Question | Answer |
Naming convention for neurons | Function (sensory, motor, inter)
Location (cortex, striatum, retina)
Shape (pyramidal, bipolar) |
Basic neuron shapes | -bipolar (interneuron)
-unipolar (sensory)
-multipolar (motor)
-pyramidal (brain) |
What is the most common cell type in brain? What is the 2nd most common cell type in the brain? | -Neurons
-Glial Cells |
What are the glial cells in the CNS? | -oligodendrocytes
-astrocytes
-microglia |
What are the glial cells in the PNS? | -Schwann cells
-Satellite cells |
What is bigger, neuron or glial cell? | Neuron |
What's the big difference between CNS and PNS slides? | CNS doesn't have connective tissue |
What is the perikaryon? | Cytoplasm of soma in neuron |
What is the axon hillock? | Beginning of electric impulse of neuron |
What is the nucleolus composed of? | Nucleic acids and proteins
It's responsible for the transcription and assembly of ribosomal RNA. |
What is the node or Ranvier? | myelin sheath gap |
What does the Nissyl stain do? | Stains cell body, mainly the rough ER because it stains RNA.
Stains dark blue.
Stains both neurons and glia. |
Weigert Myelin Stain | readily distinguishes grey matter from white matter which is stained black. |
Gogli-type Stain | stains an entire cell but usually a small fraction of cell, this is random and unknown
-silver staining
-dendrite, axon, and cell body stained |
What are the cellular components of a Peripheral Nerve? | -neurons
-Schwann cells
-fibroblasts
-endothelial cells
-blood-borne cells |
What are the connective tissue components of a Peripheral Nerve? What do they represent? | -Epineurium: Outer edge of spinal nerve
-Perioneurium: Outer edge of fascicle
-Endoneurium: around axon
-Fasicle: bundle of axons |
What does myelin do? | Makes conduction effective and efficient, thick and viscous protein. |
How many axons can a Schwann cell myelinate? | One axon |
Saltatory conduction | when nerve impulses jump from node to node, enabled by Nodes or Ranvier which speeds it up |
What is clinically relevant about multiple scerosis? | They have less myelin. |
In the PNS, what cells are myelinated? | -Somatic motor axons
-Pre ganglionic axons of autonomic nerves
-Some sensory axons like touch, pressure, muscle length, and joint position |
In the PNS, what cells are not myelinated? | -axons of post-ganglionic neurons of the autonomic nervous system
-olfactory nerves
-Some sensory nerves like pain and temperature |
Ganglia formal definition | a collection of neuron cell bodies located outside the central nervous system |
What are examples of sensory ganglia? What are examples of autonomic ganglia? | Sensory: DRG, Cranial Nerves
Autonomic: Sympathetic, Prevertebral, Paravertebral, Intramural |
What are the contents of ganglia? | -Neurons
-Satellite cells
Fibroblasts and Connective tissue
-Blood vessels |
How do you distinguish DRG (sensory ganglia) in slides? | Densely packed and very organized |
How to distinguish Sympathetic neuron cell bodies? | -often more widely dispersed, with a meshwork of nerve fibers lying between them.
-nerve fibers generally are not as well organized |
What are the sensory endings of the PNS? | 1. Free nerve endings (temperature and pain)
2. Meissner's corpuscles (touch)
3. Pacinian corpuscles (pressure) |
What makes up the CNS? | Brain, brain stem, spinal chord, gray (switch) and white (wire) matter. |
What is gray matter? | Cell bodies |
What is white matter? | Axons |
What are the three types of glial cells in the CNS? What do they do? | Astrocytes - "glue" that provide nutrients to blood stream
Oligodendrocytes - myleninate
Microglia - macrophages of CNS |
New level of Astrocytes | -regulate the level of "firing" of neurons
- release transmitters
-release trophic factors which modify processing info
-regulate neuronal death |
What do oligodendrocytes do? | Myelinate cells in the CNS, can myelinate several axons |
What do microglia do? Where are they derived? | -Recruit t cells to site.
-Important in tissue degradation and repair, and homeostasis
-derived from bone marrow |