Physiology lab exam 1

Which TWO of the following neurotransmitters commonly have excitatory effects at neuronal synapses?

Glutamate and Acetylcholine

Membrane potential becomes more negative than resting membrane potential. corresponds with

Hyperpolarization,

What are TRUE statements about the resting membrane potential?

In mammalian cells, the value of the resting membrane potential is mainly determined by the permeability of K+. It is the steady transmembrane potential of a cell that is not producing an electrical signal. The magnitude of the resting membrane potential is negative inside the cell relative to the outside the cell.

would produce EPSPs in a resting neuron

Opening of calcium (Ca2+) channels. Opening of non-specific cation channels.

Reversal of membrane potential polarity. corresponds with

Overshoot,

What is a FALSE statement about the resting membrane potential?

The resting membrane potential is negative because the intracellular concentration of sodium (Na+) is higher than the intracellular concentration of potassium (K+).

Action potential propagation in a myelinated neuron is called what

saltatory conduction.

the voltage-gated potassium (K+) channels (not leak channels) are mainly doing what before the stimulus occurs

they are closed

the voltage-gated sodium (Na+) channels (not leak channels) are mainly doing what during hyperpolarization

they are transitioning from inactive to closed

the voltage-gated potassium (K+) channels (not leak channels) are mainly doing what during hyperpolarization

they are transitioning from open to closed

the voltage-gated sodium (Na+) channels (not leak channels) are mainly doing at the peak of the action potential

they are transitioning from open to inactive

Excitatory postsynaptic potential (EPSP) is

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

Inhibitory postsynaptic potential (IPSP) is

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

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

Afterhyperpolarization

what is done for lab three

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

Membrane potential becomes less negative. corresponds with.

Depolarization,

The initial segment of a neuron will reach threshold when:

Enough excitatory postsynaptic potentials (EPSPs) summate.

what is the procedure of neurotransmitter release starting from exocytosis

Exocytosis of neurotransmitters into synaptic cleft. Neurotransmitters activate receptors and postsynaptic potentials are produced.

Spatial summation is

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

Temporal summation is

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

Which correctly describes a DIFFERENCE between a graded potential and an action potential?

Graded potential magnitude can vary depending on the strength of the stimulus.

would produce IPSPs in a resting neuron

Opening of potassium (K+) channels. Opening of chloride (Cl-) channels. (Assume ECl- = -80mV)

what is the procedure of neurotransmitter generation starting from the firing of an action potential

Presynaptic neuron fires action potential. Action potential reaches axon terminal. Voltage-gated calcium (Ca2+) channels open. Increase of intracellular calcium (Ca2+) concentrations. Synaptic vesicle fused to axon terminal.

Membrane potential returning from peak towards resting membrane potential. corresponds with

Repolarization,

Why can another action potential be elicited during the relative refractory period?

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

True or false, 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

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

false

In a biological system, the electrical charges that produce a membrane potential come from which of the following: Water molecules, Lipids, Batteries, or ions.

ions

What are the TWO channel conformations of neuronal voltage-gated potassium (K+) channels?

open and closed

What are the THREE channel conformations for neuronal voltage-gated sodium (Na+) channels?

open, closed, and inactive

the voltage-gated sodium (Na+) channels (not leak channels) are mainly doing what before the stimulus occurs

they are closed

the voltage-gated potassium (K+) channels (not leak channels) are mainly doing what during repolarization

they are open

the voltage-gated sodium (Na+) channels (not leak channels) are mainly doing what during depolarization

they are transitioning from closed to open