Neurons and Glia

Question 1

What are dendrites?

Answer 1

→ Long thin extensions making a dendritic tree

→ they are the receptive surface of the nerve cell (synaptic inputs)

Question 2

What is the dimensions of a slice for a light microscope?

Answer 2

→ 50micron

Question 3

What does a microtome slice use?

Answer 3

→ slice embedded in wax

Question 4

What is the disadvantage of a microtome slice?

Answer 4

→ The wax interferes with staining chemicals

Question 5

What is a cryostat?

Answer 5

→ A frozen version of a microtome

Question 6

How can you make the brain transparent?

Answer 6

→ Treating the tissue with solvents renders it transparent because it removes the myelin

Question 7

What does the Nissl stain stain?

Answer 7

→ stains RNA

→ but only in nerve cell bodies

Question 8

What does the Golgi method use?

Answer 8

→ Silver chromate creates a dense black stain

Question 9

What is the disadvantage of the Golgi method?

Answer 9

→ It only labels 1-2% of cells

Question 10

What is a multipolar nerve cell?

Answer 10

→ Many dendrites coming off from the cell body

Question 11

What is a pyramidal nerve cell?

Answer 11

→ dendrites form a triangular shape

Question 12

What is a spiny nerve cell?

Answer 12

→ Some dendrites have spines

Question 13

What is a pseudounipolar dendrite?

Answer 13

→ Sensory cell

Question 14

What is a bipolar dendrite?

Answer 14

→ two dendritic ends

Question 15

Describe how you visualise the axon?

Answer 15

→ Intracellular injection of biocytin with a very small pipette
→ Set of antibodies against the tracer
→ Antibodies against the tracer antibodies

Question 16

What does horseradish peroxidase do?

Answer 16

→ Linked to an enzyme that deposits a black insoluble substance around the antibodies

Question 17

What is an advantage of the antibody method?

Answer 17

→ Can see multiple features within the cell

→ Can record the electrical activity using the same electrode pipette

Question 18

What is a disadvantage of the antibody method?

Answer 18

→ Intracellular injections will not give long-range connections

Question 19

How can long range connections be seen?

Answer 19

→ Small extracellular injections of tracer are taken up and transported by the axons

Question 20

What is retrograde transport?

Answer 20

→ Transporting back to where the axons came from

Question 21

What is used to find out where axons synapse?

Answer 21

→ electron microscope

Question 22

What is the magnification and resolution of an electron microscope?

Answer 22

→ > 100,000 magnification

→ <0.5nm resolution

Question 23

Where are excitatory synapses found?

Answer 23

→ On the end of dendritic spines

Question 24

What is the function of kinesin?

Answer 24

→ kinesin moves anterogradely and retrogradely within the axon carrying structural proteins that are being made in the cell body

Question 25

What do microtubules carry away from the cell body?

Answer 25

→ Structural proteins
→ Neurotransmitter associated proteins
→ Organelles
→ they are the motorways that kinesin travels down

Question 26

What do microtubules carry towards the cell body?

Answer 26

→ Signaling proteins

→ Debris and used materials

Question 27

What is the function of actin microfilaments?

Answer 27

→ Provide support
→ help to maintain the shape of cell body and neurites
→ play a vital role in neural embryonic growth and help shape axons and dendrites

Question 28

How are actin microfilaments involved in memory formation?

Answer 28

→ change the shape of the dendritic spines hence the growth of synapses during memory formation

Question 29

What does the actin skeleton do?

Answer 29

→ Actin skeletons within the filopodia grow or shrink in response to chemical signals

Question 30

What is the function of tau protein?

Answer 30

→ proteins that bind together cytoskeletal elements

Question 31

What disease is tau protein found in?

Answer 31

→ Alzheimers

Question 32

What are the three ways mice brains can be genetically engineered to express tracer protein?

Answer 32

→ Cells that use a specific neurotransmitter
→ Cells of a specific type
→ Cells that make a specific type of connection

Question 33

Why can GFP be expressed in all animals?

Answer 33

→ Genetic code is degenerate

Question 34

What are the 6 functions of astrocytes?

Answer 34

→ They control the movement of materials into and out of tissue
→ Flush waste products from the brain
→ Remove used neurotransmitter from fast synapses
→ control synaptic development and function
→ control electrolyte level in the extracellular space
→ Manufacture/break down substances on behalf of neurons

Question 35

How is the blood brain barrier formed?

Answer 35

→ Astrocytes make contact with capillaries which induces them to form the blood brain barrier

Question 36

What do astrocytes look like?

Answer 36

→ A blanket around nerve cells

Question 37

How do astrocytes link together?

Answer 37

→ In chain gangs that transport material to and from neurons

Question 38

What are the two types of myelinating glia?

Answer 38

→ Neurolemmocytes (Schwann cells)

→ Oligodendrocytes

Question 39

What is the difference between Schwann cells and oligodendrocytes?

Answer 39

→ Schwann cells myelinate a single axon in a peripheral nerve
→ Oligodendrocytes myelinate multiple axons in the CNS

Question 40

What disease arises when myelinating glia are damaged?

Answer 40

→ Parkinsons

Question 41

What are microglia?

Answer 41

→ Immune cells that migrate into the CNS very early in development

Question 42

Why are microglia not considered glia?

Answer 42

→ they do not arise from the neural tube like other glial cells

Question 43

What are the 4 functions of microglia?

Answer 43

→ help the direct development of neurons and constantly monitor their health
→ become ameboid and travel to areas of injury/infection
→ engulf and eliminate microbes, damaged cells and other particulate matter
→ Secrete factors essential for recovery and repair