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
