biol 3320 principle of animal physiology instructor: yong zhu textbook: sherwood, klandorf, yancey...

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: zhuy@ecu.edu– 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