Histology of CNS Flashcards
Do neurons divide in adulthood
no
Neuron function
transmits chemical electrical signals of the nervous system
dendrites
receive input
Soma
neuronal cell body
axon
sends neuronal output
Nissl Substance
identifies neurons
Stains RER - located in dendrites and soma
Types of Neurons (functional - 2)
Sensory
Motor
Types of Neurons (Structural - 3)
Bipolar neuron
Pseudounipolar neuron
Multipolar neuron
Bipolar neuron
single axon emerges from either side fo cell body
SENSORY
found only in ear and eye
Pseudounipolar neuron
single axon divides into 2 br from the cell body
one goes to the periphery the other to the cord
SENSORY
found in sensory ganglia of cranial and spinal nn.
multipolar neuron
single axon w/ many dendrites
MOTOR NEURONS AND INTERNEURONS
most abundant type of neuron in brain
2 examples of multipolar neurons
pyramidal cell
purkinje cell
pyramidal cell
multipolar neuron
cerebral cortex, hippocampus, amygdala
PYRAMID/triangle shaped soma
Fxn- cognition, motor control of voluntary mov’t
Purkinje Cell
multipolar neuron
INHIBITORY neuron in the cerebellum
100s of 1000s of signals converce on purkinje cell
It sends out ONE message of what to do
only output neuron from cerebellar cortex
6 Cell Layers of Cerebrum (and cell types)
from superficial to deep
Molecular (dendritic and axonal synapses)
External granular (small pyramidal and stellate)
External pyramidal (medium sized pyramidal cells)
Internal granular (dense stellate cells)
Internal pyramidal (large pyramidal cells)
Multiform (many cell forms)
Cerebellar Layers (and cell types) superficial to deep
Molecular Layer (dendritic and axonal synapses) Purkinje Layer (purkinje cells) Granular Layer (granular cells)
Oligodendrocytes
myelinate axons of neurons in CNS
can myelinate multiple axons
“fried egg” histo appearance