Cellular Nervous System Videos Flashcards
Structure of Neurons
-Same basic components of all cells (organelles)
-Have processes for communicating with other nuerons and cells tpes
-Nissl Substance-Same organelle as endoplasmic reticulum
- Localizations of organelles may be different
-Neurons commicate with each other via electrical and chemical signals
-Neurons utliize a lot of oxygen and ATP
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Parts of Neuron
Dendrites - Receiver
Soma - Cell body where the nucleus is located and organelles
Axon Hillock - 1st part of the axon Electrical massage. Each neuron will only have one axon through which they send out information
Axon
Presynaptic terminal - electrical message will cause the release of neurotransmitter from their terminal to pass the message to other neurons
-think of electrical cable
Communication between neurons: The Synapse
Synapsing Term used for connecting point,
with muscle, glands, organs or any type of tissue in the body.
How do neurotransmitters and proteins get to the synaptic terminal?
Microtubules are train tracks so it will
How do large neurotransmitters and proteins get to the synatic terminal
- Large neurotransmitters and proteins are by Nissl Sustance (Rough ER) at the cell body and shipped to the terminal
- Cargo made at the cell body is transported by microtubles. along using kinsesins (antergrade) away and dyneins (retrograde) back towards
Morphology of Neurons
-Multiple polar neurons (multiple projections coming off the cell soma/cell body) found in brain
Bipolar - found in nose and retina 2 projections (dentrit and exon)
Unipolar - intervate our skin provide sensation for us (no dentrits on axon) on axon that goes to skin and one axon to our spine
Glial Cells
Support cells in nervous system and communicate with neurons but not sending electrical signals as neurons do
Includes oligodroctyes and Schwann cells but also astrocytes, microglia (can regenerate) and go under mitosis
Out number neurons 10 to 1
Astrocytes
- Star shaped
- Found throughout the Central Nervous System (brain and spinal cord)
- Don’t fire action potentials or communicate electrically just not at synapses
- Can release waves of calcium
- Do not have synapses, but can release some neurotransmitters
- Remove neurotransmitters from synapse (what purpose does this serve?) - shut off signal, quickly pass on the message and then stop
- play a role and not directly involved in controlling our communication in different parts of our body
- provides nutrition for neurons through connections with blood vessels
- Important for providing nutrition to neurons through the Blood Brain Barrier
- help form blood-brain barrier capillary and blood vessels in the brain are poorest -
- Tight junctions between the cell that make up the capillaries within the brain and surrounding that are Astrocytes end feet. Any molecules that do get through they have to go through the astrocytes to get to the neurons. Non polar molecules can’t get through.
Critical for drug design and keeping foreign pathogens out and keeping neurons healthy.
-Neurons can’t divide or replicate
Oligodendrocytes
- Wraps axons in the CNS with myelin (fatty coating that wraps around the axons and helps ensures the electrical message stays within the axon and travels quickly
- Found in brain and spinal cord
- Can wrap multiple axons (insulation)
What is Myelin
- Fatty insulation around our nerves
- Prevents electrical current from shorting out
- Speeds conduction velocity of the electrical current
Clinical Correlate: Multiple Sclerosis
- Attack on Oligodendrocytes
- Disease characterized by Demyelination in the CNS (although there are reports that MS can affect myelination in the PNS of some patients)
- Autoimmune disease the body mistakenly attacks protein in the myelin and starts to degrade it
- Onset age 20-40, more prominent in females living in the northern hemisphere
- Abrupt onset attacks that are often relapsing-remitting
What kind of symptoms do you think these patients might have?
- Depends on what part of the brain are attacked and see patches of sclerosis
- Motor symptoms, poor balance, difficulty with sensation or lightening bolt sensation, pain, visual symptoms, hearing difficulty, cognitive difficulty
No cure
Microglia
- Functions as phagocytes (bulk active transport Endocytosis) in CNS type of endocytosis
- Clean up damaged and debris
- Abnormal activity linked to disease (Azhlmers, parkinson,stroke)
-Sometimes find macrophages that may get in but most of the time can’t get pass the Blood Brain Barrier
Ependymal Cells
Single layer of cells that lines the fluid-filled spaces of the brain and the central canal of the spinal cord
-Help move fluid along
What are the projections coming off of their apical surfaces, and why do you think they are present?
-Cilia to produce movement with fluid
• What type of epithelial tissue are ependymal cells?
-Simple epithelium and different types of morphology
Neural Stem Cells
- We have small numbers of neural stem cells in the brain
- Located around the ventricles (cavities of the brain)
- Found in hippocampus (memory)
- Damaged brain areas appear to attract stem cells
-Recovery might be poor
- Do we make enough to make a difference?
- Induce repair
- Can we transplant neural stems cells into damaged brain regions to induce repair?
- Will they know when to stop dividing
- Can the new neuro cells actually form the right connect or form improper connection
Tumors in the Nervous Systems
-Brain tumors are not due to neurons because they don’t divide
-Gliomas are tumors of glial cells (ie.astrocytoma)
Why are tumors even benign ones (not going to spread) problematic in the CNS? - We have fixed cavaties within the skull and spinal cord as the tumors grow there will compress brain or spinal cord tissue
Metastatic tumors (from elsewhere in the body are likely more common than all other CNS tumors combined)
