BIOL 3320 Principle of Animal Physiology
• Instructor: Yong Zhu• Textbook: Sherwood, Klandorf, Yancey “Animal Physiology”
(2005)
• 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 reproduction
– will be discussed from homeostatic, comparative, and adaptive aspects.
Course Introduction
• Course Objectives:– structures and functions of vertebrate organ
systems– physiological processes and molecular
mechanisms– regulation, adaptation, signaling pathways etc
Course Introduction
Evaluation:
• 5 Test periods, 100 points for each test periods (exam 70, quiz 10, attendance 20) , attendance 20)
• Final exam300 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
Adaptation
•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
•Acclimatization
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.
•Acclimation
Refers to the same process as acclimatization when changes are induced experimentally in the laboratory or in the wild by an investigator
Homeostasis:
the tendency of organisms to regulate and maintain relative internal stability
Fall in body temperature below set point
Temperature-monitoringnerve cells
Temperaturecontrol center
Skeletal muscles(and other effectors)
Heat production throughshivering and other means
Fall in body temperature below set point
SetPoint
* Relieves
(negative feedback)
Fig. 1-8c, p.13
Uterus begins contractions
Stretchsensors
Mother’s hypothalamus
Pituitary gland
Contractionsenhanced
(c) Example of positive feedback: birth of a mammal
Oxytocin secreted
Signal from mature fetus
Fig. 1-10c, p.17
Feedback:
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.
Methods in physiology researchPhysiological problems can be approached by physiological, pharmacological, biochemical, cellular and molecular techniquesFrequently 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?
Physiological Methodology
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
immunohistofluorescence
Physiology Methodology
In situ hybridization
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
• How is process controlled?
– Regulators to be tested
» in vivo: whole animal experiment
» in vitro: cell and tissue culture
– measurement:
» RIA
» ELISA
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 concentration
– 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 rolesRemoval and replacement therapy
remove the organ and observe consequences
In vivo and in vitro approaches
Immunoneutralization
use antibody to abolish endogenous molecules action
Physiology Methodology
Pharmacological studies
use agonists and antagonistsMolecular 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?
Receptor
radioreceptor assay: binding characteristics
receptor cloning: primary structure
gene knockout and knockdown: function
Physiology Methodology
Second messengers and downstream signalsenzyme 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 techniques
Physiology Methodology
– Transgenic studies
Physiology Methodology
• Common Vertebrate models used in physiological research– 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 development
– Birds: chicken are common models– Mammals: focus of endocrine research; e.g. mouse, rat
Physiology Methodology