9/4/2013

Chapter 1 Introduction

Physiology

Genetics Ecology Behavior

Evolution

History of Physiology ancient Greek physis = "nature, origin“; logia, = "study of" Hippocrates (460-370 BC) 420 BC Hippocratic School of Medicine wrote about physiology Aristotle (384 BC - 322 BC) relationship between structure & function pioneer of physiology Galen (Claudius Galenus ( ~129-200/216) Greek physician in Rome founder of “experimental physiology” William Harvey (1578-1657) English physician studied fish, amphibians, reptiles, birds & mammals 1628 publication blood circulation – heart «capillaries» epigenesis Marcello Malphigi (1628-1694) Italian physician microscope anatomy Malphigian tubules

1 9/4/2013

Matthias Schleiden (1804-1881) German botanist cell theory Theodor Schwann (1810-1882) German physiologist Claude Bernard (1813-1878) French physiologist Father of Animal Physiology Ivan Pavlov 1891 conditioning reflex 1904 Nobel Prize in Medicine & Physiology Walter Cannon (1871-1945) American physiologist 20th century comparative physiology & ecophysiology August Krogh (1874-1949) Danish Per Scholander (1905-1980) Swedish C. Ladd Prosser (1907-2002) American Knut Schmidt-Nielsen (1915-2007) Norwegian George Bartholomew 1919-2006 American environmental physiology Peter Hochachka (1937-2002) Canadian biochemical adaptation George Somero (1940- current) American biochemical adaptation

Physiology: study of functions & their structural components

functions: physical & chemical processes in organisms

How organisms operate Salmon life history physiologically

1) Fundamental biology of all organisms 2) Non-human health & diseases 3) Human health & diseases

2 9/4/2013

Applied practical aspects of physiology Comparative approach nonhuman animals “models” understanding human health & diseases

Frog -- understanding human circulatory system

squid neuron cells — large axons for implanting electrodes

3 9/4/2013

Central Questions in Physiology Mechanism a) components of living animal b) interactions among these components allowing animal to perform

Firefly

1) What is mechanism by which function accomplished? How?

2) How did mechanism originate? Why?

2009 Dante Fenelio How do you like your eggs cooked, with bacon? Significance Inferences from past

4 9/4/2013

Evolutionary origins Natural selection differential survival & reproduction

Adaptation physiological mechanism/trait, product of evolution by natural selection

Adaptive significance: reason why trait is asset reason why natural selection favored evolution of trait Adaptation: mechanism of light production not implied Adaptive significance: mate attraction François Jacob: French biologist 1965 Nobel laureate engineering vs tinkering engineering: new tinkering: pre-existing & modify*

5 9/4/2013

Physiology

Mechanistic study of mechanisms Evolutionary study of evolutionary origins Comparative synthetic study of function of all animals

Environmental physiological ecology: study of how animals respond to physiologically to environmental conditions Integrative synthesis across levels of biological organization, e.g. relations between molecular & anatomical features of organs

animals structurally dynamic animals organized systems requiring energy maintaining organizations time & body size fundamental significance in lives of all animals

6 9/4/2013

Structurally dynamic Schoenheimer (1930s) first used radioisotopes in research

Organized systems requiring energy maintaining organizations

structurally dynamic losing elements/compounds daily-need to replenish them

Time & body size fundamental significance Structure relative constant through time but particular atoms constructing molecules of change from time to time

Claude Bernard (1813-1878 physician) Father of Comparative Physiology Coined: Constancy of “milieu intérieur” = internal environment Cells bathed tissue fluids/blood constancy of solutes (Na+), pH, temperature within an animal’s body external environment = conditions outside body constancy of mammalian blood glucose

“Constancy of the internal environment is the condition for free life” Animals are able to lead lives of greater freedom and independence to the extent that they maintain a stable internal environment, sheltering their cells from the variability of the outside world

7 9/4/2013

Conformity internal & external conditions equal Regulation internal constancy against varying external conditions

Homeostasis

Walter Cannon (1871-1945) physician/researcher developed term observed animals interact with environment which constantly alters stability of internal parameters (e.g. temperature, pH, ion concentrations) expanded Bernard’s constancy of internal mileu to also include existence of regulatory systems that automatically make adjustments to maintain internal constancy Homeostasis = “the coordinated physiological processes which maintain most of the constant states in the organism.”

Cannon (1933)

8 9/4/2013

Homeostasis Negative feedback controlled variable

+

set point

-

chronic change acclimation chronic response to an environment change under lab conditions acclimatization chronic response to several environmental changes under field conditions phenotypic plasticity Individual ability to express 2 or more genetically controlled phenotypes

9 9/4/2013

1 2

Internally Programmed Changes in Two Time Frames physiological change occurs even external environment constant e.g. hemoglobin: HbF (fetus/newborn) α2γ2 ~12 weeks postnatal to HbA adult) α2β2 1) developmentally e.g. metamorphosis

2) biological clocks endogenous (daily— circadian) hibernation

jet lag

10 9/4/2013

Body Size scaling: mammalian physiological/morphological traits vary systematically with size

26.5:32

27: 26

dikdik duiker zebra duiker water buffalo

Environment animals do not live in a vacuum Environment: all chemical, physical & biotic components of animal’s Immediate surroundings Microenvironment/microclimate

11 9/4/2013

Key environmental parameters temperature

O2

H2O salinity pH pressure Masking Factors wind temperature

Temperature

Antarctica rock cod lay eggs, hatch, grow feed & mate at ~-1.9 C

Desert iguana up to 42 C; can survive 48.5 C

12 9/4/2013

O2

High Altitude

Lower Depth in Oceans

13 9/4/2013

Temperature effects on Coral Reefs

14 9/4/2013

Bernard & Cannon: studied mammals & humans presumptuous elevation of mammals “superior” to other taxa

mammalian homeostasis – achievement of evolutionary/ecological success

Questions physiologists ask

Proximal causes/cues: how Ultimate causes/cues: why

15