nervous system consist of…
- peripheral nervous system PNS
what causes impulses?
nervous system stimulation causes electrical signals
stimulus
causes change in internal + external environment
receptors
converts energy from stimulus into electrical impulses (functional cell of nervous system)
PNS portion of body
nerves
CNS portion of body
brain + spinal cord
effectors consist of…
muscles + glands
cells of nervous system
- neurons
glial cells (neuroglia) characteristics
types of glial cells in CNS
astrocytes
form portion of the blood brain barrier
- surround blood capillaries
microglia
function in protection against infection - becomes phagocyte
ependymal cells
lines cavities in CNS, ventricles + spinal canal
- secrete + circulate cerebrospinal fluid
oligodendrocytes
function to produce myelin
what is myelin?
fatty insulating substance that surrounds the axons of neurons
types of glial cells in PNS
2. satellite cells
schwann cells
produce myelin sheath of neuronal axons located in PNS
satellite cells
found around neuronal cell bodied in ganglia
neuron characteristics
neuronal structure consist of…
cell body characteristics
why are centrioles not in the cell body of neurons?
centrioles cannot complete mitosis
dendrites characteristics
- receive incoming messages + send to cell body
axons characteristics