Unit 12

Where are synaptic vesicles located a. Axon terminals b. Dendrites c. Cell body d. Both a and b are correct e. All of the above

a. Axon terminals

Neurotransmitters that bind the postsynaptic membrane generally generate a/an a. Local potential b. Action potential c. Resting membrane potential d. Pacemaker potential

a. Local potential

What was the effect of increasing the voltage? Why did you see this effect?

all or nothing, if the voltage reaches the threshold then an action potential occurs and if it doesn't reach threshold than nothing occurs. the action potential is always the same meaning that a stronger stimulus doesn't cause a larger impulse

What is the function of astrocytes?

anchor neurons, facilitate formation of blood brain barrier in CNS

What triggers exocytosis of synaptic vesicles a. Arrival of a local potential at the cell body b. Hyperpolarization of the postsynaptic membrane c. Neurotransmitters binding to the postsynaptic membrane d. The influx of calcium ions into the axon terminal

d. The influx of calcium ions into the axon terminal

What is the function of the endoneurium?

encloses the myelin sheath of nerve fiber

Axons are enclosed in several layers of connective tissue. What are the layers from the most inner to the most outer?

endoneurium, perineurium, epineurium, fascicles

What are the functions of oligodendrocytes?

form myelin in CNS

What is the function of schwann cells?

form myelin in PNS

Why does addition of NaCl elicit an action potential?

more sodium causes depolarization which opens more sodium channels causing more depolarization and depolarization causes action potentials

What are neurons?

nerve cell capable of generating and transmitting electrical signals

_______ cannot generate action potentials.

neuroglia

Define postsynaptic neuron

neuron that receives message

Define presynaptic neuron

neuron that sends messages

What was the effect of lidocaine and why?

no depolarization of cell because it blocks or closes sodium channels

What is the function of microglia?

phagocytic cells that remove debris and dead cells from CNS

What is the function of satellite cells?

regulate environment around neuron in PNS

What are the type of neuroglia cells?

schwann cell, satellite cells, oligodendrocyte, astrocyte, microglia, ependymal cell

What are the four functional neural zones?

signal reception, signal integration, signal conduction, signal transmission

What is the function of the perineurium?

surrounds fascicles

What is the function of the epineurium?

surrounds peripheral nerve

When does an action potential occur?

when the membrane potential at the axon hillock reaches a certain threshold

What are neuroglia?

cells that support and protect neurons

What is the function of ependymal cells?

ciliated cells that form and secrete cerebrospinal fluid in CNS

Which part of the neuron is capable of generating an action potential? a. Dendrite b. Axon c. Myelin sheath d. Cell body

b. Axon

What are fascicles?

bundles of axons

Put the following events of the neuronal action potential in the correct order a. Voltage-gated sodium ion channels close, and voltage-gated potassium ion channels open b. Potassium ions continue to exit the cell, causing hyperpolarization c. Voltage-gated sodium ion channels open, and the axon depolarizes d. Potassium ions exit the cell, causing repolarization

c, a, d, b

The neuron pictured in figure 12.8 is a a. Pseudounipolar neuron b. Bipolar neuron c. Multipolar neuron d. Unipolar neuron

c. Multipolar neuron

What was the effect of curare and why?

causes muscle to not contract because ACH receptors are blocked so ACH can't bind

What was the effect of ether and why?

causes the cell to hyperpolarize because it opens potassium channels

Define hyperpolarization

cell becomes more negative

Define depolarization

cell becomes positive

Define repolarization

cell goes back to resting potential

What is the function of myelin?

insulates nerves, speeds up action potential