What are the 4 types of cells in the CNS?
Neurons
Glia
Sensory Receptors
Stem cells
What are the two types of ways that have been used in past neuroscience research to stain the brain, and what are the advantages and disadvantages of each? What were the common correct and incorrect interpretations of these stains?
Nissl stain - stains all of the cells in the brain which makes it look like a jumbled mess. This staining caused a debated between the neuron doctrine and syncitium which was a debate about whether or not the brain was many individual cells, or one large cells with interconnecting cytoplasm.
Golgi stain - only stains some cells in the brain, but helped scientists discover that the brain is made up of many individual cells that work together
What is the purpose of the dendritic spine, and what can issues with these spines cause?
The dendrite spine drastically increases the surface area of the dentate so more signals can be captured.
Extra dendritic spines are associated with mental retardation and fragile X syndrome
Not enough dendritic spines are associated with schizophrenia
What intracellular components are extra important in neurons, and why?
Significant rough and smooth ER, as well as golgi apparatus. This shows that neurons are very good at producing and packaging substances.
How are chemicals made in the neuron soma moved to the terminal end of the neuron?
Axoplasmic transport transports cell products from the some, through the axon, the the pre-synaptic terminals. This is how packaged neurotransmitters are moved through the cell.
What kinds of signals are for inter, and intraneuronal communication
Neurons communicate with other neurons through chemical signals, and neurons communicate inside the neuron with electrical signals
What types of neurons are there?
Multipolar (most common)
Bipolar (associated with retina)
Unipolar (sensory neurons usually)
What are the two general types of glia?
Macroglia and microglia
What are the sub-types of macroglia?
Astrocytes
Oligodendrocytes
Schwann Cells
What can and cannot pass through the BBB? How can we get around a drug not being able to pass through, and what is an example of this?
Small non-polar molecules (like ethanol) can pass through the BBB
Larger, charged or polar molecules can pass through the BBB
Sometimes, if a drug cannot pass through the BBB, the precursor to that molecules can pass through. When treating Parkinson’s, you would want to treat with dopamine but dopamine cannot get through the BBB. However, the “K-dopa” precursor molecules can get through.
What is the BBB made up of?
2 main components
Tightly packed and organized capillaries
Astrocytes with foot plates on neurons that act as BBB filter
How does the brain deal with immune responses?
The body’s immune system does not act on the brain because the BBB will not allow the body’s immune response components through. In the brain, microglia act as the brain’s immune response by cleaning the damaged brain. However, microglia cannot fix things, only clean.
What is the role of glial cells in brain development?
In development, microglia prune down unnessary synapses which is necessary.
What do oligodendrocytes and Schwann cells do? How are they different?
Both oligodendrocytes and Schwann cells produce myelin for neurons.
Oligodendrocytes are found in the CNS, and one of these cells can wrap multiple axons
Schwann cells are found in the PNS and each cell is a “sausage” like component of the myelin, so there are multiple of these cells per axon.
What are 2 neurological issues that characterize multiple sclerosis?
With MS, there are holes in the BBB, and myelin is damaged / reduced around axons
List some of the many functions of astrocytes.
Large structural component of CNS Help form BBB Maintaining homeostasis (regulated ion concentration, get rid of metabolic waste, regulate blood flow etc...)
Astrocytes can talk to neurons
What is the difference between afferent and efferent neurons?
Afferent neurons are approaching the brain, brining information to the brain
Efferent neurons are exiting the brain, brining information to the body
What are the three meninges?
Dura mater - hard and strong
Arachnoid membrane - blood flow and sub arachnoid space is where CSF flows
Pia mater - thin membrane right outside of cortex
Where is CSF made, and what is the name of this structure?
CSF is made in the choroid plexus which is on the floor of the lateral ventricles and the roof of the third ventricle.
What is the name for the canal between the third and fourth ventricles?
The cerebral aqueduct.
What are the two general evolutionary purposes for CSF?
Protection and support
Helps with homeostasis
What is the “glymphatic system”?
CSF penetrates around individual brain cells and this acts like the body’s lymphatic system
What happens with hydrocephalous?
Swollen ventricles can cause a blockage of the cerebral aqueduct
What is the difference between grey matter and white matter? Why is white matter white?
Grey matter consists of cell bodies, synapses, and dendrites
White matter consists entirely of axons. It is white because of the myelin on the axons
