Chapter 3 Flashcards
cell body (soma)
Core region of the cell containing the nucleus and other organelles for making proteins.
dendrite
Branching extension of a neuron’s cell membrane; greatly increases the cell’s surface area; collects information from other cells.
axon
Root, or single fiber, of a neuron that carries messages to other neurons.
neural network
Functional group of neurons that connects wide areas of the brain and spinal cord.
connectome
Comprehensive map of all structural connectivity (the physical wiring) in an organism’s nervous system.
dendritic spine
Protrusion that greatly increases the dendrite’s surface area; typical point of dendritic contact with the axons of other cells.
axon hillock
Juncture of soma and axon.
axon collateral
Branch of an axon.
terminal button (end foot)
Knob at the tip of an axon that conveys information to other neurons.
synapse
Spatial junction between one neuron and another; forms the information transfer site between neurons.
sensory neuron
Cell that detects or carries sensory information into the spinal cord and brain.
interneuron
Association cell interposed between a sensory neuron and a motor neuron; in mammals, interneurons constitute most of the brain’s neurons.
motor neuron
Cell that carries efferent information from the brain and spinal cord to make muscles contract.
bipolar neuron
Sensory neuron with one axon and one dendrite.
somatosensory neuron
Brain cell that brings sensory information from the body into the spinal cord.
pyramidal cell
Distinctively shaped interneuron found in the cerebral cortex.
Purkinje cell
Distinctively shaped interneuron found in the cerebellum.
glial cell
Nervous system cell that provides insulation, nutrients, and support and that aids in repairing neurons and eliminating waste products.
ependymal cell
Glial cell that makes and secretes CSF; found on the walls of the brain’s ventricles.
hydrocephalus
Buildup of fluid pressure in the brain and, in infants, swelling of the head, if the flow of CSF is blocked; can result in intellectual impairment.
tumor
Mass of new tissue that grows uncontrolled and independent of surrounding structures.
astrocyte
Star-shaped glial cell that provides structural support to CNS neurons and transports substances between neurons and blood vessels.
blood–brain barrier
Tight junctions between the cells that compose blood vessels in the brain, providing a barrier to the entry of an array of substances, including toxins, into the brain.
microglia
Glial cells that originate in the blood, aid in cell repair, and scavenge debris in the nervous system.
myelin
Glial coating that surrounds axons in the central and peripheral nervous systems; prevents adjacent neurons from short-circuiting.
oligodendroglia
Glial cells in the CNS that myelinate axons.
Schwann cell
Glial cell in the PNS that myelinates sensory and motor axons.
paralysis
Loss of sensation and movement due to nervous system injury.
gene
DNA segment that encodes the synthesis of a particular protein.
protein
Folded-up polypeptide chain that serves a particular function in the body.
channel
Opening in a protein embedded in the cell membrane that allows the passage of ions.
gate
Protein embedded in a cell membrane that allows substances to pass through the membrane on some occasions but not on others.
pump
Protein in the cell membrane that actively transports a substance across the membrane.
allele
Alternative form of a gene; a gene pair contains two alleles.
homozygous
Having two identical alleles for a trait.
heterozygous
Having two different alleles for the same trait.
mutation
Alteration of an allele that yields a different version of its protein.
Tay-Sachs disease
Inherited birth defect caused by the loss of genes that encode the enzyme necessary for breaking down certain fatty substances; appears 4 to 6 months after birth and results in intellectual disability, physical changes, and death by about age 5.
wild type
Typical allele (most common in a population).
Huntington disease
Hereditary disease characterized by chorea (ceaseless involuntary jerky movements) and progressive dementia, ending in death.
Down syndrome
Chromosomal abnormality resulting in intellecutal impairment and other abnormalities, usually caused by an extra chromosome 21.
transgenic animal
Product of technology in which one or more genes from one species is introduced into the genome of another species to be passed along and expressed in subsequent generations.
gene (DNA) methylation
Epigenetic process in which a methyl group attaches to the DNA sequence, suppressing or enabling gene expression.
