STRUCTURE OF A NEURON Flashcards
It is the neuron’s control center, containing the nucleus and other organelles. it process incoming signals and maintains the neurons health
CELL BODY (SOMA)
contains the cell genetic material (DNA)
NUCLEUS
includes various organelles such as mitochondria (energy production) ribosomes (protein synthesis)
CYTOPLASM
are branching extensions that receive signals from other neurons. they conduct electrical message to the cell body.
DENDRITES
carries electrical impulses away from the cell body to other neuron, muscles or organelles
AXON
The cone-shaped region where the axon joins the cell body. it is the site where action potential are initiated.
AXON HILLOCK
A fatty layer that covers the axon in segments. it acts as an insulator, increasing the speed of signal transmission
MYELIN SHEATH
Gaps in the myelin sheath where ion channels are concentrated, allow the action potential to jump from node to node (saltatory conduction)
NODES OF RANVIER
the end points of axon where neuron makes contact with other cells. where neurotransmitter release into synaptic cleft to communicate with other neurons or affector cells
AXON TERMINAL (SYNAPTIC BOUTONS)
It is a fluid within cells
ICF (INTRACELLULAR FLUID)
What are the 3 major ions in the ICF
POTASSIUM (K+)
PHOSPHATE (HPO4^2-) AND PROTEINS
SODIUM (Na+)
The predominant ion with a high concentration inside the cell
POTASSIUM (K+)
These are negatively charged and help balance the positive charged and help balance the positive charge of K+
PHOSPHATATE (HPO4^2-) AND PROTEINS
Present in lower concentrations compared to the extracellular fluid.
SODIUM (Na+)
the fluid outside cells, including interstitial fluid and blood plasma
ECF (EXTRACELLULAR FLUID)
Major ions in the ECF
SODIUM (NA+)
CHLORIDE (CL-)
CALCIUM (CA2+)
POTASSIUM (K+)
The predominant ion with a high concentration outside the cell.
SODIUM (NA+)
The main anion in the ECF
CHLORIDE (CL-)
Also, present in a significant amount
CALCIUM (CA2+)
present in lower concentrations compared to the intracellular fluid.
POTASSIUM (K+)
It plays a pivotal role in generating and propagating action potential
ELECTROCHEMICAL GRADIENT
This gradient is formed due to differences in the concentration of ions across the membrane. ions will naturally move from an area of higher concentration to an area of lower concentration to reach equillibrium
CHEMICAL GRADIENT
this gradient is formed due to differences in the concentration of ions across the membrane. ions are attracted to areas of opposite charge.
ELECTRICAL GRADIENT
a brief electrical impulse that travels along the axon of a neuron triggered when the membrane potential reaches a certain threshold it results in the rapid depolarization and repolarization
ACTION POTENTIAL
the stable voltage difference across a cell membrane when the neuron is not actively firing an action potential
RESTING POTENTIAL
is the movement of particles from an area of higher concentration to an area of lower
concentration.
DIFFUSION
These are proteins that create specific pathways for charged ions to pass
through the cell membrane.
ION CHANNELS
Always open, allowing ions to move down their concentration gradient.
LEAK CHANNELS
Open or close in response to specific stimuli (voltage-gated, ligand-
gated, or mechanically gated).
GATED CHANNELS
Active transport mechanisms that move ions against their concentration
gradients using ATP.
ION PUMPS
a membrane protein that actively transports sodium ions out of the neuron and potassium into the neurons
SODIUM-POTASSIUM PUMP
the process by which the membrane potential of a neuron becomes less
negative (more positive) than its resting potential. This is a critical step in the generation of an action
potential.
DEPOLARIZATION
refers to the process by which the membrane potential becomes more negative than the resting
potential.
HYPERPOLARIZATION
occurs after an action potential has been fired. During an action potential, the neuron’s
membrane potential becomes more positive (depolarization) due to the influx of sodium ions (Na+) into the cell.
REPOLARIZATION
play a crucial role in maintaining
the fidelity of neuronal signaling. These
mechanisms are essential for proper neuronal
communication and overall nervous system
function.
REFRACTORY PERIODS
This is the period immediately following the initiation of an action potential during which no
stimulus, no matter how strong, can trigger another action potential.
ABSOLUTE REFRACTORY PERIOD
period, there is a phase during which a neuron can fire another
action potential, but only in response to a stronger-than-usual stimulus.
RELATIVE REFRACTORY PERIOD
An action potential either occurs fully or not at all. Once the
threshold is reached, the action potential will propagate along the entire length of the
axon without decreasing in size.
ALL-OR-NOTHING PRINCIPLE
This process ensures that electrical signals are
transmitted quickly and accurately within the nervous system, allowing for complex
functions such as sensation, movement, and cognition.
PROPAGATING ACTION POTENTIAL
neurons that release neurotransmitters that promote the firing of an
action potential in the receiving neuron.
EXCITATORY NEURON
They release neurotransmitters
that decrease the likelihood of the postsynaptic neuron firing an action potential.
INHIBITORY NEURON
They are the principal excitatory neurons in these regions and play a crucial role in
cognition, memory and motor control.
PYRAMIDAL NEURONS
These cells also use glutamate as their
neurotransmitter, which excites other neurons and helps propagate neural signals.
GRANULE CELLS
receive input from the thalamus and excite other neurons in the
visual cortex, contributing to visual perception.
SPINY STELLATE CELLS
receptors are both types of glutamate receptors, which are the primary excitatory neurotransmitter
receptors in the central nervous system.
AMPA and NMDA
WHAT IS AMPA?
A-AMINO-3-HYDROXY-5-METHYL-4-ISOXAZOLEPROPIONIC ACID
WHAT IS NMDA
N-METHYL-D-ASPARTATE
These neurons release GABA, which binds to receptors on the postsynaptic neuron, opening ion
channels that allow chloride ions (Cl−) to flow into the cell. The influx of negative ions hyperpolarizes the
membrane, making it less likely that an action potential will occur.
GABAergic NEURONS
These inhibitory neurons are found in the hippocampus and cerebral cortex and are known for
their ability to control the output of excitatory pyramidal neurons.
BASKET CELLS
These are fast-spiking GABAergic neurons that provide rapid and precise
inhibitory signals. They are involved in controlling the timing of neuronal activity and are crucial for
processes like attention and sensory processing.
PARVALBUMIN-POSITIVE (PV) NEURONS
These specialized inhibitory neurons target the axon initial segment of pyramidal neurons,
where action potentials are initiated.
CHANDELIER CELLS
These large, elaborate neurons release GABA and provide inhibitory input to the deep cerebellar
nuclei, which helps modulate motor movements and ensure precise coordination.
PURKINJE CELLS
Because the relative permeability of the membrane greatly
favors sodium, the membrane potential goes to a value close to E Na ,
which is greater than 0 mV.
OVERSHOOT
In myelinated axons,
action potentials skip from node to node. This type of action
potential propagation is called
SALTATORY CONDUCTION
The process of
information transfer at a synapse is called
SYNAPTIC TRANSMISSION
a type of synapse thatrelatively simple in structure and function, and
they allow the direct transfer of ionic current from one cell to the next.
ELECTRICAL SYNAPSE
allow neighboring cells to
share both electrical and chemical signals that may help coordinate their
growth and maturation.
GAP JUNCTIONS
These vesicles store neurotransmitter, the
chemical used to communicate with the postsynaptic neuron.
synaptic vesicles
Synapses in which the membrane differentiation on the
postsynaptic side is thicker than that on the presynaptic side are called
ASYMMETRICAL SYNAPSE
those in which the mem-
brane differentiations are of similar thickness are called
SYMMETRICAL SYNAPSE
________________requires that neurotransmitters be synthe-
sized and ready for release. Different neurotransmitters are synthesized in
different ways.
CHEMICAL SYNAPTIC TRANSMISSION
slower, longer, lasting, and much more diverse postsynaptic actions.
G-PROTEIN-COUPLED RECEPTORS
excitatory. A transient postsynaptic membrane depo-
larization caused by the presynaptic release of neurotransmitter is called an
EPSP (EXCITATORY POSTSYNAPTIC POTENTIAL)
A transient hyperpolarization of the postsynaptic mem-
brane potential caused by the presynaptic release of neurotransmitter is called an
INHIBITORY POSTSYNAPTIC POTENTIAL (IPSP)
neurotransmitter receptors are also commonly found in the membrane of the
presynaptic axon terminal.
AUTORECEPTORS
This method uses labeled antibodies to identify the location of molecules within cells.
IMMUNOCYTOCHEMISTRY
a synthetic probe is constructed containing a sequence of complementary nucleotides that will allow it to stick to the mRNA.
IN SITU HYBRIDIZATION
This method enables a researcher to apply drugs or neurotransmitter candidates in very small amounts to the surface of neurons.
MICROIONITOPHORESIS
are a class of drugs, derived from the opium poppy, that are both
medically important and commonly abused.
OPIATES
The idea that a
neuron has only one neurotransmitter is often called
DALE’S PRINCIPLES
When two or more transmitters are released from
one nerve terminal, they are called
CO-TRANSMITTERS
is the neurotransmitter at the neuromuscular
junction and is therefore synthesized by all the motor neurons in the spinal cord and brain stem.
ACETYLCHOLINE (ACH)
the small lipid molecules, can be released from postsynaptic neurons and act on postsynaptic terminal
ENDOCANNABINOIDS
It serve as a kind of feedback system to regulate the conventional forms of synaptic transmission, which of course go from “pre” to “post.”
RETROGRADE MESSENGERS
The whole process that couples the neurotransmitter, via multiple steps,
to activation of a downstream enzyme is called a
SECOND MESSENGER CASCADE
the breakdown of neurotransmitter in the synaptic cleft by enzymes
NEUROTRANSMITTER DEGRADATION
the brains ability to change and adapt in response to experience or injury, involves the strengthening and weakening.
NEUROPLASTICITY
The small gap between the pre and post synaptic neurons across which neurotransmitter are released
SYNAPTIC CLEFT
small changes in membrane potential that occur in the dendrites and cell body of an neuron
GRADED POTENTIAL
a principle stating that once the threshold is reached an action potential will fire completely
ALL-OR-NONE PRINCIPLE
the process by which multiple excitatory and inhibitory signals combine at the postsynaptic membrane
SUMMATION
refers to the summing of signals overtime
TEMPORAL SUMMATION
it refers to the summibg of signals from different synapses
SPATIAL SUMMATION
Proteins that bind to neurotransmitters
NEUROTRANSMITTER RECEPTORS
Receptors that acts as a ligand gated ion channels
IONOTROPIC RECEPTORS
A type of receptor that does not directly open ion channels, instead activate second messenger systems through g-protein
METABOTROPIC RECEPTORS
the breakdown of neurotransmitters in the synaptic cleft by enzymes
ENZYMATIC DEGRADATION
a receptors regulate motor and sensory pathways
GLYCINE
A catacolamine neurotransmitter involved in the regulation of mood motivation and reward pathways.
DOPAMINE (DA)
a monoamine neurotransmitter involved in mood regulation, emotional processing, sleep and appetite
SEROTONIN (5 HT)
another catacolamine that is both a hormone and neurotransmitter involved in stress response, increasing heart rate blood flow and glucose availability during fight and flight response
EPINEPHRINE
also called noradrenaline that involves in the body’s fight and flight response
NOREPINEPHRINE (NE)
A neuropeptides that acts a natural pain reliver by binding to oipiods receptors
ENDORPHINS
A neuropeptide and hormone involved in social bonding, reproduction and maternal behavior. also called a love hormone
OXYTOCIN
Involved in both CNS and PNS. It plays a role in memory, learning and muscles contraction
ACETYLCHOLINE
The enzyme responsible for synthesizing acetylcholine in the presynaptic neuron.
ACETYLCHOLINESTERASE
Neurotransmitter released candidate molecule likely acting as the natural neurotransmitter
SYNAPTIC MIMICRY
The enzyme catalyzed the formation of acetylcholine by transforming an acetyl group from acetyl COA to CHOLINE
ACETYL TRANSFERASE
