BME 603 - Ch. 2

medicineman's version from 2016-02-02 19:38


Question Answer
NeuronBasic functional unit of the nervous system. Senses changes in the environment, communicates these changes to other neurons, and commands the body's responses to these changes
Glia (glial cells) Mainly insulate, support, and nourish neighboring neurons
HistologyThe microscopic study of the structure of tissues
CytoarchitectureThe arrangement of neurons in different parts of the brain
Nissl stainStains the nuclei of all cells as well as clumps of material surrounding the nuclei of neurons (rough ER). Distinguishes between neurons and glia
Golgi stainStains a small percentage of neurons in their entirety
Cell body/Soma (somata)/Perikaryon (perikarya)Different names for the swollen region of a neuron containing the nucleus. About 20 microns in diameter
NeuritesThe thin tubes that radiate from the soma. Two types: axons and dendrites
AxonCell body usually gives rise to one axon. Carries output information of the neuron
DendriteReceive inputs for the neuron
Neuron doctrineThe idea that cell theory also applies to neurons. Neurites of different cells are not continuous, they communicate by contact
Neuronal membraneServes as a barrier to enclose the cytoplasm inside the neuron and to exclude certain substances that float in the fluid that bathes the neuron. It is studded with proteins that pump substances into and out of the cell or that from pores that regulate which substances can cross the membrane
CytosolSalty, potassium rich solution inside a cell
OrganelleA membrane-enclosed structure within the soma (nucleus, ER, Golgi apparatus, mitochondria, etc.)
CytoplasmEverything contained in the cell membrane including the organelles but excluding the nucleus
NucleusContained within a double envelope called the nuclear envelope which is perforated
ChromosomesLocated within the nucleus and contain the genetic material called DNA (deoxyribonucleic acid)
GenesSegments of DNA that determine how to assemble cells
ProteinsPerform many different functions and are the result of gene expression. Protein synthesis occurs in the cytoplasm
mRNA (messenger ribonucleic acid)Carries genetic information in DNA outside the nucleus. The information is coded by various sequences of nucleic acids
TranscriptionThe process by which mRNA is assembled
PromoterRegion of a gene where the RNA-synthesizing enzyme , RNA polymerase, binds to initiate transcription. The binding of the RNA polymerase is regulated by other proteins called transcription factors
Terminator (stop sequence)Marks the end point of transcription for the RNA polymerase
IntronsStretches of DNA in a gene that cannot be used to code for a protein
ExonsSequences in a gene that are used for protein coding
RNA splicingThe process by which introns are removed and the remaining exons are fused together. In some cases, specific exons are also removed with the introns, leaving an "alternatively spliced" mRNA that encodes a different protein
Amino acidsThe building blocks for proteins. There are 20 different kinds.
TranslationThe process by which proteins are assembled from amino acids under the direction of mRNA
GenomeThe entire length of DNA that comprises the genetic information in our chromosomes
Knockout miceMice in which one gene has been deleted
Knock-in miceMice in which one native gene has been replaced with a modified transgene
Transgenic miceMice in which genes have been introduced and over-expressed. These genes are called transgenes
RibosomesDense globular structures where protein synthesis occurs. Not all ribosomes are attached to the ER. Many are free floating and are called free ribosomes
Rough endoplasmic reticulum (rough ER)Stacks of membrane that have ribosomes attached to them. Proteins that are destined to be inserted into the membrane of the cell or into an organelle are synthesized on the rough ER
PolyribosomesSeveral free ribosomes that are attached by a single strand of mRNA. The associated ribosomes are working to create multiple copies of the same protein. Proteins that are to remain within the cytosol are made in free ribosomes
Smooth endoplasmic reticulum (smooth ER) (called sarcoplasmic reticulum in muscle cells)Looks like rough ER without the ribosomes. Some smooth ER is continuous with rough ER and is believed to be a site where proteins are folded. Other types of smooth ER regulate internal concentrations of substances such as calcium
Golgi apparatusThe stack of membrane-enclosed disks in the soma that lies farthest from the nucleus. It is believed to sort certain proteins that are to be delivered to different parts of the neuron
Mitochondrion (mitochondria)The site of cellular respiration. Pyruvic acid and oxygen are pulled into the cell and adenosine triphosphate (ATP) is produced through the Krebs cycle and the electron-transport chain. ATP is the energy source of the cell
CytoskeletonGives the cell its shape. The elements of the cytoskeleton are in constant motion
MicrotublesRun longitudinally down neurites and are composed of the protein tubulin. Their assembly is regulated by microtubule-associated proteins (MAPs). MAPs are known to anchor microtubules to one another and to other parts of the neuron
MicrofilamentsComprised of the protein actin. Believed to play a role in changing cell shape
NeurofilamentsCalled intermediate filaments in all other cells. Part of the cytoskeleton
Axon hillockTapers away from the soma to form the initial segment of the axon proper. No rough ER in the axon but some free ribosomes in mature axons
Axon collateralsBranches of the axon. Recurrent collaterals communicate with the same cell or with the dendrites of neighboring cells
Nerve impulseThe electrical signal that sweeps down the axon
Axon properMiddle of an axon
Axon terminal (terminal bouton)The end of an axon
SynapseThe point of contact between an axon terminal and another cell
Terminal arborCollective term for axon branches that synapse in the same region
InnervateTo supply with neurons
Cytoplasm of the synaptic terminalMicrotubules do not extend into the terminal. The terminal contains synaptic vesicles. The inside surface of the membrane that faces the synapse has a dense covering of proteins. The axon terminal cytoplasm has numerous mitochondria
Synaptic cleftThe space between the presynaptic and postsynaptic membranes
Synaptic transmissionThe transfer of information at a synapse
NeurotransmitterChemical signal for synaptic transmission. Stored in and released from the synaptic vesicles
Axoplasmic transportThe movement of material from the soma down the axon
Anterograde transportTransport from the soma to the axon terminal. Transport protein is kinesin
Retrograde transportTransport from the terminal to the soma. Transport protein is dynein
Dendritic treeThe collective term for all the dendrites of a neuron
ReceptorsFound in postsynaptic membranes. They detect neurotransmitters
Dendritic spinesSpecialized structures on some dendrites that receive some type of synaptic input
Cytoplasm of dendritesMostly resembles the cytoplasm axons, but polyribosomes can be observed
Unipolar neuronA neuron with a single neurite
Bipolar neuronA neuron with two neurites
Multipolar neuronA neuron with three or more neurites. Most neurons in the brain are multipolar
Stellate cells Star shaped cells in the cerebral cortex
Pyramidal cells Pyramid shaped cells in the cerebral cortex
Primary sensory neuronsNeurons with neurites in the sensory surfaces of the body
Motor neuronsNeurons that have axons that synapse with muscles
InterneuronsNeurons that form connections with other neurons
Golgi type I neuronsNeurons with long axons that extend from one part of the brain to the other (pyramidal cells)
Golgi type II neurons (local circuit neurons)Neurons with short axons that do not extend beyond the vicinity of the cell body (stellate cells)
Green fluorescent protein (GFP)Used commonly in neuroscience. When illuminated with the appropriate wavelength of light, it fluoresces green. Used to visualize neurons
Classification of neurons based on neurotransmittersCholinergic neurons release acetylcholine
AstrocytesMost numerous glia in the brain. Fill most of the space between neurons. They regulate the chemical content of the extracellular spaces. They envelope synaptic junctions, thereby restricting the spread of neurotransmitters. Astrocytes also have neurotransmitter receptors and control the extracellular concentration of substances that could interfere with proper neuronal function such as potassium ions
Oligodendroglial (CNS, several axons) and Schwann cells (PNS, one axon)Provide layers of membrane, called myelin, that insulate axons
Node of RanvierRegion of the axon where the axonal membrane is exposed
Ependymal cellsLine the ventricles of the brain. Direct cell migration during brain development
MicrogliaFunction as phagocytes to remove debris