Lecture2_Neuroanatomy I Flashcards
Can you name three human brain facts?
- composed of <100 billion neurons, glia, stem cells, blood vessels
- convoluted (wrinkled)
- consumes ~20% of your energy and weights ~3lbs (2-3% of your body weight)
Can you name the two general types of cells within the nervous system?
- Neurons
- Glia
What is the difference between gray and white matter?
- Gray matter= part of the brain where the body’s of neurons and unmyelinated neurons are
- White matter= part of the brain where the large myelinated axons are
What are the three types of staining?
- Nissl staining (cresyl violet)
- Fiber staining
- Golgi stain
How does Nissl staining work?
the stain binds to our cell bodies (i.e., gray matter) and reveals the gray matter in our brain (appears purple)
Why use Nissl staining?
great for seeing larger parts of the brain (ex: where the amygdala starts and ends)
How does Fiber staining work?
the stain will bind to some aspect of our myelin and turn it into a darker colour , now we can see where all the white matter is
How does a Golgi stain work?
the stain will only bind to ~10% of the neurons in a section of the brain (a subset of neurons). This helps us see the shape of cells and their cell type
How are neurons different than other communicator cells?
in a neuron, an axon can fire action potentials allowing for fast responses (milliseconds to reach target)
Can you name the four types of Glial cells?
- Astrocytes
- Microglia
- Oligodendrocytes
- Schwann Cells
What is the function of microglia?
As the blood brain barrier blocks lots of toxins from reaching your brain, you brain has no immune cells protecting it. Microglia has receptors that are sensitive to proteins (of parasites, bacteria, viruses, etc.) and become active when it detects this. They will follow the gradient of the signal to where they think the toxin is, then blow up and engulf the foreign body. (note: microglia are not part of the bbb)
What is the function of Oligodendrocytes?
we find them in our central nervous system (i.e., brain and spinal cord) and they myelinate a few axons. (note: “oligo” is Latin for several, or a few)
What is the function of a Schwann Cell?
act as a form of insulation for axons outside the central nervous system by wrapping themselves around axons to speed up ap’s
What is the function of Astrocytes?
“superstar glial cells” because it has has many roles:
1. make up half of our bbb by wrapping their “feet” around blood vessels to stop things getting in and out
2. meditate nutrients coming into the brain
3. connected to synapses
What is meant by a “tripartite synapse”?
“a conversation of three” including the presynaptic & postsynaptic neuron, and an astrocyte. An astrocyte engulfs the whole synapse so they can send and receive signals known as gliotransmitters. This influences how active/not dendrites are.
How do signals flow through the neuron?
Info comes in through receptors at the DENDRITE, the signal travels to the SOMA (aka: cell body), then the ap travels through the AXON, then it the signal will release neurotransmitters at the AXON TERMINALS
What are the two basic types of neurons?
- Projection Neurons
- Interneurons
What is a Projector Neuron?
have large axons that project to different areas (i.e., they don’t stay local)
What are Interneurons?
have short axons that project locally to the neurons around them
Why do we need Interneurons?
interneurons are inhibitory by nature and act to allow for synchronization, creating rhythms in the brain, and modifying the signal
Can you describe the central dogma of molecular biology?
the flow of genetic information which occurs in one direction: DNA makes RNA, and RNA makes protein
What does transcribe mean?
DNA —> RNA
What does translation mean?
RNA —> Protein
What is the function of Mitochondria?
Your soma and axon terminals have lots of mitochondria which produce energy for them to use. Mitochondria takes O2 and sugar to produce ATP, and the byproduct of ATP is CO2 which is expelled from your body
