Dr. Z's lectures Flashcards
white matter
axons
gray matter
neuron cell bodies, dendrites, fine branches of axons, and their synapses
neuropil
background between neuron cell bodies, dense dendrites, axons, and synapses
nucleus
collection of nerve cell bodies in the CNS
tract
bundle of neurons in the CNS (axons that are functionally similar)
nerve
bundle of neurons in the PNS
decussation
the act of nerves crossing
ganglion
collection of nerve cell bodies in the PNS
fissure
deeper, longer sulcus
tract
large axon bundle
fascicle
small axon bundle
interneurons
create neural circuits, enabling communication between sensory or motor neurons and the CNS
dorsal horn
contains interneurons that process sensory info, which enters through the dorsal root
dorsal root ganglion
contains sensory nerve cell bodies whose axons travel through dorsal root
ventral horn
contains motor axons that exit through ventral root
white matter in spinal cord
contains descending and ascending tracts
central canal
ventricular system of the spinal cord
cranial nerve
sensory and motor nerves emanating from the brain
peripheral nerve
sensory and motor nerves emanating from the spine
what are “special sensory” nerves?
related to derivatives of placodes, brain, taste buds
what are “special motor” nerves?
related to derivatives of branchial arches
which nerves have parasympathetic function?
3,7,9,10 - all general, visceral, efferent (GVE)
CN I nucleus
olfactory peduncle
CN II nucleus
lateral geniculate body
CN III nucleus
oculomotor nucleus
CN IV nucleus
trochlear nucleus
CN V nucleus
main sensory nucleus of V, spinal nucleus of V, mesencephalic nerve of V (GSA), motor nerve of V (SVE)
CN VI nucleus
abducens nucleus
CN VII nucleus
facial motor nucleus (SVE), rostral solitary nucleus (SVA), caudal solitary nucleus (GVA)
CN VIII nucleus
vestibular nucleus
CN IX nucleus
spinal nucleus of V (GSA), nucleus of the solitary tract (GVA), rostral solitary nucleus (SVA), caudal salivatory nucleus (GVE), and nucleus ambiguus (SVE)
CN X nucleus
spinal nucleus of V (GSA), caudal solitary nucleus (GVA), rostral solitary nucleus (SVA), dorsal efferent nucleus (GVE), nucleus ambiguus (SVE)
CN XI nucleus
accessory nucleus in the spinal cord
CN XII nucleus
hypoglossal nucleus
sensory neurons
receptors in the PNS, cell bodies in ganglia, a peripheral axon innervates the receptor and the signal travels through central axon to CNS
sensory neuron fxn:
detect events occurring in periphery
motor neurons
cell bodies in CNS for skeletal, cell bodies in autonomic postsynaptic ganglia for visceral
motor neuron fxn:
movement
interneurons
all axons confined to CNS, projection interneurons travel from one brain region to another, local interneurons confined to vicinity of their cell body
neuroglial cells
support functions for CNS, do not form synapses, do not generate action potentials, have only one process, divide throughout lifepsan, just as numerous as neurons
astrocytes
structural matrix (BBB) and homeostasis (CNS)
oligodendrocytes
form myelin in CNS, 1 oligodendrocyte forms many myelin segments
microglia
immune system function, brain macrophages (CNS)
satellite cells
support for PNS
ependymal cells
line ventricles, circulate cerebral spinal fluid (CSF)
choroid plexus
specialized ependymal cell that produces and secretes CSF
dendrite
input, increase contact expanse
soma
cell body
axon
output, can reach long distances
role of interneurons
interneurons create neural circuits, enabling communication between sensory or motor neurons and the CNS
schwann cell
support for PNS, 1 cell forms 1 myelin segment
electrical synapse
current flows passively through gap junctions in pre and post synaptic membranes
chemical synapse
synaptic vesicles filled with neurotransmitter on the pre-synaptic side, synaptic cleft, post synaptic side has receptors
________give rise to neurons, oligodendroglia, astroglial cells, and ependymal cells
neuroepithelial cells
________give rise to microglial cells
mesenchymal cells
_________give rise to cartilage, bone, connective tissue
cranial neural crest cells
________give rise to hair, skin, feathers
trunk neural crest cells -dorsal
_______give rise to neurons of DRG, schwann cells, neurons of sympathetic ganglia, chromaffin cells of adrenal medulla, and neurons around aorta
trunk neural crest cells - ventral
_______ give rise to PS ganglia and enteric nervous system (peristalsis)
vagal and sacral neural crest cells
_________ give rise to aorticopulmonary spetum
cardiac neural crest cells
_________ gives rise to olfactory receptor cells
olfactory placodes
______ give rise to sensory cells of trigeminal ganglion
trigeminal placodes
_______give rise to geniculate, petrosal, and nodosal ganglion of face (CN VII, IX, X, respectively)
epibrachial placodes
role of radial glial cells
help organize the cortex into its distinct layers, with earlier formed neurons located deep to later formed neurons
node of ranvier
gap between the myelin sheaths of a nerve. action potentials leap between the nodes to travel down the axon
development of nose
nasal placode>olfactory receptors>olfactory nerves>enter olfactory bulb through cribiform plate
development of eye
optic vesicle>lens vesicle>optic vesicle>optic cup>sensory retina and pigmented epithelium>retina ganglion>travel through retina to brain
development of inner ear
auditory placode>otic cup>otic vesicle>cochlea and receptor cells
development of middle ear
- pharyngeal pouch I >tympanic cavity and eustachian tube
- brachial arch I - malleus and incus
- brachial arch II - stapes
development of outer ear
brachial groove I - external auditory meatus
critical period
times during gestation where developing components of the CNS are most susceptible to disruption. cerebral cortex and cerebellum have extended development and therefore extended critical periods - more susceptible to malformation
spina bifida occulta
defect in vertebra, looks normal on the outside
meningomyelocele
spinal cord and dura protrude, skin covering, neural tube defect
myeloschisis
a cleft in the neural tube (neural tube close defect)
meningomyelocele with hydromyelia
spinal cord and dura protrude, skin covering, neural tube defect + with cerebrospinal fluid
meningocele
protrusion of dura
typical blood supply to brain
carotid and vertebrobasilar arteris
typical blood supply to spinal cord
segmented arteries in throacolumbar region and vertebral/segmented arteries in cervical region
horse blood supply
internal carotid (forebrain) basilar artery (hindbrain)
dog blood supply
internal carotid and some external carotid (forebrain) basilar artery (hindbrain
cat/small ruminant blood supply
external carotid (maxillary branch) and small internal carotid (forebrain) basilar artery (hindbrain)
cow blood supply
external carotid (maxillary branch) and basilar (forebrain) basilar artery (hindbrain)
_____________supply rostral and medial portions of cerebral hemisphere, cortex and medullary substance
rostral cerebral arteries
_____________supply cortex and medullary substance, central branches supply basal nuclei
middle cerebral arteries
____________supply caudomedial cerebral hemispheres
caudal cerebral arteries
__________supply rostral and middle cerebellum
rostral cerebellar arteries
__________ supply caudal cerebellum
caudal cerebellar arteries
collateral pathways
provide redundancy, avoids brain damage if vessels are obstructed
typical brain venous drainage
jugular and vertebrobasilar veins
typical spinal cord venous drainage
segmented veins in throacolumbar region and vertebral veins in cervical region
acetylcholine (ACh) fxn
A neurotransmitter used by somatic motor neurons to control skeletal muscles. Used in numerous CNS pathways, including circuits involved in memory formation. Generally considered an excitatory NT in CNS.
Dopamine (DA)
A neurotransmitter that produces feelings of pleasure when released in “reward” circuits of the brain. Dopamine has multiple functions, including regulation of movement, mood and reward.
Opioid Peptides
Include several families of small to intermediate size peptides. Members of this family play important CNS roles in pain perception and mood; in addition, opioid peptides exert major actions in the GI tract.
Serotonin (5-HT)
A neurotransmitter involved in many functions including mood, aggression, appetite, and sensory perception. In the spinal cord, serotonin is inhibitory in pain pathways.
Norepinephrine (NE)
A neurotransmitter that also acts as a hormone. In the peripheral nervous system, it is part of the flight-or=flight response. In the brain, it acts as a regulator of attention, wakefulness, CV status and sensitivity to pain.
Glutamate (GLU)
THE MAJOR EXCITATORY neurotransmitter in the brain.
Gamma-Amino-Butyric Acid (GABA)
THE MAJOR INHIBITORY neurotransmitter in the brain.
endothelial cells and BBB
make a non fenestrated monolayer of cells lining the inside of the capillary, contain tight intercellular junctions and a continuous basement membrane
astrocytes (BBB)
support cells with end feet that wrap around capillaries
pericytes (BBB)
contractile cells that lie next to cerebral capillaries
BBB
- protects the brain from harmful “foreign” substances in the blood
- protect the brain from hormones and neurotransmitters in the rest of the body
- maintains a constant environment for the brain
T/F: large, hydrophilic, and polar molecules can cross the BBB easily
False
T/F: lipophilic molecules can cross the BBB
True
T/F: the BBB allows H+ ions to pass
False
T/F: the BBB is selectively permeable to oxygen, carbon dioxide, and other volatile substances
True
T/F: There aren’t very many diseases in non-human species where there is a disruption of NT formation or storage, nor are there many significant therapeutic benefits derived from the use of agents that alter the synthesis or storage of NTs. (not a big drug target)
True
• The BOTTOM LINE on transmitter elimination processes:
• These are vital processes that are a common target for numerous drugs of therapeutic importance.
• The BOTTOM LINE on transmitter receptor activation:
• This is a vital process that is a common target for numerous drugs of therapeutic importance.
• The BOTTOM LINE on transmitter release:
• There are limited circumstances where there appears to be a therapeutic benefit derived from the use of agents that alter NT release.
5 general requirements that must be met in order for an endogenous substance to be considered a synaptic neurotransmitter
- The substance should be present in presynaptic nerves, usually sequestered in synaptic vesicles.
- A mechanism must exist for the synthesis or accumulation of the substance within the presynaptic nerve.
- Application of the substance to the postsynaptic cell should mimic the effects caused by stimulation of the presynaptic nerve.
- Agents that alter (block, augment, etc.) the postsynaptic response to presynaptic stimulation should have the same effect on exogenously applied transmitter.
- A mechanism for inactivation of the transmitter must exist within the synaptic region, including degradative enzymes, a reuptake (transport) system, or other processes.
T/F: The primary site for neurochemical communication is the synapse or neuroeffector junction.
True
