Nervous Tissue Flashcards
does the brain contain connective tissue?
no, apart from connective tissue present in the meninges and blood vessels
are mature neurons mitotically active?
no, they cannot divide
what are the 2 process that extend from the cell body of the neuron?
dendrites and axons
how many axons can a neuron have?
only one which extends from the axon hillock and forms boutons at the end
where are neurotransmitters contained?
in synaptic vesicles
what is the most prominent excitatory transmitter in the CNS?
L-glutamate
what is the most prominent inhibitory transmitter in the CNS?
GABA
what are neuroglia?
non-neuronal supporting cells of the CNS
what function do astrocytes provide?
physical and metabolic support to the neurons of the CNS and the maintenance of the composition of the extracellular fluid and form scars
what function do oligodendrocytes provide?
form myelin sheath around axons in the CNS
what function do microglia provide?
In the case of tissue damage, microglia differentiate into phagocytotic cells
what allows a free exchange between cerebrospinal fluid and nervous tissue?
The lack of tight junctions between ependymal cells in the ventricles of the brain and the central canal of the spinal cord
how do glial cells communicate with each other?
GAP junctions
what are the principle neurotransmitters in the PNS?
acetylcholine and noradrenalin
where do afferent sensory fibers enter the spinal cord?
the dorsal roots
where do the efferent motor fibers leave the spinal cord?
the ventral roots
what surrounds the axon in the PNS
Schwann cells
are PNS type B fibers myelinated?
yes
do peripheral nerves contain connective tissue?
yes, a lot
what surrounds peripheral nerves?
thick layer of dense connective tissue, the epineurium
what are ganglia?
Ganglia are aggregations of nerve cells (ganglion cells) outside the CNS
what surrounds ganglion cells?
a layer of satellite cells
do ganglion cells in dorsal root ganglia receive synapses?
no, their function is the trophic support of their neurites
