chapter 2 Flashcards
central nervous system
the brain and spinal cord
peripheral nervous system
the part of the nervous system outside of the brain and spinal cord, including the nerves attached to the brain and spinal cord
nerves
bundles of individual neurons contained within a protective membrane that relay sensory to the CNS from the body and relay motor information from the CNS to the rest of the body.
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
a 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
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
myelin sheath
a sheath that surrounds axons and insulates them, preventing messages from spreading between adjacent axons
terminal buttons
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 an 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
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 the cell (tracks for the axoplasmic transport)
cytoplasm
the viscous, semiliquid substance contained in the interior of a cell
nucleus
a structure in the central region of a cell, containing the chromosomes
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
enzyme
a molecule that controls a chemical reaction, combining two substances or breaking a substance into two parts
mitochondria
organelles that are responsible for extracting energy from nutrients
adenosine triphosphate (ATP)
a molecule of prime importance to cellular energy metabolism; its breakdown liberates energy
gila
the supporting cells of the central nervous system
astrocyte
a gila 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
oligodendrocytes
a type of gilial cell in the central nervous system that forms myelin sheath
node of ranvier
a naked portion of a myelinated axon between adjacent oligodendroglia or schwann cells