Resting Membrane Potential Flashcards
exam 2 material
what is the cell membrane made out of?
phospholipid bilayer
what does the cell membrane contain?
channel proteins, receptor proteins, and ion pumps/pump proteins
what are channel proteins?
quaternary structures of proteins containing subunits that act as channels for the passage of select ions
what are receptor proteins?
ionotropic-like receptors that bind to neurotransmitters, causing the release of something else within the cell
what are ion pumps/pump proteins?
enzymes that use ATP to move ions across the membrane
what is membrane potential?
difference in electrical charge between the inside and the outside of the cell, voltage
what is current?
the rate of flow of ions
what are the cations and anions that control current?
cations: sodium (Na+) and potassium (K+)
anions: chloride (Cl-) and proteins (A-, too large to cross membrane)
what is membrane potential determined by?
differences in ion concentrations across the membrane (active transporters) and the membrane being selectively permeable to some ions (ions channels)
what are the 7 components of the electrophysiology rig and what do they do?
faraday cage: blocks outside electric signals
air table: prevents vibrations
amplifier: compares signals of recording and reference electrode
oscilloscope/digitizer: visualizes the voltage
microscope/stereotax: allows you to visualize and move the electrode
microelectrodes: electrolyte filled micropipette that measures charge
reference (ground) electrode: records reference charge
what are the three types of electrophysiology techniques?
extracellular recording, intracellular recording, and patch clamp recording
ex vivo vs in vivo
ex vivo: tissue slices, cultured cells, or cell lines
in vivo: anesthetized or freely moving animals
what is extracellular recording?
least sophisticated, measurements are taken away from the cell so that only the strongest signals (action potentials, uV) are recorded, single/multi unit recordings can be taken, the spike pattern of each cell can be analyzed in order to identify cell types, local field potentials are recorded to determine if a certain cell population is active or not
what is intracellular recording?
more precise than extracellular, measures graded local potentials (IPSPs and EPSPs, mV), voltage clamp allows you to fix voltage and measure current, current clamp allows you to inject a current and measure the resulting membrane potential (voltage)
what is patch clamp recording?
most advanced, measure channel dynamics and currents using a micropipette with electrodes in electrolyte solution; current or voltage clamp
what are the four types of patch clamp recording?
cell attached recording, whole cell recording, inside-out recording, and outside-out recording
what is cell attached recording?
uses mild suction to surround individual channel and record current and channel dynamics from that small patch of membrane
what is whole cell recording?
uses strong suction to create a hole in the membrane that allows you to measure potentials/currents in the whole cell and inject chemicals
what is inside-out recording?
uses suction to remove a channel from the membrane, allowing the cytoplasmic side to be manipulated, currents are then recorded from that channel to investigate how the manipulation can altered that channel
what is outside-out recording?
suction is used to grab either side of the membrane surrounding a channel and flip the channel, allowing the external side of the channel to be manipulated, currents are then recorded from that channel to investigate how the manipulation has altered that channel
what is in vivo microendoscopy?
a camera that films the inside of the brain in order to detect color changes that are caused when calcium is present (indicating the presence of an action potential)
what is fiber photometry?
less sophisticated version of in vivo microendoscopy, a fiber is used to detect fluorescence by recording the amount of brightness emitted
