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