Histology of the CNS Flashcards
most common excitatory NT
glutamate
meissner’s corpuscles (light touch) cell bodies are located in..
the DRG
glial cells vs neurons on cell division
neurons rarely divide; glial cells divide
spinal cord H is made up of
grey matter (unmyelinated)
axons are made up of ____ that form _____
white matter; white matter tracts (like the corticospinal tract)
upper motor neurons are contained in the
brain
lower motor neurons are contained in the
spinal cord
the cerebral cortex cell bodies are made of which type of matter?
grey matter (cortex is on outside/ made of neuron cell bodies)
the PNS consists of
axons (to skeletal muscle is referring to motor neurons)
stain used to stain myelin of the axons
cresyl violet stain
a cluster of neurons outside the CNS is termed
ganglion
a cluster of neurons inside the CNS is termed
nucleus
smooth muscle/gland motor innervation is done by
autonomic NS
brain stem or spinal cord autonomic neurons are termed
preganglionic
autonomic ganglion (outside the CNS) are termed
postganglionic
3 famous motor neurons
purkinje, pyramidal, alpha motor neurons
where are purkinje motor neurons located?
cerebellum (damage would cause tremors, ataxia)
where are pyramidal motor neurons located?
cerebrum, upper motor neurons
where are alpha motor neurons located?
brainstem, spinal cord, lower motor neurons (damage would cause twitching, vasiculation)
what are interneurons?
inhibitory usually between 2 neurons*
largest neurons in the cerebellum?
purkinje neurons
**upper motor neurons are made of ___ found in the ____
pyramidal neurons* in the cerebral cortex (cereBRAL, pyramiDAL)
where are alpha motor neurons found?
lower motor neurons (ventral horn of spinal cord, to skeletal muscles, in brainstem motor nuclei)
where are preganglionic cell bodies located?
brainstem nuclei, lateral horn of spinal cord
where are preganglionic axons to post ganglionic neurons located?
in PNS ganglia
the post ganglionic sympathetic neurons to sweat glands are adrenergic or cholinergic?
cholinergic (as are the preganglionic neurons to sweat glands)
where are ANS sympathetic neurons located?
lateral horn T1-L2; chain and collateral ganglia
where are ANS parasympathetics located?
cranial (brainstem nuclei, ganglia) and sacral (lateral horn S2-S4, ganglia in organs)
glial to neuron ratio
10:1
*protein that all types of astrocytes have (astrocyte marker)
Glial Fibrillary Acidic Pritein (GFAP)- an intermediate filament; amt. increases during reactivity
function of astrocytes
scavenge for ions, neurotransmitters, GLIAL SCAR, tell endothelial cells to form BBB, produce cytokines
protoplasmic astrocytes are made of ____ matter; fibrous astrocytes are made of ____ matter
grey; white; both types form vascular end feet
describe the structural characteristics of oligodendrocytes
few processes, pycnotic nucleus, near neurons, no basal lamina, myelinate MANY axons
origin of microglia
bone marrow
where are microglia found?
grey matter, white matter, spines on cell body and processes
microglia produce cytokines and express
MHC-I and MHC-II
what is the neuropil?
substance between neurons; collection of neuronal and glial processes
what cells form the brain-CSF barrier?
ependymal cells (have cilia to move CSF)
what do ependymal cells line?
ventricles of the brain and central spinal cord canal
function of tight junctions
to block reactive substances from entering the space
*what is the BBB composed of? (the actual barrier)
capillary endothelial cell TIGHT JUNCTIONS
where is the BBB absent?
circumventricular organs like the pineal gland
what forms the blood-CSF barrier?
pia, ependymal, blood vessels
which layer of meninges is adherent to the brain?
pia mater
what makes the meninges?
fibroblasts of pia, arachnoid, and dura mater
name the spaces where hematomas occur
epidural space, subdural space, subarachnoid space
