Histology - ANS and PNS Flashcards


What parts of the neuron receive the excitatory and inhibitory signals?
Soma and dendrites
If cell body receives enough excitatory signals, it will approach threshold.
True/False
True
Where on a neuron are the highest density of Na+ channels?
Nodes of ranvier
What is the ion channel profile like at the axon hillock?
Transitioning from ligand gated / GPCR to voltage gated Na+ and K+
In […] syndrome, anitbodies against schwann cells are produced which causes the schwann cells to be opsonized by the host’s own immune system and the result is unmyelinated neurons.
Guillain-Barré syndrome


What are nissl bodies?
Rough endoplasmic reticulum with a rosette of ribosomes




When referring to a multipolar, unipolar, or bipolar neuron, what is the “polar” portion?
The number of sensory poles


What is the difference between a schwann cell and an oligodendrocyte?
Schwann cells myelinate only 1 portion of 1 axon in PNS
Oligodendrocytes can myelinate multiple portions of the same axon or multiple portions of different axons in CNS
[…] myelinate axons in PNS
Schwann cells
[…] myelinate cells in CNS
Oligodendrocytes


Describe the process of myelin sheath forming in the PNS.
The schwann cells wraps itself around the axon multiple times folding its cytoplasm over itself for many turns







What is this structure and how do you know?

Dorsal root ganglia –> indicated by central nucleus that has an “owl’s eye” appearance


The myelinated axons are located in the […] matter
White
The cell bodies and dendrites are located in the […] matter
Grey
The […] carries efferent signals away from the spinal cord
Ventral nerve
The […] is the site in the spinal cord where efferent signals are generated.
Ventral horn

The […] carries signals from the body to the spinal cord.
Dorsal nerve
Sensory signals from the body terminate at the […] in the spinal cord
Dorsal horn

Where are the alpha motor neurons of the spinal cord located? What is unique about these neurons?
Ventral horn
They are the largest cells in the CNS


Are unmyelinated cells truly unmyelinated?
No - they are loosely myelinated. They possess a single concentric layer of myelin around the axon.
- Unmyelinated cells are also called […]
- They transmit […] signals
- Their conduction speed is […]
- Their diameter is […]
- C-fibers
- Pain
- Slow
- Small
Neurons with their cell bodies in the brain that are part of the corticospinal tract have their synapse in the […] of the spinal cord.
Ventral horn

What is the structure that is boxed? What are they?

Schmidt - Lanternman Incisures
These arise from a build up of cytoplasm when the schwann cell is wrapping itself around the axon
What is the boxed structure and what does it contain?


Can you tell the difference between sympathetic and parasympathetic nerves on a histology slide?
No
In the sympathetic nervous system, the preganglionic nerves originate in the […] and they are […] in length. They synapse on postganglionic nerves that are located […] the spine and are […] in length.
- Thoracic and lumbar division of the spinal cord
- Short
- Near
- Long
In the parasympathetic nervous system, the preganglionic nerves originate in the […] and they are […] in length. They synapse on postganglionic nerves that are located […] and are […] in length.
- Brain (they are cranial nerves) and sacral spinal nerves
- Long
- near the tissues they innervate
- Short
What are the vertebral column levels that correspond to sympathetic preganglionic nerves?
T1 - L2
What are the parasympathetic cranial nerves?
3, 7, 9, 10
What regions of the sacral spine contain parasympathetic preganglionic nervs?
S2 - S4
What is the general role of the sympathetic NS?
Fight or flight
What is the general role of the parasympathetic NS?
Rest and digest
All […] nerves are myelinated.
All […] nerves are unmyelinated.
Preganglionic
Postganglionic
What are chromaffin cells?
Cells that are located in the adrenal medulla that produce epinephrine and norepinephrine and release them into the blood vessels






Label these structures.

Green = epineurium
Blue = perineurium

Blue = perineurium
Green = epineurium