CBNS 120 FINAL QUESTIONS WITH VERIFIED
ANSWERS
Santiago Ramón y Cajal, 1885-90 (Neurons and Signalling) - Answers - Principle 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) - Answers - The
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) - Answers - 2003
Nobel Prize winner. Studied K+ leak channels, discussing their selectivity and rapid rate
of ion travel.
J.Z. Young, 1936 (Resting Membrane Potential) - Answers - SQUID GIANT AXON....
discovered by the great zoologist J.Z. Young in 1936
J.Z Young demonstrating dissection of squid giant axon
Baker, Hodgkin & Shaw, 1961, 62 (Resting Membrane Potential) - Answers - Baker,
Hodgkin & Shaw (1961; 62)
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 -
Answers - The 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
K.S. Cole, 1949 (Action Potentials) - Answers - K.S. Cole (1949) invented the "voltage
clamp."
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) - Answers - The 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) -
Answers - Mathematics 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) - Answers - Proved Direct inhibitory
chemical
synaptic transmission -
cat spinal motoneuron.
, Bullock & Hagiwara, 1957 (Synaptic Transmission III) - Answers - A) Presynaptic
depolarization triggers transmitter release;
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) - Answers - EVIDENCE for quantal
release of NT at the
neuromuscular junction:
Rodolfo Llinás, 1980s-90s (Synaptic Transmission III) - Answers - Localization of Ca++
entry near the sites of transmitter release...
Depolarization of presynaptic terminal is not sufficient for release.
Ca++ entry is required ....
Heuser et al., 1979 (Synaptic Transmission III) - Answers - Freeze-fracture technique
used with scanning EM to "capture" presyn. vesicles
The "slammer" (cryopress)
Lowenstein & Mendelson 1965 (Sensory Receptors and Transduction I) - Answers -
!Pacinian corpuscles!
Mechanical component of adaptation in
Pacinian corpuscles (Lowenstein and
Mendelson, 1965):
Removal of layered capsule changes
receptor potential from rapidly to slowly
adapting. A local anesthetic (procaine)
was used in these experiments to block
APs.
A.J. Hudspeth (1982) - Answers - Extracellular recording of micro currents flowing
around hair cell and hair bundle during movement of hair bundle
Site of current influx of hair cell during movement of hair bundle is at the tips of
stereocilia.
Georg von Békésy, 1950s (Sensory Receptors and Transduction I) - Answers - In the
cochlea, Low freq. sound causes greatest vibration at apex; high freq. sound causes
greatest vibration at base.
George Wald, 1950s (Sensory Receptors and Transduction III) - Answers -
ANSWERS
Santiago Ramón y Cajal, 1885-90 (Neurons and Signalling) - Answers - Principle 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) - Answers - The
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) - Answers - 2003
Nobel Prize winner. Studied K+ leak channels, discussing their selectivity and rapid rate
of ion travel.
J.Z. Young, 1936 (Resting Membrane Potential) - Answers - SQUID GIANT AXON....
discovered by the great zoologist J.Z. Young in 1936
J.Z Young demonstrating dissection of squid giant axon
Baker, Hodgkin & Shaw, 1961, 62 (Resting Membrane Potential) - Answers - Baker,
Hodgkin & Shaw (1961; 62)
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 -
Answers - The 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
K.S. Cole, 1949 (Action Potentials) - Answers - K.S. Cole (1949) invented the "voltage
clamp."
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) - Answers - The 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) -
Answers - Mathematics 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) - Answers - Proved Direct inhibitory
chemical
synaptic transmission -
cat spinal motoneuron.
, Bullock & Hagiwara, 1957 (Synaptic Transmission III) - Answers - A) Presynaptic
depolarization triggers transmitter release;
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) - Answers - EVIDENCE for quantal
release of NT at the
neuromuscular junction:
Rodolfo Llinás, 1980s-90s (Synaptic Transmission III) - Answers - Localization of Ca++
entry near the sites of transmitter release...
Depolarization of presynaptic terminal is not sufficient for release.
Ca++ entry is required ....
Heuser et al., 1979 (Synaptic Transmission III) - Answers - Freeze-fracture technique
used with scanning EM to "capture" presyn. vesicles
The "slammer" (cryopress)
Lowenstein & Mendelson 1965 (Sensory Receptors and Transduction I) - Answers -
!Pacinian corpuscles!
Mechanical component of adaptation in
Pacinian corpuscles (Lowenstein and
Mendelson, 1965):
Removal of layered capsule changes
receptor potential from rapidly to slowly
adapting. A local anesthetic (procaine)
was used in these experiments to block
APs.
A.J. Hudspeth (1982) - Answers - Extracellular recording of micro currents flowing
around hair cell and hair bundle during movement of hair bundle
Site of current influx of hair cell during movement of hair bundle is at the tips of
stereocilia.
Georg von Békésy, 1950s (Sensory Receptors and Transduction I) - Answers - In the
cochlea, Low freq. sound causes greatest vibration at apex; high freq. sound causes
greatest vibration at base.
George Wald, 1950s (Sensory Receptors and Transduction III) - Answers -
