Cell Physiology & Homeostasis: Key Concepts and Processes

Order of Complexity

Molecules, organelles, cells, tissues, organs, organ systems, organism

Receptors

Stucture that senses change in the body

Integrating (control) center

control center that processes the sensoryinformation, "makes a decision," and directs the response (e.g., cardiac center of thebrain)

Effector

cell or organ that carries out the final corrective action to restorehomeostasis

Gradient

difference in chemical concentration, charge, temperature, or pressurebetween two points

Plasma membrane functions

• Defines cell boundaries

• Governs interactions with other cells

• Controls passage of materials in and out of cell

Simple diffusion

net movement of particles from place of high concentration toplace of lower concentration

Osmosis

net flow of water through a selectively permeable membrane

Tonicity

ability of a surrounding solution (bath) to affect fluid volume andpressure in a cell

Hypotonic solution

causes cell to absorb water and swell (has a lower concentration of non-permeating solutes than intracellular fluid)

Hypertonic solution

cell to lose water and shrivel (Has a higher concentration of non-permeating solutes than ICF)

Isotonic solution

causes no change in cell volume (Concentrations of non-permeating solutes in bath and ICF are the same)

Facilitated diffusion

carrier moves solute down its concentration gradient ( doesn't require ATP)

Primary active transport

carrier moves solute through a membrane UP its concentration gradient (requires ATP)