Bio Exam III

During synaptic transmission, the influx of ________ causes vesicles in the axon terminal (bulb) to fuse with the cell membrane, releasing ________.

Ca2+, neurotransmitter

Inhibitory neurotransmitters reduce the generation of new electrical impulses by which one of the following? stimulating saltatory conduction causing hyperpolarization in postsynaptic neurons inhibiting postsynaptic neurons from repolarizing inhibiting presynaptic neurons from depolarizing

Causing hyper polarization in postsynaptic neurons

Which event is associated with the transmission of an impulse across a synapse occurs last?

Ligand (ie, chemically) gated channels for sodium open.

Which one of the following happens during repolarization of a neuron? a. Sodium channels inactivate, and potassium rushes out of the cell to temporarily reestablish the membrane potential. b. Potassium channels close, preventing further loss of positive ions. c. The sodium-potassium pump is turned off. d. Sodium channels open to allow sodium ions to rush back out of the cell. e. The membrane potential is eliminated.

a. Sodium channels inactivate, and potassium rushes out of the cell to temporarily reestablish the membrane potential.

Which of the following are true regarding the ions discussed in class as they relate to nerve function? a) Na+, Cl-, Ca2+, and K+ are found in equal concentrations across the cell membrane. b) Na+, Ca2+, and K+ are found in higher concentrations inside the cell compared to outside the cell c) K+ concentrations are greater inside the cell compared to outside the cell. d) High concentrations of Cl- inside the cell make the resting membrane potential negative.

b)

The central nervous system is composed of what?

brain and spinal cord

Excitatory neurotransmitters initiate the generation of new electrical impulses (ie action potentials) by which one of the following? stimulating saltatory conduction causing depolarizing postsynaptic neurons inhibiting postsynaptic neurons from repolarizing inhibiting presynaptic neurons from depolarizing

causing depolarizing postsynaptic neurons

T or F The autonomic division of motor output is under voluntary control.

false

Which one of the following cells transmit impulses away from the central nervous system to the muscles and other organs? motor neurons interneurons sensory neurons neuroglia

motor neurons

Cells that provide direct protection and physical support to neurons are

neuroglial cells

Toxins that block the activity of potassium channels would have what effect on nerve and muscle action potentials?

prevent repolarization

During which phase of an action potential do the sodium channels inactivate and potassium channels open, releasing potassium from the neuron?

repolarization

A neuron at rest has a charge difference across its cell membrane, with the interior of the cell negative relative to the exterior. This difference in charge across the plasma membrane is referred to as ________ potential.

resting

Which one of the following provides the central nervous system with information about the outside environment? - motor division - sympathetic division - parasympathetic division - sensory division - autonomic division

sensory division

Saltatory conduction is

the process of conduction leaping along myelinated neurons