lecture 16 Flashcards
what are the two general classes of cell in the CNS and PNS
neurons and Glia
what makes the PNS
peripheral nerves and ganglia
role of neurons
cells specialised for transmission of information
role of glia
support for neurons
in the CNS, but not cerebrum or spinal cord, what is a group of cell bodies
Nucleus (pl. = Nuclei)
what is a group of axons in the CNS, excluidng the cerebrum and spinal cord
a tract
Group of cell bodies in
cerebral cortex or spinal cord
grey matter
- Bundle of axons in
cerebral cortex or spinal cord
white matter
whats a group of cell bodies in the PNS
a ganglion
what is a group of axons in the PNS
a nerve
what is the summation zone on the neuron
the axon hillock
describe a multipolar axon
many processes extend from the cell body
describe a unipolar axon
one process extends out of the cell body, this one process branches out into the dendrite and axon.
describe a bipolar axon
two processes extending out of the cell body, one is concerned with information input, the other output
describe an anaxonic axon
No distinct axon
* All processes look alike
what are the four CNS Glia types
oligodendrocytes, ependymal cells, microglia and Astrocytes.
what are the three features of the astrocytes
injury response, Supply nutrients to neurons
* Ensheath blood capillaries
what are the two features of microglia
Immune cells of the CNS
* Engulf microorganisms and
debris
what are the 2 features of ependymal cells
line the fluid-filled spaces in the CNS and spinal cord, the ventricles
Have cilia (hair-like processes) to circulate CSF
what are the 2 features of oligodendrocytes
Support nerve fibres
* Ensheath them with myelin
in the PNS what makes the myelin sheath
the Schwann cells
what are the two features of the schwann cells
Support peripheral nerve fibres
* Ensheath them with myelin
what cells are the schwann cells similar to
- Similar to oligodendrocytes (CNS)
what is the myelin sheath made of and what does it do
its made of lipids, as they wrap their plasma membrane around the axon, and it serves to increase the speed at which an action potential is propogated
