Cells of the Nervous System

Question 1

What parts of the body are in the Central Nervous System (CNS)?

Answer 1

The brain and the spinal cord

Question 2

What region refers to the Peripheral Nervous System (PNS)?

Answer 2

This system makes up all of the nerves which extend from the spinal cord.

Question 3

What are the three primary functions of neurons?

Answer 3

· Receive information
· Conduct information
· Transmit information

Question 4

How many types of neurons are there?

Answer 4

There are more than 10,000 types of this cell.

Question 5

The electrical signals exchanged between nueral cells refer to the passage of what particle group?

Answer 5

Ions are used for this method of communication!

Question 6

What are the three functional regions of a “typical” neuron?

Answer 6

Input (receiving)

Conducting

Output

Question 7

What structures are found within the input region of a typical neuron?

Answer 7

This region of the neuron contains pre-synaptic fibers, dendrites, the cell body, and the nucleus.

Question 8

What structures are found within the ‘conducting’ region of a typical neuron?

Answer 8

Axons (nerve fibers), myelin and Nodes of Ranvier make up this region of the typical neuron.

Question 9

What structures are found within the ‘output’ region of a typical neuron?

Answer 9

This region of the typical neuron contains synaptic boutons and terminal branches.

Question 10

What is the Nissl Substance of a neural cell?

Answer 10

These intracellular structures are unique to neural cells; granular bodies made of polyribosomes and an expanded rER

Question 11

Why are neurons known the have large nucleoluses?

Answer 11

Neurons are largely secretory cells, undergoing very frequent transcription, therefore they have large…

Question 12

What two cellular structures can be found at the base of dendrites?

Answer 12

The rER and sER can be found at the base of these neural structures

Question 13

What cellular organelles can be found within dendrites?

Answer 13

Mitochondria, free ribosomes, microtubules and microfilaments are found in this cellular structure

Question 14

What is another word used to refer to the cell body?

Answer 14

Soma is another term used to refer to the…

Question 15

What are dendritic spines and what purpose do they serve?

Answer 15

Dendritic spines are tiny, numbered protrusions from dendrite branches which each facilitate a unique synaptic connection with the cell it interacts with

Question 16

What two features can dendritic spines be indicative of?

Answer 16

These structural features can be indicative of the frequency of a neuron’s input activity and of the presence/absence of neural disease

Question 17

What are the 4 parts which make up an axon?

Answer 17

1. Initial segment (axon hilock)
2. Axon process
3. Synaptic boutons
4. Growth cones (from synaptic boutons)

Question 18

What accomplishment is attributed to Ramon y Cajal?

Answer 18

This figure first used silver staining techniques to observe embryonic specimens

Question 19

Where can a growth cone be found on a neuron?

Answer 19

Growth cones can be found at the output end of the axon

Question 20

What are the 3 domains of a growth cone?

Answer 20

1. thin fan sshaped sheet at the tip (lamellipodia)
2. many thin spikes radiating forward (filopodia)
3. Peripheral domain
4. Transition domain
5. Central domain

Question 21

How do growth cones relate to synaptic boutons?

Answer 21

Once growth cones have reached the target cell, they differentiate into synaptic boutons

Question 22

What are filopodia on growth cones?

Answer 22

On growth cones, these are many thin spikes radiating forward

Question 23

What are lammellipodia on growth cones?

Answer 23

On growth cones, this is a thin fan shaped structure at their tip

Question 24

What is contained in the peripheral domain of a growth cone?

Answer 24

Lamellipodia and fillopodia

Question 25

What is contained in the Transition domain of growth cones?

Answer 25

This is the transition between the P and C domains

Question 26

What is contained in the Central domain of a growth cone?

Answer 26

A think region containing organelles and vesicles

Question 27

What are the three stages of axon growth?

Answer 27

1. Protrusion
2. Engorgement
3. Consolidation

Question 28

Briefly describe the first stage of axonal growth.

Answer 28

Protrusion; rapid extensions of
filopodia / thin lamellae containing
actin

Question 29

Briefly describe the second stage of axonal growth.

Answer 29

Engorgement: microtubules invade
protrusions bringing vesicles and
organelles

Question 30

Briefly describe the third stage of axonal growth.

Answer 30

Consolidation: actin depolymerises
in the neck of the growth cone,
membrane shrinks forming
cylindrical shaft

Question 31

What is the length of a spinal motorneuron?

Answer 31

This type of neuron is 1mm — incredibly long by cellular standards!

Question 32

What are the two types of signals which can activate a neural signalling pathway?

Answer 32

Chemical and physical signals

Question 33

What are three examples of chemical signals that activate neural signalling pathways?

Answer 33

1. Growth factors (e.g.: Nerve Growth Factor) secreted by cells
2. Substrates (e.g.: laminin-1, fibronectin)
3. Other cells using adhesion receptors (eg: integrins, cadherins)

Question 34

What are three examples of chemical signals that activate neural signalling pathways?

Answer 34

1. Tactile: if scratch surface, growth occurs along groove
2. Electrical
3. Photonic: light!

Question 35

Name 8 major neurotransmitter substances.

Answer 35

1. Acetylcholine (ACh)
2. Noradrenaline
3. Adrenaline
4. Dopamine
5. 5-Hydroxytryptamine
   (5-HT, serotonin)
6. Gamma- aminobutyric acid
   (GABA)
7. Glycine
8. Glutamic acid