Coordination, association, and integration
What are the three dominant roles of the nervous system?
Twelve Cranial nerve pairs (24 total)
How man cranial nerves are there?
31 spinal nerve pairs (62 total)
How man spinal nerves are there?
Brain and Spinal Cord
The central nervous system consists of what?
Cranial nerves III, VII, IX, and X and Sacral nerves 2, 3, and 4
What nerves are involved in the parasympathetic division, known as the "craniosacral" subdivision?
Short
Are post-ganglionic axons in the parasympathetic division long or short?
Spinal nerves from T1-L2 level
What nerves are involved in the sympathetic nervous system, known as the "thoracolumbar" subdivision?
Norepinephrine
The sympathetic nervous system is said to be "adrenergic", which means it releases what neurotransmitter?
Sweat glands and arrector pili muscles
What are the exceptions to the adrenergic rule of the sympathetic nervous system?
1:17
What is the ratio of preganglionic to postganglionic neurons in the sympathetic nervous system?
1:2
What is the ratio of preganglionic neurons to post ganglionic neurons in the parasympathetic nervous system?
Ectoderm
What germ layer does the central nervous system come from?
Prosencephalon, Mesencephalon, Rhombencephalon
What are the three primary brain vesicles?
Telencephalon and Diencephalon (Te-Di is a Pro)
What are the two divisions of the prosencephalon?
Metencephalon and Myelencephalon (Rhom Met Mye)
What are the divisions of the Rhombencephalon?
First vestige of the nervous system
What is significant about the neural plate?
Spinal Cord
What does the neural tube form into?
Peripheral Nervous System (PNS)
What does the neural crest form into?
Cerebral cortex, basal ganglia, lateral ventricles
What are the mature structures of the telencephalon?
Thalamus, hypothalamus, pineal gland, 3rd ventricle
What are the mature structures of the diencephalon?
Corpora quadrigemina, cerebral peduncles, cerebral aqueduct
What are the mature structures of the mesencephalon?
Cerebellum, Pons, 4th ventricle
What are the mature structures of the Metencephalon?
Medulla oblangata, 4th ventricle
What are the mature structures of the myelencephalon?
10% of body weight, uses 60% of the oxygen of the body
What percentages of total body weight and consumption of oxygen is the brain at birth?
2-2.5% of body weight, uses 20% of the oxygen of the body
What percentages of total body weight and consumption of oxygen is the adult brain?
Neuroblasts, ependymal cells, and glioblasts
What three cells do neuroepithelial cells give rise to?
Astrocytes and oligodendrocytes
What does the glioblast divide into?
Yes
Can glioblasts undergo mitosis?
5-10x as many
How many glioblasts (and their derivatives) are there compared to neurons?
Astrocytes
What are the most numerous cell in the adult central nervous system?
Protoplasmic astrocytes
What type of astrocyte is found in gray matter?
Fibrous astrocyte
What type of astrocyte is found in white matter?
Astrocytes
What are necessary for the function of the blood brain barrier? (BBB)
Astrocytes
What cell forms scar like tissue in CNS injuries?
Glutamate, dopamine, and serotonin
What neurotransmitters may be directly affected by astrocytes?
Perineuronal oligodendrocytes
What type of oligodendrocyte is found in the gray matter?
Interfasicular Oligodendrocytes
What type of oligodendrocyte is found in the white matter?
Interfasicular Oligodendrocyte
What forms the myelin covering in CNS neurons
Ependymal Cells
What cells line the central canal and the ventricles of the CNS?
Ependymal cells
What cells secrete CSF and form coroid plexus?
Tanycytes
Ependymal cells have specialized cells in the 3rd ventricle that transport CSF from the 3rd ventricle to the hypophyseal portal system. What are these cells called?
Astrocytoma
What is the most common type of tumor regarding glial cells?
Gliobastoma
What is the most lethal tumor regarding glial tumors?
Ependymoma
What type of glial tumor is said to be "restrictive"?
Mesoderm
Where does the microglia derive from?
Microglia
What cell has a phagocytic function, which involves clearing dead tissue?
Microglia
What cell mediate immune responses in the CNS?
Radiation and alcohol
Exposure to what may cause over/undershooting of designated targets during critical embryonic stages?
Unipolar
What type of neuron is found in sensory neurons or ganglia?
Bipolar
What type of neuron is found in special sensory pathways (taste, smell, sight, hearing)
Multipolar
What is the most abundant type of neuron?
Long
Do golgi type I neurons have long or short axons?
Short
Do golgi type II neurons have long or short axons?
Golgi Type II
What is the most common type of multipolar neuron?
Internuncial
If a neuron is entirely within the CNS it is said to be what type of neuron?
Commissural
What type of internuncial neuron connects equivalent structures of the CNS?
Ipsilateral projection
What type of internuncial neuron starts at one structure and ends at another structure, but on the same side of the midline?
Contralateral Projection
What type of internuncial neuron starts at one structure and ends at another structure on opposite sides of the midline?
Intrasegmental
What type of internuncial neuron starts at one cord level and ends at the same cord level?
Intersegmental
What type of internuncial neuron starts at one cord level and ends at a different cord level?
Neuropodia
What part of the neuron is the neurotransmitter released?
Telodendria
What part of the neuron is the term for axon terminals?
Axon Hillock
Where is the action potential initiated in a neuron?
Axodendritic
What type of synapse is most common in the CNS?
Nissl Bodies
What are clumps of rough E.R. in the CNS?
Tigroid bodies
What is another name for nissl bodies?
Axon or axon hillock
Where do nissl bodies not appear?
Retrispersion of the golgi apparatus
What is chromatolysis of the nissl bodies often confused with?
20-30 nm in diameter
How big are microtubules?
3-5 nm in diameter
How big are microfilaments?
9-10nm in diameter
How big are neurofilaments?
Slow transport
What type of transport doesn't require energy, but moves large molecules like protein?
Anterograde
What direction(s) can slow transport move?
Fast transport
What type of transport requires energy and moves small items like lysosomes and enzymes?
Anterograde or retrograde
What direction(s) can fast transport move?
Unmyelinated
Will a fiber less than one micron in diameter be myelinated or unmyelinated?
Sometimes myelinated
What happens if a fiber is 1-2 microns in diameter?
Always myelinated
Will a fiber greater than 2 microns be myelinated?
Fiber diameter and myelination
What two things determine conduction velocity?
Yes
Will every fiber in the PNS have a schwann cell covering?
No
Will every fiber in the PNS be myelinated? (Remember the diameter rule)
Node of Ranvier
What is the small space between schwann cells?
Endoneurium
What layer of connective tissue on a nerve is highly vascular, but covers the smallest portions of the nerve?
Perineurium
What layer of connective tissue on a nerve is fairly elastic and is continuous with the pia mater?
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