Lecture 15 Flashcards
Nervous Tissue
What cellular structure holds the nucleus?
Cell body
What are the extensions off the cell body called?
Dendrites
What is the origin of the axon, where the AP is generated?
Axon hillock
Describe the axon
- usually one per neuron
- VG channels, AP
- mitochondria and MT
- no nissel bodies, Golgi or RER.
- terminates in telodendrites
What is the pathway to the CNS called?
Afferent or sensory
What is the pathway away from the CNS called?
What are its divisions?
- Efferent, motor
- Somatic - goes to skeletal m
- Autonomic - goes to smooth muscle, cardiac muscle and glands
_____ is completely contained in the CNS.
Interneuron
Neurons can be named on number of processes.
1) Multipolar
2) Bipolar
3) Pseudounipolar
1) Single axon, multiple dendrites
2) 2 processes, (at each end of cell body) - special senses
3) single process form cell body that bifurcates towards CNS and out to periphery
Neurons can be named based on length of axon:
1) Golgi I
2) Golgi II
1) long axons leaving grey matter
2) Short axons, ramify thru grey matter (so they don’t leave it)
1) _____ is a bundle of axons in PNS
2) _____ is a bundle of axons in CNS
3) _____ is an aggregation of cell bodies and dendrites in the PNS.
4) _____ is an aggregation of cell bodies and dendrites in the CNS.
1) Nerve
2) Tract
3) Gaglion
4) Nucleus
1) What surrounds entire nerve?
2) What surrounds fascicles?
3) What surrounds the individual fibers and Schwann cells?
1) Epineurium
- type 1 collagen
2) Perineurium
- dense CT
- fibroblast are connected via tight jxns (zona occuludens)
- blood nerve barrier also linked by tight junctions
3) Endoneurium
- type 3 collagen
What are the 4 membrane specializations of neurons?
Receptors, ion channels, presynaptic membrane and postsynaptic membrane
What direction is anterograde transport?
What organelle is involved?
Cell body toward distal end of axon
- Kinesin
What direction is retrograde transport?
What organelle is involved?
Axon toward cell body
- dynein
1) What are glial cells, where are they derived from, and what are the types?
Glial cells = non-neuronal, support/”glue” cells; support fxns in both CNS and PNS
- derived from embryonic neural crest (except for microglia)
- Astrocytes
- Oligodendrocytes
- Schwann cells
- Microglial cells
- Ependymal cells
Which is the only glial cell that does not derive from embryonic neural crest tissue?
Microglia
Astrocytes are found only in _____. They provide ____ support and are associated with the _____ barrier.
- CNS
- structural
- blood-brain
- they mediate exchange of nutrients b/w blood and neurons
- their end feet form glia limitans
What cells myelinate axons in CNS?
Oligodendrocytes
What cells myelinate axons in PNS?
Schwann cells
Where do microglial cells derive from and what is their function?
- from bone marrow (from macrophage precursors - monocytes)
- phagocytic in CNS
In the choroid plexus, what are the main cells that secrete CSF?
Ependymal cells
- ciliated cuboidal cells
- line ventricular system of CNS
- fxn in transport
- derive from neuroepithelium
Satellite cells fxn as ____ and form moons/crescents around cell bodies in _____.
Insulators
Ganglia (outside of CNS)
Process of myelination in PNS:
1) ____ cell plasma memb wraps around axon, cytoplasm squeezed out leaving behind ____ layers of fat around the axon.
2) ____ line is b/w adjacent outer leaflets
3) ___ line is b/w adjacent inner leaflets
4) Schimdt-Lanterman clefts (incisures) are areas of residual cytoplasm within ____ line.
1) Schwann; concentric
2) Intraperiod
3) Major dense
4) major dense
1) ______ protein is found in both PNS and CNS and is associated with inner leaflets and the _____ line.
2) _____ = transmembrane prtn that forms homodimers and is found only in the PNS. It is associated with ____ line.
1) Myelin basic prtn; major dense line
2) Myelin protein zero; intraperiod line
Presynaptic membrane contains:
- VG ____ channels
- _____ bind synaptic vesicles to presynaptic memb
- _____ proteins are SNAP receptors
- Ca+2
- SNAPs
- vesicle docking proteins
Axosomatic: axon to? Axoaxonic: axon to? Axodendritic: axon to? Axospinous: axon to? Excitatory is more \_\_\_\_ Inhibitory is more \_\_\_\_\_
- Cell body
- Axon
- dendrite
- dendritic spine
- positive
- negative
Superficial to deep order:
Bone–> ____ space –> ____ mater —> ___ space with venous sinus —-> ____ with vili and trabeculae –> ____ mater.
- epidural space
- dura
- subdural
- arachnoid
- pia
What is considered the periosteum of the cranial cavity (lines the cranial vault bones)?
Dura mater
- tough, thick sheet of dense fibrous CT
- also forms CT tube around spinal cord
- not tightly attached
What attaches the arachnoid to the underlying pia mater?
Arachnoid trabeculae
What is the space that holds the CSF?
Arachnoid space
Which mater would cause damage to brain or spinal cord if removed?
Pia mater, bc it is a very delicate sheet of CT directly attached on the surfaces
What is the highly infolded simple cuboidal epithelium that extends into ventricles from roof plate?
What are its cuboidal cells linked by?
- Choroid plexus
- tight junctions — form CSF-barrier
What structure is a layer of simple cuboidal epithelium that lines the ventricular walls of the brain?
What are its cells linked by?
- Ependyma
- zona adherens
- ** in contact with astrocytic processes taht form glia limitans – part of the blood-brain barrier
What are also tightly linked to teh ependyma, that sends processes through the glia limitans forming end-foot processes on BV?
Tanycytes
What type of ganglia contains pseudounipolar neurons, myelinated post-ganglionic axons, and satellite cells that form a single layer around each neuron?
Sensory, dorsal root ganglia
What type of ganglia contains multipolar neurons, unmyelinated post-ganglionic axons, and not very many satellite cells?
Autonomic ganglia
