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 is an advantage of the antibody method?

Answer 16

→ Can see multiple features within the cell

→ Can record the electrical activity using the same electrode pipette

Question 17

What is a disadvantage of the antibody method?

Answer 17

→ Intracellular injections will not give long-range connections

Question 18

How can long range connections be seen?

Answer 18

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

Question 19

What is retrograde transport?

Answer 19

→ Transporting back to where the axons came from

Question 20

Where are excitatory synapses found?

Answer 20

→ On the end of dendritic spines

Question 21

What do microtubules carry away from the cell body?

Answer 21

→ Structural proteins
→ Neurotransmitter associated proteins

→ Organelles
→ they are the motorways that kinesin travels down

Question 22

What do microtubules carry towards the cell body?

Answer 22

→ Signaling proteins

→ Debris and used materials

Question 23

What is the function of actin microfilaments?

Answer 23

→ 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 24

How are actin microfilaments involved in memory formation?

Answer 24

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

Question 25

What does the actin skeleton do?

Answer 25

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

Question 26

What is the function of tau protein?

Answer 26

→ proteins that bind together cytoskeletal elements

Question 27

What disease is tau protein found in?

Answer 27

Alzheimers

Question 28

What are the 6 functions of astrocytes?

Answer 28

→ 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 29

How is the blood brain barrier formed?

Answer 29

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

Question 30

What do astrocytes look like?

Answer 30

→ A blanket around nerve cells

Question 31

How do astrocytes link together?

Answer 31

→ In chain gangs that transport material to and from neurons

Question 32

What are the two types of myelinating glia?

Answer 32

→ Neurolemmocytes (Schwann cells) | → Oligodendrocytes

Question 33

What is the difference between Schwann cells and oligodendrocytes?

Answer 33

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

Question 34

What disease arises when myelinating glia are damaged?

Answer 34

→ Parkinsons

Question 35

What are microglia?

Answer 35

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

Question 36

Why are microglia not considered glia?

Answer 36

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

Question 37

What are the 4 functions of microglia?

Answer 37

→ help the direct development of neurons and constantly monitor their health → become ameboid and travel to areas of injury/infection- microglia contract their processes going from a ramified shape into an ameboid structure → engulf and eliminate microbes, damaged cells and other particulate matter → Secrete factors essential for recovery and repair

Question 38

What are the four types of glial cells?

Answer 38

→astrocytes →microglia →ependymal →oligodendrocytes/Schwann

Question 39

What are ependymal cells?

Answer 39

provide the lining of the ventricular system of both the brain and spinal cord.

Question 40

What are the functions of the ependymal cells?

Answer 40

→Osmotic regulation of cerebrospinal fluid →Flow of cerebrospinal fluid →Directing cell migration during brain development →act as a physical barrier separating brain tissue from cerebrospinal fluid (CSF)

Question 41

What do deficits in ependymal cell function link with?

Answer 41

→severe neurological condition hydrocephalus

Question 42

What is brainbow mice?

Answer 42

→Fluorescence microscopy and genetic manipulation techniques (e.g. Cre-Lox) allow us to see brain regions and individual neurons/glial cells in breath-taking detail

Question 43

What does a prototypical neuron look like?

Answer 43

→cell body →axon →dendrites

Question 44

What are neurofilaments?

Answer 44

→A type of intermediate filament – particularly abundant in axons and important in regulating axonal shape

Question 45

What are axons composed of?

Answer 45

→Axon hillock →axon proper →axon terminal

Question 46

What is the axon hillock?

Answer 46

→tapers away from the soma to form the initial segment of the axon

Question 47

What is the axon proper?

Answer 47

axon can branch to form axon collaterals (and recurrent collaterals)

Question 48

What is the axon terminal?

Answer 48

→site at which the axon comes into contact with other neurons at a synapse

Question 49

How do the cytoplasm of the axon proper and terminal differ?

Answer 49

→microtubules in proper do not extend to terminal →terminal contains a pool of synaptic vesicles for neuron to neuron contact. → higher levels of mitochondria in terminal

Question 50

What are the two types of dendritic spines?

Answer 50

→pyramidal | →stellate

Question 51

What are the three types of neurones according to the connections they make?

Answer 51

→sensory →interneuron →motor neuron

Question 52

What are the two types of axon length?

Answer 52

→Golgi type I- extend to other regions | →Golgi type II- localised

Question 53

What are the 6 types of neurotransmitters in neurons?

Answer 53

``` →acetylcholine →GABA →glutamate →dopamine →serotonin →noradrenaline ```