Histology - Nervous System Flashcards
nervous tissue is comprised of what two things?
neurons and neuroglia
what is the basic functional unit of the nervous system?
neuron
what provides metabolic and structural support to the nervous system?
neuroglia
most neurons in the body are what type of neuron?
multipolar
where are bipolar neurons commonly found?
special senses eg in the eye
what are unipolar neurons also known as?
1st order sensory neurons
what are the 4 types of neuroglia in the CNS?
- astrocytes
- oligodendrocytes
- microglia
- ependymal cells
what is the role of astrocytes?
maintains chemical environments, provides nutrients, remove excess neurotransmitter and contribute to the blood brain barrier
what is the role of the microglia?
engulf invading microorganisms, migrate to areas of nerve injury to clear dead cells
what is the role of oligodendrocytes?
produce the myelin sheath around axons of the CNS neurons
what is the role of ependymal cells?
line the ventricles of the brain and central canal of spinal cord, form CSF and assist in its circulation
why is the white matter in the spinal cord white?
there are axons found in the white matter, and they are covered in myelin sheath - this appears white
what part of the neuron is located in the gray matter?
nerve cell body
the ventral horn contains what?
nerve cell bodies of motor neurons
the dorsal horn contains what?
nerve cell bodies of sensory neurons
what does the lateral horn contain?
nerve cell bodies of autonomic neurons
what shape are nerve cell bodies of motor neurones?
pyrimidal
what are the two neuroglia of the PNS?
schwann cells
satellite cells
what is the role of schwann cells?
- produce the myelin sheath around the axons of the PNS neurones
- participate in the regeneration of PNS axons
what is the role of satellite cells?
- located in the PNS ganglia
- provide metabolic support for the neurones and remove excess neurotransmitter
ganglion
a collection of nerve cell bodies in the peripheral nervous system
nucleus
a collection of nerve cell bodies in the central nervous system
nerve
bundle of axons traelling in the peripheral nervous system
tract/fasiculus
a bundle of axons travelling in the central nervous system
a collection of nerve cell bodies in the peripheral nervous system
ganglion
a collection of nerve cell bodies in the central nervous system
nucleus
bundle of axons traelling in the peripheral nervous system
nerve
a bundle of axons travelling in the central nervous system
tract/fasiculus
endoneurium
connective tissue later surrounding a single nerve fibre
fascicle
bundle of nerve fibres
what is a fascicle surrounded by?
perineurium - connective tissue layer
what is a peripheral nerve made of?
bundles of fascicles
bundles of fascicles are surrounded by what?
epineurium
list the layers of a peripheral nerve, from innermost layer to outermost:
- endoneurium
- fascicle
- perineurium
- nerve
- epineurium
what are the 3 types of ganglia?
sensory - no synapses
sympathetic - synapse occurs
parasympathetic - synapse occurs
q
what do the sensory ganglia contain?
nerve cell bodies of first order sensory neurons
which cranial nerves have sensory ganglia?
- trigeminal
- geniculate
- superior and inferior glossopharyngeal
- superior and inferior vagal
where are the sympathetic ganglia located?
located in the sympathetic chains (paravertebral ganglia) or in prevertebral ganglion
what do sympathetic ganglia contain?
nerve cell bodies of post ganglionic sympathetic neurones
where are parasympathetic ganglia located?
close to, or within the walls of, the organs that they innervate
what do parasympathetic ganglia contain?
nerve cell bodies of postganglionic parasympathetic fibres
which 4 cranial nerves have parasympathetic ganglia associated with them?
- oculomotor
- facial
- glossopharyngeal
- vagus
