Chapter 3: The Nervous System's Functional Units Flashcards
Cell body/soma
core region of the cell; contains the nucleus and other organelles for protein making
Dendrite
branching extension that increases the surface area and collects info
Axon
root, single fibre of a neuron that carries messages to other neurons
Dendritic spine
protrusion that increases dendrite’s surface area; usually the place where dendritic contact occurs
Axon Hillock
juncture of soma and axon
Terminal button
knob end tip of axon that conveys info
Synapse
spatial junction between one neuron and another; forms information transfer gate between neurons
Sensory neurons (2 types)
they conduct info from sensory receptors
1) Bipolar: 1 axon and 1 dendrite
2) Somatosensory: brings sensory info in from body to spinal cord
Interneurons (2 types)
also called association cells; they link sensory and motor information and branch widely
1) Pyramidal cell: long axon, pyramid body and 2 dendrite sets
2) Purkinje cell: extremely branched with a fan shape (info from cerebellum)
Motor neurons
extensive dendritic networks, large cell bodies and axons; located in the lower brainstem and spinal cord
Glial cell
provides insulation, nutrients and support that aids in repairing neurons and eliminating waste products; 5 types; can result in tumors
Ependymal cell
a glial cell that makes and secretes CSF; found on the walls of the ventricles
Astrocyte cell
glial cell that is star shaped; provides structural support to CNS and transports nutrients; located in the blood brain barrier; enhance brain activity and healing
Microglia
a glial cell that originates in the blood and aids in cell repair and scavenging debris; essentially immune cells that multiply in response to injury/disease; sensitive to K+
Oligodendroglia
a glial cell that myelinates axons in the CNS
Schwann cells
a glial cells that myelinate sensory and motor axons in the PNS; function as “sign posts” for when axons are severed; decay in MS
Myelin
coating that surrounds axons; prevents adjacent neurons from short circuiting and allows for fast movement of impulses
Lysosome
transport incoming supplies and remove/store wastes
Cell membrane
double layer; regulates movement in and out of cell; phospholipid bilayer
Genes
DNA segment that encodes synthesis of a particular protein; thousands of genes in each chromosome
Chromosome’s and their components (4)
double strand of DNA; adenine-thymine & guanine-cytosine
Protein Manufacturing (3)
1) DNA opens up and is a template for RNA to be formed (transcription)
2) mRNA carries protein code to endoplasmic reticulum
3) Ribosome translates mRNA into amino acids (protein molecules) (translation)
Protein
folded up polypeptide chain that serves a particular function in the body
Golgi Body function
“wraps” and labels the proteins based on location they are being sent to
Channel
opening in a protein embedded in the cell membrane that allows for the passage of specific ions
Gate
protein in cell membrane that allows substances to pass through the membrane on some occasions but not others
Pump
actively transports a substance across the membrane (a protein)
Allele
alternative form of a gene; a gene pair contains 2 alleles
Homozygous vs Heterozygous
having 2 identical alleles for a trait vs having 2 different alleles for a trait
Mutation
alteration of an allele that yields a different version of its protein
Tay Sachs Disease
loss of genes that code the breakdown of certain lipids in the brain; intellectual disability and death by 5; recessive allele on the 15th chromosome
Huntington Disease
build up of huntingtin protein that kills brain cells; involuntary movements, dementia and death; dominant allele on chromosome 4
Transgenic techniques
one or more gene is introduced or removed from a species to alter what is passed on and expressed (knock in vs knock out)
Gene (DNA) methylation
methyl group attaches to a DNA sequence, suppressing or enabling expression (transcription is blocked or enabled)
Histone modification
disables the unspooling of DNA or allows for it to happen
