Histology of the CNS

Question 1

What are dendritic spines?

Answer 1

Extensions of neuronal plasma membrane to increase receptive area on a neuron

Question 2

What is a neuropil?

Answer 2

Dense network of nerve fibers and their branches and synapses, together with glial filaments

Question 3

What type of proteins are involved in an electrical synapse?

Answer 3

Connexon proteins link pre-synaptic and post-synaptic membranes making gap junctions for ions to transfer between cells

Question 4

What are astrocytes?

Answer 4

Supportive cells with numerous processes that wrap around blood vessels in the brain to make the BBB. They also reuptake NTs and regulate ion concentration in the immediate environment

Question 5

What are oligodendrocytes?

Answer 5

Create myelin in the CNS, wrap around many different axons (vs Schwann cells in PNS only wrap around one axon)

Question 6

What are ependymal cells?

Answer 6

Line the brain ventricles and the central canal of the spinal cord to facilitate movement of CSF and help with absorption

Question 7

Histologically, what do ependymal cells look like?

Answer 7

Low columnar or cuboidal, may have cilia and long microvili

Question 8

What is the choroid plexus made of?

Answer 8

Ependymal cells + vasculature from the pia

Question 9

Where is the choroid plexus found?

Answer 9

Roofs of 3rd and 4th ventricles and parts of lateral ventricular walls

Question 10

How does the choroid plexus work?

Answer 10

Removes fluid from blood and releases it as CSF

Question 11

What is the blood-CSF barrier?

Answer 11

Made by tight junctions between epithelial cells of the choroid plexus

Question 12

What are microglia?

Answer 12

Derived from monocyte progenitors, macrophages of CNS. Migrate around to pick up damaged gray and white matter as well as microbes

Question 13

What are the three layers of the cerebellar cortex?

Answer 13

Molecular layer (outer), Purkinje cells, and granular layer (inner)

Question 14

What are the five types of cells found in the neocortex of the cerebral cortex?

Answer 14

Pyramidal cells, granule (stellate) cells, cells of Martinotti, fusiform cells, and horizontal cells of Cajal

Question 15

What are the 6 cortical layers of the cerebrum?

Answer 15

Molecular layer (outer)
External granular layer
External pyramidal layer
Inner granular layer
Ganglionic layer
Multiform (polymorphic) layer

Question 16

What lobes are involved with Alzheimer’s disease?

Answer 16

Thinning is seen in the gyri of the frontal and temporal lobes

Question 17

What brain abnormalities are associated with Alzheimer’s disease?

Answer 17

Amyloid plaques and neurofibrillary tangles

Question 18

What is the substantia nigra?

Answer 18

Important in fine control of motor function. Neurons contain granules of neuromelanin pigment which contains dopamine

Question 19

What can happen with degeneration of neurons in the substantia nigra?

Answer 19

Parkinson’s disease (loss of dopamine)