Download Chapter 1 - Weber State University

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
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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
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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
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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
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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
Adaptive significance: mate attraction
not implied
François Jacob: French biologist 1965 Nobel laureate
engineering vs tinkering
engineering: new
tinkering: pre-existing & modify*
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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
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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
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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)
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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
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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
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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
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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
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O2
High Altitude
Lower Depth in Oceans
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Temperature effects on Coral Reefs
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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
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