Week 2 Flashcards
How many neurons do we approximately have?
100 billion
What is the neuron network?
A huge network for communication and complex processing
How many neurons do we loose over time?
50%
What is the white matter?
Axons
What is the grey matter?
Pink oozy bloody part.
Cell bodies
How many neurons does the cerebrum have in it?
14 billion
How many neurons does the cerebellum have in it?
70 billion- mini brain that orchestrates the behaviours
Hind brain and brain stem and spinal cord- how many neurons?
1 billion neurons
What are the types of brain cells
Neurons-
Glial cell- astrocytes and oligodendrocytes
Ependymal cells- line the CSF- filled ventricles (neurogenesis)
Microglia- remove dead or degenerating neurons or glia (phagocytosis)
What are neurons?
Most have 4 main parts. 1- Soma (cell body) 2- Dendrites 3- Axon 4- Presynaptic terminals
What are axons and dendrites known as?
Neurites type II- sma
How can you classify neurons?
The number of Neurites (from cell body)
Their dendrites- how many and if they have spines or not
Their axon length- golgi type 1-long internuncial. Golgi type II- small interneurons
The neurotransmitter used by the neuron
Neuronal connections- primary sensory neurons or motor neurons
What is an internuncial neuron?
A neuron that goes from brain area 1 to brain area 2
What is an interneuron?
A neuron that stays within one brain area
What are the 3 types of neurites?
Unipolar
Bipolar
Multipolar
How do they determine whether a neurite is a certain type of polar?
Defined by the number of neurites connected to the soma
What is a pyramidal cell?
If it is an apical dendrite it extends from the apex of the pyramidal cell soma.
If it is a basilar dendrite it connects to the base of the soma (not the axon)
How are neurons classified by Dendrites?
Stellate (star shaped) vs Pyramidal (triangular) Has spines (spinous) vs No spines (aspinous)
What are dendritic spines involved in?
Learning and memory
How do dendritic spines improve learning and memory?
There is more surface area so greater communication between neurons
What does dendritic trees change to aid?
Neuroadaptation
What is the purpose of dendrites?
They are sources of information for the neuron. The more dendrites we have the more info the neuron receives.
What is the difference between afferent vs Efferent neurons?
Afferent is to the connection (a for arrive)
Efferent is from the connection (e for exit)
What are the 4 parts to a neuron?
Soma, dendrites, axons, pre synaptic terminal
What does the phosopholipid bilayer?
The skin that keeps the cell intact.
Has two layers of phospholipid
Only certain chemicals can pass through the layer- the uncharged molecules can grow through, but charged molecules cant go through on their own. They have to go through the protein molecules
Can uncharged molecules (ions) go through the layer?
Yes
Can charged molecules (ions) go through by itself?
No it must go through a protein in the layer
What is it called inside the phospholipid bylayer?
Cytoplasm/ Intracellular fluid
What is it called outside the phospholipid bylayer?
Extracellular fluid
What is the soma full of?
Organelles
What is the fluid in the Soma called?
Cytosole
What is the cytoplasm?
The fluid and organelles in the soma
What does the golgi aparatus do?
Sorts proteins for destinations- delivery to specific parts of the neuron. Also refines protein into its final form
What does the Smooth Endoplasmic reticulum do?
3D folding of new proteins
What does the Nucleus do?
Contains DNA to provide information for protein synthesis in the neuron
What does the Rough Endoplasmic reticulum do?
Major site of protein synthesis and ribosomes help them
What are Ribsomes
Translate protein making instructions from messenger RNA
What are polyribosomes?
Free floating ribosomes working together on the same strand of mRNA
What are mitochondria
Energy producers of the cell
Release ATP produced by Krebs cycle.
What is the process where ATP is released?
The Krebs cycle
What do axons do?
Carry information to the terminal (presynaptic) boutons
How does the axon keep its shape?
Microtubules (tubulin)
Neurofilaments
Microfilaments (actin)
How do proteins made in the soma reach the terminal?
Axoplasmic transport- molecules in vesicles attach via kinesin to microtubules and move toward the terminal.
What is the axoplasmic transport ties?
Slow is 1-10 mm/day
Fast is 1000 mm/day
What is anterograde transport?
Going forward
How does Axoplasmic transport work?
Vesicle fills with protein that is just made.
It walks with kinesin, down microtubules requiring ATP to get to terminal.
What are the types of Glial cells?
Astrocytes Oligodendrocytes Schwann cells (periphery) Radial glia Microglia
What does the Astrocytes do?
Most numerous
Fills space between neurons and keep them safe
Regulate chemical environment of the extracellular space
supplies nutrients, ions, oxygen from blood supply
Synchronise neurons
Can be regulated by neurotransmitters
What does the Oligodendrocytes do?
Wrap cells in myelin
Myelin sheath is interrupted by nodes of Ranver
Shares myelin with several axons
What does the Schwann cells
Similar to Oligodendrocytes but does not share myelin- each cell myelinates only one axon
What does the Radial Glia do?
Guide neuron migration and axon growth
What does Microglia do?
Rids toxins
