Nervous System II Flashcards
Gray matter (spinal cord)
On the inside of the spinal cord. They are not myelinated and are distinguished by a H shape.
White matter (spinal cord)
On the outside of the spinal cord. It contains myelinated axons, but no perikaryon
Layers of cortical gray matter (cerebrum)
Superficial and pyramidal layer. Located on the outside of the cerebrumm
Medullary white matter
Located on the inside of the cerebrum
Cerebral cortex
Responsible for higher thought processes and coordination of movements
Cerebrum
Controls thinking and speaking. Largest park of the brain.
Cerebellum
Coordinates movements, motions, reflexes, and balance. Shaped like a cauliflower
Layers of cortical gray matter (cerebellum)
Molecular, purkinje, and inner granular layers. Located on the outside of the cerebellum
Gray matter
neurons and glial cells
White matter
nerve fibers and glial cells
Central white matter
Located on the inside of the cerebellum
Molecular layer
Outer most layer of the cerebellum that contains unmyelinated nerve fibers
Purkinje layer
Middle layer of the cerebellum that contains large axons and dendrites that penetrate the molecular layer
Inner granular layer
Inner most layer of the cerebellum that is packed with small multipolar neurons.
Basal ganglia
Controls and synchronizes movements. Found at the base of the cerebrum.
Amygdala
Important for emotional behavior and memory. Small spot below the midbrain.
Hippocampus
Transfers memories from short term to long term. Encapsulates the bottom part of the midbrain
Midbrain
Involved in hearing and sight reflexes. Located between the cerebrum and cerebellum
Brain stem
Consist of the midbrain, medulla, and pons
Pons
Responsible for R.E.M sleep. Located above the medulla as a bulge in the brain stem
Medulla
Regulates heart rate, breathing, and digestion. Located at the base of the brain, contiguous with the spinal cord
Oligodendrocytes
Glial cells that form and maintain a myelin sheath that wraps around axons. They are found between myelinated fibers and are able to bind to adjacent cells
Microglia
Glial cells that differentiate into immune cells of the brain. They are small cells with large amount of processes,
Ependymal cells
Epithelial glial cells in the brain that maintain and produce the cerebral spinal fluid. Contains cilia and pseudostratified columnar epithelium
Astrocytes
Glial cells that bind and protect axons and sometimes blood vessels. They are shaped like starfish and completely engulf capillaries. They can be found between tracts of axons and dendrites
Fibrous astrocytes
Only found in white matter
Protoplasmic astrocytes
Only found in gray matter. They have fewer filaments and processes and are found in synapses.
Meninges
Layer immediately under the skull. It facilitates the distribution of blood to the top layers of the brain while also providing another layer of protection
Layers of the meninges
Dura mata, arachnoid, pia mata
Dura mata
Layer immediately under the skull. It is well vascularized and filled with dense connective tissue.
Arachnoid
Middle layer that forms columns that act as a spring to provide protection from any force acting on the brain. It is well vascularized as well and filled with cerebral spinal fluid.
Dura pia
Consist mainly of collagen fibers covered with squamous epithelial cells.
Blood brain barrier
A protection barrier of endothelial and neuroglial cells. It limits the entry of material into the brain from the blood.
Cerebrospinal fluid
Liquid within the brain that provides circulation of ions and protection.
Choroid plexus
Epithelial structure lining portions of cerebral ventricles that produce the spinal fluid. It has a simple cuboidal cell layer.
Hydrocephalus
Caused when the central spinal fluid is blocked from exiting ventricles
Peripheral nervous sytem
all nerves and supportive cells outside the CNS
Central nervous system
Cerebrum, Cerebellum, and Spinal chord
Peripheral nerves
They contain many axons that are packed into nerves. They have specific connective tissue coverings and myelination.
Ganglia
Groups of nerve cell bodies located outside of the CNS
Dorsal root ganglia
Afferent pseudounipolar neurons. They are located at the posterior root of spinal nerves.
Autonomic root ganglia
Efferent multipolar neurons. They are located within the ANS.
Connective tissue coverings of peripheral neves
Epineurium, perineurium, and endoneurium
Epineurium
Covers most moderate and large nerves
Perineurium
Directly covers bundles of nerves
Endoneurium
Vascularized loose connective tissue between individual nerves
Chromatolysis
Regeneration of nerve fibers. Slow regeneration is due to the Schwann cell division and column formation
Steps of Chromatolysis
1) 2 weeks post trauma, changes begin to occur. Nissl bodies dissolve, perikaryon expands, and nucleus moves to one side
2) After 3 weeks, myelin sheath dissolves. Schwann cells increase their activity and proliferate.
3) A continuous column of Schwann cells is formed
4) About 3 months, the nerve fiber slowly penetrates the Schwann cell column.
Nerve endings
Sensory or motor nerve endings that convert physical or chemical stimuli into electrical energy
Autonomic nervous system
Efferent branch of the PNS. It contains sympathetic and parasympathetic systems. Both branches innervate the same organ, but have different pathways.
Parasympathetic nerves
Arise from cranial and sacral regions
Sympathetic nerves
Arise from thoracic and lumbar regions
3 types of autonomic root ganglia
Paravertebral, prevertabral, and terminal
Paravertebral autonomic ganglia
Located in the sympathetic system immediately outside of the spinal column
Prevertabral autonomic ganglia
Located in the abdomen. They have ends in both systems.
Terminal autonomic ganglia
Located in the parasympathetic system near the organs.
