Which one of these is an example of an excitatory postynaptic potential in a typical neuron? a) A voltage change from -70mV to -70.5mV b) A voltage change from +35mV to 0MV c) A voltage change from 0mV to +0.35mV d) A voltage change from -69.5mV to -70mV

The normal concentrations for intracellular and extracellular potassium in a neuron are [K+]in = 150 mM and [K+]out = 5 mM, respectively. Due to an electrolyte imbalance, a patient has the following intracellular and extracellular concentrations of potassium: [K+]in = 140 mM and [K+]out =2 mM. Using the Nernst equation (Chapter 4), calculate the equilibrium potential for potassium in the cells with normal K+ distributions and of the diseased patient. Refer back to Question #1. Will it be easier or more difficult to generate an action potential in the diseased neuron as compared to the normal neuron? Why?

After the depolarisation phase of an action potential, the resting potential is restored by ______.   Question 15 options:   A)  the opening of voltage-gated potassium channels and the closing or inactivation of sodium channels.   B)  the opening of more voltage-gated sodium channels.   C)  a decrease in the membrane's permeability to potassium and chloride ions following closing of the chloride-potassium pump.   D)  a brief inhibition of the sodium-potassium pump.

When someone feels a chafing sensation in their legs. In order to perceive this chafing sensation, neural impulses would travel in one direction from the a) skin b) spinal cord c) skeletal muscle d) brain to his a) brain b) skin c) spinal cord d) skeletal muscle. This information would travel via a) GSA neurones b) GSE neurones c) GVA neurones d) GVE neurones   A person starts to sweat. This info to the sweat glands would be transmitted via A) GSA neurones b) GSE neurones c) GVE neurones d) GVA neurones in order to regulate their body temperature. The neural impulses would travel in one direction from a) dura mata b) CNS c) PNS d) skin to a) dura mata b) PNS c) CNS d) skin.   Select correct answer from options : a, b, c, d

Compound X has been shown to block voltage-gated K+ channels with an IC50 of 0.1 mM. Which of the following is the most likely to occur in neurones following application of 0.03 mM X?     Action potentials would be prolonged and the resting potential would be depolarised.     Action potentials would be prolonged but the resting potential would remain the same.     Neither resting potential nor action potentials would be affected because the concentration of X is less than the IC50 value.     The resting membrane potential would depolarise but there would be no effect on action potentials.

Separately, draw a table using arrows to depict the appropriate magnitude and direction of the forces and ion fluxes at different membrane potentials for a ligand-gated channel that is equally permeable to both ion X+ and ion Y+.   The equilibrium potential for ion X+ is -60 mV, and the equilibrium potential for ion Y+ is -20 mV. Which item (a, b, c, or d) best represents the forces and fluxes for a membrane potential of +20 mV? Upwards arrows means outward direction and downwards arrow means inward direction. The length of the arrow determines the magnitude.

What is the intracellular voltage for Cl- if the intracellular concentration was 5 mM and the extracellular concentration was 130 mM. Write the voltage as a number in mV inside the cell relative to that outside, eg. -72 or + 90. Question 2. What is the intracellular voltage for Ca++ if the intracellular concentration was 0.0008 mM and the extracellular concentration was 0.6 mM. Write the voltage as a number in mV inside the cell relative to that outside, eg. -72 or +90. Round to the nearest milli Volt.

What is a typical speed of action potential propagation in the absence of myelination?  (Not the maximum speed, just the typical speed). A) 1 m/min B) 1 m/sec C) 10 m/sec D) 100 m/sec E) 1000 m/sec

A neuron is moving from a voltage of -60 mV to -40 mV. This neuron is .... A) hyperpolarizing B) is making a contraction. C) repolarizing D)depolarizing

A sodium channel in a nerve membrane a)Inactivation gate closes when the membrane reaches ~+30 mV. b)Opens and closes quickly. c)Activation gate opens when the membrane reaches threshold voltage. d)'Resets' when the membrane reaches resting potential .