Nervous System 2 Flashcards
2 main glial cells of the PNS
1) schwann cells: produces myelin
2) satellite glia: associated with and support neurons. Surrounds them in ganglia.
The schwann cells make myelin in layers surrouding the PNS neuron. Sometimes, the schwann cell cytoplasm gets stuck between the layers of myelin, forming ___ ___ ___.
Schmidt Lanterman Lines.
T/F: one oligodendrocte (myelin producing in CNS) myelinates multiple fibers
TRUE. therefore, they do not surround each individual fiber with their cell membrane (neurillemma)
What are the grey matter areas of the spinal cord? What do they contain?
gray matter is located in the posterior, lateral and anterior horns. They are filled with neuron cell bodies and astrocytes.
what are the white matter areas of the spinal cord? What do they contain
white matter (myelin) is found in the dorsal, lateral and ventral columns. They contain fiber tracts and oligodendroctytes.
a ___ ___ and ___ ___ join to form a spinal nerve
posterior root and anterior root
___ ___ is internal, forming a roughly H—shaped structure that consists of two ____ horns and two ____ horns all joined by the gray commissure around the central canal
GREY MATTER. Two posterior and two anterior horns.
which image is grey matter? white matter?
(c): Micrograph of the gray matter showing large nuclei, prominent nucleoli, and cytoplasm rich in chromatophilic substances (Nissl substance) (d): white matter showing fiber tracts seen here in cross—section with empty myelin sheaths surrounding axons. Also seen tracts running from one side of the cord to the other, seen here as several longitudinally sectioned tracts. H&E.
White versus gray matter, stained. A cross section of spinal cord shows the transition between white matter (left) and gray matter (right). The white matter consists mainly of nerve fibers whose myelin sheaths were dissolved in the preparation procedure, leaving the round empty spaces shown. Each such space surrounds a dark—stained spot which is the axon. Neuronal cell bodies predominate in the gray matter
dorsal gray horns of the spinal cord contains ___ ___ ___ and ___ ___ that carry impulses to the thalamus.
dorsal gray horns of the spinal cord contains INTERNEURON CELL BODIES and SENSORY NEURONS that carry impulses to the thalamus.
Ventral gray horn contains ___ ___ ___ cell vodies
somatic motor neuron
Lateral gray horns are involved in the ___ ___ __
autonomic nervous system
purpose of CSf
1) shock absorber
2) maintains chemical homeostasis in brain
3) provides buoyancy
3 layers of the meninges. Where do blood vessels and CSF flow thorugh?
1) dura
2) arachnoid
3) pia.
CSF and blood vessels are in the subarachnoid space between arachnoid and pia mater.
Nerves in the PNS can either be ___ or ___
sensory or mixed
T/F : fiber bundles in the CNS are associated with connective tissue and can be sensory or mixed
FALSE. Fibers form tracts in the CNS and are not associated with connective tissue. They can be ascending or descending, but they cannot be mixed, unlike PNS nerves.
Nerves in the PNS are associated with ____ connective tissue. What’re the three connective tissue associations?
COLLAGENOUS (kind of like muscle bundles)
1- epineurium: ON SURFACE. fibrous covering that wraps and supports the nerve, separating it from fascia
2) perineurium: derived from epineurium, enters the nerve and forms nerve fiber bundles called fascicles.
3) endoneurium: delicate connective tissue layer derived from perineurium that surrounds each fiber and Schwann cell.
neuron cell bodies in the PNS are found in structures called ____
ganglia
dorsal root ganglia are located on the spinal cords at the dorsal root and are ___polar. They are ____ neuron cell bodies and are surrounded by ___ cells.
dorsal root ganglia are located on the spinal cords at the dorsal root and are UNIpolar. They are SENSORY neuron cell bodies and are surrounded by SATELLITE cells.
Sympathetic ganglia enter the ___ side of the vertebral column. The are ___polar with ____ granules. Do they contain satellite cells?
Sympathetic ganglia enter the VENTRAL side of the vertebral column. The are MULTIpolar with LIPOFUSCHIN granules. They do not have as many satellite cells as dorsal root ganglia
group of functionally related neurons in the CNS is called a ____
nucleus
each spinal nerve is connected to the spinal cord by two roots these are the ___ root and the ___ root.
- even though all spinal cords are mixed, sensory and motor fibers segregate in the roots. All sensory fibers enter the spinal cord through the ___ ___ ganglion, and all motor fibers leave the cord through the ___ ___
each spinal nerve is connected to the spinal cord by two roots these are the DORSAL root and the VENTRAL root.
- even though all spinal cords are mixed, sensory and motor fibers segregate in the roots. All sensory fibers enter the spinal cord through the DORSAL ROOT ganglion, and all motor fibers leave the cord through the VENTRAL ROOT
the cerebrum consists of 2 ____ connected by the ___ ___
2 hemispheres connected by the corpus callosum
3 functions of cerebrum
1) higher thought processes (thoughts, reasoning)
2) interpretation of sensory info
3) memory
4 lobes of each hemisphere of the cerebrum
frontal, parietal, temporal, occipital
the cerebrum has an outer cortex of ___ ___ and an inner layer of __ ___
outer = grey matter
inner = white matter
the cortex consists of ___ layers. Pyramidal cells are located in layer __ and __
6 layers. you can find pyramidal cells in layers 3 and 5
What kind of neurons are these? where are they found?
pyramedal neurons. found in the cerebrum
the ___ ___ joins the brain to the spinal cord. it also contains pyramidal tracts that cross to the opposite side at the ___ ___ ___ ___. These fibers continue down into the spinal cord to synapse with somatic motor neurons in the ventral gray horns.
the MEDULLA OBLONGOTA oins the brain to the spinal cord. it also contains pyramidal tracts that cross to the opposite side at the DECUSSATION OF THE PYRAMIDS. These fibers continue down into the spinal cord to synapse with somatic motor neurons in the ventral gray horns.
Function of cerebellum. How are the two hemispheres connected at the cerebellum?
coordinating and refining motor activities. 2 hemispheres connected at the vermis.
the outer cortex of the cerebellum is made of ___ matter and the inner medullary cortex is made of __- matter
he outer cortex of the cerebellum is made of GREY matter and the inner medullary cortex is made of WHITE matter
the grey matter layer of the cerebellum is aka: ___ ___. what three layers are there?
aka CEREBELLAR CORTEX. Has a molecular layer (unmyelinated, minimal neurons), purkinje cell layer, and granular layer (more neurons)
What part of the brain is this?
cerebellum
T/F: purkinje cells are found in other regions of the brain other than the cerebellum
false. only found in cerebellum
the body of the purkinje cells in the cerebellum are embedded in the ___ layer, while the dendritic processes project into the ____ layer
the body of the purkinje cells in the cerebellum are embedded in the GRANULAR layer, while the dendritic processes project into the UPPER MOLECULAR layer
ML= molecular layer
GL= granular layer (there are purkine cells between the two layers)
M= cerebellar medulla. White matter.
Purkinje cell of the cerebellum. Dendrites and dendritic spines are in the upper molecular layer of the cerebellar cortex, while the cell bodies of the purkinje cells rest in the granular layer.
What structure is this? What is it comprised of? Purpose?
This is the choroid plexus. Makes CSF. The choroid plexus is specialized for transport of water and ions across the capillary endothelium and ependymal layer and the elaboration of these as CSF. made of Pia mater joined with cuboidal epyndymal cells.
Explain this image. Which part of the nervous system would you find these structures?
Peripheral nerve connective tissue. Three layers of connective tissue in (a). (b): The outer epineurium (E) consists of a dense superficial region and a looser deep region that contains large blood vessels (A,V) and fascicles in which nerve fibers (N) are bundled. Each fascicle is surrounded by the perineurium (P), consisting of a few layers of unusual epithelial—like cells. Axons and Schwann cells are in turn surrounded by a thin layer of endoneurium. X140. H&E. (c): perineurium (d): This micrograph shows a longitudinally oriented nerve. Within fascicles is the endoneurium (En) is produced by the Schwann cells. Collagen of the endoneurium is stained blue and a node of Ranvier (N) and a Schwann cell nucleus (S) are also clearly seen. X400. Mallory trichome.
ONLY FOUND IN THE PERIPHERAL NERVES. FIBERS OF THE CNS ARE CALLED TRACTS AND DO NOT HAVE CONNECTIVE TISSUE
lautonomic ganglia are associated with the Autonomic Nervous System (ANS) –maintains internal homeostasis. Where do sympathetic autonomic ganglia lie? para symp?
lsympathetic lie alongside the vertebral column in thoracic and lumbar regions
parasympathetic lie near organ
craniospinal ganglia contain sensory nerves are are unipolar. The cell bodies are surrounded by satellite cells.
In sympathetic ganglia, neurons are mutlipolar, and the satellite cells are smaller and less regular.
In parasympathetic ganglia, there are fewer cell bodies, and are generally much smaller than sympathetic ganglia. What is an example of parasympathetic ganglia?
Auerbachs plexus.
Sensory receptors can either be ___ ___ or ___ cells.
nerve endings or specialized cells.
are meissner’s corpuscles encapsulated? Location? Function?
they are encapsulated. Location: upper part of the dermal papillae. Function: detect light touch
name the structure
meissners corpuscles
are pacinian corpuscles encapsulated? Location? Function?
they are encapsulated. Location: deeper in dermis, mesenteries, ligaments, some viscera. Function: detect pressure.
What is this?
Pacinian corpuscles. Looks like onion and surrounded by fatty tissue.
6 layers of the cerebral cortex
1) molecular layer. most superficial. closest to the pia.
2) outer granular layer
3) pyramedal cells
4) inner granular layer
5) pyramedal cells
6) multiform cell layer. Deepest in cortex. contains fusiform cells and white matter.
white matter of the cerebrum is located under the 6th grey matter layer. What three tracts compose the white matter?
1) projection tracts: both ascending and descending tracts
2) commissural: connects the two hemispheres
3) association tracts: connects regions within a hemisphere
What is this? What cell bodies does it house? Compare to a sympathetic ganglion.
Dorsal Root Ganglion. houses sensory, unipolar cell bodies.
Contains mores satellite glial cells for support, looks more organized.
Sympathetic ganglion is part of the peripheral NS but leaves from the ventral root horn (considered “efferent”). looks more messy because of lipofuscian granules.
What is this? What makes it distinguishable from dorsal root ganglion? What type of cells are housed?
Sympathetic ganglion. Has LESS satellite cells, is LESS organized than dorsal root ganglion, and often has lipofuscian granules. Multipolar/efferent neurons are housed in the sympathetic ganglion, and they are found in the thoracolumbar region of the spinal cord
the medulla has mainly ____ ganglion
parasympathetic ganglion. The medulla is responsible for a lot of subconcious processes/ breathing/blinking.
parasympathetic or sympathetic? Where is this located?
auebachs plexus. parasymp. located between the inner circular and outer longitudinal layers of the muscularis externa.
