Ch 11 A&P HW

Destruction of which of the neuroglial cell types leads to the disease multiple sclerosis (MS)?

A

Which of the following is true of axons?

A neuron can have only one axon, but the axon may have occasional branches along its length.

In which area of the neuron is an action potential initially generated?

C

Which of the cell types shown is most associated with the production and flow of cerebrospinal fluid (CSF)?

D

Arrange the parts in order, from left to right, of a successful direct depolarization path within one neuron.

Dendrite, cell body, axon hillock, axon, presnaptic terminal

Which of the neuroglial cell types shown are found in the peripheral nervous system (PNS)?

E

Na+ leaks through neuron membranes faster than K+ because of the properties of the non-gated leak channels. True or False

False

Predict the possible effect of a drug that totally blocks the neurotransmitter receptor on the postsynaptic membrane. For example, curare is a neurotoxin used by several South American cultures. The primary effect of curare is that acetylcholine, a major neuromuscular neurotransmitter, cannot bind at its receptor because curare is blocking it. Predict the possible effects of curare on the postsynaptic membrane and muscle.

Local graded potential and action potential transmission is blocked, and there is no response by the postsynaptic cell, the muscle.

Which statement best describes exocytosis?

Membrane organelles fuse with the membrane and release contents out of the cell.

Which of the following peripheral nervous system (PNS) neuroglia form the myelin sheaths around larger nerve fibers in the PNS?

Schwann cells

The mechanism by which the neurotransmitter is returned to a presynaptic neuron's axon terminal is specific for each neurotransmitter. Which of the following neurotransmitters is broken down by an enzyme before being returned?

acetylcholine

Drag and drop the descriptive labels of events into the correct sequence at the chemical synapse.

action potential sweeps down presynaptic axon, calcium channels open in axon terminal, synaptic vesicles fuse and exoctytize neurotransmitter, diffusion of neurotransmitter into extracellular fluid separating two neurons membranes, graded potential at postsynaptic membrane.

What condition will increase the diffusion of molecules, such as neurotransmitters?

an increase in the amount of neurotransmitter exocytized by the presynaptic axon

Release neurotransmitters into the extracellular space

axon terminal

The neurotransmitter __________.

bound at postsynaptic receptors to open postsynaptic ion channels

As you start working out, you notice that your heart rate and breathing rate start to increase. Which division of your nervous system is generating this response? Be as specific as possible.

the sympathetic division of the autonomic nervous system

Which of the following choices best represents synaptic transmission?

presynaptic axon to synapse to dendrite or postsynaptic cell body

In a synapse, neurotransmitters are stored in vesicles located in the __________.

presynaptic neuron

Plasma membrane exhibits chemically gated ion channels.

receptive region

Receives stimuli.

receptive region

Plasma membrane exhibits voltage-gated Ca2+ channels.

secretory region

Which of the following best characterizes depolarization?

small, consecutive steps of Na+ penetration into the axon along its length

What division of the nervous system is most specifically responsible for voluntary motor control?

somatic nervous system

Which is the main receptive portion of the neuron?

the dendrite

Area where nerve impulse is generated.

trigger zone

An action potential releases neurotransmitter from a neuron by opening which of the following channels?

voltage-gated Ca2+ channels

Binding of a neurotransmitter to its receptors opens __________ channels on the __________ membrane.

chemically gated; postsynaptic

Plasma membrane exhibits voltage-gated Na+ and K+ channels.

conducting region

Binding of the neurotransmitter to its receptor causes the membrane to __________.

either depolarize or hyperpolarize

Which of the following pairings does NOT fit? *association neuron: functional classification multipolar neurons: peripheral nervous system sensory neurons *motor neurons: efferent neurons. *afferent neurons: sensory neurons

multipolar neurons: peripheral nervous system sensory neurons

During the action potential of a neuron, which ion is primarily crossing the membrane during the depolarization phase, and in which direction is the ion moving?

Na+ is entering the cells

Which of the following is NOT one of the basic functions of the nervous system? *Integrate sensory input for decision making. *Release hormones into the bloodstream to communicate with other cells in the body. *Generate direct, electrical signals. *Decode sensory information from the environment.

Release hormones into the bloodstream to communicate with other cells in the body.

When an action potential arrives at the end of the axon terminal, a series of events take place that result in the release of neurotransmitter from the presynaptic axon. Select the answer that correctly describes the primary stimulus for vesicles to move toward the cell membrane and eventually release their contents.

Voltage-gated membrane channels open, and Ca+2 enters the cytoplasm, increasing intracellular calcium.

Ependymal cells line many open cavities in the central nervous system (CNS). Ependymal cells have cilia on the side of the cell that face these openings. What is the most likely function of these ciliated cells?

movement and circulation of cerebrospinal fluid