Nervous System Histology Flashcards
somatic NS is made of
skeletal muscle
autonomic NS is made of
smooth muscle, heart, and glands
- sympathetic NS - parasympathetic NS
What are Nissl bodies?
stacked RER making neurotransmitter
4 parts of neuron
cell body (soma)
dendrites
axons
axon terminals
receive stimuli and have spines located on surfaces that regress with age and poor nutrition
dendrites
conduct impulses
axons
anterograde transport is _________
retrograde transport is _________
from cell body to axon terminal
from axon terminal to cell body
where synapse happens
axon terminal
nerve cell body inclusions (3)
melanin
lipofuscin
lipid droplets
affects of age on lipofuscin
increases with age
3 functional types of neurons
sensory (afferent)
- info from nerves TO CNS
motor (efferent)
- infro FROM CNS to nerves
interneurons
- interconnectors between neurons
3 structural types of neurons
bipolar
- one dendrite, one axon - ear and eye
unipolar
- DRG, cranial nerves
multipolar
- mainly motor neurons - typically have one axon
what do neuroglia do?
what do neuroglia NOT do?
support (physical, metabolic, regulatory) neurons
propagate action potentials
Cells that can respond to CNS injury and can form scar tissue, are part of the BBB, and have pedicels that connect to vessels
astrocytes
describe fibrous astrocytes
cells processes are long and unbranched near pia mater
Layers of the BBB (from capillary lumen)
endothelium with tight junctions and molecular transport
basement membrane
astrocytes
cells that provide myelin sheath around axons of the CNS
aligned in rows along axons in WHITE MATTER
Can wrap around MULTIPLE AXONS
oligodendrocytes
CNS phagocytes
microglia
cells that line ventricles and spinal canal and help produce CSF
ependymal cells
vessels pass through which layer of the meninges
arachnoid
what is in gray matter
neuron cell bodies organized into groups:
- layers in cortices - nuclei in medulla and brain stem - ventral and dorsal horns in SC
what is white matter
myelinated tracts of axons
if the cerebrum is arranged in gyri and sulci, then the cerebellum is arranged in ______
folia
3 layers of neurons in the cerebellum
molecular layer
Purkinje cell layer
Granular layer
what makes up the brain stem? (3)
diencephalon
mesencephalon
medulla oblongata
what happens in ventricular system?
CSF generation and circulation
how many ventricles are there, and where?
2 lateral in cerebral hemispheres
3rd in mesencephalon
4th in medulla oblongata
ependymal cells organize into _______ which produce ______
choroid plexuses
CSF
what happens in dorsal and ventral horns of SC
dorsal - sensory input
ventral - motor output
cells that form myelin sheaths in PNS
1 cell can myelinate 1 axon
Schwann cells
gaps between myelin sheath
Nodes of Ranvier
General structure of peripheral nerve
bundle of axons surrounded by Schwann cells and connective tissue sheaths
levels of connective tissue sheath in a nerve
epineurium - around entire nerve
perineurium - around a bundle of axons (fascicle)
endoneurium - around each axon
motor axons to skeletal muscle –> motor end plate
somatic efferent axons
motor axons to organs
visceral efferent (involve 2 neurons - pre- and post-ganglionic)
where are cell bodies of sensory nerves?
in sensory ganglia outside CNS
where can you find sensory peripheral ganglia?
dorsal root ganglia
ganglia for CN V, VII, IX, X
where can you find sensory autonomic ganglia?
paravertebral chain of ganglia
adjacent to abd aorta, adrenal gland
head
scattered and small clusters of neurons in intestinal wall
myenteric and submucosal plexuses
in PNS nerve regeneration, what happens:
at site of the damage
distal to site of damage
proximal to site of damage
at site –> severed ends of axons retract away from each other
distal –> Waller-ian degeneration - distal portion of axon disintegrates
proximal –> prox axon degenerates and regrows new axon
four types of synapses
axodendritic
axosomatic
axoaxonic
dendrodendritic
what is the terminal bouton
axon terminal end
three types of neurotransmitter
small-molecule transmitters
neuropeptides
gases
small-molecule transmitters
Ach, GABA, catecholamines
neuropeptides
endorphins, ADH, oxytocin
Gases
nitric oxide (NO), carbon monoxide (CO)
Ach is excitatory at ____ and inhibitory at _______
neuro-muscular junction
heart
excessive amount of CSF in ventricles due to increased production, decreased absorption, etc.
hydrocephalus
progressive demyelination of the CNS due to autoimmune disease
Multiple Sclerosis
Rapid demyelination of peripheral nerves and motor nerves
Guillain-Barre
loss of cells that produce GABA, leading to spastic movements (hereditary)
Huntington’s Chorea
loss of dopamine in brain leading to slow movement and resting tremor
Parkinson’s disease
slow growing tumors of the meninges
meningiomas
inflammation of the meninges resulting from infection of CSF
meningitis
