DLA 25 + DLA 26 + lecture 35 Flashcards
What are the two functional domains of the PNS?
somatic (voluntary) and visceral (involuntary)
What makes up the PNS?
- cranial nerves
- spinal nerves
- ganglia
- enteric plexuses
- sensory receptors
Functions of the nervous system?
- sensory function
- integrative function
- motor function
What are motor efferent neurons?
conveys impulses to effector cells
somatic- muscle cells
visceral - cardiac muscle and glands
typically multipolar
What are sensory afferent neurons?
conveys impulses from receptors for integration
somatic - pain, temp, touch, pressure, proprioception
visceral - distension, ischemia, inflammation, physiological processes
typically pseudounipolar or bipolar
What are interneurons?
communication and integration between sensory and motor neurons, tendon reflexes
what are the neuroglial cells in the CNS?
- astrocyte
- oligodendrocytes
- microglia
- ependymal cells
What are the neuroglial cells in the PNS?
- schwann cells
2. satellite cells
collection of cell bodies in the CNS?
A nucleus
collection of axons in the CNS?
A tract
collection of cell bodies in the PNS?
ganglion
collection of axons in the PNS?
peripheral nerve
What are the characteristics of sensory ganglia?
central axons
large pale staining of central nuclei
no synaptic connections
groups of pseudounipolar cell bodies
What are the characteristics of autonomic ganglia?
large cell bodies
random bundles of fibers
groups of multipolar cell bodies
synapsing
explain fibrous astrocytes?
prevalent in white matter
straight processes
Explain protoplasmic astrocytes?
prevalent in gray matter
branching cytoplasmic processes
maintain the BBB
differences between schwann cells and oligodendrocytes?
oligo = CNS and can myelinate several axons
schwann = PNS and can myelinate one axon
clean up debris
What do ependymal cells do?
they are cuboidal / columnar
fluid transporting / absorbing cells
found in choroid plexus
secrete CSF
Explain satellite cells?
small cuboidal cells
surround the cell body of neurons in the PNS
regulate the perineuronal environment
regulate metabolic exchange
explain the formation of myelin?
A schwann cell plasma membrane forms two
distinct polarized domains
-abaxonal plasma membrane
-adaxonal plasma membrane
The mesoaxon connects the abaxonal and
adaxonal membranes and closes off the
extracellular environment
What protein/gene regulates the thickness of the myelin?
neuregulin (ngr-1)
the types of cytoplasm found in the myelin sheath
Inner collar of Schwann cell cytoplasm- between axon and myelin
Schmidt-Lantermann clefts- small islands of cytoplasm within
lamellae of myelin
Perinodal cytoplasm at node of Ranvier
Outer collar of Schwann cell cytoplasm
- around myelin
