PHYS Lab Quizzes

The Nernst equation can describe the membrane potential at which the chemical and electrical fluxes become equal in magnitude but opposite in direction for a particular ion. True or False?

True

Excitatory postsynaptic potential (EPSP)

A depolarization in the membrane of a postsynaptic neuron caused by the activation of postsynaptic receptors.

Inhibitory postsynaptic potential (IPSP)

A hyperpolarization in the membrane of a postsynaptic neuron that makes it more difficult for a postsynaptic neuron to generate an action potential.

During the absolute refractory period of an action potential, another action potential can be elicited if the second stimulus is strong enough. True or False?

False

Spatial summation

Graded membrane potential produced as multiple inputs, occurring at different synapses, are added together

Temporal summation

Graded membrane potential produced as repetitive inputs at one synapse, occurring at different times, are added together.

Depolarization

Membrane potential becomes less negative.

Hyperpolarization

Membrane potential becomes more negative than resting membrane potential.

Afterhyperpolarization

Membrane potential becomes more negative than resting potential at the end of an action potential.

Repolarization

Membrane potential returning from peak towards resting membrane potential.

Overshoot

Reversal of membrane potential polarity.

Which of the following THREE will you be doing in lab 3? a. Applying multiple stimuli at different time delays to differentiate relative and absolute refractory period of an action potential. b. Applying different stimuli strength to differentiate relative and absolute refractory period of an action potential. c. Applying toxins to neurons to investigate summation. d. Applying toxins to neurons to investigate postsynaptic potentials.

a. Applying multiple stimuli at different time delays to differentiate relative and absolute refractory period of an action potential. b. Applying different stimuli strength to differentiate relative and absolute refractory period of an action potential. d. Applying toxins to neurons to investigate postsynaptic potentials.

What are the three channel conformations for neuronal voltage-gated sodium channels? a. closed b. inactive c. popped d. open

a. closed b. inactive d. open

What are the two channel conformations of neuronal voltage-gated potassium channels? a. open b. inactive c. closed d. popped

a. open c. closed

Which TWO of the following neurotransmitters commonly have excitatory effects at neuronal synapses? a. Glycine b. Glutamate c. Acetylcholine d. GABA

b. Glutamate c. Acetylcholine

Which of the following statements is TRUE about action potentials? a. The generation of action potentials is never preceded by a graded potential. b .The direction of action potential propagation is towards the membrane segment that is in absolute refractory period. c. Action potential propagation in a myelinated neuron is called saltatory conduction. d. Action potentials decrease in magnitude with distance (from the stimulus) along the axon.

c. Action potential propagation in a myelinated neuron is called saltatory conduction.

The initial segment of a neuron will reach threshold when: a. Enough inhibitory postsynaptic potentials (IPSPs) summate. b. Enough equal magnitude of EPSPs and IPSPs summate. c. Enough inhibitory neurotransmitters are released and bind to their respective receptors. d. Enough excitatory postsynaptic potentials (EPSPs) summate.

d. Enough excitatory postsynaptic potentials (EPSPs) summate.

Which correctly describes a difference between a graded potential and an action potential? a. A graded potential is a type of membrane potential b. Graded potentials have a threshold and refractory period. c. Graded potentials can only depolarize. d. Graded potentials magnitude can vary depending on the strength of the stimulus.

d. Graded potentials magnitude can vary depending on the strength of the stimulus.

In a biological system, the electrical charges that produce a membrane potential come from... a. Batteries b. Water molecules c. Lipids d. Ions

d. Ions

Which of the following statements is true about this lab? a. You, the researcher, will only be changing intracellular concentrations of ions to manipulate membrane potential. b. You, the researcher, will not be using the Nernst equation to calculate the equilibrium potential of an ion. c. You, the researcher, will be stimulating intracellular recordings on a human axon. d. Tetraethylammonium (TEA) blocks K+ channels. e. The "Results" window shows the conductance traces for Na+ and Ca+2.

d. Tetraethylammonium (TEA) blocks K+ channels.

Which of the following is FALSE about the resting membrane potential? a. In mammalian cells, the value of the resting membrane potential is mainly determined by the permeability of K+. b. The magnitude of the resting membrane potential is negative inside the cell relative to the outside of the cell. c. It is the steady transmembrane potential of a cell that is not producing an electrical signal. d. The resting membrane potential is negative because the intracellular concentration of sodium is higher than the intracellular concentration of potassium.

d. The resting membrane potential is negative because the intracellular concentration of sodium is higher than the intracellular concentration of potassium.

Why can another action potential be elicited during the relative refractory period? a. There are enough voltage-gated sodium (Na+) channels in the inactive state before the next stimulus. b. There are enough voltage-gated potassium (K+) channels in the open state before the next stimulus. c. There are enough voltage-gated sodium (Na+) channels in the open state before the next stimulus. d. There are enough voltage-gated sodium (Na+) channels in the closed state before the next stimulus.

d. There are enough voltage-gated sodium (Na+) channels in the closed state before the next stimulus.