Lecture 1 Flashcards
Physiology, defined
Study of the normal functioning; includes all chemical and physical processes
Return to and maintenance of homeostasis
Organization of life
Cells –> tissues –> organs –> organ systems –> organisms
Unit of life
The cell
Emergent properties
Properties generated by the interaction among “lifeless molecules” at each successive level of organization
What is an example of an emergent property?
Human consciousness; no single neuron holds the ability to generate this attribute, it is a sum of all the neurons that make complex emotions/thoughts
Integumentary system
Protection from external environment
Pathophysiology
Functional changes associated with disease and aging; study of failure to compensate to changes in condition (inability to return to homeostasis)
Pathology
Abnormal functioning, non-homeostasis (opposite of physiology, normal function)
Teleological approach to physiology
Explains “why” –> more philosophical, ex: why do red blood cells transport O2? Because cells need oxygen and red blood cells bring it to them.
Mechanistic approach to physiology
Describes “how” –> objective, ex: How do red blood cells transport O2? O2 binds to hemoglobin molecules contained in red blood cells.
Life processes of the human body
Metabolism, responsiveness, movement, growth, differentiation, reproduction –> all are interrelated
Homeostasis
Relatively constant internal environment, the ability to return to normal despite change or interruption (remaining stable)
Homeostasis is not equal to
Equilibrium –> homeostasis is constant changes to keep system stable, equilibrium implies same input and output, which is not always the case with homeostasis
Homeostatic control mechanism
Stimulus disrupts homeostasis –> alters a control variable –> change detected by receptors –> receptors signal control center (input) –> control center signals effectors (output) –> effectors bring change (response) –> response alters controlled variable to return system to homeostasis
Positive feedback mechanism vs. negative feedback mechanism
Positive feedback = more input from control variable causes output that increases control variable (ex. childbirth, hunger hormones)
Negative feedback = more input from control variable causes output that decreases control variable (or vice versa) (ex. blood pressure)
Independent vs. dependent variable
Independent: manipulated by experimental design
Dependent: measured to observe changes caused by independent variable
Why are human experiments difficult to perform?
Difficult to interpret results: genetic and environmental variability, placebo and nocebo effect, ethics
Histogram
Distribution chart (ex. use to show distribution of exam scores in a class)
Recurrent themes in physiology
- Homeostasis
- Biological energy use
- Structure-function relationship
- Communication
Components of an atom
Proton, neutron, electron
Atomic number
Number of protons
Atomic mass
Number of protons + neutrons
Isotopes
Different number of neutrons (more or less atomic mass)
Radioisotopes
Unstable, emit energy; used as tracers in medicine
Importance of electron shell
Dictates how molecules interact; full e- shell= inert, partial e- shell= reactive
Superoxide free radical
O2 gains an electron; can damage DNA, organelles, etc.
Cation vs. anion
Cation (+), anion (-)
Ionic bonds
Electron transfer, easily broken (ex. H2O dissolves NaCl)
Example of ionic, hydrogen and covalent bonds
Ionic: Na+, Cl- (table salt)
Hydrogen: Between water molecules
Covalent bonds: CH4 (methane) - sharing between C and H
Strongest to weakest bonds
Covalent –> ionic –> hydrogen –> van der waals interactions
Primary roles of electrons
- Ion and ionic bonds (transfer)
- Covalent bonds (share)
- High-energy electrons (ex. bioluminescence)
- Free radicals
Antioxidants
Inhibits oxidations; give electrons without damage (ex. Vitamins C, E)
Protection against free radicals
Where is energy stored within a molecule?
Within bonds
Molecule
2 or more linked atoms - can be atoms of same element, or compounds
**compounds can be molecules but molecules cannot be a compound
Covalent bonds
Strongest bonds, sharing of e-, creates polarity (positive and negative regions) of molecules
Van der Waals forces
Weak interaction between two nonpolar molecules
Aqueous
Water-based
Solution
Solutes (substances) dissolved in solvents (liquids)
Solubility
Ease of dissolution
