Exam 4: Principles of Neural and Hormonal Communication

For the following questions, assume a hypothetical postsynaptic neuron has three presynaptic inputs: neurons X, Y, and Z. Also, assume neuron Z is excitatory. If neurotransmitter from X causes a slight hyperpolarization of the postsynaptic cell, then the

Use this figure to answer the corresponding questions. Label "3" is a. a sec ond me ssenger b. an active kinase protein c. a $\mathrm{G}$ protein d. a $\mathrm{G}$ protein coupled receptor e. an inactive kinase protein

Adenylyl cyclase and diacylglycerol are more associated with hydrophilic hormones than with lipophilic hormones.

For graded potentials, the magnitude of triggering is coded for in frequency rather than amplitude of depolarizations.

Multiple sclerosis develops from a buildup of myelin of a neuron.

Amplification is a phenomenon associated with hormones derived from cholesterol.

Describe an action potential and explain why a region of the membrane that is in the absolute refractory period cannot experience another action potential until repolarization is complete. Include the following in your

Nerve and muscle cells establish resting membrane potentials.

Which statement is incorrect?

Use this figure to answer the corresponding questions. This figure shows a. the mechanism by which some lipid-soluble hormones affect their target cells b. the way insulin affects certain cells c. the method in which IP3 forms d. a common second messenger system for hormone that is derived from cholesterol e. none of these

Use this figure to answer the corresponding questions. A second messenger is labeled a. 1 b. 2 c. 3 d. 4 e. 5

Select the last step for synaptic signaling when the action potential arrives at the axon terminal of a presynaptic neuron.

The cells of excitable and nonexcitable tissues share

For the following questions, assume a hypothetical postsynaptic neuron has three presynaptic inputs: neurons X, Y, and Z. Also, assume neuron Z is excitatory. What changes would you expect at the postsynaptic neuron when neuron X is stimulated? (Remember that the postsynaptic neuron becomes hyperpolarized by neuron X.)

The myelin covering the axon promotes the leakage of ions from an axon, but it promotes conservation of ATP in the neuron.

Hormones derived from cholesterol are bound to proteins in the blood and primarily alter preexisting proteins via second-messenger systems.

Complete each of the following statments. Schwann cells stimulate the formation of a(n) ____________________ tube to rebuild damaged neurons.

Complete each of the following statments. The resting membrane potential of a typical nerve cell is about ____________________ millivolts.

During the peak of the action potential, the membrane becomes most permeable to

In a graded potential, the direction of current flow is designated by the movement of positive charges.