BIOB34 Module 1 Lecture Slides-updatedSept6
Animal Physiology
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Animal physiology is the study of how animals work (function)
It involves the study of integrated function
Protein structure is an important aspect of animal physiology
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Erasistratus, a Greek physician and anatomist, is considered the father of physiology by some
He applied physical laws to the study of human function
He was the first to suggest that the heart was a pump and identified the function of the cardiac tricuspid valve
Galen, a Roman physiologist, used systematic experiments to probe function
He tied the laryngeal nerve off in a pig, resulting in no more squealing, and tied the ureters off in apes, resulting in swelling of the kidneys
Galen also described pulmonary circulation, heart anatomy, and coronary circulation
He confirmed that the heart was a pump and corrected some of Galen's erroneous beliefs
Ibn al-Nafis emphasized the relation of structure and function and classified organisms by "blood/no-blood"
He speculated on body function
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Antoine Lavoisier identified and named oxygen and hydrogen
He discovered the role of oxygen in combustion and aerobic metabolism
Claude Bernard suggested 'blind' experiments to ensure objectivity
He discovered that hemoglobin carries oxygen and that nerves can regulate blood flow
Bernard coined the term "Milieu intérieur" to describe the stability of the internal environment
He also coined the terms "fight or flight response" and "homeostasis"
Walter Cannon provided the first complete description of the circulatory system and properties of blood
He showed that contractions of the heart powered blood movement
William Harvey described the concept of pulmonary circulation and confirmed that the heart was a pump
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The August Krogh principle states that for every biological problem, there is an animal on which it can most conveniently be studied
The Bar-headed goose was studied to understand adaptation to hypoxia
The Giraffe was studied to understand dynamic control of blood pressure
The Fly was studied to discover Cytochrome C and eventually the "Krebs cycle"
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Physiological processes are governed by the laws of chemistry and physics
The mechanical theory is useful in understanding locomotion, cell motility, muscle function, and skeletal dynamics
The laws of electricity apply to excitable cells, membrane potential, and neural circuits
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Metazoans are eukaryotes
They are distinguished from prokaryotes
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Metazoans, like all eukaryotes, are multicellular
However, not all eukaryotes are multicellular
Multicellularity has evolved several times independently
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There are many potential selective advantages to evolving multicellularity
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Homeostasis and regulation are unifying themes in animal physiology
Animals are exposed to a changing environment and need to regulate various factors such as food sources, pH, temperature, oxygen, toxins/waste products, etc.
Single-cell organisms have direct interaction with the environment
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Multi-celled animals like the Rufous hummingbird have no/few cells directly exposed to the environment
The "environment" of cells is the interstitial fluid
Homeostasis is the defense and maintenance of the environment in which cells exist
Homeostasis is defended by behavior and multiple organ systems
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Temperature and body size play a role in physiological processes
Digesting large meals and controlling metabolites and ions require more control over temperature
Larger animals have more cells and more control over the internal environment
Size and temperature impact almost every physiological function
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Scaling relationships exist in animal physiology
Length, surface area, and volume are related to each other
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Some things are a function of volume, such as total metabolic rate and total heat production
Some things are a function of surface area, such as respiration and absorption/expulsion
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Surface area-based and volume-based phenomena scale differently with size
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Heat production scales with volume
Heat loss/gain scales with surface area
Larger animals have relatively less surface area for dissipating extra heat
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Basal metabolic rate does not scale with body size
There is a logarithmic relationship between body size and metabolic rate
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Complexity and specialization are unifying themes in animal physiology
Animals have different cell types, tissues, organs, and organ systems
Multicellularity permits divisions and distinctions
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Phenotypic plasticity and ontogenetic changes occur in response to the environment
Physiological phenotype is a product of genotype and environment
Acclimation and acclimatization are examples of reversible changes
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All animal species can utilize sexual reproduction
Some animals can also utilize asexual reproduction
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Sexual reproduction enables greater genetic variation across generations
This greater variation might make some individuals better suited if climate/ecosystem changes
Could enhance chance of survival for species
Inter-individual genetic variability exists in both sexual and asexual reproduction
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Some animals still use asexual reproduction despite the benefits of sexual reproduction
Genetic variability of sexually-produced offspring may mean some possess better "adapted" genes
Asexual reproduction creates clones of an individual
If an individual has "good genes," all of their offspring will also have them
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Adaptation can be observed in phenotypic traits over generations
Not all phenotypic traits are a result of adaptation
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Comparative physiology helps understand how animals deal with unique environments/challenges
It helps understand how animals exploit different niches
It helps make sense of species diversity
It reveals similarities and differences among species
It shows how evolutionary relationships shape the above
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Comparative physiology is important for:
Advancing veterinary medicine
Informing conservation of species and ecosystem services
Advancing human medicine
Using model organisms (Krogh principle)
Identifying commonalities in physiological design and function
Providing novel medical insights,