Animal Physiology-Introduction to Physiological Principles

What does it mean that physiology is integrative?

-Animal physiologists study phenomena at multiple levels of organization, from molecules to ecosystems -Animal physiologists address both basic and applied questions

What does it mean that physiological processes are shaped by evolution?

-Natural selection can cause a relationship between form and function -Differences among taxa can be adaptations as a result of evolution by natural selection, or can result from random processes -Similarity among traits can be due to homology (shared ancestry) or homoplasy (independent evolution)

What does it mean that physiological processes obey the laws oh physics and chemistry?

-The mechanical properties of materials influence physiological processes -Electrical laws are needed to understand the functions of membranes in all cells, including excitable cells such as neurons and muscle -Chemical laws, which govern interactions between biological molecules, help to explain the effects of temperature on physiological processes -Physical laws can be used to explain why body size affects many physiological processes

Many physiological processes have a scaling coefficient that is between:

0 and 1

What are Fick's 2 laws of diffusion?

1. First law demonstrates that substances diffuse from areas of high concentration to areas of low concentration 2. Second law summarizes the idea that the amount of a substance that diffuses across a surface is proportional to the area of that surface and inversely proportional to the distance across which the substance must diffuse

What are the 3 key components of the phenotype of an organism?

1. Morphology 2. Physiology 3. Behaviour

What are the 4 unifying themes in animal physiology?

1. Physiology is integrative 2. Physiological processes obey the laws of physics and chemistry 3. Physiological processes are shaped by evolution 4. Physiological processes are usually regulated

Give 2 reasons why model organisms are studied by a wide community of researchers:

1. They have features that are conductive to experimentation 2. Understanding a process in the model provides insight into how the process works in other species of interest

Fick's second law considers the amount of diffusion that across across a surface such as:

A cell membrane or an epithelial tissue

Scaling relationships are often plotted on:

A log-log scale, because this transformation linearizes the equation

The phenotype includes:

All of the observable traits of an organism at all levels of biological organization, from the biochemistry of the cell to the anatomy, physiology, and behaviour of the animal

When body shape or physiology changes disproportionately as body size increases, the relationship is said to be:

Allometric

Genotype controls the way:

Animals can alter their phenotype in response to physiological and environmental conditions

Substances will move from:

Areas of high pressure to areas of low pressure

Heat flows from:

Areas of high temperature to areas of low temperature

What is reductionism?

Assumes that we can learn about a system by studying the function of its parts

Give the levels of biological organization in order:

Atoms, molecules, cells, tissues, organs, organ systems, organisms, populations, communities, ecosystems, biosphere

This approach of using an animal model with features that are favourable for scientific study is known as the:

August Krogh principle

For these charged particles, what is important for determining the extent and rate of diffusion?

Both the concentration gradient AND the electrical gradient

At high temperatures, many of the intermolecular interactions that stabilize proteins begin to:

Break down and protein function declines

Animal physiologists are interested in both the _____ and _____ of this great diversity

Causes, consequences

What is the lowest level of biological organization capable of independent life?

Cells

The strength of a bone is related to its _____, but the weight that bone must support is directly related to the animal's _____

Cross-sectional area, volume

Because the surface area increases by a power of 2 while volume increases by a power of 3, the ratio of surface area to volume:

Decreases as the length of the side increases

What is the practical consequence of this relationship in the previous flashcard?

Diffusion is rapid across short distances, but extremely slow across long distances

A voltage gradient, which represents a source of electrical potential energy, can:

Drive the movement of charged particles

Animal physiologists are also concerned about the _____ consequences of physiological processes

Ecological

What are emergent properties?

Emergent properties of a system are properties that can be observed at one level of biological organization and are due to the interactions of the component parts of the system

Fick's second law is critical for understanding the form and function of:

Epithelia such as the lungs and the gut that are involved in the exchange of substances by diffusion

Each species has acquired countless unique properties through:

Evolution

What is the ultimate cause of the enormous diversity of animal species?

Evolutionary change

Differential survival of organisms with distinct phenotypes may result in:

Evolutionary change in the genotype of a population over many generations

What is emergence?

Feature of complex systems; another way of saying that the whole is often more than the sum of its parts

What is cellulose?

Fibrous material

In addition to mechanical properties, what other engineering concepts are important in physiology>

Flow, pressure, resistance, stress, strain (ex. understanding how heart pumps blood through blood vessels has many parallels with understanding how mechanical plumbing systems work)

What is the August Krogh principle?

For every biological problem there is an organism on which it can be most conveniently studied

It is impossible to understand the physiology (function) without an understanding of:

Form (anatomy)

Physiological traits, like other characteristics of animals, are determined in large part by:

Genes of the genome-the genotype-but are also influenced by the way the genes are regulated, particularly in response to external conditions

How can we get around this limitation mentioned in the previous flashcard?

Have a different shape (ex. a very long thin cell would have a much higher surface area-to-volume ratio than would a spherical cell)

Give an example of a body part that follows a roughly isometric relationship with body mass:

Heart in humans-when b is negative, the variable decreases with body size; the heart rate of mammals is an example of a physiological process with negative b, the heart rate of an elephant is much lower than the heart rate of a shrew

The same pricnicples that apply to the diffusion of substances apply to the conduction of:

Heat

Agricultural production of animals for food also requires a substantial knowledge of animal physiology to:

Help develop optimal rearing practices to maintain health and promote the growth of farm animals

Understanding the physiological functions of animals can:

Help us predict their responses to environmental changes such as pollution, climate warming, and ocean acidification

In multicellular organisms such as animals, exchange surfaces are often:

Highly folded to maximize surface area

Basic research in animal physiology provides profound insights into:

How animals work and the evolutionary causes and consequences of variation in physiological processes

Physiologists are usually interested in emergent properties, and thus physiologists study:

How molecules, cells, and tissues interact to produce the complex system that is an organism

What is Rubner's hypothesis about heat dissipation:

If metabolism scaled isometrically with body size, Rubner suggested that large animals would generate too much heat to dissipate across their relatively small surface area, and thus they must have lower metabolic rates per gram of tissue than smaller animals

Phenotypes are the result of:

Interactions between the genotype and the environment acting on processes at all levels of biological organization

When morphology or physiology change in direct proportion to body mass, the scaling relationship is said to be:

Isometric

Often a physiologist interested in a process at one level of organization also studies:

Its function at a LOWER level

The phenotype (morphology, physiology, behaviour) of an animal influences:

Its reproductive success

Biologists often organize the living world by dividing it into what are termed:

Levels of biological organization

Because volume increases more than does surface area of radius increases, the surface available for exchange of materials becomes:

Limiting

What are endotherms?

Maintain a relatively constant body temperature by generating metabolic heat

If the larger volume is made up of repeating smaller units, each with its own surface area, the surface area-to-volume ratio can be:

Maintained as overall size increases

Despite the great diversity of organisms on Earth, there are:

Many commonalities within physiology-unifying themes that apply to all physiological processes

The face that both concentration and voltage gradients can drive movements of substances is important in physiology because:

Many important physiological processes, such as signalling in neurons and muscle cells and the active transport of materials into cell, involve the movement of charged molecules such as sodium across membranes

What is an important example of a physiological process that has a positive scaling coefficient that is less than 1

Metabolic rate-matabolic rate of one gram of tissue from a larger animal is lower than the metabolic rate of one gram of tissue from a smaller animal (Rubner's hypothesis about heat dissipation)

Such medical research is often performed on:

Model organisms

Cells establish a charge difference across biological membranes by:

Moving ions and molecules to create ion and electrical gradients (membrane potential)

What 2 kinds of cells use changes in membrane potential to send signals?

Muscle cells and neurons

These epithelia have to have what characteristics to maximize the exchange of materials?

Must have as large a surface area as possible and be as thin as possible

Animals are constructed from natural materials and thus:

Obey the same physical and chemical laws that apply to every thing that we see around us

What does the second law of thermodynamics mean?

Over time, differences in concentration, charge, temperature, or pressure will tend to equalize within a system, unless energy is added to maintain this difference

Variation in morphology, physiology, and behaviour can influence:

Performance and reproductive success

An individual genotype can have the capacity to produce more than one:

Phenotype

Both the genotype or an organism and its environment interact through development to produce the _____ of the adult organism

Phenotype

The physiological properties of an animal are aspects of an animal's:

Phenotype

A concentration gradient can be thought of as a source of:

Potential energy that can be used to drive diffusion

The phenotype is itself the product of:

Processes at many levels of biological organization, including the biochemical, cellular, tissue, organ, and organ system levels

Give some examples of biological materials/biomaterials:

Proteins, carbohydrates, lipids

As a result of this focus on chemistry and physics, physiology is a _____ science

Quantitative

Because most biochemical reactions involve proteins as catalysts, when these catalysts break down, the:

Rate of the reaction falls

The form and function of many animals is shaped by the need to:

Regulate heat loss or gain

Although the same genes are found in each cell, they are:

Regulated in combinations to allow animals to develop distinct tissues

Much of our medical knowledge is gained from:

Research on animals, and thus understanding animal physiology is crucial for those involved in medical research

What did Kleiber's work suggest against the hypothesis of Rubner?

Scaling coefficient was closer to 0.75 (3/4) rather than the value of 0.67 (2/3), implying that the surface area-to-volume ratios cannot explain metabolic scaling relationships

The relationships between anatomical or physiological traits and body size are termed:

Scaling relationships

Animals also use changes in electrical potentials to:

Send signals within and between cells

Differences in the molecular properties of proteins may be a result of the differences in the:

Sequences of the proteins, but they can also be the result of the modification of an existing protein(ex. keratin can be made more rigid by the addition of bonds that cross-link multiple keratin proteins together)

Pressure gradients also act as:

Sources of potential energy that can move substances

What are model organisms?

Species that are chosen because they have features that make them particularly suitable for specific experiments

Give an example of a model organism:

Squid have specialized neurons that are large enough to be easily seen and readily manipulated-the use of squid as a model system was critical in the development of our understanding of how neurons work in all animals

Fick's first law is a special case of a much more general principle in physics and physiology:

That substances move from areas of high potential energy to low potential energy

Give an example of how molecular properties make biomaterials useful for some processes but not others:

The aorta-one of the largest blood vessels in a vertebrate, contains high levels of the protein collagen to help the aorta withstand high pressure generated by the heart (smaller blood vessels such as capillaries that are not exposed to such high pressure have much less collagen, which allows them to be thin to maximize the exchange of materials by diffusion)

If animals skeletons scaled isometrically, the bones would not be sufficiently strong to support the weight of a large animal, because:

The cross-sectional area of the bone (its strength) would not increase as fast as would the weight of the animal (thus, larger animals have thicker bones than would be expected based on the proportions of smaller animals)

What happens when b = 1?

The physiological variable increases proportionally with body mass, and the process scales isometrically

What happens when b = 0?

The process is unaffected by body size

The fundamental reason why the bones of an elephant are proportionately thicker than the bones of a cat has to do with:

The relationship between area and volume

This movement of high potential to low potential energy is a consequence of:

The second law of thermodynamics, which states that isolated systems spontaneously move toward a state of maximum entropy

We can demonstrate from considering Brownian motion, or the random movement of particles in a solution, that the time needed for a particle to diffuse across a given distance is proportional to:

The square of the distance

What do animal physiologists study?

The structure and function of 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

What is animal physiology?

The study of how animals work

Physiology is a central discipline in biology linking:

The underlying molecular and cellular mechanisms to characteristics of whole organisms such as performance and fitness

The physicochemical characteristics of these biomaterials are determined by:

Their molecular properties

Note how the bones of an elephant are much _____ than the bones of a cat

Thicker

Another area in which animal physiology plays an important practical role is in:

Understanding human health and disease

Give the previous equation, but in log form:

logy = loga + blogM (straight line, slope of b, intercept of loga)

What would this equation be for a sphere?

y = aM^2/3 because the surface area increases as the square of the radius, while volume increases as the cube of the radius

Describe the equation y = aM^b

y = surface area, M is the body mass (or volume), a is a constant, and b is a term called the scaling coefficient