01 Animal Physiology - Foundations of Physiology

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Principles of Animal Physiology

Introduction

What is LIFE?

LIFE

Things organized to use energy and raw materials

from their environment, maintain their integrity and

reproduce.


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Introduction

What is PHYSIOLOGY?

PHYSIOLOGY is FUNCTION!!!

PHYSIOLOGY is an INTEGRATIVE science

Uses Anatomy, Physics, Chemistry . . .

SUBDISCIPLINES of Animal Physiology

Comparative; Environmental; Evolutionary;

Development; Cell ...


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Introduction

Why study Animal Physiology?

Curiosity - I just want to know.

Applications - I want to profit from what I know.

Insights - Now what do I do with what I know?

Human Physiology share:- The same fundamental biological processes.

A common set of laws of physics and chemistry.

The same principles and mechanisms of genetics. A linked evolutionary history.

August Krogh principle:

For a large number of physiological problems, there will besome animal on which it can be most conveniently studied.


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Introduction

A physician and medical researcher who

understands physiology - both its potentialcontributions and limitations -is better equipped

to make intelligent and perceptive decisions

about the body.


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Introduction

Physiological processes arise through evolution

Natural selection - process by which traits thatenhance a species survival are able to produce moresurviving members than others not having those

characteristics Mechanistic (proximate) explanation

How does it work? Process by which events occur.

Traditional core of the physiological sciences Evolutionary explanation

How did it evolve to be the way it is?

Teleological approach Why does it work? Purpose for the event/system.

Sometimes assumes that features are always logically evolved


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Introduction

The Hypotheticodeductive Method (Scientific Method)

Science is a way of thinking.

Science is a logical way to investigate the universe.

Observation

And ask questions Experimentation

Hypothesis

testable and falsifiable

Control

Data

Analysis

l f l h l


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Use of Animals in Research

Animal Rights vs Animal Welfare

Animal Welfare - have changed drastically over theyears

Physiologists accept certain moral responsibilities

Animals are used only for worthwhile experiments All necessary steps are taken to minimize pain and

distress

All possible alternatives to the use of animals areconsidered

Institutional Animal Care and Use Committee

Animals rights - Animals have the same legal andmoral rights as humans do

P i i l f A i l Ph i l


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Levels of Organization

To understand how the body

unctions and coordinates itsactivities, we will first examine

its components. Organizational levels

Know and define these levelsup to the organism



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Basic cell functions include:

Self-organization: Using resources from the

environment to create the cell

Self-regulation: Maintain self-integrity in the face ofdisturbances

Self-support and movement: Having structrures that

give specific form to the cell and to move materialswithin the cell or to move the cell itself

Self-replication: Reproducing to carry on thespecies, and to repair damage



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Four primary tissue types:

Muscular tissue - specialized for contraction andorce generation Skeletal, cardiac and smooth

Nervous tissue - specialized for initiation andransmission of electrical impulses

Epithelial tissue - specialized in the exchange of

aterials Sheets and secretory glands

Connective tissue - have relatively few cells

ispersed within an abundance of extracellualar

aterial that the secrete



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Homeostasis

Most cells are NOT in contact with the external

environment

Most cells CANNOT function without other cells

Most cells are in contact with the internal environment

The internal environment consists of material outsidethe cell, but inside the body

Define ExtraCellular Fluid (ECF)

Define IntraCellular Fluid (ICF)

Define InterStitial Fluid (ISF)



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Homeostasis

Components of the ExtraCellular Fluid (fig 1-5)



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Homeostasis

Cells can live and function only when they are

bathed by ECF that is compatible with theirsurvival

The cell must obtain nutrients and dischargewaste to the ECF

Claude Bernard (1813-1878)Le milieu interieur

Walter B. Canon (1871-1945)

Coined the term Homeostasis



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Homeostasis

Homeostasis

Maintenance of relatively stable conditions in the

internal environment and in other body states


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Homeostasis

Factors affecting Homeostasis

Amount of energy-rich molecule - fuel

O2 & CO2 concentration - for chemical reactions

Waste products - toxcicitypH - acid/base balance, enzymatic activity

Water, salt & electrocytes - cell sizeVolume & pressure

Temperature - narrow range

Social parameters - social insects (termites)



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Homeostasis

Feedback-Control Systems

Conformers - animals internal changes parallel the

external conditions e.g. starfish - salinity; annelid worms O2

Regulators - animal defend a relatively constant stateAvoiders - minimize internal variations by avoiding

environmental disturbances

Some fish avoid temperature changes by changing location

Enantiostasis (allostasis) - change in one

physiological variable to conteract a change in

another Blue crabs - change blood pH to increase O2 binding when in brachish



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Homeostasis

Comparisons of negative feedback control systems (Fig 1-8)

a -componentsof a basic

feedback

system b - control of roomtemperature

c - control ofmammalian body

temperature



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Homeostasis

Feedback effectors

Antagonistic control: Opposes change in the variable Temperature falls -> effectors produce change to increase temperature(thermostatic effect)

Behaviors as effectors: Animal seeks out a different

location (Avoiders) Migration of Monarch butterflies to avoid the cold north

Killifish seeks out water to keep its internal salinity about 35 to 45%that of normal seawater



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Homeostasis

Enhancement & expansion of basic negative

feedback systems (Fig 1-9)

Antagonistic effectors Feedforwardcontrol



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Homeostasis

Flaws of Negative Feedback Systems

It must first suffer a disturbance before it can act

Delayed response

Overshoots the set point

Flaws Overcome by:

Feedforward system (Anticipation) Predicts results of a disturbance

Prevents overshooting of the set point

e.g. increased insuling secretion while meal is still in digestive tract

Acclimatization systems



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Homeostasis

Adaptation, Acclimatization and Acclimation

Adaptation - evolution by natural selection

Acclimatization - physiological, biochemical, oranatomical change within an individual from chronic

exposure to a new environment

Acclimation - same as above, but induced

experimentally



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Homeostasis

Other Controlled Systems

Rheostasis - non-homeostatic regulation

Reset system - changes the setpoint temporarily,

permamently or cyclically

Fever

Sex hormone concentrations - at puberty

Reproductive cycle - menstrual cycle

Positive feedback system

Creates rapid change

Reinforces the change in the same direction

e.g. neuron action potentials, lactation, blood clotting, orgasms . . .



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Homeostasis Mechanisms for regulated change


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Ten Physiological Organ Systems

Circulatory: transports gases, nutrients & wastes

Digestive: obtains nutrients, water & electrolytes

Endocrine: regulates processes for durationImmune: defends against foreign invaders

Integumentary: proctective barrier

Musculoskeletal: support, protect & movement

Nervous: controls rapid response of body

Reproduction: perpetuation of the speciesRespiratory: O2 and CO2, regulates pH

Documents

01 Animal Physiology - Foundations of Physiology