Exam 4: Principles of Neural and Hormonal Communication

An unmyelinated fiber with a large diameter can conduct action potentials more rapidly than an unmyelinated fiber with a smaller diameter.

Indicate whether the membrane is more permeable to K⁺ or to Na⁺ or is equally permeable to these ions under the stated conditions: a.more permeable to K+ than to Na+ b.more permeable to Na+ than to K+ c.equally permeable to Na+ and K+ -At resting potential

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

Threshold potential is the peak potential achieved during an action potential.

A balance of IPSPs and EPSPs will negate each other so that the grand postsynaptic potential is essentially unaltered.

All of the following may be considered second messengers except

Use this figure to answer the corresponding questions. -Label "3" is a.a second messenger b.a kinase protein c.a G protein d.a G protein coupled receptor e.an effector enzyme

Match neural disease/influence with correct characteristic. a.multiple sclerosis b.tetanus c.strychnine d.roseola e.Parkinson's disease -Destroys myelin

G proteins in the plasma membrane of certain cells may become activated in response to the binding of water-soluble hormones, whereas protein phosphatases are continuously active in these cells.

Presynaptic inhibition is brought about when dendrites of a postsynaptic neuron alter the signals sent from an axon terminal of a presynaptic neuron.

The negative charge established along the cytosolic border a nerve cell membrane is due to

Preprohormones give rise to lipophilic hormones.

Select the neuropeptide.

An IPSP is

Drugs may influence synaptic transmission by

Use the answer code below to answer this section. a.increased PNa+ and no change in PK+ b.decreased PNa+ and decreased PK+ c.increased PK+ and no change in PNa+ d.increased PK+ and increased PNa+ e.increased PK+ and decreased PNa+ f.Na influx g.Na+ efflux h.K+ influx i.K+ efflux -Permeability changes at threshold voltage

Indicate the direction that the force in question tends to move the involved ion under the stated conditions by writing the appropriate letter in the blank, using the following answer code: a.tends to move the involved ion out of the cell b.tends to move the involved ion into the cell -Concentration gradient for Na⁺ at threshold potential

One "strong" stimulus can cause more than one action potential, but a "weak" stimulus may or may not generate an action potential.

Local current flow

The neuronal relationship where many presynaptic cells terminate on a single postsynaptic cell is called ____________________.