Histology - Nervous Tissue Flashcards
choroid epithelial cells
involved in cerebral spinal fluid
White Matter
Myelin is lipid-rich, and on gross inspection appears white. Thus, in the ‘white matter’ of the brain and spinal cord, myelinated axons are the predominant neuronal component, whereas ‘gray matter’ contains relatively more neuronal and glial perikarya and non-myelinated (e.g. dendritic) processes.
bipolar neurons
retina, cranial nerve I, cranial nerve VIII
ependymal cells
cells line ventricular spaces (spinal fluid)
Dorsal Root Ganglia
Contain the cell bodies of sensory neurons.
The neuron cell bodies belong to large, pseudounipolar sensory neurons that have a single “T-shaped” process; these are the afferent fibers carrying sensory information from the periphery (sensory receptors in the skin, joints and muscles that respond to touch, temperature, pain, stretch) to the dorsal horn, where they synapse on neurons in the spinal cord.
NOTE: these sensory neurons are an exception to the typical neuron, in that they do not have separate dendrites and an axonal process, but rather one branched process that serves both functions.
sensory ganglia
pseudounipolar neurons, high neuron density, large # of satellite cells, and NO synapses.
axonal retrograde transport
uses microtubules and dynein, how viruses can spread between neurons.
oligodendrocytes
Branched processes that myelate CNS axons. Has multiple internodal segments on multiple axons. . Involved in MS.
multipolar neurons
99% of all neurons
autonomic ganglia
motor, multipolar, low neuron density, fewer satellite cells, synapses. Takes two neurons to get to target.
neural crest
origin of PNS: neurons, Schwann cells, satellite cells.
epimeirium
the outermost layer of dense irregular connective tissue surrounding a peripheral nerve.
endoneurium
a layer of delicate connective tissue that encloses the myelin sheath of a nerve fiber.
perineurium
protective sheath that surrounds nerve fasciles.
CNS Neurons - spinal cord
Parasympathetic ganglia located in the organ that is being innervated.
pseudounipolar sensory neurons
Afferent fibers carrying sensory information from the periphery (sensory receptors in the skin, joints and muscles that respond to touch, temperature, pain, stretch) to the dorsal horn, where they synapse on neurons in the spinal cord.
NOTE: these sensory neurons are an exception to the typical neuron, in that they do not have separate dendrites and an axonal process, but rather one branched process that serves both functions.
oligodendrocytes
A type of glial cell responsible for myelination of CNS axons.
axodendritic
axon synapses on a dendrite
major dense lines
(dark line) formed by the closely apposed cytoplasmic faces of the plasma membrane, and measuring 2.5nm thick, in myelin sheath.
meningeal cells
connective tissue layes lay outside CNS, protection.
dendrites
contains same organelles as cell body except nucleus, Nissl bodies and Golgi complexes only in proximal portion.
glial cells that produce myelin in peripheral nerves.
axosomatic
axon of one neuron synapses with cell body of a second neuuron
cell body (perikaryon/soma)
contains nucleus, nucleolus, Nissl bodies, Golgi complexes, mitochondria, neurofilaments, microtubules.
pseudounipolar neurons
sensory ganglia
neuropil
meshwork of processes of neurons and glia in gray matter of CNS
Axon and Nissl bodies. Characteristic clusters of ribosomes and rough ER termed Nissl bodies or substance scattered in the cytoplasm
axonal anterograde transport
uses microtubules and kinesin
perikarya of large somatic motor neurons - innervate the skeletal muscles of the limbs and trunk, which are embryologically derived from somites (hence, “somatic” muscles).
astrocyte
star-shaped glial cells regulating ionic environment of extracellular space, guiding of neuron migration during early development, proliferation at sites of injury. the most abundant cell of the human brain.
axoaxonic
one axon synapses on another axon.
neural tube
origin of CNS: neurons, astrocytes, oligodendrocytes, ependymal cells
Glioblastoma multiforme
most common and most aggressive malignant primary brain tumor in humans, involving glial cells
myelin sheath
up to 50 lipoprotein lamellae/Pligodendrocytes in CNS, Schwann cells in PNS. Internodal segnment and node of Ranvier.
Dorsal Root Ganglia, near, but outside of the spinal cord. Afferent fibers carrying sensory info from perifery to dorsal horn, where they synapse with neurons in the spinal cord.
axon
contains mitochondria, neurofilaments and microtubules, but NO protein making machinery.
Neurolemmocytes
myelination of PNS axons, a single internodal segment. Basal lamina guides regenrating axons, allows for better regeneration/recovery than CNS.
microglial cells
resident macrophages of the brain and spinal cord, and thus act as the first and main form of active immune defense in the central nervous system (CNS).
Meningeal cells
consist of three layers: the dura mater, the arachnoid mater, and the pia mater that are membranes which envelop and protect the central nervous system. CNS is unique in that it has NO internal connective tissue.
Schwann cells
Peripheral equivalent of the oligodendrocytes. Mylenate PNS axons, basal lamina guides regeberating neurons. Single Schwann cell mylenates a single internodal segment.
