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BIO270H1 Study Guide - Midterm Guide: Albrecht Von Haller, Herman Boerhaave, Central Pattern Generator

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David Lovejoy
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BIO270 Midterm 1 Test
Lecture 1
10 Body Systems & Their Functions
- Integumentary (skin): covers.
- Musculoskeletal: support & movement.
4 exchange b/w the internal & external
- Respiratory: exchange gases.
- Digestion: nutrients & water, waste.
-Urinary: removes excess waste & water.
- Reproductive: produces eggs & sperm.
4 extend throughout the body
- Circulatory: distributes materials.
- Nervous: coordinate body functions
-Endocrine: coordinate body functions.
- Immune: protect interior.
What is Physiology?
- “The knowledge of nature” – Aristotle
- “The healing power of nature” – Hippocrates
- Definition: The study of the normal functioning of a living organism & its component parts, including all
its chemical & physical processes.
- “The study of how animals work” – Knut Schmidt-Nielsen
- Structure & function of various parts – how these parts work together.
oOne of the basic premises of physiology in any science is that function follows structure, what the
function is going to be depends on what the structures are like.
- Diversity of animals – more than 1 million species live on Earth.
oOne of the things in physiology that we look at is that over 1 million species that live on earth,
what are the commonalities & what is unique about them & what does that mean about their
functioning & how they’ve adapted to the environment that they’re in so what does that mean
about our bodies & how our functions work?
- Unifying themes – apply to all physiological processes.
Physiological Sub-Disciplines
- Based on:
oBiological level of organization: Atoms Molecules Cells Tissues Organs Organ
Systems Organisms Populations Communities Ecosystems Biosphere
Cell & molecular physiology: genetics, metabolism, organelles the physiology that they
work with is more on the cellular level, how the functioning of all cells & the molecules
will affect the function of the organism.
Systems physiology: function of organs
Organismal physiology: whole animal
Ecological physiology: animal & its environment
Integrative physiology: multiple levels of organization
Physiologists often study processes at more than one level:
Reductionism: understand a system by studying the function of its parts.
Emergence: the whole is more than the sum of its parts.
oProcess that cause physiological variation
Developmental physiology: Change as the animal grows.
Environmental physiology: Change in response to environment.

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Evolutionary physiology: Change due to natural selection.
oUltimate goals of the research
Pure physiology: No specific goal, other than knowledge.
Applied physiology:
Medical physiology
Comparative physiology
August Krogh principle: “For every biological system there is an organism on
which it can be most conveniently studied.
oMany physiological questions encompass elements from each sub-discipline
History of Animal Physiology: Ancient Times
- Hippocrates: Father of medicine; Careful observation.
-Aristotle: Father of natural history; Relationship b/w structure & function.
-Claudius Galenus, “Galen”: 1st experimental physiology; Founder of physiology.
oHe was taking care of a lot gladiators & while he was doing that, he was learning about the human
body, how the blood worked & how to stop blood flow & severed limbs & also he was doing some
animal studies & try to figure out the similarities b/w them, how to work with the animals in order
to better serve the humans he did a lot of experimental work to try out things on animals to see
how they would affect them.
History of Animal Physiology: Middle Times
- Ibn al-Nafis: Anatomy of heart & lungs.
oIt was not until we go to the Muslim community where they started to question things in the middle
of the 13th century.
- Jean-Francois Fernal: Outlined current knowledge of human health & disease.
oHe was one of the 1st ones to really look at a combination of physio & health.
-Andreas Vesalius: 1st modern anatomy textbook.
- William Harvey: Circulation of blood through the body by contractions of the heart.
Chemical or Physical? The Answer
- Herman Boerhaave & Albrecht von Haller: Bodily functions are a combination of chemical & physical
oPrior to this all physiologists were either: Iatrochemists (body functions involved only chemical
reactions) or Iatrophysicists (body functions involved only physical processes).
- Matthias Schleiden & Theodar Schwann: “Cell theory” – organisms are made up of units called cells.
- Claude Bernard: Milieu interieur (internal environment) internal environment distinct from external
- Walter Cannon “Homeostasis”: the body needs to regulate itself to maintain a proper environment to
- Per Scholander: Comparative physiology to start looking at different animals/organisms & comparing
them to see what they have in common & seeing what they have that are distinct.
-C. Ladd Prosser: Central pattern generators the idea that you have specific cells in your brain or in
different areas of the body that are the processors that make something happen.
- Knut Schmidt Nielsen: Animals in harsh & unusual environments to test their limits of what their
processes are & then to try to relate that back to humans.
- George Bartholomew: Ecological physiology.
- Peter Hochachka & George Somero: Biochemical adaptations.
Unifying Themes in Physiology
1. Physiological processes obey physical & chemical laws.
2. Physiological processes are usually regulated: Homeostasis – maintenance of internal constancy.
3. Physiological phenotype is the product of genotype & environment

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- Genotype: genetic makeup.
- Phenotype: morphology, physiology & behaviour.
- The phenotype is dependent on your genes interacting with the environment not only outside your body but
also within your body. This is why every cell in your body isn’t identical although every cell in your body
has the same DNA, aside from the reproductive cells due to epigenetics, it’s how the environment reacts
with genes & vice versa the genotype & the environment will then be displayed as your morphology,
physiology & behaviour.
4. Genotype is the product of evolution.
Physics & Chemistry
- Physical properties of cells & tissues are linked to structure & function.
- Molecular interactions are governed by chemical reactions – Thermodynamics & kinetics.
- Electrical laws describe membrane function, especially excitable cells – Nerves & muscles.
oExcitable cells: every cell in the body has an electrical potential, a difference in electrical potential
in the charge within the cell compared to the outside of the cell, there’s an electrical field around
every cell but excitable cells can change & adapt depending on what those signals are.
- Body size influences physiological processes: Allometric scaling.
oOriginally, people thought body mass was directly related to the metabolic rate in the organism,
that the bigger the organism, the higher the metabolic rate was. So if this is true, if there was a
direct relationship b/w the 2, it should follow the line of unity, however it doesn’t. There isn’t a
direct relationship b/w the body surface compared to the metabolic rate & they did that through
Physiological Regulation
- Strategies for coping with changing conditions:
oConformers: allow internal conditions to change with external conditions not humans, but other
animals such as snake & fish.
oRegulators: maintain relatively constant internal conditions regardless of external conditions
- Homeostasis:
oMaintenance of internal conditions in the face of environmental perturbations.
oControlled by feedback loops or reflex control pathways:
Negative feedback loops: the idea is that when the conditions change in one direction, there
is a counter-change to bring it back to the set point.
Positive feedback loops: things that tend to perpetuate & it make it stronger & stronger
Phenotype, Genotype & the Environment
- Phenotype is the product of genotype & its interaction with the environment.
oGenotype: genetic makeup.
oPhenotype: morphology, physiology & behaviour.
oPhenotype plasticity: single genotype generates more than one phenotype depending on
environmental conditions.
- Factors Influencing Phenotype: The adult phenotype is dependent on the genotype, which is dependent on
the evolution & the genotype will influence the development of that organism through the adult stage but
the environment is also involved in that & the adult phenotype will determine the quality of reproduction
which will again help feedback into the evolution.
- Ex: Daphnia can change its phenotype depending on the environment around them you can see how
differently they’ve changed based on whether they were reared in the presence/absence of predator extract.
- Phenotype Plasticity: Can be irreversible or reversible.
oIrreversible: Polyphenism – developmental plasticity.
oReversible: Acclimation – under laboratory conditions; Acclimatization – natural environment.
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