BIO211 Final Exam (nervous tissue)

ependymal (CNS)

-line the ventricles of the brain -form the choroid plexuses -have cilia that help move cerebrospinal fluid

astrocytes (CNS)

-vital for synapse formation -take up neurotransmitters -play an energy supporting role

place the events in the correct sequence:

1. action potential reaches synaptic knob 2. voltage-gated calcium channels opne 3. calcium enters the synaptic knob 4. synaptic vesicles merge with synaptic knob plasma membrane 5. neurotransmitter is released by exocytosis 6. neurotransmitter crosses synaptic cleft 7. neurotransmitter attached to receptors on a muscle, neuron, or gland cell

place the follow structures in the order that an electrical impulse would travel beginning with the postsynaptic membrane

1. dendrites 2. soma 3. axon hillock 4. neurofibril node 5. synaptic knobs

what is produced when depolarization of a cell membrane reached threshold?

a new action potential is produced

the __________ is a period when a membrane cannot respond to stimulus (no matter how strong)

absolute refractory period

to enhance the effect of ACh has in particular synapse, a drug may block AChE so that:

acetylcholine is not destroyed and will remain in the synapse longer

pain receptors in the skin send signals to the CNS for processing. these pain receptors are an example of _______ neurons.

afferent

when a neurotransmitter binds a protein channel, it opens and lets sodium diffuse down its concentration gradient. this is an example of a

chemically gated sodium channel

central nervous system

consists of the brain and spinal cord

neurons that carry signals from the CNS to skeletal muscle for contraction would be classified as _______ neurons

efferent

activation gates in the membrane for voltage-gated sodium ion channels open into the

extracellular fluid

ganglia are clusters of neuron cell bodies located within the CNS

false: ganglion are clusters of neuron bodies located in the PNS

neurons are unique in that they do not require glucose or oxygen to function

false: neurons have a very high metabolic rate, and require high amounts of glucose and oxygen

glial cells help neurons by generating action potentials

false; glial cells do not generate action potentials

in neurons, protein pumps allow substances to move passively down their concentration gradients

false; pumps are not involved with passive transport

the inside of the cell membrane becomes negative at the time of an action potential

false; the inside of a cell membrane become positive at the time of an action potential

at resting membrane potential, voltage-gated potassium ion channels are open

false; voltage-gated potassium ion channels are closed in resting membrane action potentials

one function of the nervous system is to always respond to sensory input

false; when the nervous system evaluates information, the CNS determines whether or not a response is required

oligodendrocytes (CNS)

form myelin sheaths around several axons

peripheral nervous system

includes cranial nerves, spinal nerves, and ganglia

the fundamental physiological properties that enable nerve cells to communicate with other cells

is carried out by nerve cells, or neurons; these cells have three fundamental physiological properties that enable them to communicate with other cells: -excitability -conductivity -secretion

the cell membrane immediately adjacent to an action potential depolarizes because of

local currents

the vagus nerve contains afferent and efferent neurons; therefore it is an example of a(n) ___________ nerve

mixed

depolarization is initiated by a stimulus that makes the membrane potential

more positive

depolarization of a cell membrane occurs because

more sodium ions diffuse into the cell than potassium ions diffuse out of it

the most common type of neuron contains many dendrites and a single axon. structurally, this is classified as a(n) ___________ neuron

multipolar

what type of cells produce myelin sheath in the central nervous system (CNS)?

oligodendrocytes

the absolute refractory period assures that action potential propagation is

only in one direction

microglia (CNS)

phagocytize microorganisms

myelin sheaths mainly consist of which part of the glial cells that form them?

plasma membrane

when sodium enters the neuron via chemically gated sodium channels, the membrane will depolarize. therefore, the membrane potential will become more

positive

the ______ nervous system transmits information from receptors to the CNS, while the ________ nervous system transmits information from the CNS to the rest of the body

sensory; motor

scorpion agitoxin is a neurotoxin that blocks the activity of voltage-gated potassium channels. in the presence of agitoxin, which will occur during an action potential?

the neuron will remain depolarized and unable to repolarize

the negative value of the resting membrane potential means that

there are more negatively charged particles on the inside of the membrane than on the outside

axonplasmic flow is an example of slow axonal transport

true

fast retrograde transport returns used synaptic vesicles and other materials to the soma and informs the soma of conditions at the axon terminals

true

on a typical neuron, the axon is usually longer in length that the dendrites

true