Exam 1 Flashcards
acetylcholine
neurotransmitter produced and released by parasympathetic postganglionic neurons
arachnoid
the middle of the meninges of the brain, between dura mater and pia mater
astrocyte
star-shaped glial cell with numerous extensions in all directions; provides structural support for the brain
autonomic ganglia
collections of nerve cell bodies in the peripheral nervous system
autonomic nervous system
part of peripheral nervous system that supplies neural connections to glands and smooth muscles of internal organs; has sympathetic and parasympathetic divisions
axon
single extension from nerve cell that carries nerve impulse from cell body to other neurons
axon hillock
cone-shaped area from which axon originates out of the cell body; integration zone of the neuron
axon terminal/synaptic bouton
end of an axon, which forms a synapse on a neuron
blood-brain barrier
makes movement of substances from blood vessels into brain cells more difficult; protects brain from chemical damage
central nervous system
portion of nervous system that contains the brain and spinal cord
cerebrospinal fluid (CSF)
fluid that fills cerebral ventricles
cranial nerve
nerve connected directly to the brain; 12 motor/sensory nerves; part of PNS
dendrite
extension of cell body; receptive surface of neuron
dura mater
outermost of the meninges that surround brain and spinal cord
glial cells
nonneuronal brain cells that provide structural, nutritional, and other types of support to the brain
innervate
to provide neural input
interneuron
neither sensory nor motor; receives input from and sends input to other neurons
meninges
three protective sheets of tissue around brain and spinal cord (dura mater, arachnoid, pia mater)
motor neuron
neuron in brain or spinal cord that transmits motor messages to a muscle
multiple sclerosis
disorder characterized by widespread degeneration of myelin
multipolar neuron
nerve cell with many dendrites and single axon
myelin
fatty insulation around an axon, formed by glial cells; improves speed of conduction of nerve impulses
nerve
collection of axons bundled together in the PNS
neurotransmitter
chemical released from presynaptic axon terminal that serves as the basis of communication between neurons
nodes of Ranvier
gap between successive segments of myelin
norepinephrine
hormone secreted by adrenal medulla under control of sympathetic nervous system; prepares body for action
oligodendrodcyte
type of glial cell that forms myelin in the CNS
parasympathetic nervous system
division of autonomic nervous system that arises from cranial nerves and sacral spinal cord; calms body
peripheral nervous system
includes all nerves and neurons outside the brain and spinal cord
pia mater
innermost of the three meninges
postganglionic neurons
run from autonomic ganglia to innervate parts of body
postsynaptic
region of a synapse that receives and responds to neurotransmitter
postsynaptic membrane
specialized membrane on surface of cell that receives info; contains receptor proteins that allow it to respond to neurotransmitter molecules
preganglionic neurons
neurons in CNS that innervate autonomic ganglia
presynaptic
region of synapse that releases neurotransmitter
presynaptic membrane
specialized membrane of axon terminal of the neuron that transmits info; vesicles bearing transmitter can bind to this membrane and release contents
Schwann cell
glial cell that forms myelin in the PNS
sensory nerve
nerve that conveys info from periphery into the CNS
spinal/somatic nerve
nerve that emerges from spinal cord; 31 pairs
sympathetic chain
chain of glia that runs along each side of the spinal column; part of the sympathetic nervous system
sympathetic nervous system
division of autonomic nervous system that arises from thoracic and lumbar spinal cord; excites body
synapse
gap between neurons where info is passed from one to the other
synaptic vesicle
structure that contains molecules of a neurotransmitter
tract
bundle of axons in the CNS
unipolar neuron
nerve cell with a single branch that leaves the body and extends in two directions; one end is receptive and the other is the output zone
ventricular system
system of fluid-filled cavities inside the brain
dualism
promoted by Decartes; the mind is subject only to spiritual interactions, while the body is subject only to material interactions
action potential
propagated electrical message of a neuron that travels along the axon to the presynaptic axon terminals
agonist
molecule (drug) that binds to a receptor molecule and initiates a response similar to a neurotransmitter
all-or-none property
the fact that the amplitude of an action potential is independent of the magnitude of the stimulus
anion
negatively charged ion
batrachotoxin
selectively interferes with sodium channels
bungarotoxin
selectively blocks acetylcholine receptors
cation
positively charged ion
curare
alkaloid neurotoxin that causes paralysis by blocking acetylcholine receptors in a muscle
degradation
the chemical breakdown of a neurotransmitter into inactive parts
depolarization
a reduction in membrane potential; interior of neuron becomes less negative; gets closer to action potential
down-regulation
compensatory reduction in receptor availability at the synapses of a neuron
electrical synapse
presynaptic and postsynaptic membranes are so close that the action potential can jump across it without being translated into a chemical message
electrostatic pressure
charge molecules move via diffusion towards areas with opposite charge
excitatory postsynaptic potential (EPSP)
depolarizing potential in the postsynaptic region that is caused by excitatory connections; increase probability that neuron will fire an action potential
exocytosis
synaptic vesicle fuses with presynaptic terminal membrane to release transmitter into synaptic cleft
G proteins
class of proteins that reside next to intracellular portion of receptor and are activated when the receptor binds to an appropriate ligand on the extracellular surface
hyperpolarization
increase in membrane potential; inside of neuron becomes more negative; further away from action potential
inhibitory postsynaptic potential (IPSP)
hyperpolarizing potential in postsynaptic neuron causes by inhibitory connections; decrease probability that neuron will fire action potential
ion channel
pore in cell membrane that permits passage of certain ion when open
ionotropic receptor
receptor protein that includes an ion channel that is opened when the receptor is bound by an agonist
ligand
substance that binds to receptor molecules
ligand-gated ion channel
ion channel that opens or closes in response to the presence of a particular chemical; ionotropic receptor
local potential
electrical potential that is initiated at a specific site; graded response that spreads passively across cell membrane, decreasing in strength with time and distance
metabotropic receptor
receptor protein that doesn’t contain an ion channel but may when activated use a G protein system to open a nearby ion channel
resting membrane potential
difference in electrical potential across the membrane of a nerve cell during an inactive period
retrograde synapse
synapse in which a signal (usually a gas transmitter) flows from the post to presynaptic neuron
reuptake
process by which released synaptic transmitter molecules are taken up and reused by the presynaptic neuron, thus stopping synaptic activity
saltatory conduction
action potential jumps from one node to the next
saxitoxin
blocks sodium channels
second messenger
slow-acting substance in postsynaptic cell that amplifies the effects of the synaptic activity
sodium-potassium pump
energetically expensive mechanism that pushes 3 sodium ions out of a cell and pulls 2 potassium ions in
tetrodotoxin
blocks voltage-gated sodium channel, preventing action potential
transporters
receptors in the presynaptic membrane that recognize transmitter molecules and return them to the presynaptic neuron for reuse
up-regulation
compensatory increase in receptor availability at the synapses of a neuron
voltage-gated sodium channel
sodium-selective channel that opens or closes in response to changes in the voltage of the local membrane potential
the most basic excitable element of the neural cell
ion channel
Wallerian degeneration
when detached section of a chopped-off axon dies
retrograde degeneration
when the axon still attached to the soma dies after having a part chopped off
chromatolysis
soma begins to degenerate after part of axon chopped off and starts to lose Nissl substance
can PNS or CNS reverse neural cell damage
PNS: Schwann cells stimulate neural growth via nerve growth factor
axons in PNS vs CNS
axons in PNS: nerves
axons in CNS: tracts
cell bodies in PNS vs CNS
in PNS: ganglia
in CNS: nuclei
bundles of axons and cell bodies in PNS
axons: nerves
cell bodies: ganglia
bundles of axons and cell bodies in CNS
axons: tracts
cell bodies: nuclei
two types of acetylcholine receptors
nicotinic and muscarinic
sympathetic and parasympathetic preganglionic release
acetylcholine onto nicotinic (main) and muscarinic (minor)
parasympathetic postganglionic releases
acetylcholine onto muscarinic
sympathetic postganglionic releases
norepinephrine
what part of brain is not protected by blood-brain barrier
area postrema
hydrocephalus
abnormal amount of cerebrospinal fluid (CSF) within the brain
alzheimer’s
accelerated atrophy (dying of neuron); neurofibrillary tangles; senile plaques; many affected areas supposed to produce acetylcholine
what allows for local graded potentials
capacitance of cell membrane and conductance of cytoplasm
what do we need ATP for
sodium-potassium pump
sodium-calcium pump
forces on potassium during resting state
forced in due to electrical gradient; forced out due to concentration gradient
forces on sodium during resting state
forced out by electrical and concentration gradients
receptor for GABA
GABA-A
receptor for glycine and acetylcholine
nicotinic
receptors for glutamate
NMDA, kainite, AMPA
tricyclics
inhibit norepinephrine reuptake
fluoxetine and prozac
inhibit 5-HT reuptake
dorsal root of spinal cord
gets sensory info from the PNS
transmitter associated with sympathetic
produces and uses norepinephrine
transmitter associated with parasympathic
releases acetylcholine
