chapter 12 - introduction to the nervous system bio lab

an action potential is generated at the a. trigger zone of the axon b. postsynaptic membrane c. cell body d. axon terminal

a

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

function of astrocytes

anchor neurons and blood vessels, maintain extracellular environment around neurons. and assist in the formation of the blood brain barrier

function of Schwann cells

create the myelin sheath in the PNS

what triggers exocytosis of synaptic vesicles a. arrival of a local potential at the cell body b. hyper polarization of the postsynaptic membrane c. neurotransmitters binding to the postsynaptic membrane d. the influx of calcium ions into the axon terminal

d

what is the difference between an excitatory postsynaptic potential and an inhibitory postsynaptic potential

excitatory postsynaptic potential triggers a positive change in membrane potential while inhibitory neurons trigger a negative change in the membrane potential

function of oligodendrocytes

form the myelin sheath in the CNS

multiple sclerosis is a demyelinating disease, in which the patients immune system attacks and destroys the cells that form the myelin sheath in the central nervous system. What types of symptoms would you expect from such a disease? Why? would Schwann cells or oligodendrocytes be affected?

muscle weakness and paralysis cause the myelin sheath is responsible for speeding up the action potential conduction in the CNS. oligodendrocytes would be effected because they wrap around the axons to form the myelin sheath

function of microglial cells

phagocytic cells of the CNS

you are examining another neuron, and you find that it has two processes, both of which generate action potentials. What is the structural class of this neuron>

pseudo unipolar and cause this type of neuron has two axons, a central recess and a peripheral process. In this neuron both processes are capable of generating action potentials

function of satellite cells

surround the cell bodies of neurons in the PNS

function of ependymal cells

ciliated cells in the CNS that form and circulate cerebrospinal fluid

axon terminal of presynaptic neuron

2

you are examining a neuronal process and you find that it generates action potentials. Is this an axon or a dendrite? How can you tell?

axon and cause they are responsible for generating action potential and dendrites are responsible for receiving the messages. However, they are unable to generate action potential themselves

the main function of an axon is to a. generate EPSPs or IPSPs when neurotransmitters bind their membranes b. generate and transmit singlas in the form of action potentials c. function as the biosynthetic center of the neuron d. forms the myelin sheath

b

certain inhaled anesthetic agents are thought to open cl- channels in the membranes of postsynaptic neurons in the brain, an effect that causes IPSPs. Why might this action put a person to sleep during anesthesia

because it prevents the action potentials from being generated in the affected neurons, essentially putting a person to sleep

a damaged axon in the PNS may be able to regenerate only if the cell body is intact. Why do you think that the cell body must be intact for regeneration to occur

cause it houses the nucleus and almost all of the other organelles necessary for protein synthesis. If the cell body was not intact, the neuron can not make all the cellular parts it needs to repair itself

the bacterium clostridium tetani produces a toxin called tetanospasmin, the causative agent of the disease tetanus. The toxin prevents the release of inhibitory neurotransmitters in the CNS and so blocks the resulting IPSPs they would normally generate. What are some of the functions of inhibitory synapses? Considering this, what symptoms would you expect from the disease tetanus and why

inhibitory synapse are responsible for functions such as preventing antagonist muscles from contracting. Symptoms might include painful muscle contractions. This is because when inhibitory synapses are presented the antagonist and agonist muscles would contract at the same time

predict what would happen if calcium ion channels in the axon terminal were blocked

it would allow exocytosis of the neurotransmitters into the synaptic cleft. This would basically shut down the synaptic transmission between two neurons