Nervous System Cells Flashcards by Libby Sarra

signaling units encoding stimulus from our environment to our ns to be processed

neurons

How well did you know this?

Not at all

Perfectly

______ neurons in the human nervous system

~100 billion

How well did you know this?

Not at all

Perfectly

initial segment
the region where the plasma membrane generates nerve impulses

axon hillock

How well did you know this?

Not at all

Perfectly

what are glial cells

the “glue”
Supportive cells—supply firmness and support the chemical environment
10 times more glial cells than neurons (trillion)

How well did you know this?

Not at all

Perfectly

surrounding axons

myelin sheath

How well did you know this?

Not at all

Perfectly

cell body

soma

How well did you know this?

Not at all

Perfectly

terminal bouton

ending, where synapse occurs at end of axon

How well did you know this?

Not at all

Perfectly

two common structures in our nervous system

pseudounipolar
multipolar
bipolar

How well did you know this?

Not at all

Perfectly

bipolar

unique to special senses, like auditory system

How well did you know this?

Not at all

Perfectly

Supporting cells of the PNS
Forming myelin around peripheral axons
Separating unmyelinated axons
Become phagocytes when there is injury or inflammation

glial cells

How well did you know this?

Not at all

Perfectly

what is a special type of glial cell?

schwanna cells

How well did you know this?

Not at all

Perfectly

flattened type of glial cell in the PNS & produce myelin

schwann cells

How well did you know this?

Not at all

Perfectly

why is it important to have myelin?

increases the speed of transmission of action potentials to carry the electrical signals/messages; separates unmyelinated axons, become phagocytes when there is injury or inflammation

How well did you know this?

Not at all

Perfectly

eat up any debri/bacteria
cleaning up and go around injury to clean up

phagocytes

How well did you know this?

Not at all

Perfectly

provide structural and metabolic support—star-shaped
in CNS

Astrocytes

How well did you know this?

Not at all

Perfectly

myelin forming glial cells in CNS

Oligodendrocytes

How well did you know this?

Not at all

Perfectly

Make up only about 5-10% of the glia
They become active in response to antigens
Once activated they are called macrophages or phagocytes and can migrate to damaged areas and devour or phagocytose pathogens, neuronal debris and injured neurons

Microglia

How well did you know this?

Not at all

Perfectly

inside CNS

oligodendrocytes - myelin
migroglia - phagocytes

How well did you know this?

Not at all

Perfectly

in PNS

scwhann - makes myelin
phagocytes

How well did you know this?

Not at all

Perfectly

No meninges
Cell types:
Neurons
Glia
Mostly Schwann Cells

PNS

How well did you know this?

Not at all

Perfectly

Covered by meninges
Cell types:
Neurons
Glia
Oligodendrocytes
Similar to Schwann Cells
Astrocytes
Microglial Cells
Ependymal Cells

CNS

How well did you know this?

Not at all

Perfectly

oligodendrocytes are done making myelin and schwann cells take over is where

cns turns to pNS

How well did you know this?

Not at all

Perfectly

soma

cell body (perikaryon)
Supports the metabolic and synthetic needs
Synthesize macromolecules needed by the cell and integrate electrical signals

How well did you know this?

Not at all

Perfectly

dendrites

Branching processes
Receiving information from other neurons

How well did you know this?

Not at all

Perfectly

Conducts information away from the cell body and to other neurons or other organs

axon

Can have series of terminal branches at the end

Single cylindrical projection

transmits info to other neurons at the synapse

terminal bouton

bilayer of lipid molecules and protein molecules Maintains the ionic concentration Selectively permeable Also has active pumping mechanisms

cell membrane

outside of the cell body and membrane

extracellular fluid

more than a meter, extending from the cerebral cortex to the lower spinal cord

axons (single neuron)

axon having synapse with cell body

axosomatic

terminal bouton synapse on anothers terminal bouton (modulation)

axoaxonic

one axon carries info to dendrite of next cell

axodendritic

what is a neuron composed of

cell body with processes (extensions) called dendrites and an axon, which carry impulses to and away from the cell body, respectively.

how can synapses happen

synapse with another neuron neuromuscular neuroglandular

motor axon neurotransmitter (excitatory)

acetycholine

Most common in vertebrates Multiple dendritic projections coming off of the cell body and usually an axon

multipolar

two processes coming off of the cell body Special sensory neurons such as CN I, CN II and CN VIII are true bipolar neurons

bipolar

Only one process coming off the cell body common in invertebrates

unipolar

started out as bipolar and grew to have only on stalk coming off the cell body that then branches into to processes (i.e. most cranial nerves)

pseudounipolar / pseudomonipolar

are there one type of cell in nervous system

no globular, pyramidal (such as in the cerebrum), Purkinje cells (cerebellar), granule, stellate, octopus

arbor vitae is made to look like tree due to

purkinje cells

Groups of functionally related cell bodies in the CNS

nuclei

(bundle of cell bodies grouped together in the central)

nuclei

mainly cell bodies and dendrites

grey matter

areas of mainly axons

white matter

an area of layered gray matter covering some part of the CNS (cerebral and cerebellar cortices)

cortex

Many names for collections of axons in the CNS

Fasciculus, funiculus, lemniscus, peduncle, and commonly tract (i.e. medial longitudinal fasciculus, lateral lemniscus and cerebellar peduncles, optic tract)

Names of tracts often tell the location of the cell bodies of origin and the site of termination (i.e. spinocerebellar tract)

axons

Clusters of functionally related cell bodies in the PNS

ganglia

Axons in the PNS form

peripheral nerves

group of subcortical cell bodies that process things related to movement and function of brain, CNS

basal ganglia

what is the formation of myelin

Lipids and proteins Wrapping axons

ganglia and nerves

PNS

a gap in the myelin sheath of a nerve, between adjacent Schwann cells.

node of ranvier

bare spaces without myelin

node of ranvier

produces one segment of myelin along a single axon

single schwann (PNS)

extends processes to several axons to envelope them

single oligodendrocyte (CNS

one to one schwann in PNS vs one to many oligodendrocyte in CNS?

more tightly packed and encased in sc, brain and bs, so it makes sense for one to wrap around to many more compact in CNS so why oli wraps around many axons

where do neurons depolarize on an axon?

at the node of ranvie

inside neural tissue wrapping

Endoneurium

several axons together inside fascicle

Perineurium

multiple of fascicle bundles wrapped in perineurium

Epineurium

jumping from node to node

SALTATORY CONDUCTIONe

explain process of SALTATORY CONDUCTION

Speed increased by myelin drove sodium inside at the node and switched to a + inside that node next one is at rest with - inside and volt change at one triggers it to stimulate and open at 2nd node (voltage gated ion channels opened) forward propagating

what is grey matter

Actually pinkish gray in color due to abundant blood supply Nuclei-functionally related cell bodies in the CNS Also cerebral cortex and cerebellar cortex which are layered surface coverings in parts of the CNS Other named areas of gray matter such as the putamen, a nucleus in the cerebral hemispheres (subcortical nuclei - thalamus, hypothalamus, etc.)

outside surface of brain and cerebellum (about 4mm of it all around it)

grey matter

what is white matter

mostly axons due to the myelin sheath around many axons Myelin is mostly composed of lipids and has a fatty white appearance

lipids give this its color

white matter

what is multiple sclerosis?

a disease of myelin body attacks itself (autoimmune) Destruction of myelin in patchy areas of CNS

what would we see and symptom of MS?

slowing of failure of action potentials conduction muscle weakness

why is ms hard to treat

hard to treat because it is at the cellular level of a single schwann wrapping around cannot repair this not sure what chemical or what to change to make the cells work better

what is guillain barre

May follow acute respiratory illness * Autoimmune attack on peripheral (including cranial) nerves * Patchy demyelination

what would we see and symptom of guillain barre

May follow acute respiratory illness Slowing and failure of AP conduction * Muscle weakness * Ventilator dependency * Functional recovery 2-4 wks after stabilization of symptoms (usually)

what DEMYELINATING DISORDERS can have recovery?

guillain barre, Functional recovery 2-4 wks after stabilization of symptoms (usually)

_____ can recover better with demyelinating disorders than ____ can

PNS, CNS