BIOM 3200 Chapter Notes - Chapter 2: Voltage-Dependent Calcium Channel, Inhibitory Postsynaptic Potential, Resting Potential

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tealcattle906

16 Aug 2016

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All cells in the body maintain a potential difference across the membrane (resting membrane potential) Inside is charged in comparison to the outside. Largely the result of the permibility properties of the membrane. The membrane traps large, negatively-charged organic molecules within the cell and permits only limited diffusion of positively-charged inorganic ions. Result is unequal distribution of ions across the membrane. **na+/k+ pump results in high [na+] in extracellular fluid, and high [k+] inside the cell. The ability of neurons muscle cells to produce and conduct changes in membrane potential. Membrane potential to a specific ion results in the diffusion of the ion down its concentration gradient. Ion currents only occur across limited patches of membranes. Potential difference is reduced, excitatory in dendrites/cell body. Hyperpolarization inside of cell is more than rmp (inhibitory) Changes in membrane potential are caused by changes in the net flow of ions through ion channels in the membrane.

Related Questions

1. The plasma membrane of rod and cone cells are

a) At resting potential in the dark and deploarized in thelight

b) At resting pootential in the dark and hyperpolarized in thelight

c) Depolarized in the dark and hyperpolarized in the light

d) Hyperpolarized in the dark and at resting potential in thelight

e) Hyperpolarized in the dark and depolarized in the light

2. The equilibrium potential of K+ ions in nerve cells is about-90mV. The membrane potential of a typical nerve cells at rist is-70mV. Therfore

a) Increasing the permeability of a resting neuronal membrane toK+ ions will increase the membrane potential (that is, make it morenegative, inside with respcect to outside)

b) In nerve cells at rest, there is a net diffusion of K+ ionsout of the cell

c) Increasing the membrane potential of a nerve cell would slowthe diffusion of K+ ions out of it.

d) K+ is not the only ion that is permeable at rest

e) All of the above

3. Which of the following is responsible for the replarizingphase of the action potential?

a) Voltage-gated Na+ channels are opened.

b) The Na+-K+ pump restores the ions to theri original restingstate.

c) The permeability to Na+ increases greatly.

d) ATPase destroys the energy supply that was maintaining theaction potential at its peak.

e) The permeability to K+ increases greatly while that to Na+decreases

4. The Relative refractory period of an axonm conincides withthe period of

a) Activation and inactivatioin of voltage-gated Na+channels

b) Increased Na+ flux into the cell

c) Increased K+ flux into the cell

d) Increased K+ flux out of the cell

e) Increased Na+ flux out of the cell

5. The plasma membranes of rod and cone cells are

a) At resting potential in the dark and epolarized in thelight

b) At resting potential in the dark and hyperpolarized in thelight

c) Depolarized in the dark and hyperoplarized in the light

d) Hyperpolarized in the dark and tat resing potential in thelight

e) Hyperpolarized in the dark and depolarized in the light

Santiago Ramon y Cajalâs theory of dynamic polarization refers to the:

(a)membrane potential of a neuron at rest.

(b)membrane potential of a neuron firing action potentials.

(c)opening and closing of gated channels in the membrane.

(d)one way flow of information in neurons from dendrites to axon terminals.

(e)one way flow of information in neurons from axon terminals to dendrites.

Over the course of scientific history, there are many examples of scientists reaching the right conclusion for the wrong reasons. When Schwann first proposed that the nervous system was made of individual cells, he based it on observations of:

(a)synapses.

(b)dendrites

(c)axon terminals.

(d)astrocytes.

(e)Nodes of Ranvier.

The synaptic cleft was finally seen in the 1950s. What prevented scientists from seeing it earlier?

(a)The resolution of the light microscope.

(b)They were looking in the wrong place.

(c)Their tissue was not appropriately stained.

(d)Myelination of the axons.

(e)all of the above

The resting membrane potential of a neuron is approximately:

(a) +65 V

(b) +65 mV

(d) -65 mV

What is largely responsible for the resting membrane potential in a neuron?

(a)Axonal insulation by myelin

(b)Voltage-Gated Sodium Channels

(c)The Action Potential

(d)Potassium Leak Channels

Which of the following would DECREASE the propagation velocity of an action potential down an axon?

(a)Increase in axon diameter

(b)Increase myelination between nodes of Ranvier

(c)Remove myelination between nodes of Ranvier

(d)Decrease density of voltage-gated Na+ channels except at the Nodes of Ranvier

The resting membrane potential of a neuron can be estimated using the:

(a)Nernst equation

(b)Goldman equation

(c)Hodgkin and Huxley equation

(d)Ohmâs law

18. What would happen to the resting membrane potential of a neuron if you added K+ to the extracellular fluid?

(a)Resting membrane potential would increase (become more positive)

(b)Resting membrane potential would decrease (become more negative)

(c)Resting membrane potential would not change

(d)Resting membrane potential would be abolished

. Which of the following statements is FALSE for Graded Potentials

(a)Magnitude changes with magnitude of triggering stimulus

(b)Magnitude decreases with distance from initial site

(c)Cannot be summed

(d)No refractory period

In the nervous system, the strength of the stimulus is coded into:

(a)The frequency of action potentials generated

(b)The amplitude of action potentials generated

(c)Both the frequency and amplitude of action potentials generated

(d)The duration of individual action potentials generated

Ion movement during both the depolarization and repolarization phases of an action potential are the result of:

(a)active transport pumps along the neuron membrane.

(b)diffusion of ions down their electrochemical concentration gradients.

(c)negative feedback loops.

(d)All of the above

At the peak of the action potential, the membrane potential is:

(a)Exactly at the Na+ equilibrium potential

(b)Greater (more positive) than the Na+ equilibrium potential

(c)Above 0 mV but less positive than the Na+ equilibrium potential

(d)0 mV

**Please only answer if you are 100% correct!

1. Why are Na+, K+, and Clâ the only ions considered in the GK equation when calculating resting membrane potential (Vm)?

A. These ions are found in the highest concentrations inside the cell

B. These are the ions to which cell membranes are permeable at rest

C. Only these ions have enough charge to influence Vm

D. These ions bind to receptors that increase the charge on the membrane

2. Voltage-regulated channels are located

A. on the neuron cell body only

B. within the cytosol only

C. in the membranes of axons only

D. in the membranes of dendrites only

E. in the membranes of dendrites, in the membranes of axons, and on the neuron cell body

3. As the charge on the membrane of a typical neuron approaches 0 from -70 mV, the cell is

A. hyperpolarizing and becoming more difficult to stimulate

B. only becoming more difficult to stimulate

C. only hyperpolarizing

D. only depolarizing

E. only repolarizing

BIOM 3200 Chapter Notes - Chapter 2: Voltage-Dependent Calcium Channel, Inhibitory Postsynaptic Potential, Resting Potential

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