Cells of the Nervous System 04 28 2014 Compare and contrast neurons w other cells of the body Alike have all of the organelles as other cells have plasma Different different morphology shape post mitotic communicate membrane with each other Know the organelles that we discussed and what they do Nucleus Membrane Mitochondrion Nucleolus Neurotransmitter NT consists of mostly lipid molecules that define the outer a chemical released by a terminal button organelle responsible for extracting energy from in central region of cell contains nucleolus and structure within nucleus that produces ribosomes boundaries of a cell chromosomes has excitatory or inhibitory effect on another neuron nutrients energy metabolism its breakdown liberates energy the cytoplasm proteins that are secreted by the cell segregation of molecules involved in various cellular processes that wraps the products of a secretory cell contains ribosomes and is involved with production of Parallel layers of membrane found within complex of parallel membranes in the cytoplasm site of synthesis of lipids and provides channels for the a molecule of importance to cellular Adenosine triphosphate ATP Endoplasmic reticulum Golgi apparatus Smooth ER Rough ER What are transcription and translation Transcription molecule of messenger RNA where the protein is produced Translation when a gene section of DNA has a copy made into a mRNA leaves the nucleus and attaches to a ribosome What are non coding regions of DNA Are they important Non coding DNA attached to and modify proteins that regulate gene expression can be transcribed to RNA but doesn t result in the production of protein What are the parts of a neuron and what do they do Could you label those parts of a neurons What is different between schwann cells and oligodendrocytes in terms of how they myelinate axons BTW are all axons the same w regard to length diameter and level of myelination Schwann PNS Oligodendrocytes CNS Axons vary in length thickness and amount of myelination What are the 3 types of protein strands that form the cytoskeleton of the neuron Which one is for fast axonal transort What other molecules are involved in this hint there is one for anterograde transport soma to terminal and one for retrograde transport terminal to soma Cytoskeleton matrix of insoluble proteins that five cell shape and structural support o Microtubules o Actin microfilaments thickest run length of axon important in transferring between cell body and terminal like pearls very dynamic make up skeleton of spines neuron shape o Intermediate filaments smallest strung together pieces of actin called neurofilaments in neurons give Walk down microtubules carrying cargo Fast axoplasmic transport from soma to terminal buttons o Kinesin cell body to terminal o Dyein terminal to cell body What is a synapse Terms presynaptic postsynaptic synaptic gap ie synaptic cleft ie synapse Synapse where two cells meet What are the 3 main types of neurons think polar Multipolar typical Unipolar one process off soma Bipolar 2 processes off soma What is the difference between an inhibitory neuron an excitatory neuron and a modulatory neuron Inhibitory inhibits the postsynaptic cell Excitatory excites the postsynaptic cell What are glial cells What are specific functions of astrocytes microglia oligodendrocyes schwann cells and radial glia Glial cells non neuronal cells that maintain homeostasis form myelin and provide support and protection for neurons in the brain and PNS Astrocytes surround capillaries and neurons of the CNS o Delivers nutrients from capillaries to neurons control synaptic environment BBB Microglia assist with repair after damage Oligodendrocytes and Schwann cells myelinate axons Radial glia provide scaffolding to help guide migrating neurons and axons during development What is the blood brain barrier structure and function A semipermeable barrier between the blood and the brain produced by the cells in the walls of the brain s capillaries o Keeps out viruses and bacteria chemicals nutrients active transport to get them across o Lets through small uncharged particles fat soluble molecules glucose sometimes viruses What are circumventricular organs Know an example or two Structures in the brain that are characterized by their extensive vasculature and lack of a normal BBB What is a neurotransmitter NT a chemical released by the communicating neuron to receiving neuron either excites or inhibits the receiving neuron o Released from terminal Neurophysiology 04 28 2014 Who used the giant squid axon to test how nerve impulses traveled along the axon and determined that axon firing is electrochemical involving sodium entering the axon and potassium leaving it Giant squid axon test Hodgkin and Huxley tested how nerve impulses travel along axon o Determined that axon firing is electrochemical involving sodium entering the axon and potassium leaving it Understand resting potential what is the voltage How are the ions distributed across the cell membrane What forces are acting upon them Voltage 70 mv Resting potential The membrane potential when it is not being altered by excitatory or inhibitory postsynaptic potential o At resting potential there is more K inside the cell and more Na and Cl outside of the cell Where does the action potential occur What part of the neuron is the decision center Why is that the decision center what s special about it AP occurs on the axon of a neuron Decision center the axon hillock it decides whether or not the neuron will fire an AP AP are all or nothing when it reaches the right voltage What ions are involved in the action potential Sodium Potassium Chloride Understand the terms Polarization Depolarization Hyperpolarization Polarization a cell becoming more or less negative Depolarization when a neuron becomes less negative more positive reduction towards zero membrane potential Hyperpolarization when a neuron becomes more negative increase in membrane potential relative to resting What is a voltage gated channel Voltage gated channel a trans membrane ion channel activated opened by changes in electrical membrane potential Starting w threshold being reached at the axon hillock what happens during an action potential When the threshold is reach at the axon hillock 50 mv o VG sodium channels open up sodium rushes in and depolarizes cell o VG sodium channels close VG potassium channels open potassium rushes out of cell and it becomes hyperpolarizes o VG potassium