NEUR 305 Practice Exam 1
True or False: The Nernst equation determines the overall membrane potential
False
Purkinje cells are located in the ____________.
Cerebellar cortex
True or False: Current, I, is the movement of ions across the membrane.
True
What are usually generated at the axon hillock and are conducted away from the cell body?
Action Potentials
Which of the following properties of neuronal projections affect the electrotonic potential? Membrane resistance Length constant Diameter All of the above
All of the above
Slow axonal conductance travels in which direction and what motor protein is most commonly associated with this function?
Anterograde; dynein
In an electron micrograph, what is the category of synapse where there is more darker shading on one side of the synapse?
Asymmetric synapse
Which ions are important when discussing the electrical properties of neurons?
Ca2+, Cl-, K+, Na+
In an electron micrograph, what region of the cell is shown by a presynaptic neuron wrapping around a postsynaptic neuron
Axon terminal
What do axons not have, regarding the function and morphology of axons and dendrites?
Axons usually have a significant taper and small spinous processes that give them a n irregular cross section.
What is not a function of microglia?
Control levels of extracellular glutamate
I
Current
What is the correct sequence of events for synthesis of an integral membrane protein?
DNA -> mRNA -> ribosome of rough ER -> protein -> vesicle -> golgi apparatus -> vesicle -> outside cell membrane
Nernst Equation
Eion = RT/zF * log10 ([ion]outside/[ion]inside)
Rm * Cm
Equal to the time constant
Eion
Equilibrium potential for an ion
True or False: Every neuron in the brain has the same type of firing activity.
False
F
Faraday's constant
In order to determine the overall membrane potential, you would use which equation?
Goldman-Hodgkin-Katz Equation
What is the difference between a house mouse and a grasshopper mouse's reaction to scorpion venom?
House mouse has extended flow of sodium ions; grasshopper mouse has decreasing flow of sodium ions
When K+ ions flow down their concentration gradient out of the neuron, this leads to what?
Hyperpolarization
Which statement is true about neuronal projections?
Increasing the internal resistance of a neuronal projection will decrease the length constant.
Ri
Internal Resistance
________________ usually send inhibitory signals to its targets.
Interneurons
During an action potential, the membrane potential of the cell rapidly overshoots 0 mV , and approaches the equilibrium potential for what ion?
K+
The axon hillock and axon intial segment contain large numbers of __________.
voltage-sensitive ion channels
Rm
Membrane Resistance
Cm
Membrane capacitance
What component is not considered in the equation for the length constant (aka space constant) but does affect the speed of electrotonic spread (time constant)?
Membrane capacitance
What is not delivered by fast axonal conductance?
Microtubules
During an action potential, when reaching the top of the rising phase, the membrane potential becomes close to the equilibrium potential of what ion?
Na+
Saltatory conduction is due to the high concentration of voltage-gated _____ channels in the nodes of Ranvier.
Na+
What ion current does TTX block?
Na+
Where does saltatory conduction occur in a neuron?
Nodes of Ranvier
Where is the voltage sensitivity domain of the voltage-gated sodium channel located?
The S4 unit of the alpha subunit
Spread of electrotonic potential is __________ while propagation of action potentials is _________
Passive; active
The components of a synapse include a presynaptic element, a cleft, and a _____________.
Postsynaptic element
What level of protein structure do missense mutations occur?
Primary
Which of the following cell types is/are excitatory? Pyramidal cells Purkinje cells Medium-sized spiny cells All of the above
Pyramidal cells
What do the letters R and T represent in the Nernst equation?
R represents the gas constant; T represents temperature
In what stage of the action potential do voltage-gated K+ channels begin to open?
Repolarization/Hyperpolarization
Which of the following is NOT a type of glial cell in the nervous system? Schwann cell Astrocyte Oligodendrocyte Microglia
Schwann Cell
Which type of glial cell is found in the peripheral nervous system
Schwann cells
What specialized structure increases the surface area of the dendrites and is usually the site of excitatory synapses?
Spines
What is the difference between TTX and homobatrachotoxin?
TTX blocks voltage-gated sodium channels; homobatrachotoxin prevents voltage-gated sodium channels from closing
In order to determine the equilibrium potential specifically for K+, you would use which equation?
The Nernst Equation
What does the Nernst Equation tell us?
The equilibrium potential of a single ion
Which of the following statements is FALSE? -Some synaptic vesicles released at the presynaptic terminal are recycled via membrane endocytosis -Microtubules in axons have mixed polarity with both plus and minus ends oriented distal to the cell body -The golgi apparatus is responsible for modifying, sorting, and targeting membrane-bound proteins
The golgi apparatus is responsible for modifying, sorting, and targeting membrane-bound proteins
What does the Goldman-Hodgkin-Katz equation tell us?
The overall membrane potential
Myelination increases the membrane resistance of an axon
True
The thickness of myelin can vary amongst different neurons
True
True or False: Integral membrane proteins, peripheral proteins, and cytoplasmic proteins are all synthesized by ribosomes of the rough endoplasmic reticulum and trafficked through the Golgi apparatus.
True
What is the correct term to properly classify the type of neuron pictured below?
Unipolar
GHK equation
Vm = RT/F * ln((p[K+]o + p[Na+]o + p[Cl-]i)/(p[K+]I + p[Na+]I + p[Cl-]o))
What is an example of an integral membrane protein?
Voltage-gated sodium channel
Which correctly identifies the components of a tripartite synapse?
a presynaptic axon terminal, postsynaptic dendrite, and an astrocyte
What portion of the golgi does a protein enter and what is something that gets removed from the protein?
cis golgi network, sugars
As internal resistance (Ri) increase, the length of the electrotonic spreads ____________
decreases
As the membrane resistance (Rm) increases, the length of electrotonic spread ___________
increases
Vm
membrane potential
Increasing the ____________________ and __________________ of a neuronal projection will increase the length constant of that projection.
membrane resistance; distance
What do the letter p and the brackets represent in the equation?
p represents membrane permeability; the brackets represent the concentration
The sodium/potassium pump works to pump ____________ inside the cell and __________ outside the cell.
potassium; sodium
Gamma
the space/length constant
z
valence of an ion
The neurotoxin TEA blocks _____________
voltage-gated potassium channels