Key Terms
- 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