Ch. 5 Membrane Dynamics Flashcards
ECF
1/3 of body water volume
Blood plasma+interstitial fluid
ICF
2/3 of body water volume
Diffusion
Movement of solutes down the gradient
-can be simple or facilitated (needs transport protein)
Osmosis
Movement of water to equalize solute concentration
-Moves from hypotonic to hypertonic
Protein Pump
Direct Active transport
- uses exergonic reaction to drive transport
ex: Na/K Pump
Concomitant Transport
Indirect (secondary) Active Transport
Uses diffusion of another molecule to drive transport
(ex: Na/glucose symporter uses diffusion of Na into the cell to drive import of glucose)
Vesicular Transport
Indirect (Secondary) Active Transport
Membrane bound compartments interact at plasma membrane
-Endo- Exo- Phago- cytosis
Na/glucose symporter
Indirect (Secondary) Active Transport
Uses diffusion of Na into the cell to drive import of glucose
Molarity
Concentration of a solution (moles per liter)
Osmolality
Number of osmotically active particles per liter (OsM)
Dissociation of Particles
Affects osmolality
1M NaCl=1OsM Na and 1 OsM Cl
Osmometer
Measures osmolality
Membrane Receptors
Protein Mediated Transport
Lingand binding domain on outside of cell -> triggers response
Carrier Proteins
Protein Mediated Transport
Change shape
Protein Mediated Transport Devices
- Channel Protein (open and gated)
- Carrier Proteins
- Membrane Receptors
Phagocytosis
Actin microfilaments and myosin motor proteins of cytoskeleton change shape of membrane
-Vesicle fuses with lysosomes to degrade contents
Exocytosis
-Increase in intracellular Ca
-Rabs facilitate plasma membrane docking
SNARES facilitate membrane fusion
Endocytosis (receptor-mediated)
Receptor and clathrin coated pits trigger formation of vesicle
Endocytosis (caveolae)
Involve lipid rafts, receptors, and caveolins
- caveolins create caveolus shape
- viral infections
Hypercholesterolemia
Receptor-mediated cholesterol transport (endocytosis) with too few receptors
Apical Membrane
Faces inside of organ
-microvilli increase surface area for more transport proteins
Basolateral Membrane
Faces ECF
-separated from apical membrane by tight junctions
Types of Epithelial Transport
Paracellular transport
Transcytosis movement
Transcellular transport
Paracellular Transport
Epithelial Transport
-movement of molecules b/w cells
Transcytosis Movement
Epithelial Transport
-Through cells via vesicles
Transcellular Transport
Epithelial Transport
-Movement through cells uses transport proteins
Electrical cell-cell communication
Action potentials
Neurotransmitters
Chemical cell-cell communication
- Local mediators
- Gap junctions
- Autocrine and paracrine signals diffuse through ECF to nearby cells
- Hormones
Range of RMP
-65mV to -85mV
neurons are at -70mV
