Histology Flashcards
(25 cards)
What are the major cells of CNS
neurons and glia cells
What are the five sorts of glia cells in the CNS
astrocytes, oligodendrocytes, ependymal cells, satellite cells
What are the immune cells of CNS
microglia
What is special about the most superficial 1cm of the brain?
consists of 6 layers of different densities. Layer 1 being the most superficial. This 6-layers arrangement is found in different regions of the brain
What is the advantage of using silver stain over H&E stain on neurons
can see processes under silver stain and see different neuronal morphology
Where is the CSF formed?
CSF is formed by cuboidal cells of the choroid plexus, which is the vascular structure on the wall of ventricles
What is the function ependymal cell?
They line the ventricular system and have finger like projections that help the movement of CSF in central canal
Give four distinct qualities of neurons
1) specialised for signalling
2) high level of protein synthesis
3) metabolically limited, rely on blood supply for energy
4) terminally differentiated, apart from a group of adult stem cells
What are the characteristics of actin
actin is dynamic and can allow shape change and movement. It forms small spines for signal input and output
Intermediate filaments are ________ cytoskeletal structures
permanent
What are the characteristics of microtubules?
dynamic, composed of tubulin, important for axonal transport, important in disease
What is the name of the 1) input zone 2) cell body 3) output zone of a neuron
dendrite, soma, axon
Where are the proteins produced in a neuron
in the nissl bodies of the soma. They are rough ER and free ribosomes
What are the passive functions of astrocytes
1) neurotransmitter uptake and degradation
2) K+ uptake as depolarisation releases a lot of K+
3) neuronal energy supply. Take in glucose and convert it to something neurons can use
4) maintenance of BBB
5) injury response and recovery
What happens if astrocytes are not there to reuptake the neurotransmitters?
the intensity and duration of action potential increase, which is harmful for the neuron
How does astrocyte perform its active function
Astrocytes are excitable (by NT, trauma, spontaneous or inflammatory mediators). Calcium is released, which trigger synaptic vesicle release
How does astrocyte use calcium to communicate with other nearby cells?
Calcium release from cell will initiate release of gliotransmitters via mechanisms with calcium dependent vesicular release
T/F astrocyte releases calcium to directly cause vasoconstriction of blood vessels
False, calcium triggers the release of gliotransmitter vesicles, and it’s the transmitter that causes the vasoconstriction
Why is it important that astrocyte has a role in blood vessel tone control
Glial cells can directly regulate vascular tone and respond to the energy requirement for the neurons
What is the main difference between oligodendrocytes and Schwann cells
Oligodendrocytes (CNS) wrap around several axons Schwann cells (PNS) wrap around one axon
What are Nodes of Ranvier
small gaps between myelin sheath designed for ion conduction
What does microglia resemble
phagocytic macrophages
What is the function of microglia in 1) normal state 2) injury
1) send out / retract processes to sample nearby synapses
2) converge processes onto inflamed area, release harmful chemicals to control damage
Endoneurium surrounds ___1___ , forming the bundle called ___2___ , which is surrounded by ___3___ . Multiple nerve bundles will form a peripheral nerve, which is surrounded by ___4___
1) individual axon
2) fascicle
3) perineurium
4) epineurium
