Evolution through natural selection leading to an organism whose
physiology, anatomy and behavior are matched to demands of its
environment. Adaptation typically occurs in a gradual manner over
many generations
Physiological, biochemical, or anatomic change within an
individual animal during its life that results form that animal’s
chronic exposure in its native habitat to new, natural occurring
environmental conditions.
Refers to the same process as acclimatization when changes are
induced experimentally in the laboratory or in the wild by an
the tendency of organisms to regulate and
maintain relative internal stability
Fall in body temperature
below set point
* Relieves
nerve cells
control center
Skeletal muscles
(and other effectors)
Heat production through
shivering and other means
Fall in body temperature
below set point
(negative feedback)
Fig. 1-8c, p.13
Signal from mature fetus
Uterus begins contractions
Mother’s hypothalamus
Pituitary gland
Oxytocin secreted
(c) Example of positive feedback: birth of a mammal
Fig. 1-10c, p.17
The return of output to the input part of a system.
In negative feedback, the sign of the output is
inverted before it is fed back to the input so as to
stabilize the output. In positive feed back, the
output is unstable because it is returned to the
input without siganl inversion, and thus becomes
self-reinforcing, or regenerative.
August Krogh principle:
Choose appropriate animal to study a defined
physiological system.
Physiological Methodology
Methods in physiology research
Physiological problems can be approached by
physiological, pharmacological, biochemical,
cellular and molecular techniques
Frequently asked questions
Where is the signaling molecules produced?
What is the structure of the molecule?
How is the process controlled?
What are the physiological roles?
What are the mechanisms of action?
Physiology Methodology
• Where is the signaling molecules produced?
Surgical methods: removal and replacement
Use antibodies to locate the molecules involved in
physiological process
Use nucleotide probes to locate the mRNA for the
molecules involved in physiological process
Physiology Methodology
Physiology Methodology
Physiology Methodology
In situ
Physiology Methodology
• What is the structure of the molecules?
– Is it a peptide?--digest with a protease
– is it extractable in organic solvents?—
steroids and eicosanoids
– Purification
– cDNA cloning (peptide molecules)
Physiology Methodology
Physiology Methodology
Physiology Methodology
• How is process controlled?
– Regulators to be tested
» in vivo: whole animal experiment
» in vitro: cell and tissue culture
– measurement:
Physiology Methodology
• Radioimmunoassay (RIA)
– principles: high-affinity, high-titer anti-hormone
antibodies are able to bind radioisotope-labeled
hormone in a reversible manner and such binding is
competitively inhibited by unlabeled hormone
– highly sensitive: detect hormones in minute
– highly specific: do not cross-react with other hormones
Physiology Methodology
Physiology Methodology
A Sandwich ELISA (1) Plate is coated with a capture antibody; (2) sample is
added, and any antigen present binds to capture antibody; (3) detecting antibody is
added, and binds to antigen; (4) enzyme-linked secondary antibody is added, and
binds to detecting antibody; (5) substrate is added, and is converted by enzyme to
detectable form.
Physiology Methodology
• What are the physiological roles
Removal and replacement therapy
remove the organ and observe consequences
 In vivo and in vitro approaches
use antibody to abolish endogenous molecules
Physiology Methodology
Pharmacological studies
use agonists and antagonists
Molecular and genetic techniques
Knockdown approaches: decrease the production
of molecule
gene knockout: deleting the gene encoding a
hormone or its receptor
overexpression: increasing the amount of
hormone production
Physiology Methodology
• What are the mechanisms of action?
radioreceptor assay: binding characteristics
receptor cloning: primary structure
gene knockout and knockdown: function
Physiology Methodology
Second messengers and downstream signals
enzyme assay: phosphorylation
electrophysiological methods: ion movement
pharmacological studies:
Physiology Methodology
• Why do we clone
proteins and receptors
– provide structural
information, can be
used to synthesize
small peptides
– production of
hormones by
recombinant DNA
Physiology Methodology
– Transgenic studies
Physiology Methodology
• Common Vertebrate models used in physiological
– Bony fish: largest and most diverse group; some unique
features; great models to study neuroendocrine
regulation and early development
– Amphibians: good model to study hormones in early
– Birds: chicken are common models
– Mammals: focus of endocrine research; e.g. mouse, rat
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