Anatomy and Physiology Lecture 1 Quiz

Anatomy and Physiology, I Lecture 1 Quiz                   Anatomy the study of structure Physiology The study of function Principle of complementarity function always reflects structure; OR physiology of a structure depends on its specific anatomy. EXAMPLE: various shapes of teeth reflect their action Chemical atoms and molecules Cellular cells and their organelles Tissue groups of similar cells that have a common function Organ contains two or more types of tissues Organ System organs that work together closely Organism all organ systems working together Homeostasis Maintence of a relatively stable internal environment despite continuous outside changes; a dynamic state of equilibrium Homeostatic Control Mechanisms involves continuous monitoring and regulation of many factors (variables); Nervous and endocrine systems send signals (communication channel) to cells, tissues, and organs via nerve impulses and hormones 3 components Receptor (sensor), control center, effector Receptor (sensor) monitors the environment; responds to stimuli (changes in controlled variables) Control Center determines the set point at which the variable is maintained; receives input from the receptor; determines appropriate response Effector receives output from the control center; provides the means to respond; response acts to reduce or enhance the stimulus (feedback) Negative Feedback response reduces or shuts off the original stimulus. EXAMPLES: regulation of body temperature (a nervous mechanism); regulation of blood sugar (an endocrine mechanism) Positive Feedback response enhances or exaggerates the original stimulus; may exhibit a cascade or amplifying effect; usually controls infrequent events. EXAMPLES: enhancement of labor contractions by oxytocin; platelet plug formation and clotting Elements -substances that cannot be broken down by ordinary chemical means; each element has unique physical and chemical properties; major elements of the human body-> O, C, H, N (96%) * Atom - unique building block for each element; composed of subatomic particles. * Neutrons - No charge (mass = 1 amu) * Protons - Positive charge (mass = 1 amu) * Electrons - Negative charge ( orbits around the nucleus, equal to number of protons in an atom, 1/2000 the mass of a proton -> 0 amu) * Atomic Number - number of protons in the nucleus; determines element * Mass Number - mass (or number) of the protons and neutrons in the nucleus * Isotopes - structural variations of elements that differ in the number of neutrons they contain-> different mass number *Radioisotopes - unstable isotopes that decompose spontaneously * Atomic Weight - weighted average of mass numbers of all isotopes of an atom as found in the nature * Molecule - two or more atoms bonded together; EXAMPLE: H2, C6H12O6 * Compound - Two or more different kinds of atoms bonded together; properties are very different from those of the atoms they contain; EXAMPLE: H2O, C6H12O6 * Chemical Bonds - Chemical substances being held together by the attraction of atoms between sharing or exchanging of electrons. * Chemically Inert Elements - stable and unreactive; outermost energy level fully occupied or contains eight electrons. EXAMPLE: Helium, Neon * Chemically Reactive Elements - outermost energy level not fully occupied by electrons; tend to gain, lose, or share electrons with other atoms to achieve stability -> chemical bond formation * Types of Chemical Bonds - ionic, covalent, hydrogen * Iconic Bonds - ions are formed by transfer of valence shell electrons between atoms; attraction of opposite charges results in an iconic bond; iconic compounds form crystals instead of individual molecules. EXAMPLE: NaCl (sodium chloride) * Anions - (- charge) -> gained one or more electrons * Cations - (+ charge) -> lost one or more electrons * Covalent Bonds - formed by sharing of two or more valence shell electrons; allows each atom to fill its valence shell at least part of the time Molecules Created By Covalent Bonds non polar molecules