Exam 8: Neurons: Cellular and Network Properties

Match the term with its description (answers may be used more than once). -cells that myelinate several axons

Define temporal and spatial summation.Where does the summation occur? Are these processes mutually exclusive,or can they occur at the same time in a typical multipolar neuron? What key property of neurons do these forms of summation demonstrate?

What causes a graded potential to degrade?

Detailed understanding of the cellular basis of signaling in the nervous system has led to good understanding of consciousness,intelligence,and emotion.

Match the term with its description (answers may be used more than once). -occupy(ies)the least amount of cell volume

Which of the following does NOT influence the time necessary for a nerve impulse to be conveyed by a particular neuron?

The portions of a neuron that extend off of the roughly spherical cell body are usually collectively called

What does the Goldman-Hodgkin-Katz equation take into account that the Nernst equation does NOT?

The disease rabies is caused by a virus that attacks the central nervous system.The virus is normally introduced when an infected animal bites another,breaking the surface of the skin and allowing the entry of saliva containing the virus.Since the virus cannot move by itself,how does it get to neurons in the central nervous system?

"A refractory period occurs following all types of potentials." Is this statement What structures are actually refractory? Why or why not?

We have finally discovered life on Venus.NASA scientists are investigating a newly discovered life form: a single-celled organism found in the swampy canals.You have been contracted by NASA to perform an electrophysiology study.Using intracellular electrodes to measure the electrical charge inside the cell,you find it has a resting membrane potential of -45 mV when the outside fluid is arbitrarily set to 0 mV.Additionally,you have determined ion concentrations and listed them below. For fun,you have used new molecular biology techniques to insert protein channels into the cell membrane that allow only Na⁺ and Cl^- to pass.Predict which ion(s)will move.Tell what direction it (they)will move and what force(s)is/are acting on it (them).

Which of the following is NOT a known drug effect on synaptic function?

Which type of synapse is most prevalent in the nervous system?

The pattern of synaptic connectivity where a large number of presynaptic neurons provide input to a single postsynaptic neuron,is known as

The enteric nervous system is a network of neurons that function in controlling

Draw graphs showing the effect on action potentials in a cell following effective doses of each of the listed neurotoxins.Assume that the cell is normally brought to threshold by an electrical stimulus applied to it,so that any abnormality is due to the toxin.Precise values for voltage and duration are not important,just a general trend in how the action potential may be different from normal. 1.puffer fish poison (blocks voltage-gated sodium channel activation) 2.tetraethylammonium (blocks voltage-gated potassium channels) 3.ouabain (blocks sodium-potassium pumps) 4.sea anemone toxin (blocks voltage-gated sodium channel inactivation)

When sodium channels open during an action potential,the opening is caused by

Tetrodotoxin is a toxin that blocks voltage-gated sodium channels.What effect does this substance have on the function of neurons?

Explain the processes that lead to the exocytosis of neurotransmitter from a presynaptic cell.Which components are recycled? Which ion is important in triggering exocytosis?

Glial cells communicate primarily using