4. Nervous Tissue Flashcards
Where are Nissl bodies found and what is their function?
Found in the cell body and dendrites of neurons. Involved in protein synthesis, ie ion channels and neurotransmitters (NTs)
What are neurofibrils and where are they found?
Microtubules and neurofilaments in the cell body of a neuron.
What creates the structure of axons?
Microtubules and neurofilaments
Why do axons contain sER?
Modulate and regulate the calcium content in the neuron
What are the differences between neurons and neuroglia?
Neuroglia do not propagate APs but can divide and multiply
Which neuroglia are found in the CNS and PNS?
CNS: Astrocytes, Microglia, Ependymal cells, Oligodendrocytes
PNS: Schwann cells, Satellite cells
What are the functions of astrocytes?
Maintain chem. environment, BBB, form scar tissue after brain injury, provide nutrients + guidance to neurones, take up excess NTs
What is the function of microglia?
Protect CNS by phagocytosis of invading microbes and debris
Which cells line the ventricles of the brain and central canal of the spinal cord?
Ependymal cells
Form and circulate CSF
What are two specialisations of ependymal cells?
Cilliated and form tight junctions. Selectively permeable
How do oligodendrocytes myelinate cells?
Foot process wraps around cell to be myelinated. May have one oligodendrocyte with many processes to different axons
How do Schwann cells differ from oligodendrocytes?
Found in the PNS, only myelinate one axon. Also help guide and regenerate axons
What are the functions of satellite cells?
Regulate chem. environment and repair. Located around cell body
What is the difference between MS and Guillain Barre Syndrome?
MS destroys myelin in CNS, G-B affects myelin in PNS and can recover from it.
How does diffuse axonal injury occur?
What is it?
Occurs by rapid acceleration/deceleration of body (commonly head).
Caused by damage to axons when grey and white matter move relative to each other, ie shearing of the axon.
