BackChapters 3 and 5 (Physiology)
Terms in this set (28)
Physical isolation, regulation of exchange with environment, communication via proteins, and structural support stabilizing cytoskeleton and forming junctions.
Phospholipids, sphingolipids, cholesterol, integral proteins, peripheral proteins, and carbohydrates form a dynamic lipid bilayer.
Decreases permeability to small water-soluble molecules and maintains membrane fluidity across temperatures.
Integral proteins span the bilayer and have enzymatic, receptor, or transport roles; peripheral proteins are loosely attached and often linked to the cytoskeleton or enzymatic functions.
Gap junctions, tight junctions, and anchoring junctions connect cells and regulate communication and barrier functions.
Allow ions and small molecules to pass directly between cells via connexons made of connexins; important in smooth and cardiac muscle.
Seal cells together with claudins and occludins to create a selective barrier, forcing solutes to cross cells (transepithelial transport).
Cell-cell junctions use cadherins; adherens link actin fibers, desmosomes link intermediate filaments; cell-matrix junctions use integrins like hemidesmosomes and focal adhesions.
Neural, muscle, connective, and epithelial tissues.
Excitable cells that transmit electrical and chemical signals.
Excitable cells capable of contraction to produce force.
Protect internal environment and regulate exchange between intracellular and extracellular fluids.
One or more cell layers separated from underlying tissue by basal lamina composed of collagen and laminin.
Layering: simple or stratified; Shape: squamous, cuboidal, or columnar.
Exchange (simple squamous), transporting (cuboidal/columnar with microvilli), ciliated, protective (stratified, keratinized), and secretory (glands).
Exocrine glands release products via ducts to external environment; endocrine glands release hormones into extracellular fluid or blood.
Intracellular fluid (ICF) is 2/3 total body water; extracellular fluid (ECF) is 1/3, subdivided into interstitial fluid and blood plasma.
The body's ability to maintain a relatively constant internal environment despite external changes.
Osmotic equilibrium means water concentration is balanced; chemical equilibrium is not reached due to uneven solute distribution maintained by energy use.
Osmolarity is osmoles per liter of solution; osmolality is osmoles per kilogram of water, used clinically to estimate body water content.
Tonicity describes a solution's effect on cell volume (water movement), depending on nonpenetrating solutes; osmolarity compares total solute concentration between solutions.
Hypotonic causes water influx into cells; hypertonic causes water efflux; isotonic causes no net water movement.
Sodium-potassium pump uses ATP directly to move ions against their concentration gradients.
Uses energy stored in ion gradients created by primary active transport to move other molecules, often sodium-driven symport or antiport.
Channels allow rapid passive movement of small ions without binding; carriers bind molecules and undergo conformational changes, slower but can move larger molecules.
Phagocytosis (cell eating), pinocytosis (cell drinking), receptor-mediated endocytosis, and exocytosis for large molecule transport; all require energy.
Paracellular passes substances between cells; transcellular passes substances through cells using membrane transporters and vesicular transport.
Control paracellular permeability, forcing solutes to cross via transcellular routes.