Zool 4409/5409
Comparative Animal
Physiology
4/13/2015
Zool 4409/5409
4/13/2015
Zool 4409/5409
Introduction
• Introduction
• Basic Principles of Physiology
4/13/2015
Zool 4409/5409
Introduction
• Animal physiology is an attempt to
answer the question- How do animals
work?
• Requires a background in chemistry,
physics, anatomy and zoology
– physiological principles follow basic
laws of physics and chemistry
• Principally a science of the last 3
centuries
4/13/2015
Zool 4409/5409
Hemodynamics
Q = blood flow rate (mL/sec)
P= pressure difference
between ends of vessels
P
= Q
R = resistance
R
P2
P1
4/13/2015
Zool 4409/5409
Georg Simon Ohm
OHM'S LAW
• V=IxR
• V/R = I
• I, current; R, resistance; V, voltage
Introduction (con’t)
I. Search for generalizations
– Can we study the heart of a frog
and make predictions about how
the human heart works?
– Can we study nerve function in an
invertebrate and learn how our
nervous system works?
4/13/2015
Zool 4409/5409
Squid axons are important to physiologists, and to the squid
4/13/2015
Zool 4409/5409
YES!
4/13/2015
Zool 4409/5409
• At the cellular level, there are
many similarities in function
among all animals
• Animals cells use ion movement
across the cell membrane to
maintain water balance.
• Plant cells use a thick cell wall in
plants.
4/13/2015
Zool 4409/5409
At the organ system level, many
similarities amongst the vertebrates
• Frog skeletal muscle is great for lab
study.
• Can be maintained at low temps.
• Low oxygen demands.
• Most of what we know about how human
muscle works is based on frog studies.
4/13/2015
Zool 4409/5409
• All animals are faced with the same
sorts of physiological problems
– obtain and digest food
– supply oxygen to tissues
– get rid of carbon dioxide and
other wastes
– maintain body fluids
– study how a system works in a
simple model and learn how this
works in humans
4/13/2015
Zool 4409/5409
Introduction (con’t)
II. Search for oddities
(“gee-whiz” physiology)
– How do fish survive in the seas off
antarctica?
– How do some animals such as turtles survive
after their body fluids have frozen?
4/13/2015
Zool 4409/5409
Fish around Antarctica spend their entire
lives at body temperatures near –1.9°C
4/13/2015
Zool 4409/5409
McMurdo Sound,
Antarctica
4/13/2015
Trematomus bernacchii
Zool 4409/5409
Antifreeze
glycoproteins
4/13/2015
Zool 4409/5409
Introduction (con’t)
Knowledge of how animals adapt to
extreme environmental problems may be
useful for learning about human
performance in extreme situations; eg.
Space, underseas, etc.
4/13/2015
Zool 4409/5409
4/13/2015
Zool 4409/5409
Bar-headed GooseFly at 30,000 feet
Unique hemoglobin
III. Knowledge for Knowledge’s sake
• basic science is required for all advances
and applications in science
• emphasis on “product-oriented” science
will result in fewer new discoveries.
4/13/2015
Zool 4409/5409
Introduction (con’t)
IV. Physiology is the cornerstone of human
medicine.
• Good physicians must have a solid
understanding of how the body functions
normally in order to diagnose disease
4/13/2015
Zool 4409/5409
Basic Principles of Physiology
I. Form follows function
over time (geologic time), form evolves
with function
4/13/2015
Zool 4409/5409
4/13/2015
Zool 4409/5409
4/13/2015
Zool 4409/5409
4/13/2015
Zool 4409/5409
Basic Principles of Physiology
II. Homeostasis
• Ability to regulate internal environment within
narrow limits
Homeostasis = balance
• Claude Bernard (maintenance of the internal milieu,
late 1800s)
• Walter Cannon (coined the term homeostasis,
early 1900s).
Basic Principles of Physiology
II. Homeostasis (con’t)
• Maintained by multiple control systems
– eg. Blood pressure is regulated by both
short-term (seconds) and long-term (min, hr,
days, wks)
4/13/2015
Zool 4409/5409
Control systems involved in
blood pressure regulation
Short term
Long term
Baroreceptor reflex
(sec)
Renal filtration
Angiotensin (hormone, minhr)
Aldosterone (hormone, minhr,days)
4/13/2015
Zool 4409/5409
4/13/2015
Zool 4409/5409
Disruption of homeostasis- stress
Stressor
4/13/2015
Zool 4409/5409
4/13/2015
Zool 4409/5409
4/13/2015
Zool 4409/5409
Figure 1.6 Mixed conformity and regulation in a single species
4/13/2015
Zool 4409/5409
Basic Principles of Physiology
III. Regulatory systems
• Nervous system
DETECT
INTEGRATE
RESPOND
storage
integrate
learning
retrieval
4/13/2015
Zool 4409/5409
Basic Principles of Physiology
III. Regulatory systems (con’t)
• Endocrine system
stimulus
endocrine
cell
hormone
RESPONSE
4/13/2015
Zool 4409/5409
blood
Target
Neuroendocrine Integration
Endocrine system
Nervous system
Neuroendocrine system
Endocrine organs cannot detect environmental
changes on their own- they require input
from nervous system
4/13/2015
Zool 4409/5409
Basic Principles of Physiology
IV. Feedback control
• Negative feedback
– reduces the difference between the
output and setpoint. eg. thermostat
4/13/2015
Zool 4409/5409
• Positive feedback
– increases difference between outpoint
and setpoint
4/13/2015
Zool 4409/5409
4/13/2015
Zool 4409/5409
4/13/2015
Zool 4409/5409
Feedback Control of Body Temperature
HBC
Higher brain center
Set point = 98.6o F
-
integration
THERMORECEPTORS
hypothalamus
coordination
effector
Response
hypothalamus
eg., muscle
Basic Principles of Physiology
V. Critical thinking and the scientific
method
A. Inductive reasoning
B. Hypothesis
C. Deductive reasoning
D. Testing hypothesis
4/13/2015
Zool 4409/5409
Basic Principles of Physiology
A. Inductive
reasoning-Francis Bacon, 1620
• Collecting information in an unbiased
way.
• In 1620 Bacon published Novum
Organum (Or True Directions Concerning
the Interpretation of Nature)
Without inductive reasoning:
Example of bad science:
• >400 years ago, Bishop Usher concluded
that the earth began on October 9th, 4004
BC, 9:30 AM by counting the number of
“begats”.
4/13/2015
Zool 4409/5409
TRUE DIRECTIONS CONCERNING
THE INTERPRETATION OF NATURE
Francis Bacon
1620
• “The formation of ideas and axioms by
true induction is no doubt the proper
remedy to be applied for the keeping off
and clearing away of idols. To point them
out, however, is of great use. “
The Four Idols of Bacon that Prevent
Accurate Interpretations of Nature
• The Idols of the Tribe-erroneous
preconceived ideas common to one’s
tribe or community
The Four Idols of Bacon that Prevent
Accurate Interpretations of Nature
• The Idols of the Cave- erroneous
beliefs of one’s mind; individuals
tend to favor their own ideas
4/13/2015
Zool 4409/5409
The Four Idols of Bacon that Prevent
Accurate Interpretations of Nature
• The Idols of the Marketplaceeveryday language is not sufficient
for describing scientific ideas
4/13/2015
Zool 4409/5409
The Four Idols of Bacon that Prevent
Accurate Interpretations of Nature
• The Idols of the Theatreadherence to theological and
philosophical modes of thought
where truth is deduced from
what is assumed to be true.
Hypothesis Follows Observation
B. A hypothesis is a testable
prediction, falsifiable. Ie., based on
data, we can either accept or reject
the hypothesis.
4/13/2015
Zool 4409/5409
Falsifiable hypothesis
The adrenal gland is involved in regulating blood
sugar.
– Based on data we accept or reject hypothesis.
Non-falsifiable hypothesis
God created the earth in 7 days. This
hypothesis can’t be falsified.
4/13/2015
Zool 4409/5409
NOTE: Nothing is ever proven or
disproven in science.
Scientific theories are accepted or rejected
based on collection of evidence.
4/13/2015
Zool 4409/5409
Basic Principles of Physiology
C. Deduction– if adrenal gland is involved in regulating
blood sugar, then removing adrenal should
alter blood sugar.
D. Testing hypothesis- state of the art
technology.
4/13/2015
Zool 4409/5409
Theory of evolution
•
•
•
•
Populations increase
variability within species
resources are limited
those best fit to utilize resources
reproduce and survive -
• Descent with modification!
Industrial melanism in Biston betularia
(see
H.B.D. Kettelwell. 1973. Industrial Melanism. Oxford Univ. Press, Oxford, U.K.)
•Two forms of the pepper moth in Britain, light form and melanistic form
•Single gene difference leads to more melanin pigment synthesis
•In the last 150 years, switch from fewer to more melanistic forms
Basic Principles of Physiology
geoscience
paleontology
archeology
Theory of Evolution
(Descent with modification)
biochemistry
4/13/2015
molecular biology
Zool 4409/5409
OTHER THEORIES
RELATED TO PHYSIOLOGY
• CELL THEORY
• THEORY OF GENETIC
INHERITANCE
4/13/2015
Zool 4409/5409