Nervous Tissue Flashcards
divisions of the central nervous system
cerebrum and cerebellum
components of the cerebrum
frontal lobe, parietal lobe, occipital lobe, temporal lobe
characteristics of the central nervous system
brain, brainstem, spinal cord
characteristics of the peripheral nervous system
nerve fibers, nerve endings, sympathetic and parasympathetic, autonomic nervous system
summarize embryonic development of the nervous system
dorsal ectoderm thickens, becomes indented forming the neural groove with neural folds on each side which close to form a tube which becomes the CNS, PNS is derived from neural crest cells
structure of a neuron
soma (cell body), axon, dendrites, terminal button, and synapses
3 types of neurons
sensory, interneurons, motor neurons
summarize axonal transport
transport system for organelles, enzymes, and metabolites from the cell body to the synapses; enzymes and cytoskeletal elements are transported slowly, membrane bound organelles are transported quickly
3 layers of the meninges
dura mater, arachnoid, pia mater
difference between white and grey matter
white matter is lots of myelinated axons and grey matter has low myelin with many neuron bodies
4 types of glial cells
astrocytes, oligodendrocytes, ependymal cells, microglial cells
luxol fast blue
differentiates between white and grey matter by staining white matter deep blue; in the spinal column white matter is on the outside, in the brain white matter is on the inside
pyramidal
multipolar, found in the hippocampus
astrocytes
large, oval nuclei, multiprocessed with a stellate appearance,
maintains the blood/brain barrier, found near blood vessels and acts as scaffolding for specialized neural elements
oligodendrocytes
small dark nuclei with a white halo, abundant mitochondria, RER, golgi complex and free ribosomes. myelinates several nearby axons in the CNS
ependymal cells
secretory and ion transportation epithelium, cilliated simple columnar cells that produce cerebrospinal fluid
microglial cells
multiprocessed, fixed phagocytic cells (macrophages of the CNS) with cigar shaped nuclei, first and main form of active immune defense in the CNS
endoneurium
cellular matrix composed of longitudinal collagen fibers that surrounds individual axons and schwann cells
epineurium
outer sheath of fibrocollagenous tissue that binds nerve fascicles into a nerve trunk
perineurium
surrounds groups of axons and endoneurium to form small bundles called fascicles, composed of layers of flattened cells separated by concentric layers of collagen
fascicle
small bundles of axons and endoneurium contained by the perineurium
nissl substance
basophilic clusters of ribosomes and rough endoplasmic reticulum sometimes visible in the cytoplasm of neurons
cell body (soma)
contains the nucleus and perinuclear cytoplasm, different sizes and shapes based on location and function
axon
conducts impulses away from the cell body to other neurons, muscles, or glands. may receive stimuli from other neurons
dendrites
increase the surface area for interacting with axons of other neurons, specialized for receiving information from sensory cells, axons and other neurons, transmits impulses towards the cell body
dura mater
tough fibrocollagenous layer which forms the outer coat of the CNS, dense irregular connective tissue
arachnoid
delicate fibrocollagenous layer with web like strands that contain cerebrospinal fluid
pia mater
delicate layer of loose fibrocollagenous tissue that completely envelopes the CNS
ultrastructure of a neuron
highly metabolic, large nucleus and central nucleolus because of high transcriptional activity, nissl substance found in the cell body and dendrites but NOT the axon, well developed golgi complex for secretion, large number of mitochondria and lysosomes for high cell turnover (but not cell division)
schwann cells
myelinate single axons in the PNS
synapses
the space between an axon and other cells that allows for electrical and chemical communication between neurons and other effector cells such as skeletal muscle
fibrous astrocytes
long processes found mostly in white matter, rich in Gfap
protoplasmic astrocytes
long thin processes mostly found in grey matter, low in Gfap
terminal button
end portion of the axon which associates with another neuron in a synapse
