BCMB Definitions.doc

Human Physiology BCMB 230 Section 003 BCMB Definitions Chapter 1 Physiology- the study of how things function Molecular Cellular Tissue Organ Organ system Cell- the simplest structural unit Muscle- generate the mechanical forces that produce movement Nerve- initiate and conduct electrical signals, often over long distances; controls cell activities Epithelial- secretion and absorption of ions and organic molecules and for protection; rest on the extracellular protein layer called the basement membrane, which forms the boundaries between compartments and function as selective barriers regulating the exchange of molecules Connective- connect, anchor, and support the structures of the body; found in loose meshwork of cells and fivers and include adipose cells, bone cells, red blood cells, and white blood cells External environment- the environment surrounding the body Cell differentiation- each cell becomes specialized for the performance of a particular function; the process of transforming an unspecialized cell into a specialized cell Tissue- differentiated cells with similar properties Muscle Nerve Epithelial Connective Organ- a combination of tissues (heart, lungs, kidneys); many are organized into functional units Organ system- a combination of organs working together (urinary system) Extracellular fluid- the immediate environment that surrounds each individual cell in the blood in the body, which is found within a complex extracellular matrix- this combination of proteins (rope-like collagen fibers and rubberband-like elastin fibers) provides a scaffold for cellular attachments and transmits info in the form of chemical messengers to the cells to help regulate their activities, migration, growth, and differentiation; 20-25% plasma, 75-80% interstitial fluid Intracellular fluid- fluid inside cells that regulate events like growth and metabolism Internal environment- fluid that surrounds cells and exist in the blood Homeostasis- state of balance; dynamic not static; dynamic constancy- a given variable may vary in the short term, but is fairly constant when averaged over long-term Steady state- a condition when something is being added to maintain balance; equilibrium- unchanging but nothing is being added; set point- steady state condition Negative feedback- results with something being shut down Ex: thermostat- heat builds up and heater shuts down once homeostasis is reached Positive feedback- accelerates a process to an explosive system, less common Ex: blood clotting- cut yourself and blood clots quickly to prevent blood loss Feedforward- anticipates changes in regulated variables and minimized the amount of deviation from set point Ex: step into cold weather and body shivers before temp changes Reflex- involuntary, unlearned response to a stimulus Reflex arc- pathway mediating a reflex Stimulus- detectable change in internal/external environment Receptor- detects environmental change Integrating center- stimulus acts on a receptor and produces a signal that is sent to the integrating center by the afferent pathway and leaves by the efferent pathway and is sent to the effector Stimulus Receptor Afferent Pathway Integrating Center Efferent Pathway Effector Response Hormone- type of chemical messenger secreted into the blood by the endocrine system Neurotransmitter- chemical messengers that allow nerve cells to communicate with each other of with effector cells Adaptation- survival in specific environmental conditions; changes in a population not an individual Acclimatization- environmental change Chapter 2 Covalent bond- strongest chemical bond between 2 atoms; shared electrons around nucleus of both molecules Polar- unequal charge of sides; hyrdophillic (water-loving), lipophobic (lipid-fearing) Non-polar- lipophillic, hydrophobic Ionic bond- strong attractions between two oppositely charged molecules occurs when a loss/gain of electrons happens; relatively easily broken Amphipathic- small polar and large non-polar ends Hydrogen bond- attraction between 2 covalent bonds Concentration- amount of solute present in a unit volume of solution Solute- dissolved substance Solvent- the liquid in which solutes dissolve in Solution- the combination of solutes dissolving in a solvent