Cells In The Nervous System Flashcards
What are the 2 main types of glial cells (including the subgroups for one type)
Macroglia
- astrocytes
- radial glia
-oligodendrocytes
-Bergmann glia
- ependymal cells
- tanycytes
- Schwann walls
Microglia
Give some features of astrocytes
- They have end feet which connect to blood vessels and neurons acting as an intermediary which can increase the neurons blood supply when needed
- Different types of astrocytes are in different places eg. Fibrous astrocytes are present in white matter tracts, the spinal cord and optic nerve
Give Some features of radial glial cells
- They have two main processes between the ventricle wall and the developing brain
- They act as scaffolding for developing brains and disappear once it is fully constructed
Where would you find bergmann cells
They are present in the cerebellum, cell body and in pukinjie layer but some processes extend outside of the cerebellum
What is and Where would you find the muller cell
It is a type of glial cell
Present in the retina
What do ependymal cells do
They line the ventricles (which are fluid filled holes in the brain) and release cerebrospinal fluid
Where are tanycytes found and what do they do
They line the 3rd ventricle wall and extend very long processes into the hypothalamus and they regulate food uptake
Where are opigodendrocytes found
In white matter and they wrap around axons
Where are microglia found and what do they act as
Microglia are found throughout the whole nervous system and act as immune cells for the nervous system
What do Schwann cells do
There are 2 types of Schwann cells
1. Mylinating the entire cell wraps around and mylinates an axon above 1 micrometer in length
2. Non-mylinating this ensheathes multiple axons below 1 micrometer in length forming bundles
What is the composition of myelin
70% fat and 30% protein
How are oligodendrocytes and myelin related
Oligodendrocytes send out projections called myelin lamellae that can wrap around multiple axons
How do myelin lamellae wrap around an axon
They underweave themselves so the newest myelin is always nearest the axon, due to the trapezoid shape of myelin lamellae the increase in thickness decreases with each wrap
What is the name of the protein between myelin sheathes and the nodes of ranvier and what do they do
Anchoring proteins and they hold the myelin wrap in place
What 2 values determine the length constant and what values maximise the length constant
- Membrane resistance
- Axiomatic resistance
Increase in membrane resistance and decrease in axoplasmic resistance
What would we do to conduction velocity of axoplasmic resistance decreases
Conduction velocity increases
What is the g ratio
The ideal ratio of axon diameter too axon and myelin diameter (usually around 0.75 for all CNS axons)
How big are most neurons cell bodies
Generally they are somewhere between 10-50 micrometers long
What do microtubules in neurons do
They move proteins up and down the axon of a neuron with help from a protein called kinesin
What are some of the different pieces of information used to classify neurons
- The way the axon is projected
- The dendritic pattern
- The number of processes that they are involved in
- Where they connect too
What does a neurons cytoskeleton do
Provides structure
Aids in protein transport
What is another name for the sodium pump
Na+/K+ ATPase
What is the equation for membrane potential (Em)
Membrane potential = inside voltage (Vi) - outside voltage (Vo)
Which two types of gradients affect movement of ions across membranes and what is the name of the equilibrium between these two gradients
Concentration gradient
Electrical gradient
The point of equilibrium between these two is called electrochemical equilibrium
