CBNS 120 Final Test Questions & Answers 2024/2025
Santiago Ramón y Cajal, 1885-90 (Neurons and Signalling) - ANSWERSPrinciple of Dynamic Polarization
- Information flows in a predictable and consistent direction within a nerve cell.
- Information flow begins at the receiving (input) sites o...
Santiago Ramón y Cajal, 1885-90 (Neurons and Signalling) - ANSWERSPrinciple of Dynamic Polarization
- Information flows in a predictable and consistent direction within a nerve cell.
- Information flow begins at the receiving (input) sites on the dendrites and soma to
the trigger zone at the axon hillock (initial segment).
- At the axon hillock, the action potential is initiated and propagated unidirectionally
along the axon to the presynaptic transmitter-release sites at the axon terminal.
- Neurons differ greatly in form and function, but most adhere to this pattern of
information flow.
Visualizing Neuron Anatomy
-Visualized first nerve cells.
-Perfected the Golgi Silver Stain, staining only 5% of neurons it contacted. Was used to see entire nerve
cells. It was the first time that individual nerve cells had been visualized, providing evidence for the
Neuron Doctrine or cellular hypothesis of neurons.
Sakmann & Neher, 1978-81 (Structure and Function of Ion Channels) - ANSWERSThe patch clamp was
invented by Erwin
Neher and Bert Sakmann in 1978, earning
them a 1991 Nobel Prize.
This technique has been used to observe
current flowing through single ion channels,
using extremely sensitive current-to-voltage
converters.
,Roderick MacKinnon, 2001 (Structure and Function of Ion Channels) - ANSWERS2003 Nobel Prize winner.
Studied K+ leak channels, discussing their selectivity and rapid rate of ion travel.
J.Z. Young, 1936 (Resting Membrane Potential) - ANSWERSSQUID GIANT AXON.... discovered by the great
zoologist J.Z. Young in 1936
J.Z Young demonstrating dissection of squid giant axon
Baker et al. were able to squeeze out the axoplasm and perfuse the giant axon, allowing them to change
ionic concentrations both outside and inside the axon while monitoring the resulting changes in
membrane
potential.
Julius Bernstein, 1902, 1912 (Resting Membrane Potential, Action Potentials)ees - ANSWERSThe idea
that Erest in nerve and muscle cells results from an unequal inside/outside distribution of ions (mainly
K+) dates back to the "Membrane Theory" of Julius Bernstein (1902).
measurement of "injury potentials" in muscle and nerve (1902) Bernstein found that injury potentials
recorded from frog muscle or nerve varied linearly with
changes in absolute temperature as would be predicted from the NERNST EQUATION, assuming K+ to be
the main permeant ion. Injury potentials were an early method of monitoring membrane potential from
a population of muscle fibers, before intracellular recording techniques were developed.
- Julius Bernstein (1912) suggested that all ionic "gates" open up during an AP ("breakdown" of
membrane resistance). If true, Em should go to 0 mV during an AP
The feedback amplifier generates a current that is
directly proportional to the difference between the
measured membrane potential and the command
, potential.
Hodgkin & Huxley, 1952 (Action Potentials) - ANSWERSThe Hodgkin-Huxley model for the squid giant
axon was used to reconstruct the voltage changes occurring during the action potential...
William Thomson ("Lord Kelvin"), 1855-56 (Neurons as Conductors of Electricity) -
ANSWERSMathematics and analyzation of passive membrane properties were first formulated for the
trans-Atlantic undersea telegraph cable. Passive membrane properties are sometimes referred to as
"cable properties
Furshpan & Potter, 1959 (Synaptic Transmission I) - ANSWERS- Demonstrated rectifying synapse is the
electrical connection between the lateral giantaxon and the giant motor axon that innervates fast flexor
muscles of the tail in the crayfish ventral nerve cord. When this synapse was first described by Furshpan
& Potter in 1959, it was the 1st demonstration of an electrical synapse.
John Eccles, 1950s (Synaptic Transmission I) - ANSWERSProved Direct inhibitory chemical
the amount of transmitter release is a function of the level of presynaptic depolarization
B) Ca++ entry into the presynaptic terminal is both required and sufficient for release.
C) Voltage-gated Ca++ channels are located near sites of transmitter release.
Fatt & Katz, 1952 (Synaptic Transmission III) - ANSWERSEVIDENCE for quantal release of NT at the
neuromuscular junction:
Rodolfo Llinás, 1980s-90s (Synaptic Transmission III) - ANSWERSLocalization of Ca++ entry near the sites
of transmitter release...
Depolarization of presynaptic terminal is not sufficient for release.
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