A&P Ch 12: Nervous Tissue
True
A regenerating axon in the PNS is guided by the regeneration tube and grows at a rate of about 5 millimeters per day.
Catalyzes hydrolysis of ACh to remove it form the synaptic cleft
Acetylcholinase
May result from positively charged ions entering the postsynaptic cleft
An EPSP
the postsynaptic neuron's membrane potentional to become more positive
An EPSP causes:
Faster
An axon with a large diamater transmits an impulse (Faster/Slower) than an axon with a smaller diameter
1.) The damaged neuron is in the PNS 2.) Some neurolemma remain 2.) The distance b/w the site of the damaged axon and the effector organ is relatively short
Check all that are factors that increase the chance of a damaged axon being able to regenerate.
The postsynaptic cell hyperpolarizes
Describe what happens in an IPSP
CSF
Epededymal cells help create:
1.) These EPSPs will be summed at the axon hillock 2.) Summation will not occur b/c the EPSPs need to be generated in quick succession from a single presynaptic neuron
Fifty presynaptic neurons all briefly release a single burst of excitatory neurotransmitter, generating excitatory postsynaptic potentials (EPSPs) in a postsynaptic neuron. Using this example, select all that apply.
Form myelin sheaths around several axons
Function of oligodendrocytes
Oligodendrocytes
Large cells that ensheath many different axons in the CNS
1.) Vital for synapse formation 2.) Take up NTs 3.) Play an energy supporting role
List 3 functions of astrocytes in the CNS
1.) Line the ventricles of the brain 2.) Form the choroid plexus 3.) Have cilia that help move cerebrospinal fluid
List 3 functions of ependymal cells in the CNS
1.) Endoneurium 2.) Nerve 3.) Perineurium 4.) Fasicles 5.) Epineureum 6.) Neurolemmocytes 7.) Axolemma
List the structures of a PNS nerve from outside to inside
Multipolar neuron
Most common neuron type; innervates muscles and glands
Bipolar neurons
Most neurons in the PNS are this type
1.) ACh 2.)Amino Acids 3.) Monoamines 4.) Neuropeptides
Name 4 classes of neurotransmitters
Neurolemmocytes (Schwann cells, PNS)
Nerve growth factors that stimulate outgrowth of severed neurons are secreted by:
Interneurons
Neuronal pools are composed of:
EPSPs
On a graph of an action potential, the small depolarizations that lead to threshold are from
True
Postsynaptic neurons can generate both excitatory and inhibitory potentials simultaneously. T or F?
1.) More NT released from the postsynaptic neuron 2.) More chemically gated channels open in the postsynaptic neuron
Select all of the following that would increase the magnitude of a postsynaptic potential.
Intracellular calcium rushes out of the synaptic knob
Select all that occur when an action potential reaches the transmissive segment of an axon.
1.) They are the result of chemically gated ion channels opening 2.) The current generated is localized 3.) The current decreases with distance
Select all the characteristics of graded potentials.
True
T/F: Graded potentials can result from mechanical stimulation or temperature change
Multipolar
The most common type of neuron contains many dendrites and a single axon. Structurally, this is classified as a(n) ______________ neuron.
Neurofibril node
The other name for nodes of Ranvier
Schwann cells
Type of glia in the PNS, Supporting cells of the peripheral nervous system responsible for the formation of myelin.
Oligodendrocytes
Type of glial cell in the CNS that wrap axons in a myelin sheath.
Unipolar neurons
Type of neuron in special senses
Decrease NT release from postsynaptic neurons
Upon binding of endocannabinoids to their target, there is a(n)
Frequency
What can vary regarding action potentials?
phagocytize microorganisms
What is the function of Microglial cells in the CNS?
Microglial
Which glial cell acts as a phagocyte?
Astrocytes
Which glial cell is starlike in shape and helps form the blood-brain barrier?
