Chapter 1: Homeostasis and Regulation Flashcards
4 Unifying Themes of Animal Physiology
1) it’s integrative. There are multiple levels of organization and it addresses both APPLIED and BASIC questions
2) it obeys design laws: the laws of physics and chemistry
3) Physiological processes are shaped by evolution
4) most physiological processes are regulated by positive and negative feedback
_____ feedback maintains homeostasis, and ____ feedback generates an explosive response.
POSITIVE feedback maintains homeostasis, and NEGATIVE feedback generates an explosive response.
2 Central questions and EXPLANATIONS about animal physiology
1) Mechanistic explanation: “How does this work”: emphasized composition, structure and function
2) Evolutionary explanation:” “How does this become like this?” : emphasizes and loots at the roles of NATURAL SELECTION and selective environmental pressures that contribute to specific functions or structures being studied.
Homologous Traits
seen in 2 different evolutionarily related organisms (related by common ancestry), that have the same BASIC TRAIT but are FUNCTIONALLY different
(ex/ human arms vs wings)
Analogous Traits
similar structures and functions of unrelated species that evolved independently. ex/ birds and insects have WINGS (same function) but they are not related.
Hypothetico-deductive method
the process of creating a scientific theory. Using INduction and deduction
outline the hypothetico-deductive method
1) ask a question about the phenomena of nature
2) propose a bunch of hypotheses to possibly explain the phenomena via INDUCTION
3) use DEDUCTION to design the experiment and observations that test the hypothesis.
4) conduct the experiment
5) refine the hypothesis and desgin the new test
when does a new theory arise?
when a hypothesis is consistently supposed and all the alternative hypotheses have been falsified.
The Krogh Principle and an example
there is an ideal research animal that can be used to study and explore every type of phenomena.
ex/ studying nerves: use an animal with large nerves rather than a mouse. a giant squid with large axons may be the ideal animal
_____ is the father of MODERN physiology
_____ is the father of COMPARATIVE physiology
claude bernard: father of modern physiology
arther crowe; father of comparative physiology
Teleological Approach
method of studying by assuming that organism traits are explained in terms of their purpose in fulfilling a need, without questioning how this outcome is accomplished or evolved.
- there is no “mechanism” or “ultimate/evolution” question
refuting the teleological approach
some features are convoluted and not logical: why would an organism have a design that does not completely fulfill a need?
some features are vestigiaL: they no longer have purposes or fulfills a need, so why is it still in the organism?
Cost Benefit Trade Offs in Terms of evolution
adaptations have consts that negatively impact other adaptations. the largest trade off is energy. the larger structures for protection are made at a cost of reduced speed and flexibility. Many structures an organism has is not FULLY OPTIMAL, but it does balance the energy costs.
___ ___ compares systems of different species utilizing the horizontal approach.
comparative physiology
Why are comparative studies so important?
1) you can learn about the diversity of life
2) comparative studies allows us to determine universal functions.
comparative physiology research is motivated by the ____ principle.
Krogh principle: for any particular physiological process, some speices will have adapated in such a way that it proves an ideal model system for studying that process
biomimicry
the emulation of organismal adaptations by humans to create useful products (ex/ velcro imitates seed-spreading mobility mechanism)
Why are there no complex unicellular organisms?
there is a PHYSICAL SIZE CONSTRAINT that PREVENTS SPECIALIZATION. There are also diffusion limitations that effect the maximum size of a cell. If the size is too large, materials could not spread efficiently to all parts of the cell
4 main cellular functions of life
1) self organiztion
2) self regulation
3) self support and movement
4) self replication
how does a cell self-organize?
uses resources from the enviornmnet to reate the cell. It obtaines energy and raw materials and performs chemical reactions in specialized sequences (organized)
how does a cell self-regulate
maintains self-integrity in the face of disturbances aka maintains homeostasis.
the cell regulates by controlling the exchange of materials between the cell and its surrounding environment. It repairs damage to the cell and corrects deviations in internal conditions
how does a cell self-support and move
has sturctures that give form to specific cell types. Usually involves microfilaments and microtubules that allows or material and vesicle movemnet
how does a cell self-replicate
via mitosis and meiosis, it reproduces to carry on species and to repair damage.
4 main types of tissues
1) epithelial tissue
2) connective tissue
3) muscular tissue
4) nervous tissue
what is a tissue?
groups of cells with similar structure and function
function of epithelial tissues. give two types of epithelial tissues
epithelial tissues: cells that can exchange materials
includes
1) sheet tissues: covers and lines various organs. Serves as boundaries that separate the organism from external environment and from the contents of cavities
2) gland cells: cells that specialize in secretion.
2 types of glands
1) exocrine gland: secrete through ducts to the outside or into a cavity that communicates with the outside (ex/ sweat gland)
2) endrocrine gland: secrete their products directly into the blood stream with no ducts. (ex/ parathyroid hormong)
both glan systems are made of epithelial tissues.
function of connective tissues
connective tissue: a few cells dispersed within abundance of extracellular material to CONNECT, SUPPORT, and ANCHOR various body parts