Cells of the Nervous System Lecture Flashcards
Stomach to brain is sensory or motor?
sensory; brain to stomach would be motor
which part of the nervous system is responsible for slowing down the heart beat rate?
autonomic - motor control over the cardiac muscle
which part of neuron is responsible for receiving the signals
dendrites, the cell body, and part of the axon - these are all options of parts that can receive signals
what is the axon responsible for
delivering the neural signal also known as the action potential
where does the action potential start
the axon hillock or the trigger zone
what is around the axon
myelin sheath
why is myelin sheath important
speeds up the propagation of the signal; insulation; increases conduction speed
do all axons have a myelin sheath
no
is the myelin sheath continuous
no - there are segments of the myelin sheath
how is the myelin sheath formed
an independent cell makes the myelin sheath - cross section of the myelin sheath would show the axon and then the cell around it - concentric circles like a snail shell
why is the sheath not continuous
we need segments to help with action potential propagation
what are the “nascar team supporting” cells to neurons?
the glial cells
which cell is responsible for removing blood clots from the brain
microglia
what are the microglia
they serve as kind of like the immune system of the CNS; pathological agents, remnants and other residual stuff it cleans it up
what are astrocytes
make up structural framework of CNS; hold the capillaries; they support and brace neurons and they also help to control the chemical environment - astrocytes can be one of the ways to absorb, remove or secrete ions ; they can absorb neurotransmitters
what do the oligodendrocytes do
they form the myelin sheath around the axons; they make different myelin sections of different neurons by connecting to multiple cells/neurons; insulators of the thick neurons of the CNS
what do the ependymal cells do
they help with the circulation of the CSF
what is outside of the cells? what are cells embedded within
extracellular fluid - ECF or interstitial fluid
capillaries bring nutrients to the __ and then the ___ brings the nutrients into the cell
ECF , ECF
what are the myelin forming cells of the PNS
schwann cells
why do we need microglial in the CNS?
because our immune cells aren’t meant to be in the brain; CNS is too sensitive; we need to protect our brain
what keeps the immune cells out of the CNS
the blood brain barrier (BBB)
where is the BBB found
the capillaries in the brain and the ECF in the brain
T/F? we control to some extend what goes through the BBB because there are a lot of things on the capillaries that we don’t want to get into the CNS
true
do we have a spinal cord blood barrier too
yes
what induces the formation of the BBB
the astrocytes and pericytes
is the membrane that is formed by the ependymal cells permeable or impermeable and what is it called
permeable; barrier between CSF and capillaries called the CSFBB
where are the borders
between ECF and brain tissue
between capillaries and CFS
ECF is outside of line of ependymal cells (ciliated epithelial cells line the central cavities of the brain and spinal column) - what do they do
they form a permeable barrier between the CSF and nervous tissue
what do the beating cilia do on the barrier built by ependymal cells
they help circulate the CSF
where will you see a higher concentration of tie junctions
in the capillaries - like putting cement in between bricks of a well to keep things from moving through leaky part of the membrane and then the only way to get through the membrane is through the cells so we control through things like receptors
who tells the endotheilial cells in the capillaries to make more tie junctions
the astrocytes
the astrocyte’s arms bind to the endotheilial cells and molecularly tell the cells to make more tie junctions
(pericytes too)
where is the CSF found
it coats the entire brain ; the brain “floats” inside a thin layer of CSF ; CSF helps with cushioning; it is a shock absorber and it feeds the brain
inside the CSF there are spaces called
ventricles that are filled with CSF
border made up of ependymal cells that belong to epithelial family of cells
true
is the barrier formed by ependymal cells permeable
yes
we cannot have any fluid in our body that just sits there which is why cilia are used to do what
circulate the CSF
what would happen to people without ependymal cells or people with ependymal cells with cilia that are not moving? what is the condition called?
accumulation of CSF in the brain would lead to an oversized/inflammed brain?
hydrosephalus - “water on the brain”; excess CSF
