Introduction to Nervous System Flashcards
(28 cards)
Name of cell body of Neuron
Perikaryon
Compare the synaptic contacts of the perikaryon and dendrites vs the axon
The perikaryon and dendrites have hundreds to thousands of dendritic contacts while axons have few or none
Glial Cells
These cells are the helper cells of the nervous system and are necessary for a neuron to survive
They cover the parts of a neuron that is not covered by synapses
What covers the neuronal cell surface between synaptic contacts
Glial Cells (You never walk alone principle)
Thus there is no neuronal surface exposed to extracellular matrix fluid
Why are mitochondria found on pre-synaptic clefts
Providing ATP necessary for vesicle recycling and transmitter synthesis
Type of conduction caused by myelin sheaths
Saltatory Conduction
Describe the structure of Myelin Sheaths
Tightly spiralled, very thin layers of Schwann cells
Describe the shape of a Multipolar, Bipolar and Pseudo-Unipolar Neuron
What nerves are contained in the CNS and which in the PNS
Central Nervous System includes brain and spinal cord - nerve cell bodies and voluntary nervous system
Peripheral NS includes axons and dendrites travelling through the rest of the body
Discuss the casing of CNS nerves
CNS is encased by a minimally permeable, multi-layered tough connective tissue sheet
The meninges (membranes) lie inside a bone casing; fluid inside meninges is called CSF which has a different composition to interstitial fluid of the rest of the body
Grey Matter vs White Matter
White Matter: Areas with mostly dendrites/axons due to the high lipid proportion of myelin sheaths
Grey Matter: Areas with many cell bodies have more blood supply and mitochondria
What type of neurons are sensory neurons and why
Pseudo-unipolar Neurons
To allow dendrite and axon as uninterrupted strand for maximal speed of transduction
What type of neurons are sensory neurons and why
Pseudo-unipolar Neurons
To allow dendrite and axon as uninterrupted strand for maximal speed of transduction
Shape of Motor Neuron
Shape of Classic textbook neuron - Multipolar
Where is the perikaryon of a sensory neuron located
Spinal Ganglion - Just outside the border between CNS and PNS (In PNS) while some of its axons are in CNS
In reflex arcs, describe the distribution of motor neurons
Perikaryon of motor neuron is in CNS along with dendrites but most of the axon is in PNS
How do nerves tend to run when in between muscles
Grooves (Septa) for protection
Separating spaces between muscles
Annotate this cross section of a peripheral nerve
Epineurium
Collagenous connective tissue (Dense)
Lining of Nerve
Perineurium
Sheath with flat cells of epithelial character with collagen fibres between them; it bundles axons into fascicle and forms a seal
Lining of individual fascicles
Endoneurium
Loose connective tissue between axons/dendrites in a fasicle; adapted for maintaining the fascicle
Fascicle
Bundles of nerves/axons/dendrites
How do non-myelinated axons adhere to the never walk alone principle
Being hugged by Schwann cells but not wrapped in dozens of layers that would otherwise create myelin
How to differentiate between blood vessels and nerves in a stain
Larger blood vessels may have an RBC in them and a thick outline generally
Nerves tend to be wavy with elongated nuclei
Often reddish rings with whitish content when cross sections
