Myelination Flashcards
what is pia mater?
the deepest and thinnest layer of the brain that follows the curves and directly attached to the nervous system
what is dura mater?
the most superficial layer of the brain, produces the veins of the brain, and it’s tough and durable
what is the arachnoid mater?
the second/middle layer and it is spidery, web like
what is the subarachnoid space?
space between pia mater and arachnoid mater
what is the inner meningeal layer?
layer inside the dura mater that’s attached to the arachnoid mater
what is the outer periosteal layer?
layer inside the dura mater that’s attached to the periosteum
what are dural venous sinuses?
large veins that drain blood from the brain between inner meningeal and outer periosteal layers
what are vein walls formed by?
dura mater
what is the central nervous system?
brain and spinal cord (control center)
what is the peripheral nervous system?
cranial nerves, spinal nerves, and ganglia (everything outside of CNS)
what does the sensory division do?
receives information from body and transmits it to the CNS for processing, has both CNS and PNS
what does the somatic sensory do?
receives sensory information from skin, joints, muscles, and special senses (5 senses)
what is the function of visceral sensory?
receives sensory info from blood vessels and viscera (tells our body we are full)
what is afferent?
inflowing
what is the function of the motor division?
transmits info from the CNS to muscles and glands, has both CNS and PNS
what is the function of somatic motor?
innervates skeletal muscle, voluntary control
what is the function of the autonomic motor?
innervates smooth muscle, cardiac muscle, and glands of viscera (organs), involuntary
what is efferent?
conducting outward
what is the function of neurons?
respond to stimuli and conducts nerve impulses, amiotic
what is amiotic?
don’t reproduce
what is the function of glial cells?
support and protects neurons, divides by mitosis, many more glial cells than neurons
what is the function of the cell body?
neurons control center or head
what is the function of the nucleus?
contains nucleolus for protein synthesis and housing DNA
what are chromatophilic substances and its function?
darkened clumps within the cytoplasm, not in axon hillock, used for protein synthesis
what are dendrites and its function?
short nerve cell process, neurons can only have one of them, used to receive input of incoming nerve impulse, sends impulses to cell body
what is an axon and its function?
long nerve cell process, used to send output of outgoing nerve impulses
what is an axon hillock?
portion of cell body from where, axon originates, cone shaped, lacks chromatophilic substance
what is multipolar and where is it found?
one axon and many dendrites, most common, motor neurons and interneurons
What is bipolar and where is it found?
two processes with one axon and one dendrite, limited/rare, retina of eye, olfactory neurons
what is unipolar and where is it found?
single process from the cell body and divides into two branches, common, most sensory neurons
what is the function of a sensory neuron?
brings information to the CNS, and it goes from unipolar to bipolar
what is the function of the motor neuron?
takes information from CNS to other parts of the body, multipolar
what is the function of glial cells?
support and protect neurons, divide by mitosis, most numerous, PNS
what is the function of the interneuron?
helps coordinate and integrate info between sensory and motor neurons, multipolar
what are satellite cells?
surround neuron cell bodies in spinal ganglia
what is ganglion?
a group of neuron cell bodies located outside the CNS
What are neurolemmocytes?
myelinate axons in PNS, helps regenerate damaged PNS axons
what is myelin?
protective covering around an axon, used to insulate axon produce faster nerve impulses
what are astrocytes and function?
makes vessels less leaky, regulate transfer of materials from blood to the brain, helps form the blood brain barrier
what is the function of blood brain barrier?
keeps harmful substances away
what are ventricles?
spaces within brain produce CSF
what are oligodendrocytes?
myelinate axons in CNS, makes myelin
what are microglia cells and function?
phagocytize damaged neurons, remove and eat up neurons, replicate when CNS is damaged
what are ependymal cells?
line central canal and ventricles, helps circulate cerebrospinal fluid CSF
what is myelination?
process of wrapping an axon with myelin, insulates axon and produces a faster nerve impulse, dendrites are not myelinated
which axons are myelinated?
axons larger than 2 micrometers in diameter
what is the myelination procedure in PNS?
neurolemmocyte wraps around a 1mm portion of an axon, cytoplasm and nucleus of neurolemmocyte is squeezed to the outside, inner successive layers of cell membrane make up the myelin sheath
what is the myelination procedure in CNS?
one oligodendrocyte myelinates 1mm portions of many axons, takes many neurolemmocytes to myelinate entire axon, myelinated axons produce faster nerve impulses than unmyelinated axons
what are neurofibril nodes?
gap between 2 adjacent neurolemmocytes where nerve impulse generated, unmyelinated
