Intro to Cells Flashcards
Define
Glia cells
support cells of CNS
- non-neuronal components of NS (can’t transmit info)
Define
neuron
functional unit of the NS
Why are brain tumors technically not CNS tumors?
not made of neurons, made of glial cells or meninges
10-50x more glia cells/neurons in CNS
glia>neurons
where are microglia located?
CNS
3 categories of macroglia
oligodendrocytes/schwann cells, astrocytes, ependymal/choroidal cells
where are oligodendrocytes located?
CNS
where are schwann cells located?
PNS
location
astrocytes
CNS
location
ependymal/choroidal cells
CNS
Define
microglia
mononuclear phagocytes derived from macrophages, that respond to injury, infection or disease
immune cells of CNS
immune cells of the CNS
microglia
microglia express a range of ____
antigens
what activates microglia
infections and diseases (MS, AIDS-related dementia, parkinson’s, alzheimer’s)
active in all autoimmune diseases
what are the 2 types of myelin-producing cells?
oligodendrocytes (CNS); schwann cells (PNS)
Define
oligodendrocytes
envelop ~15 axonal internodes where they produce and support myelin sheaths in the CNS
what are axonal internodes?
spaces between nodes of ranvier
define
schwann cells
envelop 1 internode and produce & support myelin sheath
what type of cell is associated with the ability of the PNS to regenerate after injury?
schwann cells
schwann cells envelop ____ internode(s)
1
oligodendrocytes envelop ____ internode(s)
about 15
ependymal cells line the ____
ventricles
choroidal cells line the ____
choroid plexus
choroidal arteries
define
ventricles
cavities in the CNS filled with cerebrospinal fluid
define
choroid plexus
collection of vessels within the ventricles that secrete CSF
where is the majority of CSF located
choroid plexus
functions
astrocytes
- influence embryonic growth/retraction of neurites (synapses)
- regulate chemical contents in extracellular space (restrict spread of NT; regulate [] of potassium)
- possess NT receptors
- extend end feet on CNS neurons to form glial limiting membranes to regulate nutrient passage
- form end feet on CNS capillaries creating BBB
define
glial limiting membrane
astrocytes laid in a way to drain lymph from CNS (glymphatics) during sleep and empty into veins
describe
regulation of chemical contents in extracellular space by astrocytes
restrict spread of NT:
- prevent NT engaging with receptors
- astrocytes have NT receptors to take up extra NT in CNS
define
blood-brain barrier
tight junction between end feet of astrocytes and CNS capillaries
function
blood-brain barrier
- allows small, highly lipid soluble substances to enter CNS
- prohibits large, complex substances
- selectively transports substances such as glucose, electrolytes and aa
where do astrocyte end feet extend to?
CNS neurons (glial limiting membranes) and capillaries (BBB)
components of neuronal soma
- nucleus
- rough ER (Nissl bodies)
- smooth ER
- mitochondria
- cytoskeleton (microtubules, microfilaments, intermediate/neurofilaments)
function of microtubules in cytoskeleton of neuronal soma
wall structure and transport of molecules
function of microfilaments in cytoskeleton of neuronal soma
make proteins
cytoskeleton components
- microtubules
- microfilaments
- intermediate/neurofilaments
define
neurite
processes coming out of cell body
components of neurites
dendrites & axons
where does axoplasmic transport occur?
axon
define
anterograde axoplasmic transport
transport of synaptic vessicle from cell body to axon terminal
define
retrograde axoplasmic transport
transport of empty vessicle from axon terminal to soma to be refilled
where does the axon begin?
at the axon hillock
how can the axon be differentiated from the soma?
no RER in axon - no Nissl bodies (appear black when dyed)
bouton
axon terminal/presynaptic terminal contains synaptic vessicles
location
myelin sheaths
envelop axon at internodal spaces
define
nodes of ranvier
unmyelinated points on axon where an AP procedes from node to node (saltatory conduction)
define
saltatory conduction
AP procedes from node to node
jumps between myelin sheaths
battery effect/conduction
occurs on unmyelinated neurons
4 functional components of neurons
- input
- trigger (integrative)
- conductile
- output
define
input component
- area that receives information to be propagated
- produces graded local signal based on stimulus intensity or amount of NT released
receptor potential
stimulus intensity
synaptic potential
amount of NT released
