MA - Neurohistology Flashcards
Where are signals from the cell soma summated?
At the axon hillock
Why is the hillock considered the trigger zone?
Must reach the threshold potential to achieve an action potential
What are MAP2 proteins and where are they found?
- Neuron-specific cytoskeletal proteins
- Found in dendrites
(microtubule-associated protein)
What are βIV spectrin proteins and where are they found?
- Cytoskeletal protein
- Found in axons as well as some non-neuronal cells
How can you see multipolar neurons?
GOLGI STAIN
(Potassium dichromate and silver nitrate results in silver precipitation)
What are the 3 neuronal subtypes and what do they do?
Motor neurons relay commands from brain and spinal cord to muscles and glands
Sensory neurons are excited by specific stimuli
Interneurons integrate information from sensory to motor neurons
Where are cell bodies of multipolar motor neurons found?
In the ventral horn of the spinal cord
What are Nissl bodies?
Subcellular structures found in nerve cell bodies and DENDRITES of motor neurons
- Consist of granular RER and RIBOSOMES
- Important in protein synthesis
What are Ganglia?
Dorsal root ganglia vs Individual ganglion cells
Ganglia are aggregations of nerve cells (ganglion cells) outside the CNS
- Dorsal root ganglia are surrounded by a connective tissue capsule, which is continuous with the peripheral nerve
- Individual ganglion cells are surrounded by a layer of flattened satellite (fibroblast) cells
How many layers are present in the cerebral cortex?
6 layers
What 3 layers are found in the cytoarchitecture of the cerebellar cortex?
- outer Molecular layer
- a single layer of Purkinje cells (largest cell)
- a Granular layer (smallest cell)
What types of cells are present in the CNS and PNS?
- In the CNS there are astrocytes, oligodendroglia, ependymal cells and microglia
- In the PNS there are Schwann cells and satellite cells
What is the function of astrocytes? And the 4 types
Provide structural and metabolic support for neurons
Types
- Fibrous (white matter)
- Protoplasmic (gray matter)
- Muller glia (retina)
- Radial Glia (specialised cells in developing CNS)
What is the function of the blood-brain barrier? (4)
Form glial-limiting membrane around blood vessels and along CNS surface
Prevents diffusion of solutes and fluid into brain and spinal cord
A barrier composed of endothelial cells joined by tight junctions
Integrity highly dependent on astrocyte ‘end feet’
What is the function of microglial cells? (3)
Serve an immune function within the CNS (able to phagocytose cell debris in response to injury)
Release cytokines which can both help and hinder recovery
Become activated upon damage
