Ch.3 Flashcards
what are the basic structures of a neuron
cell body (soma), dendrites (collect info from other cells), axon (carries messages to neurons)
dendritic spines
protrusion from a dendrite that increases its surface area and is typical point of contact for other cells
axon hillock
juncture of soma and axon where action potential begins
axon collaterals
branches of an axon
telodendrion
end branches of an axon
terminal button
knob at tip of axon that conveys info to other neurons (also called end foot)
synapse
gap between neurons
what are the three types of neurons
sensory, motor, and interneurons
sensory neurons
carry info from sensory receptors in or on the body to the spinal chord
motor neurons
send signals from the brain and spinal cord to muscles
interneurons (association neurons)
associate sensory and motor activity within the central nervous system
bipolar neurons
transmit afferent sensory info from retinas light receptors to neurons that carry info to brains visual centers
somatosensory dendrite
connects directly to its axon so the cell body sits to one side of this long pathway
what are the 3 interneurons
stellate, pyramidal cell, purkinje cell
stellate cell
star shapes, small with many dendrites that extend around cell body
pyramidal cell
has long axon, a pyramid-shaped cell body, two sets of dendrites apical and basal
purkinje cell
a distinctive interneuron with extremely branched dendrites that form a fan shape
where do motor neurons reside
in the lower brainstem and the spinal cord
what are the three organizational aspects of neurons
input, association, and output
(glial cell) ependymal cell
small ovoid, found in walls of ventricles, make and secretes cerebrospinal fluid
(glial cell) astrocyte
star shaped, gives neurons structural support, transport substances between blood-brain barrier, forms scar tissue, fuels active brain areas
microglial cell (glial cell)
small, derived from blood, defensive function to remove dead tissue (phagocytosis)
(glial cell) oligodendroglial cell
forms myelin around CNS axons in brain and spinal chord
(glial cell) schwann cell
wraps around peripheral nerves to form myelin in axons
myelin
glial coating tha surrounds axons
multiple sclerosis (MS)
nervous system disorder associated with loss of myelin
how are neurons repaired
schwann cells shrink then divide to form glial cells along axons former path, neuron sends out axon sprouts and finds schwann cell path to become new axon
what determines a cells characteristics and functions?
a cells proteins, water, salts, and ions as well
what does the cell membrane do?
separates intracellular and extracellular fluid, regulates movement of things in and out of cell, and is mad up of phospholipids
chromosome
2x stranded molecule of DNA
ribosomes
protein structures that act as catalysts for protein synthesis
translation
where messanger RNA travels from nucleus to ER where mRNA is translated into amino acid sequences to form protien
transcription
DNA strands unwind and a complimentary strand of mRNA is produced
what does an amino acid consist of? sensory, motor, and interneurons
central carbon atom bound to hydrogen atom, amino group, carboxyl group and a side chain linked together by peptide bond
golgi bodies
package proteins in vesicles (membranes) and give them a label as to where they should go
microtubules
transport the vesicles to their destinations inside or outside of the cell
tay-sachs disease
inherited at birth, caused by loss of genes that encode the enzyme that breaks down fatty substances, results in intellectual disability, physical changes and death by 5yrs
huntington disease
causes by increase in number of CAG on chromosome 4 autosomal disorder, cognitive+motor disturbances
what do genetic disorders result from
aberration of a chromosome –> not a single defective allele
down syndrome
intellectual impairment and other abnormalities, occurs w/ extra copy of 21st chromosome (trisomy)
what are approaches to genetic engineering?
selective breeding, cloning, transgenic techniques, knockouts
selective breeding
alters gene expression, objective is to maintain spontaneous mutations
cloning
where you produce an offspring that is genetically identical to another, can be used to observe heredity and impact of environment
what is transgenic technique
introduction or removal of genes into embryo with knock in technology to inactivate gene
phenotypic plasticity
capacity of genome to express many phenotypes
epigenetics
the influence of environment on selection of one or another phenotype
what does the absence of a corpus callosum result from?
an epigenetic influence on whether trait is expressed in a particular mouse
what is observed in patterns of disease in identical twins?
lack of concordance (incidence of similar behavioral traits)
what can be viewed as a second genetic code?
epigenetics
what do epigenetic mechanisms influence
protein production by blocking or unblocking a gene so that it can or cant be transcribed
how can environment influence induce or remove one or more blocks of genes to regulate gene expression?
histone modification: DNA unwraps or stopped from unwrapping in histone
DNA methylation: transcription of DNA into mRNA enabled or blocked
mRNA modification: mRNA translation may be enabled or blocked
