At which point in the graph do voltage-gated potassium channels open? (Base your answer to this question on the graph below depicting an action potential.) A B C D E

Show a complete circuit diagram of the model of the neuron using the specific numerical values for each component: potassium ion concentration outside: 4.0 mmol/L potassium ion concentration inside: 77.5 mmol/L

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?

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 force(s) act(s) to move potassium ions from the inside of the cell to the outside when a neuron is about to enter the hyperpolarization phase of an action potential? O a) The sodium-potassium pump Ob) The electrical (electrostatic) gradient only Oc) The concentration (chemical) gradient only d) Both the concentration (chemical) gradient and the electrical (electrostatic) gradient

13) Draw a graph representing the changes in membrane potential across the axonal membrane before, during, and after an action potential. On your graph, use a highlighter to clearly indicate for which portions of your graph the letter corresponding to each cellular event listed below belongs. List of cellular events: A) All K* channels open B) All Na* channels close C) The Na*/K* ATPase cotransporter transports Na* and K* across the membrane. D) All Na* channels open E) The threshold value of membrane potential is attained. F) All K* channels close G) Some Na* channels open Your graph:

A membrane potential (Vm) labeled axis on the graph In the graph draw the phases of the action potential Include the channels involved and when they open and close matching them to the Vm Indicate the periods in which the action potential can or cannot occur

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 best represents the forces and fluxes for a membrane potential of -40 mV (a, b, c, or d)? Upwards arrows means outward direction and downwards arrow means inward direction. The length of the arrow determines the magnitude.

Based on the graph, the threshold voltage appears to be approximately. (Base your answer to this question on the graph below depicting an action potential.) +60 mV. +30 mV. 0 mV. −30 mV. −60 mV.