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Chapter 1&2

BIOB34H3 Chapter Notes - Chapter 1&2: Riboflavin, Phosphocholine, Microfilament

Biological Sciences
Course Code
Anna Walsh

of 36
1„h Knut Schmidt-Neilson: Animal Physiology is the Study of How Animals Work
2„h Animal physiologists study the various parts of an animal and how these parts
work together to allow animals to perform their normal behaviours and to respond
to their environments
3„h Physiological processes are a result of the activities of complex tissues, organs
and systems that can arise through complex patterns of gender regulation of
countless cells
4„h Diversity is key concept to animal physio but despite this great diversity that
exists between and within the species of earth, there are many commonalities
within physiology (unifying themes)
1o Physiological processes obey physical and chemical laws
2o Physiological processes are regulated to maintain internal condition within
acceptable ranges
3 Internal consistency, a.k.a. homeostasis, is maintained through feedback
loops that sense conditions and trigger an appropriate response
4o Physiological state of an animal is part of its phenotype which arises as a the
product of the genotype and its interaction with the environment
5 genotype +environment =phenotype physiological state of animal
6 the phenotype itself is the product or processes at many levels of biological
organization, including the biochemical, cellular, tissue, organ and organ
system levels
7o genotype is a product of evolutionary change in a group of organisms over
many generations the group can be populations or species
5„h The biological levels listed above interact to produce complex behaviours and
physiological responses
6„h With respect to the environment’s influence on phenotype organisms may
change their behaviour as a result of learning or alter their physiological responses
through modification of their phenotypes
Physiology: Past and Present:
Animal physiology is an experimental science but it plays an important role in modern
biology as the intellectual glue that holds disparate biological fields together
A Brief History of Animal Physiology
1„h Hippocrates the father of medicine, emphasized the importance of careful
observation in the treatment of disease
2„h Aristotle the father of natural history, emphasized the relationship b/w
structure and function
3„h Claudius Galenus (aka Galen) first to use systematic and carefully designed
experiments to probe the function of the body, he made extensive use of
dissection and vivisection of nonhuman primates and other mammals to test his
physiological ideas
1. o He tied of the uterus and observed that the kidneys swelled and from this
observation he concluded that the kidneys play a role in the formation of urine
2. o By tying off the laryngeal nerve, which leads to the vocal cords, of a living pig
at which point the pig stopped squealing he concluded that the brain and
nerves regulate the voice
4„h Although much of Galen’s work was fundamentally incorrect when viewed from
a modern perspective his emphasis on careful observation and experimentation
makes him the founder of physiology
1„h Ibn al-Nafis first to correctly describe the anatomy of the heart, the coronary
circulation, the structure of the lungs, and the pulmonary circulation; also first to
describe the relationship b/w the lungs and the aeration of the blood
2„h William Harvey identified the path of blood through the body and showed that
contractions of the heart power this movement
1o He couldn’t see the fine arteries that connect arteries and veins but he
hypothesized that they must exist to form a closed circulation for the blood
around the body
3„h Before the 18th century physiologists fell into one of two camps
1o Iatrochemists: believed that body function involved only chemical reactions
2o Iatrophysicists believed that only physical processes were involved
4„h Hermaan Boerhaave & Albrecht von Haller proposed that bodily functions
were a combination of both chemical and physical processes
5„h Matthias Schleiden and Theodor Schwann formulated cell theory which states
that organisms are made up of units called cells
6„h Claude Bernard discovered that hemoglobin carries oxygen, that the liver
contains glycogen, that nerves can regulate blood flow and ductless glands
produce hormones that are carried in the blood and influence distant tissues
1o Concept of the milieu interieur (internal environment) living organisms
preserve a distinct internal environment despite changes in the external
environment l
2 This was later developed more fully by Walter B Cannon who coined the term
7„h Pen Scholander first and most influential comparative physiologist
8„h C. Ladd Prossesr discovery of central pattern generators: groups of neurons
that coordinate many thythmic behaviours including breathing and walking
1o Also discovered the relationship b/w muscle diameter and conduction speed &
worked on the effects of radiation on animal life as part of the Manhattan
9„h Knut Schmidt-Nielson tried to understand how animals live in harsh and
unusual environments
1o Showed that the camel’s nose contains a countercurrent exchanger that
allows It to recapture moisture from exhaled air, resulting in an almost 60%
reduction in water loss compared to other mammals
10 „h George Bartholomew founder of ecological physiology (the study of how an
organism interacts with its environment)
1o Combined the study of animal behaviour, ecology and physiology to assess
the evolutionary significance of adjustments or adaptions in animals to their
2o He identified the individual as the principal unit of natural selection and
emphasized the importance of variation in physiology
11 „h Peter Hochachka and George Somera founded adpational biochem
1o Applied the concepts and techniques of biochem to the questions of
comparative physiology and in doins so they have extended to subcellular level
our understanding of how animals adapt to hostile environments of how
animals adapt to hostile environments, providing insights to the biochemical
mechanisms that allow animals to live in habitats as diverse as the deep sea,
the Antarctic oceans, high mountain peaks and tropical rain forests
Subdisciplines in Physiological Research
There are three main ways to categorize physiological subdisciplines: by the biological
level of organization by the nature of the process that causes physiological variation and
by the ultimate goals of the research
LEVEL OF ORGANIZATION The most common way to distinguish branches of
physiology is by reference to the many levels of organization
1o Cell and molecular physiologists study phenomena that occur at the
cellular level. Researchers studying molecular genetics, signal transduction,
metabolic biochemistry or membrane biophysics
2o Systems physiologist : concernes with how cells and tissues interact to carry
out specific responsibilities within the whole animal
3o Organismal physiologist is most often concerned with the way an intact
animal undertakes a specific process or behaviour ex. Organismal physiologist
might study changes in animal metabolic rate in response to a stressor
4 Organismal characteristic (ex. Metabolic rate) is the product of multiple
physiological systems interacting in complex ways
5o Ecological physiologist: studies how the physiological properties of an animal
influence the distribution and abundance of a species or population ex. How
nutrient distribution in the environment influences the growth rate of an animal
6o Integrative physiologist attempts to understand physiological processes at a
variety of lecels of biological organization and across multiple physiological
7 ex. Integrative physiologist might study how variation in hemoglobin genes
contributes to difference in oxygen delivery and how those differences in the
ability to extract oxygen from the environment contribute to the geographical
distribution of the species
2„h Reductionism: when a physiologist interested in a process at one level of
organization also studies its function at the next lower level. This approach
assumes that we can learn about systems by studying the function of its
partsunderstand a system by studying the functions of its parts
3„h Emergence: the whole is often more than the sum of its parts
1o Emergent properties of a system are due to the interactions of the component
parts of the system
2o Physiologists are interested in emergent properties and thus they study how
molecules, cells and tissues interact to produce the complex system that is an
August Krogh principle: For every biological problem there is an organism on which it
can be most conveniently studied
Unifying Themes in Physiology:
Physics and Chemistry: The Basis of Physiology
Animals are constructed from natural materials and thus obey the same physical and
chemical laws that apply to everything that we see around us ex. Temperature exerts its
effects on physiology by altering the nature of chemical bonds in biomolecules, or
solubility of gases in solution
Mechanical theory helps us understand how organisms work
Biological materials, or bio materials-proteins, carbs and lipids-have characteristic
physical properties that make them useful for some processes but not others ex. Some
proteins are rigid and inflexible whereas others readily deform