NEURONS & GLIAL CELLS - NEUR200

golgi

method: stilver staining technique

allows to stain a limited number of nerve cells

cajal

nerve cells remain separated

membrane

“skin”

separates inside from outside

nucleus

chromosomes

mitochondrian

metabolism (provides energy)

cortex + neurons

12 to 15 billion

spinal cord + neurons

1 billion

cerebellum + neurons

70 billion

neuron shapes and types

vary, there’s many different types

deindrites

fibers with synaptic receptors that receive information from other neurons

cell body (soma)

most of the neuron’s metabolism occurs here

also may have synapses

axon

long fiber that conveys an impulse toward other neurons, organs, or muscles

presynaptic terminal

at this point the axon releases chemicals that cross through the junction from one neuron to the next

motor neuron (efferent)

its soma s in the spinal cord (conducts impulses along its axon to a muscle)

sensory neuron (afferent)

light, sound, or touch

soma is located on the trunk

intrisnic neurons

inside the structure

multipolar neurons

many deindrites and one axon

unipolar/multipolar neurons

have an axon that branches in two directions (input and output zone)

bipolar neurons

one dendrite and one axon

genotype

genetic code

phenotype

observable characteristics

nucleus

genes for making proteins are stored, copied, and sent off

chromosomes

constantly changing shape so that genes can be expressed

dna uncoils to expose a gene

rna

gene information is transcribed

ribosomes

read and translates rna into amino acid chains, forming the proteins

glia

supporting cells

provide firmness and structure for the brain (role played by connective tissue cells in other parts of the body)

smaller but more numerous than neurons

glial functions

guidance: help with migration of neurons

form myelin: oligodendrocytes in CNS and schwann in PNS

synapse formation and matinence of synapses depends on signals from astrocytes

supply oxygen and nutrients, remove dead neurons

removal of K+ by astrocytesd to maintain proper K+ concentrations

macroglia

astrocytes + oligodendrocites

astrocytes

star-shaped cells

serve different functions

nutritive function - together with microglias, remove dead neurons after a brain injury

oligodendrocites

smaller cells

contribute the myelin sheath to the axon in the CNS (schwann cells in the PNS)

microglia

mobilized after injury, infection, or disease

tumors + glial cells

majority of malignant brain tumors are derived from glial cells (mainly astrocytes)

multiple sclerosis + glial cells

oligodendrocyte loss

type 1 charcot-marie-tooth disease + glial cells

loss of muscle

motor and sensation issues due to demyelinating schwann cells

blood-brain barrier

brain is protected against surging fluctuations in the content of many constituents of the blood

not a singular barrier, there’s man y different systems that exist for excluding substances from blood to brain

ex: morphological and functional characteristics of brain capillaries, differ from those in other organs

spindle / von economy neurons

bipolar

emotion and empathy related

frontal temporal dementia: loss of empathy