CELLS OF THE NERVOUS SYSTEM

NEURONS

A cell in the NS that is specialized to carry out the functions of information processing and communication.

GLIA

greek word for “glue”, serve a variety of support functions for neurons.

ATLEAST 10-50 GLIA

number of glia for every neuron

SOMA / CELL BODY

the main mass of a neuron, containing the nucleus and many organelles.

AXON

is the branch of a neuron responsible for carrying signals to other neurons.

DENDRITES

receive information from other neurons.

SCHWANN CELLS

are variety of glial cells that keep peripheral nerve fibers (both myelinated and unmyelinated) alive.

Produces myeline sheath

NEURON MEMBRANES

the primary task of any cell membrane is to form a boundary between the cell and its external environment. It separates the intracellular fluid and extracellular fluid.

INTRACELLULAR FLUID

fluid inside the cell

EXTRACELLULAR FLUID

fluid outside of the cell

PERMEABILITY

is the extent to which other substances may pass through it

SEMI PERMEABLE

selected substances may pass through it

NON PERMEABLE

no substance may pass through it

ION CHANNEL

is a protein structure embedded in a cell membrane that allows ions to pass without the use of additional energy.

ADENOSINE TRIPHOSPHATE

atp — energy

ION PUMP

uses energy to move ions across the membrane.

ION

an electrically charged particles in solution

VOLTAGE-DEPENDENT CHANNEL

an ion channel that opens or closes in response the local electrical environment

Doesn't require energy instead electrical impulses or neurotransmitters ang nagpapatakbo

LIGAND-GATED CHANNEL

an ion channel in the neural membrane that responds to the chemical messengers

Requires atp and neurotransmitters

NEUROTRANSMITTERS

chemical messenger of the brain

SYNAPSE

is the junction between two neurons at which information is transferred from one point to another

SODIUM POTASSIUM PUMP

an ion pump that uses energy to transfer three sodium ions to the extracellular fluid for every two potassium ions received from the extracellular fluid

CALCIUM PUMP

a protein structure embedded in the neural membrane that uses energy to move calcium ions out of the cell

CYTOSKELETON

a network of filaments and structural support that maintains the shape of the neuron is provided by _____

MICROTUBULES

the largest fiber in the cytoskeleton responsible for the transport of neurotransmitters and other products to and from the cell body.

ANTEROGRADE TRANSPORT

movement of materials from the cell body to the Axon terminal

RETROGRADE TRANSPORT

movement of material from the axon terminal back to the cell body

NEUROFILAMENTS

the neural fiber found in the cytoskeleton responsible for structural support

MICROFILAMENTS

the smallest fiber in the cytoskeleton that may participate in the changing of the length and shape of axon and dendrites

NEURAL CELL BODY

It contains many of the same small structures and carries out many of the same functions as any other cell.

NUCLEUS

the most prominent structure in the cell body, contains the DNA that directs the cell’s function.

NUCLEOLUS

is a substructure that produce ribosomes.

RIBOSOME

is an organelle involved in protein synthesis.

ENDOPLASMIC RETICULUM

participates in the synthesis, folding, modification, and transport of proteins.

SMOOTH ER

ER for lipids and fats

ROUGH ER

ER for protein

GOLGI APPARATUS

responsible for packaging proteins into vesicles prior to secretion and therefore plays a key role in the secretory pathway.

MITOCHONDRIA

powerhouse of the cell

DENDRITES

The greek word for “tree”; serves the locations at which information from other neurons is received

SYNAPTIC GAP

tiny fluid-filled space between neurons forming a synapse

DENDRITIC SPINE

a small membranous protrusion from a neuron's dendrite that typically receives input from a single axon at the synapse. It may serve as a common substrate for many neuropsychiatric disorders, particularly those that involve deficits in information processing.

AXON HILLOCK

located at the end of the soma and controls the firing of the neuron. If the total strength of the signal exceeds the threshold limit of the axon hillock, the structure will fire a signal (known as an action potential) down the axon.

MYELIN

an insulating layer, or sheath that forms around nerves. It is made up of protein and fatty substances. It allows electrical impulses to transmit quickly and efficiently along the nerve cells. If myelin is damaged, these impulses slow down.

INTERNEURONS

also known as local circuit neurons

nerve cells that only participate in the local aspects of a circuit

PROJECTION NEURONS

are neurons whose axons extend from the neuronal cell body within the central nervous system (CNS) to one or more distant regions of the CNS.

From point of origin to CNS/PNS

AXON TERMINAL

is the very end of a branch of axon, a long slender nerve fiber that conducts electrical signals to a nerve synapse. The signal then moves across the synapse to another axon by means of a neurotransmitter

SYNAPTIC VESICLES

(or neurotransmitter vesicles) store various neurotransmitters that are released at the synapse.

NODES OF RANVIER

allow for ions to diffuse in and out of the neuron, propagating the electrical signal down the axon

Para siyang portal na tumatalon para mas mabilis

UNIPOLAR NEURONS

1 structure extending from the soma

Sensory input from the skin

BIPOLAR NEURONS

one axon and one dendrite extending from the soma

Vision, smell, hearing

MULTIPOLAR NEURONS

one axon and many dendrites

For complex processing

PSEUDOUNIPOLAR NEURONS

has a single structure that extends from the soma, which later branches into two distinct structures.

For fast sensory information such as pain

SENSORY NEURONS

Are nerve cells within the nervous system responsible for converting external stimuli from the organisms environment into electrical impulses.

GLIA

also called glial cells or neuroglia, are nonneuronal cells in the CNS and PNS that do not produce electrical impulses. They maintain homeostasis, form myelin, and provide support and protection for neurons.

ASTROCYTES

star-shaped glial cells in CNS that have a number of functions, including support of the blood-brain barrier, provision of nutrients to neurons, repair to nervous tissue following injury, and facilitation of neurotransmission.

OLIGODENDROCYTES

are highly specialized neural cells whose function is to myelinate CNS axons. Myelin sheaths are extraordinarily large extensions of the oligodendrocyte cell membrane and are highly complex structures.

SCHWANN CELLS

any of the cells in the PNS that produce the myelin sheath around neuronal axons.

EPENDYMAL CELLS

to regulate the cerebrospinal fluid

SPIKE / IMPULSE

other words for action potential

DIFFUSION

is the movement of a substance from an area of high concentration to an area of low concentration.

CONCENTRATION GRADIENT

the difference in the concentration of a substance between two areas

RESTING POTENTIAL

tells about what happens when a neuron is at rest.

-70 mV

mV of resting potential

DEPOLARIZATION

is caused by a rapid rise in membrane potential opening of sodium channels in the cellular membrane, resulting in a large influx of sodium ions.

+30 mV

mV of depolatization

THRESHOLD

is the critical level to which a membrane potential must be depolarized to initiate an action potential.

-55 mV

mV of threshold - nagiging baseline if magf fire ang action potential or not

REPOLARIZATION

the process where a cell's membrane potential returns to its resting state after depolarization.

lalabas ang sodium, papasok ang potassium, babalik sa dating state.

HYPERPOLARIZATION

is a change in a cell's membrane potential that makes it more negative. It is the opposite of a depolarization. It inhibits action potentials by increasing the stimulus required to move the membrane potential to the action potential threshold.

REFRACTORY PERIOD

is a period of time during which a cell is incapable of repeating an action potential

CHEMICAL SYNAPSE

is a gap between two neurons where information passes chemically, in the form of neurotransmitter molecules.

ELECTRICAL SYNAPSE

is a gap which has channel proteins connecting the two neurons, so the electrical signal can travel straight over the synapse

20nm

width of chemical

3.5nm

width of electrical synapse

EXOCYTOSIS

is the process in which vesicles fuse with the membrane of the axon terminal and release neurotransmitter molecules into the synaptic gap.

REUPTAKE

recycling neurotransmitters

EXCITATORY POSTSYNAPTIC POTENTIAL

a postsynaptic potential that makes the postsynaptic neuron more likely to fire an action potential.

INHIBITORY POSTSYNAPTIC POTENTIAL

a kind of synaptic potential that makes a postsynaptic neuron less likely to generate an action potential

NEURAL INTEGRATION

is the algebraic representation and summation of any excitatory or inhibitory postsynaptic potentials which govern the potential for firing in the postsynaptic neuron

AXO-AXONIC SYNAPSE

a type of synapse, formed by one neuron projecting its axon terminals onto another neuron's axon. Axo-axonic synapses can induce either inhibitory or excitatory effects in the postsynaptic neuron.

PRESYNAPTIC NEURON

(anatomically) - neuron before the synapse, this neuron is delivering the "message" across the synapse to the postsynaptic neuron. The postsynaptic neuron is the "receiver" of the neurotransmitter "message".

PRESYNAPTIC FACILITATION

the increase of neurotransmitter release by the postsynaptic axon as a result of input from the presynaptic axon.

PRESYNAPTIC INHIBITION

at a synapse between two axons, the decrease of neurotransmitter release by the postsynaptic axon as a result of input from the presynaptic axon.

TEMPORAL SUMMATION

a neural mechanism wherein an urge is propagated by two consecutive postsynaptic potentials neither of which is effective or intense enough on their own to elicit a reaction. The partial depolarization elicited by the first PSP persists for a few milliseconds and is capable, with the additive impact of the second PSP, to generate an above-threshold depolarization effective enough to induce an action potential.

My timing, for example heartbeat, blinking of the eye, breathing

SPATIAL SUMMATION

is a neural impulse propagated by 2 or more post synaptic potentials that occur at the same time at different synapses on more than one neuron.

many different presynaptic neurons ang naaapektuhan and it is complex