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Flashcards in Board 5 Deck (16)
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1
Q

List the reasons why invertebrate nervous systems are commonly studied?

A

Survive well in isolation
Are composed of relatively few neurons
Contain neurons that are large and easily studied with electrical recording methods and biochemical techniques
Contain cells which can be identified from animal to animal, some of which have a known function
Produce relatively simple behaviours that can be analysed at the cellular level
Regenerate easily
Provide much information on nervous system development

2
Q

What is meant by the term ganglion?

A

Collection of nerve cell bodies

3
Q

What is the major advantage of studying isolated cells grown in culture?

A

Elaborate sprouting growth cones

4
Q

What is meant by the term iontophoresis?

A

Applying electrical current of the same polarity as the charged dye and hence expelling it

5
Q

What is the body and the nervous system of the leech?

A

Segmental and consist of a number of repeating units (segments) that are similar for each leech

6
Q

What is in each segment?

A

Ganglion (collection of nerve cell bodies)

7
Q

What does each ganglion contain?

A

Around 400 nerve cells with distinctive shapes, sizes positions and branching patterns

8
Q

What type of cells are in each ganglion?

A

T-cells (touch)
N-cells (nocipetion- pain)
P-cells (pressure)
R-cells (retrius cells- involved in swimming behaviour and release serotonin)

9
Q

What is a leech cell cultured with?

A

Mixture of isotonic saline containing a mixture of amino acids and serum which contains growth factors and many nutrients

10
Q

What happens to a cultured leech cell provided with a suitable protein substrate?

A

Cut end of cell produces process produces an elaborate sprouting of growth cones, the name given to the actively growing tip of the cell process

11
Q

What does the arborisation of a neuron provide?

A

A notion of how many connections a cell can accommodate and to how many sites it sends its own processes

12
Q

How can individual cells electrical recordings be made?

A

By injecting fluorescent dye, Lucifer Yellow or with the enzyme Horseradish Peroxidase (HRP).

13
Q

What does the method of recording individuals cells electrical recordings involve?

A

Insertion of a marker-filled microelectrode into cell

Marker expelled tip either by iontophoresis or applying positive pressure at the back of the electrode

14
Q

How is Lucifer yellow visualised?

A

Using a fluorescence microscope

15
Q

How is HRP visualised?

A

Supplying an enzyme substrate that produces a colour change (black/brown)

16
Q

What is the HRP method particularly advantageous for?

A

That the reaction product is electron dense and can be visualised in fine sections in the electron microscope, making it possible to study the synaptic connections of the neuron