Neurons and glia Flashcards
A single undifferentiated cell
Neural stem cell
What is the process of brain cells?
1) Cells begin as multipotential stem cells
2) They become progenitor cells which are the precursors for ‘blasts’
3) The precursors of blasts develop into specialised neurons and glia
Where are adult stem cells located?
In the brains ventricular zone which surrounds the ventricles, and in the spinal cord and retina or the eye!
Do blasts differentiate into neurons or glia?
Some develop into neurons while others into glia (neuroblasts and glioblasts)
How does a stem cell develop a brain?
It divides itself into 2 stem cells which both divide again. 1 stem cell dies after each divison so the mature brain contains a constant number of dividing stem cells.
Do adult stem cells serve as a source of new neurons for certain parts of the adult brain?
Yes! They may play a role in brain repair after injuries such as stroke or trauma
Are neurons specialised to function?
Yes
What are the names of the 3 types of neurons?
1) Sensory neurons
2) Interneurons
3) Motor neurons
Motor neuron
Send signals from the brain and spinal cord to the muscles.
Motor neurons in the brainstem
Project to facial muscles
Motor neurons in the spinal cord
Project to other muscles of the body
What type of neuron are called the ‘final common path’?
Motor neurons, because all behaviour produced by the brain is produced through them
What is the function of sensory neurons?
To bring information TO the central nervous system (brain and spinal cord)
What is the function of interneurons?
Interneurons within the brain and spinal cord link up sensory and motor activity in the CNS.
What is different about interneurons?
They all have many dendrites that branch extensively and also has an axon which can branch aswell
Microglial cell
Small, defensive function
Schwann cell
Wraps around PERIPHERIAL NERVES to form insulating myelin
Astrocyte
Star shaped, nutritive support and function
Ependymal cell
Small, secretes CSF
Oligodendroglial cell
Asymmetrical, forms insulating myelin around axons in brain and spinal cord
Grey matter (communities)
Acquires its colour from neuronal cell bodies that predominate there
White matter (roads)
Consists largely of axons that extend from these cell bodies to form connections with neurons in other brain areas. These axons are covered with an insulating layer of glial cells that are composed of lipids (fat).
Reticular matter (suburbia)
Contains a MIX of cell bodies and axons.
A large collection of axons projecting to OR away from a nucleus or layer in the CNS
Tract
What is the function of a tract?
To carry information from one place to another within the CNS e.g. the optic tract carries info from the retina o other visual centres in the brain.
Fibre and fibre pathways that enter and leave the CNS
Nerves
After nerves have entered the CNS they are called…
Tracts!
