Peripheral nerve, sympathetic ganglia, spinal ganglia- discussion, viva

Peripheral nerve:

1. What are the components of nervous tissue?
• The components of nerve tissue are neurons, nerve fibers and neuroglia
2. What are the parts of nervous tissue?
• Peripheral nervous tissue and central nervous tissue
3. What are the components of peripheral nerve tissue?
• Cranial nerves, peripheral nerves, sympathetic ganglia, spinal ganglia
4. Name the cells involved in myelination of peripheral nerve? 
• Schwann cells
5. What is node of Ranvier? What is its function
• Node of Ranvier is the gap present between two adjacent Schwann cells
• It helps the impulses to jump from one internode to another and helps in faster conduction of impulses
6. What are ganglia?
• Ganglia are the aggregations of cell bodies outside the central nervous system
7. What are the different types of neuroglia in peripheral nervous system?
• Schwann cells and satellite cells
8. What are the connective tissue layers covering the peripheral nerve?
• Epineurium: It is the strong dense irregular connective tissue sheath binding all the fascicles 
• Perineurium: It is a thin connective tissue surrounding the individual fascicle
• Endoneurium: It is the loose vascular connective tissue with reticular fibers surrounding the myelinated axon or cluster of unmyelinated axons
9. What is the constitution of the neurolemma sheath, Myelin sheath and Axis cylinder. What are the nerve fibrils
• Neurolemma sheath- the cytoplasm and nucleus of Schwann cell lying outside the myelin sheath
• Myelin sheath- the modified cell membrane of Schwann cell wrapped around the axon
• Axis cylinder- axon
• Nerve fibril- a delicate fibril found in the cell body and processes of a neuron
10. In what situation is the neurolemma sheath absent?
• Neurolemma sheath is absent in central nervous system
11. What is neuroglia? What are the cell types in it
• Neuroglia are the supporting cells present in the nervous system
• Cell types:
• CNS- ependyma, astrocytes, oligodendrocytes
• PNS- Schwann cells, satellite cells
12. What is axon hillock?
• Axon hillock is a special part present between the cell body and axon. It is devoid of nissl granules
13. Difference between thick and thin fiber in PNS
• Thick fiber- it is myelinated and helps in faster conduction of the impulses
• Thin fiber- it is unmyelinated and helps in slow and uniform conduction of impulses

Spinal / sensory ganglion:

1. Where is spinal ganglion situated?
• Spinal ganglion is situated on the dorsal root of spinal nerve, sensory ganglion of 5, 7, 9 and 10 cranial nerves
2. What are the other names for spinal ganglion?
• Dorsal root ganglion, sensory ganglion
3. What are the identifying features of spinal ganglion?
• Large, round pseudounipolar neurons of different sizes arranged peripherally in groups 
• Single nucleus placed in center of neuron
• Bundles of nerve fibers running between the groups of neurons
• More number of satellite cells surround the neurons
4. Give the examples for spinal ganglion
• Dorsal root ganglia of spinal nerves, sensory ganglia of cranial nerves 5, 7, 9, 10.
5. What are the functions of satellite cells?
• The satellite cells provide the structural and metabolic support to the neurons and insulate the neurons
6. What are pseudo ganglia?
• Localized thickening of the nerve trunk without cell bodies and having only nerve fibers
7. What are the differences between spinal and sympathetic ganglia?
• Refer the table below

 Sympathetic / autonomic ganglion:

1. Where is sympathetic ganglion situated?
• Sympathetic ganglion is situated along the sympathetic trunk and parasympathetic ganglia (ciliary, otic, pterygopalatine, submandibular)
2. What is the other name for sympathetic ganglion?
• Autonomic ganglion
3. What are the identifying features of sympathetic ganglion?
• Small, irregular shaped, uniform size, scattered multipolar neurons
• Nucleus placed eccentrically in the neuron
• Nerve fibers are irregularly arranged separating the neurons
• Few satellite cells arranged around the multipolar neurons
4. Give examples for sympathetic ganglion
• Sympathetic ganglia along sympathetic chain, otic ganglion, ciliary ganglion, submandibular ganglion and pterygopalatine ganglion
5. What are the functions of satellite cells?
• The satellite cells provide the structural and metabolic support to the neurons and insulate the neurons
6. What are the differences between the sympathetic and spinal ganglion?
• Refer the table below

Type	Spinal ganglia	Autonomic ganglia
Capsule	Thick.	Thin.
Neurons	Peripherally arranged, large and round pseudo-unipolar neurons.	Irreguarly arranged multipolar neurons appear star shaped and are of varying sizes in sections.
Nerve fibers	Bundles of nerve fibers separate the neurons. Regularly arranged fibers enter and leave the ganglion.	Axons and dendrites pass through the widely spaced neurons, without being involved in synapses. Irregularly scattered nerve fibers.
Satellite cells	A layer of small cuboidal cells envelopes the neurons.	Few satellite cells incompletely surround the cell body.
E.g.	Dorsal root ganglia of the spinal nerves, sensory ganglia of cranial nerves (V, VII, IX, X).	Sympathetic ganglia along sympathetic chain, Otic/ ciliary/ Submandibular/ pteryogopalatine ganglia.