Cells of the Nervous System Flashcards
What parts of the body are in the Central Nervous System (CNS)?
The brain and the spinal cord
What region refers to the Peripheral Nervous System (PNS)?
This system makes up all of the nerves which extend from the spinal cord.
What are the three primary functions of neurons?
· Receive information
· Conduct information
· Transmit information
How many types of neurons are there?
There are more than 10,000 types of this cell.
The electrical signals exchanged between nueral cells refer to the passage of what particle group?
Ions are used for this method of communication!
What are the three functional regions of a “typical” neuron?
Input (receiving)
Conducting
Output
What structures are found within the input region of a typical neuron?
This region of the neuron contains pre-synaptic fibers, dendrites, the cell body, and the nucleus.
What structures are found within the ‘conducting’ region of a typical neuron?
Axons (nerve fibers), myelin and Nodes of Ranvier make up this region of the typical neuron.
What structures are found within the ‘output’ region of a typical neuron?
This region of the typical neuron contains synaptic boutons and terminal branches.
What is the Nissl Substance of a neural cell?
These intracellular structures are unique to neural cells; granular bodies made of polyribosomes and an expanded rER
Why are neurons known the have large nucleoluses?
Neurons are largely secretory cells, undergoing very frequent transcription, therefore they have large…
What two cellular structures can be found at the base of dendrites?
The rER and sER can be found at the base of these neural structures
What cellular organelles can be found within dendrites?
Mitochondria, free ribosomes, microtubules and microfilaments are found in this cellular structure
What is another word used to refer to the cell body?
Soma is another term used to refer to the…
What are dendritic spines and what purpose do they serve?
Dendritic spines are tiny, numbered protrusions from dendrite branches which each facilitate a unique synaptic connection with the cell it interacts with
What two features can dendritic spines be indicative of?
These structural features can be indicative of the frequency of a neuron’s input activity and of the presence/absence of neural disease
What are the 4 parts which make up an axon?
- Initial segment (axon hilock)
- Axon process
- Synaptic boutons
- Growth cones (from synaptic boutons)
What accomplishment is attributed to Ramon y Cajal?
This figure first used silver staining techniques to observe embryonic specimens
Where can a growth cone be found on a neuron?
Growth cones can be found at the output end of the axon
What are the 3 domains of a growth cone?
- thin fan sshaped sheet at the tip (lamellipodia)
- many thin spikes radiating forward (filopodia)
- Peripheral domain
- Transition domain
- Central domain
How do growth cones relate to synaptic boutons?
Once growth cones have reached the target cell, they differentiate into synaptic boutons
What are filopodia on growth cones?
On growth cones, these are many thin spikes radiating forward
What are lammellipodia on growth cones?
On growth cones, this is a thin fan shaped structure at their tip
What is contained in the peripheral domain of a growth cone?
Lamellipodia and fillopodia
What is contained in the Transition domain of growth cones?
This is the transition between the P and C domains
What is contained in the Central domain of a growth cone?
A think region containing organelles and vesicles
What are the three stages of axon growth?
- Protrusion
- Engorgement
- Consolidation
Briefly describe the first stage of axonal growth.
Protrusion; rapid extensions of
filopodia / thin lamellae containing
actin
Briefly describe the second stage of axonal growth.
Engorgement: microtubules invade
protrusions bringing vesicles and
organelles
Briefly describe the third stage of axonal growth.
Consolidation: actin depolymerises
in the neck of the growth cone,
membrane shrinks forming
cylindrical shaft
What is the length of a spinal motorneuron?
This type of neuron is 1mm — incredibly long by cellular standards!
What are the two types of signals which can activate a neural signalling pathway?
Chemical and physical signals
What are three examples of chemical signals that activate neural signalling pathways?
- Growth factors (e.g.: Nerve Growth Factor) secreted by cells
- Substrates (e.g.: laminin-1, fibronectin)
- Other cells using adhesion receptors (eg: integrins, cadherins)
What are three examples of chemical signals that activate neural signalling pathways?
- Tactile: if scratch surface, growth occurs along groove
- Electrical
- Photonic: light!
Name 8 major neurotransmitter substances.
- Acetylcholine (ACh)
- Noradrenaline
- Adrenaline
- Dopamine
- 5-Hydroxytryptamine
(5-HT, serotonin) - Gamma- aminobutyric acid
(GABA) - Glycine
- Glutamic acid
