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active transport
the process of moving molecules across a cellular membrane through the use of cellular energy
adenosine 5-triphosphate (ATP)
a coenzyme that works with enzymes to transfer energy by releasing phosphate groups
anions
negatively charged ions
cations
positively charged ions
cytoplasm
fluid inside a cell but outside the nucleus
effector
an organ or tissue that receives information from the control center and acts to bring about the changes needed for homeostasis
extracellular fluid
the fluid that surrounds the cells of the body
feedback loop
a part of homeostasis that provides a mechanism for the body to maintain stability
homeostasis
a state of balance
homeostatic mechanism
a process that maintains the stability of the internal environment in response to fluctuations to external environmental conditions
homeostatic response system
a self-regulating process in which the body maintains stability
hydrostatic pressure
the pressure that any fluid in a confined space exerts
hyperosmolality
a condition in which the concentration of solutes in a solution is higher than normal
hypertonicity
a condition in which the tonicity of a solution is higher than that of the cytoplasm of a cell
hypoosmolality
a state in which the concentration of solutes in a solution is lower than normal
hypotonicity
a state in which the tonicity of a solution is lower than that of the cytoplasm of a cell
interstitial compartment
fluid that surrounds tissue cells
intracellular fluid
fluid that is contained within the cells of the body
intravascular compartment
fluid inside the blood cells and plasma
ions
atoms or groups of atoms that have one or more positive or negative electrical charges
iso-osmolality
a state in which the concentration of solutes in a solution is equal
isotonicity
a state in which the tonicity of a solution is equal to that of the cytoplasm of a cell
Na+K+ATPase pump
a protein pump that acts to transport sodium and potassium ions across the cell membrane by using adenosine 5-triphosphate (ATP)
negative feedback
a homeostatic process that counteracts a change, bringing the parameter back toward its set point
osmolality
the number of solute particles per kilogram of solvent
osmole
a unit of osmotic concentration
osmosis
the movement of water molecules from a solution with a high concentration of water molecules to a solution with a lower concentration of water molecules, through a cell’s semipermeable membrane
osmotic equilibrium
a state when the concentration of a solute in water is the same on both sides of a semipermeable membrane
osmotic pressure
the minimum pressure that must be applied to a solution to halt the flow of solvent molecules through a semipermeable membrane
positive feedback
feedback that amplifies or magnifies a change
receptor
part of the homeostatic system that receives information regarding balance within the body
semipermeable membrane
a membrane that allows certain molecules or ions to pass through it by diffusion or active transport
solutes
dissolved substances
tonicity
the ability of a solution to cause a cell to gain or lose water; it is relative to the cytoplasm of a cell
transcellular compartment
a small volume of fluid that is contained within certain body cavities and structures, also known as third space
transient change
a temporary change that can occur before the body returns to a steady state of homeostasis
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