Membrane Potential Flashcards
Body Fluid Compartments
ECF–outside cell membrane, plasma (fluid of blood), interstitial fluid (outside cells and outside confines of blood/lymph vessels)–volume and ionic composition regulated by kidneys–can change fast (1/3TBW)
ICF-within cell membrane, regulated by lipid bilayer, and various channels—changes slow (2/3 TBW)
What makes up ECF and ICF
water, electrolytes (substances that separate into ions), ions (cation and anion), other stuff (lipids and soluble proteins, ATP)
What makes up cell membrane
phospholipid bilayer (phospholipids/cholesterol), embedded proteins
Types of Embedded Proteins
- -Transporters: move stuff down a concentration gradient, or pump against gradient
- -Ion Channels: proteins that span membrane and have tunnel that allows specific ions through (absolutely or relatively specific)
Types of Ion Channels
non-gated: always open, passive
gated: can be opened or closed based on electrical, mechanical, or chemical conditions
Types of Movement Across Cell Membrane
Simple diffusion (concentration gradient--net movement!!) Active Transport (against concentration gradient)--3 Na+ out, 2 K+ in
Law of Electroneutrality
BULK!! portion of a solution must contain equal number of positive and negative charges
Location of Electrical Activity in the Body
The membrane is the only place of electrical activity
Location of Chemically Gated Channels
Dendrites
Location of Voltage Gated Channels
Axons
Location of Mechanically Gated Channels
Peripheral process of pseudounipolar sensory neurons
Why causes molecules to move (Hint: not just electrostatic force of ions)
heat
Word Definition of Resting Potential
the separation of charges that develops at the cell membrane (everything is still bulk neutral)
Relative concentrations of typical ions in mammalian cell and ECF
K+ : more in cytosol
Na+: more in ECF
Cl- : more in ECF
A- (other random anions): more in cytosol
