Ch 7 Flashcards
neurons (nerve cells)
-receives info, processes it, and generates output
glial (glial cella or neuroglia)
-supporting roles
neurons typically comm using…
-electrical & chemical signals
electrical signals
-comm within neurons
chemical signals
-comm btwn neurons
neurons
-encased in a cell membrane (plasma membrane)
cytoplasm
-material inside the cell membrane; full of organelles
neurons primary parts
-dendrites > cell body > axon
cell body (soma or perikaryon)
-site for synthesis of nearly all the neuron’s enzymes, structural proteins, membrane components, organelles & some neurotransmitters
dendrites
-tapering extensions of cell body
-specialized to receive info
-increases surface area available for synaptic inputs
dendritic tree
-total array of neuron’s dendrites
dendrites pt 2
-info is transmitted distally proximally
-contains many of the same organelles as in cell body
dendritic spines
-spiky protuberances that are preferred sites for synaptic inputs
axon
-single output unit of a neuron; transmits action potentials from cell body distally
-can range from 1mm to 1 m
axon hillock
-gives rise to the initial segment
initial segment
-just distal to axon hillock; most electrically excitable part of neuron
cytoskeleton
-network of protein filaments contained w/ in nearly all parts of neurons that give neurons their shape & assist in transport w/in neuron
axonal transport
-active process by which cells send macromolecules & organelles along an axon
-can be fast or slow; anterograde or retrograde
fast anterograde transport
-material travels from cell body to presynaptic terminal along microtubules
fast retrograde transport
-material travels from terminal back to the cell body along microtubules
related clinical conditions to axonal, anterograde, and retrograde transport
-polio
-herpes
-chemotherapy
-alzheimers disease
-chronic traumatic encephalopathy
multi-polar
-have multiple dendrites and one axon
-designed to receive & accommodate large amounts of inputs
bipolar
-have 2 primary processes that extend from cell body dendritic root and axon
pseuounipolar
-subclass of bipolar neurons; appear to have signle projection from the cell body that div into two axonal roots and no true dendrites
sensory neurons
-receptive to sensory input either directly or through connections with receptor cells
motor neurons
-end on muscles, glands or other neurons
interneurons
-located in small area in CNS
projection neurons
-neurons in the CNS with long axons that project to another past of CNS
synaptic transmission
-mechanism by which neurons comm with each other
synapse
-a special zone of contact in which one neuron comm with another
presynaptic element
-distal end of axon
post synaptic
-part of another neuron
synaptic cleft
-separation btwn the two elements
synaptic vesicles
-containing neurotransmitters
-released from presynaptic element into the cleft
-bind to receptor sites in postsynaptic neuron
axodendritic
-axon of one cell to dendrite of another
axosomatic
-axon to soma
axoaxonic
-axon to axon
dendrodendritic
-dendrite to dendrite
schwann cells
-the principal PNS glial
-1 internode
satellite cells
-flattened schwann cells
-respond to injury of the nerve
-found in PNS
astrocytes
-largest of the CNS glia; highly branched
-two types: protoplasmic & fibrous
protoplasmic
-in gray matter
fibrous
-in white matter
astrocyte roles
-structural support
-can proliferate in response to CNS injury
microglia
-smallest of the CNS glia
-injury activates microglia to migrate & clean up debris
ependymal cells
-line the walls of ventricles and choroid plexus
-produce & secrete CSF
gliomas
-tumors of glial cell origin
-tumors of the PNS usu of Schwann cell origin
schwannoma
-usu encapsulated with no nerve fiber involvement; easily removed
neurofibroma
-encapsulated but infiltrating nerves; difficult to remove
multiple sclerosis
-demyelinating disease of the CNS
-autoimmune disease: body produces antibodies that attack oligodendrocytes
multiple sclerosis pt 2
-destruction of oligodendrocytes produces patches of demyelination
-areas of demyelination are replaced by astrocytic plaques
guillain-barre syndrome
-demyelinating disease of the PNS
-acute inflammation & demyelination of peripheral sensory (some) & motor (mostly) nerve fibers
oligodendrocytes
-the CNS counterpart of the Schwann cells
-can produce several internodes on several different axons
