NeuroAnatomy Flashcards
what cells carry action potentials?
neurons
what are glial cells?
they are supporting cells that are non excitable and smaller than neuron but are much more plentiful.
how many cell populations are present in the nervous system?
2, glial cells and neurons
describe a typical neuron
multiple dendrites and one axon
are motor and sensory neurons separate?
yes as the impulse can only travel in one direction
describe the nucleus in a neuron
there is loose chromatin and prominent nucleolus
what are the prominent organelles in neurons?
> mitochondria (due to high metabolic rate)
rough endoplasmic reticulum
diffuse Golgi apparatus
what is the cytoplasm in the cell body?
perikaryon
what is axoplasm?
the cytoplasm present in the axon of a neuron
if a neuron dies will it regenerate?
no unless axons are in a proper conducive environment.
what secretes the myelin sheath?
> schwann cells in the PNS
> oligodendrites in the CNS
what does the myelin sheath do?
increases conduction speed in axons by salutatory cnduction
describe the myelination of axons
schwann cells wrap themselves around the myelinated axon and a mesoaxon is formed. the cytoplasm of the schwann cells gets extruded leaving only the cell membrane.
are non myelinated axons wrapped by schwann cells?
yes but they do not have the myelin sheath
what is the effect of multiple sclerosis on the myelin sheath?
there is patchy loss/scarring of the myelin sheath leading to abnormal nerve conduction across affected axons
motor neurons and inter-neurons are bi polar or multipolar?
multipolar: one cell body, multiple dendrites and one axon.
describe sensory neurons
pseudo unipolar: one projection from the cells body so the impulses do not have to go through the cell body. outside of sensory nervous system
where do the cell bodies in pseudo unipolar sensory cells sit?
in the dorsal ganglion
where are bipolar neurons found?
they are found in the retina or olfactory mucosa.
where do neurons in from the spinal cord synapse in the brain?
in the thalamus
what are axons organised by?
depending on the information that they are carrying
what are tracts?
bundles of axons carrying specific information within the white matter
what forms grey matter?
collection of cell bodies or unmyelinated axons that is diffuse (nuclei in central nervous system that is called nuclei)
what forms white matter or tracts?
collection of myelinated axons
what is the collection of neural cell bodies outside the central nervous system?
ganglions
what are the functions of astrocytes?
> go around synapses stopping fluid leaking
> surround the capillaries forming the blood brain barrier
what are the functions of microglia?
they form fibroblasts and are involved in scar tissue formation
what makes up the brainstem?
> pons
medulla
midbrain
what is on top of the brain stem?
diencephalon, containing the hypothalamus
what forms the ventricles?
the cavity inside the neural tube
