Neuronal Components Flashcards
Types of neurons 3
- multipolar neuron
(A neuron with one axon and many dendrites attached to its soma. - example: cortical stellate neutron) - bipolar neuron
(A neuron with one axon and one dendrite attached to its soma.
Example: retinal bipolar cell ) - unipolar neuron
(A neuron with one axon attached to its soma; the axon divides, with one branch receiving sensory information and the other sending the information into the central nervous system.
Example: dorsal root ganglion cell)
sensory neuron
A neuron that detects changes in the external or internal environment and sends information about these changes to the central nervous system.
motor neuron
A neuron located within the central nervous system that controls the contraction of a muscle or the secretion of a gland.
interneuron
A neuron located entirely within the central nervous system.
soma
The cell body of a neuron, which contains the nucleus.
dendrite
The branched, treelike structure attached to the soma of a neuron; receives information from the terminal buttons of other neurons.
synapse
A junction between the terminal button of an axon and the membrane of another neuron.
axon
The long, thin, cylindrical structure that conveys information from the soma of a neuron to its terminal buttons
terminal button
The bud at the end of a branch of an axon; forms synapses with another neuron; sends information to that neuron.
neurotransmitter
A chemical that is released by a terminal button; has excitatory or inhibitory effect on another neuron.
membrane
A structure consisting principally of lipid molecules that defines the outer boundaries of a cell and also constitutes many of the cell organelles, such as he Golgi apparatus.
nucleus
A structure in the central region of a cell, containing the nucleolus and chromosomes.
nucleolus
A structure within the nucleus of a cell that produces the ribosomes.
mitochondrion
An organelle that is responsible for extracting energy from nutrients.
adenosine triphosphate (ATP)
A molecule of prime importance to cellular energy metabolism; its breakdown liberates energy.
endoplasmic reticulum
Parallel layers of membrane found within the cytoplasm of a cell. Rough endoplasmic reticulum contains ribosomes and is involved with production of proteins that are secreted by the cell. Smooth endoplasmic reticulum is the site of synthesis of lipids and provides channels for the segregation of molecules involved in various cellular processes.
golgi apparatus
A complex of parallel membranes in the cytoplasm that wraps the products of a secretory cell.
exocytosis
The secretion of a substance by a cell through means of vesicles; the process by which neurotransmitters are secreted.
lysosome
An organelle surrounded by membrane; contains enzymes that break down waste products.
cytoskeleton
Formed of microtubules and other protein fibers, linked to each other and forming a cohesive mass that gives a cell its shape.
microtubule
A long strand of bundles of protein filaments arranged around a hollow core; part of the cytoskeleton and involved in transporting substances from place to place within that cell.
ribosome
A cytoplasmic structure, made of protein, that serves as the site of production of proteins translated from mRNA.
chromosome
A strand of DNA, with associated proteins, found in the nucleus; carries genetic information.
deoxyribonucleic acid (DNA)
A long, complex macromolecule consisting of two interconnected helical strands; along with associated proteins, strands of DNA constitute the chromosomes.
gene
The functional unit of the chromosome, which directs synthesis of one or
more proteins.
messenger ribonucleic acid (mRNA)
A macromolecule that delivers genetic information concerning the synthesis of protein from a portion of a chromosome to a ribosome.
enzyme
A molecule that controls a chemical reaction, combining two substances or breaking a substance into two parts.
cytoplasm
The viscous, semiliquid substance contained in the interior of a cell.
axoplasmic transport
An active process by which substances are propelled along microtubules that run the length of the axon.
anterograde
In a direction along an axon from the cell body toward the terminal buttons.
retrograde
In a direction along an axon from the terminal buttons toward the cell body.
astrocyte
A glial cell that provides support for neurons of the central nervous system, provides nutrients and other substances, and regulates the chemical composition of the extracellular fluid.
phagocytosis
The process by which cells engulf and digest other cells or debris caused by cellular degeneration.
oligodendrocyte
A type of glial cell in the central nervous system that forms myelin sheaths.
myelin sheath
A sheath that surrounds axons and insulated them, preventing messages from spreading between adjacent axons.
blood-brain barrier
A semipermeable barrier between the blood and the brain produced by the cells in the walls of the brain’s capillaries.
area postrema
A region of the medulla where the blood-brain barrier is weak; poisons can be detected there and can initiate vomiting.