Title: Psychology / Biopsychology / 02_Braincells
Tags: Biopsychology::02_Braincells Biopsychology::Semester_1

Q: The brain has around [...] neurons.
A: 80 billion

Q: What is the estimated ratio of neurons and GLIA?
A: Neurons: 10-50%
Glia: 50-90%

Q: What two parts does a neuron always have?
A: Soma (Cell body)
Axon (Output nerve)

Q: A neuron can have many [...] but only one [...].
A: dendrites; axon

Q: What three types of neurons are there, classified by the number of neurites?
A: Unipolar (Axon)
Bipolar (1 Dendrite + 1 Axon)
Multipolar (Many Dendrites + Axon)

Q: What is the use of Unipolar and Bipolar neurons?
A: They are mainly sensory neurons.
They take up a lot less space, so they provide a higher resolution for sensory information

Q: You can further classify multipolar neurons into [...] and [...].
A: stellate cells; pyramidal cells

Q: Uses for stellate cells vs pyramidal cells?
A: stellate: tight dendrite network, perfect for interconnection and information exchange
pyramidal: dendrite tree, perfect for transporting information over long distances

Q: Difference between DNA and RNA in terms of contained information?
A: DNA contains the entire genetic information of the body.
RNA only contains the information relevant for a specific building block

Q: What is the difference between an Intron and an Exon?
A: Exons are the parts of the DNA where the coding information is stored, introns are the noncoding redundant parts.

Q: What is the difference between transcription and splicing?
A: Transcription: DNA -> RNA (cutting out relevant part)
Splicing: RNA -> mRNA (removing redundant introns)

Q: Why do we need mRNA?
A: RNA is too big to leave the core of the cell.

Q: What do Ribosomes do?
A: Translation: They use the mRNA to produce proteins.

Q: What happens to mRNA after it leaves the cell core?
A: It gets picked up by ribosomes that produce a protein based on the mRNA (translation).

Q: What 2 parts are the molecules in the cell membrane made of?
A: Hydrophilic head (phosphates)
Hydrophobic tails (hydrocarbon)

Q: What are the advantages of the structure of the cell membrane?
A: It is watertight (being held together by water) while still being flexible and allowing proteins like the ion channels to move around freely.

Q: What is the "bilayer" shape of the cell membrane?
A: There are two layers of the molecules (inverted to each other).

Q: What is the function of ion channels?
A: When the ion channels open, ions (electrically charged molecules) are free to stream along a concentration gradient from areas with high concentration to areas with low concentration (either inside or outside the cell). This causes a shift of electrical potential in the cell.

Q: What are Axon collaterals?
A: Fibres branching off of the Axon (each of them connects to other cells with the terminal button)

Q: What three parts does the Cytoskeleton of the axon consist of?
A: Microtubule
Microfilament
Neurofilament

Q: How do Microtubule, Neurofilament and Microfilament work together?
A: The filements stabilize the microtubule vertically.

Q: How is the cell membrane of the Axon different from the cell membrane of the Soma?
A: They differ in the type and concentration of ion channels.

Q: What happens to the axons cytoskeleton in Alzheimers disease?
A: The Microtubules clash together and create clumps (neurofibrillary tangles) → Information cannot be transmitted anymore → Neurons will die off.

Q: How are signals converted at the terminal bouton?
A: Electrical signal → Chemical signal→ Electrical signal

Q: What is the purpose of the Terminal Button?
A: It connects the axon to other neurons or body cells.

Q: What is the basic purpose of the dendrites?
A: Connect to terminal buttons of other axons to make connections.
→ They take on chemical signals from the pre-synaptic neuron and carry on electrical signals

Q: What is the function of dendritic spines?
A: Large endings on dendrites → increase contact surface between neurons → highly effective synapses
They can change in appearance quickly → very important for plasticity and learning

Q: Why is there little knowledge about the GLIA cells (compared to neurons)?
A: They are more difficult to measure as they use chemical signals instead of electrical ones.

Q: What role does the Astrocyte play for synaptic clefts?
A: 1. They restrict the spread of neurotransmitters form the synaptic cleft
2. They actively remove neurotransmitters from the synaptic cleft if needed

Q: How do Astrocytes influence neurite growth?
A: They fill in the gaps in-between neurons and define paths for the neurites.

Q: How is the chemical content in the extracellular space around neurons regulated?
A: Astrocytes store and release e.g. potassium

Q: What are the main 5 types of Glia cells?
A: Astrocytes
Oligodendrocytes
Schwann Cells
Ependymal cells
Microglia

Q: What do oligodendrocytes and schwann cells have in common?
A: They both insulate axons by supplying a myelin sheath around the axon → this increases conduction speed

Q: What is the difference between oligodendrocytes and schwann cells?
A: Oligodendrocytes appear in the central nervous system
Schwann cells appear in the peripheral nervous system

Q: What are "Nodes of Ranvier"?
A: They are gaps inbetween myelin sheaths in which the electrical signal can be reactivated.

Q: What is the purpose of ependymal cells?
A: They form the lining of the ventricles.

Q: What is the job of microglia?
A: They remove dead and degenerated braincells ("immune cells of the brain"). They also play an important part in learning by shrinking certain parts of the synapses.

Q: What are the 3 processes involved in the generation of proteins from DNA?
A: Transcription
Splicing
Translation