Cell Types in the Nervous System

Question 1

How many neurons are there in the human brain?

Answer 1

10^10 - 10^12

Question 2

How many non-neuronal cells are there in the human brain?

Answer 2

> 10^11

Question 3

What are other names for glia?

Answer 3

Glial cell

Neuroglia

Question 4

What are glia?

Answer 4

Non-excitable support cells

Question 5

What types of neurons are there?

Answer 5

Unipolar 
Bipolar 
Multipolar 
Long axons (Golgi type 1)
Short axons (Golgi type 2)
No axons

Question 6

What is an example of a unipolar neuron?

Answer 6

Dorsal root ganglion

Question 7

What is an example of a bipolar neuron?

Answer 7

Retinal bipolar cells

Question 8

What is an example of a multipolar neuron?

Answer 8

Motor neuron
Purkinje cell
Cerebellar granule cell
Pyramidal cells

Question 9

What is the general structure of a neuron?

Answer 9

Dendrite 
Cell body 
Axon 
Node of Ranvier 
Synaptic terminal 
Growth cone

Question 10

What is special about a olefactory granule cell?

Answer 10

Anaxonic (no axons)

Dendrodendritic synapses

Question 11

What are the main types of glial cell?

Answer 11

Macroglia
Microglia
Ependyma

Question 12

Examples of macroglia

Answer 12

Astrocytes
Oligodendrocytes
Schwann cells

Question 13

What is an astrocyte?

Answer 13

Star shaped
Multiple, long processes
Forms the glia limitans

Question 14

What do astrocytes enwrap?

Answer 14

Blood vessels
Processes
Synapses

Question 15

What are the types of astrocytes?

Answer 15

Fibrous

Protoplasmic

Question 16

What is a fibrous astrocyte?

Answer 16

White matter

Many intermediate filaments

Question 17

What is a protoplasmic astrocyte?

Answer 17

Grey matter
Shorter, stouter processes
Fewer intermediate filaments

Question 18

Examples of specialised astrocytes

Answer 18

Retinal Muller cells

Radial glia

Question 19

What is a retinal Muller cell?

Answer 19

Span the width of the retina

Columnar cell

Question 20

What is a radial glial cell?

Answer 20

Span from pia to Purkinje cell layer

Stem cells adult/developing brain

Question 21

Astrocytes role in spatial buffering

Answer 21

Active neurons release K+
Astrocytes are very K+ permeable and are a functional syncytium
Astrocytes span from synapse to blood vessel
Spatial buffering regulates [K+]o

Question 22

Muller cells in the retina?

Answer 22

Photoreceptors release K+
Muller cells take up K+
K+ reduced near the photoreceptors

Question 23

Astrocyte role in transmitter uptake

Answer 23

Uptake is an important inactivation mechanism
Glutamate into astrocytes, GABA
Glutamate converted into glutamine
Recycling to neurons

Question 24

Astrocyte role in glucose metabolism

Answer 24

Glucose = main energy substrate
Neurons prefer 3-carbon
Astrocytes store most glycogen
Astrocytes span blood

Question 25

What are the processes on microglia like?

Answer 25

Short and spiky

Question 26

Where are microglia derived from?

Answer 26

Circulating monocytes

Question 27

Where are ependyma found?

Answer 27

In the epithelial lining of ventricles and spinal canal

Question 28

What are the types of ependyma?

Answer 28

Ependymocytes Tanycytes Choroid epithelial cells