cells of nervous system Flashcards
neurons
electrically excitable cells of nervous sytem
neuron cell body (soma)
typical cell functions
have one large, centrally located nucleus
ER of neuron called
Nissl Bodies–extensive bc do a lot of protein synthesis
Dendrites of neuron
cell extensions that receive info from other cells
often short and highly branched
dendritic spine
where axons of other cells connect with the dendrite
axon
carry AP
most neruons only have a single axon
axon hillock
cone shaped area where axons arise from cell bodies; narrows into initial segment where axon arise from
trigger zone of axon
combo of axon hillock and initial segment where APs arise from
axoplasm
cytoplasm of axon
axolemma
plasma membrane of axon
presynaptic terminal
end of axon that contains synaptic vesicles filled with NT
Anterograde axon
move things away from cell body ie mitochondria and synaptic vesicels
retrograde axon
move thing towards cell body
ie things taken in by endocytosis, damaged organelles
sensory neurons
AFFERENT
conduct APs toward CNS
functional class
motor neurons
EFFERENT
conduct APs away from CNS
functional class
interneurons
within CNS from one neuron to another
Multipolar
MOST neurons in CNS and motor neurons ins PNS
have many dendrites and one axon
bipolar
sensory in retina of eye and nose
have TWO process–one dendrite and one axon
pseudo unipolar
single process that divides into two branches
peripheral process to sensor receptors and central process to CNS
APs from peripheral to CNS
most sensory neurons are unipolar
anaxonic neruon
NO axon, only dendrites
found in brain and retina of eye
communicate using graded potentials not APs
Glial cells of CNS (4)
- Astrocytes
- ependemyal cells
- Microglia
- Oligodendrocytes
Glial cells of PNS (2)
Schwann cells
satellite cells
Astrocytes (of CNS)
star shaped cells with cytoplasmic cell processes called feet that cover surfaces of blood vessels, neurons and pia matter
functions of astrocytes (of CNS)
- regulate substances that reach brain from blood (blood brain barrier)
- produce chemicals to form tight junctions to form blood brain barrier
- regulate extracellular brain fluid
- release chemicals that promote synapses
retroactive astrocytosis
wall of injury and help reduce inflammation in brain
also produce scar tissue that limits regeneration of axons
Ependymal cells (of CNS)
line ventricles and spinal cord
special version form choroid plexus
choroid plexus (of CNS)
areas of ventricles that secrete CSF
made up of ependymal cells and blood vessel
have cilia to move CSF through
long processes that extend into brain tissue
Microglia (of CNS)
specialized macrophages
respond to inflammation, phago necrotic tissue and foreign substances that invade CNS
oligodendrocytes (CNS)
form myelin sheath for axons
one can form myelin sheath around portion of many axons
Schwann cells (PNS) (neurolemmocytes)
wrap around only one axon to form myelin sheath
wrap around it many times
cell membrane primarily phospholipids
satellite cells (PNS)
surrounds cell bodies in sensory ganglia
provides support and nutrients
satellite cells (PNS)
surrounds cell bodies in sensory ganglia
provides support and nutrients
gray matter
unmyleinated axons, dendrites and cell bodies
appears darker
in brain on outside
in spinal cord on inside
gray matter nuclei deep in white matter
white matter
bundles of parrallel myelinated axons
form nerve tracts and propagate APs from one area of CNS to another
on inside of brain but outside of spinal cord
