Chapter 2: Neurons & Glia Flashcards
A cell that is specialized for the transmission of information and characterized by long fibrous projections called axons, and shorter, branch-like projections called dendrites; the basic functional unit of the nervous system; also called a nerve cell
Neuron
A type of cell that provides physical and chemical support to neurons and maintain their environment; contributes to brain function mainly by insulating , supporting, and nourishing neighboring neurons.
Glial cell
The idea that individual cells called neurons transmit signals in the nervous system, and that these cells are not continuous with other cells as proposed by nerve net theory.
The Neuron Doctrine
the microscopic study of tissues and organs through sectioning, staining, and examining those sections under a microscope.
Histology
Stains nucleic acids, mainly RNA on rough endoplasmic reticulum; uses a variety of dyes to show charged structures (Nissl bodies) in the soma of neurons and glia.
Nissl stain
the study of the structural arrangement of neurons within the central nervous system.
Cytoarchitecture
describes the way certain tissues, such as bone membrane, skin, or brain tissues, are arranged in layers.
Laminar Structure
Soaking brain tissue in a silver chromatic solution; makes a small percentage of neuron become darkly colored in their entirety.
Golgi stain
Theory that neutrites of different cells are fused into a continuous reticulum (nerve net); permits bi-directional informational flow.
Golgi (Reticular) Theory
Aka Soma or perikaryon; the core section of the neuron. It contains genetic information, maintains the neuron’s structure, and provides energy to drive activities.
Cell Body
Small processes on developing neurons that ultimately grow out into axons OR dendrites under the control of growth stimulating or inhibiting factors from their direct extracellular environment sensed by receptors in the growth cone.
Neurite
carry electrical impulses that are the means of communication within the brain and between the brain and the rest of the body; The long portion of a neuron that conducts impulses away from the body of the cell
Axon
a thin fiber that extends from a nerve cell. Its job is to pass along electric signals it receives from other cells.
Dendrite
Proteins that regulate the transcription of genes; proteins involved in the process of converting, or transcribing, DNA into RNA.
Transcription Factor
Molecules that combine to form proteins. These molecules and proteins are the building blocks of life.
Amino Acid
The process through which information encoded in messenger RNA (mRNA) directs the addition of amino acids during protein synthesis; takes place on ribosomes in the cell cytoplasm, where mRNA is read and translated into the string of amino acid chains that make up the synthesized protein.
Translation
The entire set of DNA instructions found in a cell; contains all the information needed for an individual to develop and function.
Genome
An intercellular structure made of both RNA and protein, and it is the site of protein synthesis in the cell. It reads the messenger RNA (mRNA) sequence and translates that genetic code into a specified string of amino acids, which grow into long chains that fold to form proteins.
Ribosome
Has on it ribosomes, which are small, round organelles whose function it is to make those proteins; involved with the production, folding, quality control and despatch of some proteins.
Rough Endoplasmic Reticulum
(Rough ER)
A group of ribosomes bound to an mRNA molecule like “beads” on a “thread”. It consists of a complex of an mRNA molecule and two or more ribosomes that act to translate mRNA instructions into polypeptides.
Polyribosome
Does not have ribosomes on its surface; Synthesizes lipids, phospholipids as in plasma membranes, and steroids. It regulates internal Ca^2+ concentration.
Smooth Endoplasmic Reticulum
(Smooth ER)
A cell organelle that helps process and package proteins and lipid molecules, especially proteins destined to be exported from the cell.
Golgi Apparatus
Are membrane-bound cell organelles (mitochondrion, singular) that generate most of the chemical energy needed to power the cell’s biochemical reactions. Chemical energy produced by this cell organelle is stored in a small molecule called adenosine triphosphate (ATP).
Mitochondria
An important “energy molecule”; captures chemical energy obtained from the breakdown of food molecules and releases it to fuel other cellular processes.
ATP (Adenosine Triphosphate)
Composed of a lipid bilayer that has hydrophilic (water loving) and hydrophobic ends; the site where most processes involved in neuronal preservation and functioning are triggered.
Neuronal Membrane
Carries out three broad functions: it spatially organizes the contents of the cell; it connects the cell physically and biochemically to the external environment; and it generates coordinated forces that enable the cell to move and change shape; 3 bones: microtubules (tubulin), Neurofilaments (intermediate filaments), Microfilaments (actin).
Cytoskeleton
Are major components of the cytoskeleton. They are Large (~20nm) and They are composed of tubulin, runs down the neutrites to give basic shape, and acts as a “railroad” for transport proteins. They are found in all eukaryotic cells, and they are involved in mitosis, cell motility, intracellular transport, and maintenance of cell shape. PROMINENT IN AXONS!
Microtubules
Assist with cell movement and are made of a protein called actin. They are small (~5nm), its function is dynamic, involved in growth and movement, and enriched in spines. Actin works with another protein called myosin to produce muscle movements, cell division, and cytoplasmic streaming. They keep organelles in place within the cell.
Microfilament (Actin)
Functions as maintenance and support of the cytoskeleton. Ones that are phosphorylated are transported down into the axon, where they maintain the size and caliber of the axon. Ones that are unphosphorylated remain in the cell body serving their function there. They control thickness of neutries, enriched in AXONS, and is rope-like.
Neurofilament (Intermediate Filament)
The neuronal region in the cell body wherein the summation of the excitatory & inhibitory activity occurs; It is where the neuronal action potential is usually created. It is a cone-shaped area in the neuronal cell body from where the axon originates.
Axon Hillock
Allows individual neurons to make contacts with multiple neurons within a target and with multiple targets.
Axon Collateral
small swellings that are found at the terminal ends of axons; They are typically the sites where synapses with other neurons are found, and neurotransmitters are stored there to communicate with other neurons via these synapses.
Axon Terminal
