Synapses and Neuronal Anatomy PDF

## Synapses = junctions between 2 neurons - mean "to fasten" ### Neuron - Basic functional unit of nervous system - Conduct messages and integrate info - Variety of shapes and sizes. Example: Figs 35.4 and 35.5. - Share basic characteristics. ### Anatomy of neuron - Soma: cell bod...

## Synapses = junctions between 2 neurons - mean "to fasten" ### Neuron - Basic functional unit of nervous system - Conduct messages and integrate info - Variety of shapes and sizes. Example: Figs 35.4 and 35.5. - Share basic characteristics. ### Anatomy of neuron - Soma: cell body - Axon: one and long - Transmit away from cell body - Nerve= axons of many neurons - Axon terminal: synaptic terminal - Dendrites: many, short, branched - Recieve info - Send signals to the cell body ### Junction between 2 neurons - Synapse: a junction between 2 neurons. - Presynaptic neuron - Neurotransmitters - Postsynaptic neuron ### Chemical Synapses - Sequence of activity: Fig 9.3 - Pre-neuron - Synthesizes neurotransmitters (NT) - Examples of NT - Acetylcholine: NS, muscles - Dopamine: brain, mood - Endorphins: pain regulation - NT diffuses across the synaptic cleft (20mm wide) - Post-neuron - NT bind to specific receptors in PM (plasma membrane) - Electrical impulse ### Memory and Learning - The brain can be remodeled as a result of neuronal plasticity - Occurs mostly at synapses - Occurs in response to activity - Long-term potentiation(LTP): long-lasting in synaptic strength - Lab/workshop: LTP - LTP and learning require energy/effort ## Glial cells - Non-neuronal cells in nervous system - Do not produce electrical impulses - 10x more than neurons - More diversity and function ### Types - Ependymal: produce CSF (cerebrospinal fluid) - Astrocytes: regulate composition of CSF - Microglia: fight infections - Oligodendrocytes: electrical insulation ### Glioblastoma - Most common and most aggressive type of brain tumor - Form in the astrocytes ## Learning - A process: a change in behaviour resulting from experience that reduces the probability of unproductive outcome - Memory: physiological/anatomical changes in nervous system. - Learning & memory ### Neurophysiology of memory - Nervous tissue: neurons and glia - Central nervous system - Peripheral nervous system ### PNS/CNS: find neurons, glia, cells, pancreas - CNS: - Astrocytes - Microglia - Oligodendrocytes: conduction of nerve impulse - Radial glia: direct & support neurons - Ependymal cells: make cerebral spinal fluid - Neurons in the brain float in spinal fluid - Lining the ventricles of the brain + spinal fluid ### CC glia: figure 35.7 page 1004 - PNS: - Satellite cells - Schwann cells: similar to oligodendrocytes ## Test Review ### Chemical Synapses - Most common type in our bodies - Long term potentiation happens. ### Membrane potential - Any cell has potential - Measure potential with a voltage - All channels are made of proteins - Shape of protein=confirmation - Action potential is ions moving back and forth. - Resting potential= when nothing is happening in a neuron. - -70mV - Threshold potential: voltage on cell membrane. - -55mV - Action potential: - -55mV --> 35mV --> 70mV ### Chemical synapse (Fig 35.15) - CC: EPSP and IPSP: inhibitory post synaptic potential - Excitatory post synaptic potential ## Exam 2: Thursday 10/17 - 70 questions - Lecture content from the beginning to Thursday 10/10 - Lab 1-5 ### Review - ID/Draw chemical synapse - Presynaptic neuron - Neurotransmitters - Vesicles - Voltage channels - Synaptic cleft - Postsynaptic neuron ### Ligands - Things that bind (neurotransmitters) - Enzymes: for neurotransmitter removal - Ligand gated receptors: plasma membrane of postsynaptic neuron - Ligand has a binding site for travelling neurotransmitter - Voltage gated - Shape of protein: confirmsation - Amount of voltage can cause confirmation - Example: cooking raw meat is a change of confirmation. - Because you are changing the shape of protein. - Can change confirmation when it binds or voltage. ## October 8, 2024 ### Learning Strategy - Observation/problem? - Background information/research - Hypothesis - Prediction - Experiment/test predictions - Control - Conclusion - Science requires verification. - Use the scientific method to disprove. - Sequence chemical synapse operation ### ATP - Energy: the ability to do work - Mechanical energy: glucose - We store glucose for glycogen ### Cellular respiration - Getting energy molecules - Glycolysis, citric acid cycle, electron transfer train - To get chemical energy out of food to get ATP. - Is why we need oxygen. ## October 10, 2024 ### Exam 2: Thursday 10/17 - 70 questions. - Lecture content through the beginning to now. - Lab 1 to 5. ### Lecture Practice Questions - Glycogen -> glucose. - Glucose homeostasis: glucagon levels would be high. - Which cause hyperglycemia: both type - I and II - Facilitated diffusion creates the doors - Insulin says put doors in place. - Doors are made up of proteins - When glucagon is received by a muscle cell, the muscle breaks down. ### Action potential - Voltage change - Active transport requires energy. ## October 10, 2024 ### Chemical Synapses - CC: ESPSs and ISPSs - Summation: they link to ESPSs and ISPSs. - Emergence comes to help make decisions. ### Electrical synapses - Faster, excitatory. - Proteins are directly attached and are always open. - Have gap junctions that connect. - No summation. - No ESPS. - Doesn't need neurotransmitters. - Example: your heart. - Faster than a chemical synapse - Another example: digestive system. - Smooth muscle is an electrical synapse. ### Chemical synapses - **And memory**: - Synaptic plasticity: neuro plasticity - More gates, open more doors to get action potential started. - 2 types of receptors: NMDA and AMPA: - Allows calcium to come in - And get rid of magnesium ## October 15, 2024 - Cells don't need energy for diffusion - Temperature affects the rate of diffusion ### Synaptic plasticity - Long-term potentiation - Sodium moves in. - Magnesium leaves so calcium can go in. - Tells cell to put more AMPA. ### Hippocampus - Long term potentiation ### Types of learning - Habituation - Imprinting - Association learning: - Classical conditioning - Operant conditioning - Cognitive learning: optrant modified by consequences ## Intro to Chemistry, Ch 2.1, 10/22/2023 ### Biology - Properties of life: organization, respond to stimuli, reproduction, growth, regulation & homeostasis, energy processing, development, evolution. - Hierarchy of biological organization: organisms, population, community, ecosystem, biosphere. - Organisms: organ systems, tissues, cells, organelles, molecules, atoms. ### All physicochemical aspects of life - Physics & chemistry - Physics: scientific study of matter, motion, and energy. - Fundamental laws of nature. - Chemistry: scientific study of composition, properties, and behavior. - Transformations of matter. - Example: wax + water + carbon dioxide = heat. ### Matter - Any substance that occupies space and has mass. - Mass: measure of inertia (resistance to application of force). - Example: a boulder has more mass, resists application of force. - Living matter: people, animals, plants. - Substance: matter with characteristic properties. - Example: boiling point, melting point, heat of vaporization. ### Pure substances - Elements: substances that cannot be broken down to other substances by ordinary chemical means. ### Compounds - Contain 2 or more elements in definite proportion visible to the human eye.. - Example: water(H2O), table salt(sodium chloride=NaCl), table sugar(sucrose= C12H22O11) ### All compounds are molecules ### Molecules - Consist of 2 or more atoms bonded together. - Not visible to the human eye. - Not all are compounds. - Examples: HD, sucrose(C12H22O11), NaCl, O2, N2. ### Atoms - Atomic theory: John Dalton: elements made of identical atoms. - Smallest unit into which elements can be divided and still display the properties of that element. ### Atomic Structure (Fig 2.2) - Nucleus: center of atom. - Protons(p+): charge=+1 - Neutrons(n): charge=0. - Electrons (e-): - Orbitals around the nucleus. - Much smaller in mass than protons. - Charge= -1 - #e- = #p+ (electrically neutral atom) ### How to describe an atom - Chemical symbol= abbreviation for element. - Atomic number: number of protons. - Unique for each element. - Atomic mass: number of protons and neutrons. - Expressed in DA (amu), atomic mass unit. - 1 electron is 1/1836 of a proton. ### Isotopes - Different forms of an element that have the same number of protons but different number of neutrons. - Some are radioactive (radioisotopes). - Example: hydrogen, deuterium. ### Electrons, Ch 2.1: 10/24/2024 ### Bohr model - Draw a model - CC parts of an atom ### Orbitals - Draw orbitals - CC shells and orbitals. ### Electrons (e-) (figure 2.2) - Very small: 1/1836 of p+. - Located outside nucleus. - Charge= -1. - #e- = #p+ (electrically neutral atom). ### CC parts of an atom | Location | Proton | Neutron | Electron | |---|---|---|---| | Nucleus | +1 | 0 | -1 | | Orbitals | | | -1| | Mass (amu) | 1 | 1 | 0 | ### Bohr model - Background - Niels Bohr: Danish scientist (1885-1962). - 1913 - Electrons are located in shells. - Innermost shell. - Outer shell: - Valence shell: outermost electrons. ### Periodic Table - 7 periods: rows - All elements in a row have the same number of shells. - 18 groups: columns - All elements in a column have the same number of electrons in the outermost shell. ### Shells - Distance from the nucleus - Potential energy (E): to do work! - e- absorbed: move to higher shell. - e- released: move down to a lower shell. - Atomic nucleus - Lowest shell = low energy electrons - Example: photosynthesis. - Ground state - Excited state ### Bohr model - Does help explain the behavior of some elements. - Does not accurately reflect distribution of electrons around nucleus. - Within each shell, energy levels are orbitals ### Orbitals - Volume where an electron is most likely to be found. - Not exact path - Each orbital can hold up to 2 electrons (0,1,2) - Example: fill lowest energy level orbitals first. - Filled orbitals are most stable than partially filled orbitals. - Shapes: - S orbital: spherical - P orbital: dumbbell (8) ### Example: H - Atomic #=1 - 1 proton. - 1 electron. - Electron configuration= 1s1 (1s orbital and 1 electron). ### Example: He - Atomic #=2 - 2 protons - 2 neutrons - 2 electrons - Electron configuration= 1s2 ### Example: Li - Atomic #=3 - 3 protons - 4 neutrons - 3 electrons - Electron configuration: 1s22s1 ### Electrons 3, Ch.2.1, 10/31/2024 ### Valence - ID & draw valence shell. - ID octet rule ### Bonding ### Valence - Measure of atoms capacity to combine with other atoms. - Valence shell= outermost shell. - Valence electrons: - In valence shell: - 1 shell --> 2e- - 2 shell --> 8e- - 3 shell --> 8e- - Important in atom's behavior. ### Example: H - Electron configuration: 1s1 - Wants to have 2e- in 1 shell ### Example: He - Electron configuration: 1s2 - 2e- in valence shell (full) - Noble gas ### Octet rule - Atoms prefer 8e- in outer shell. - Participate in reactions and form bonds to produce this configuration. - Stable electron configuration (low energy) ### Bonding - Molecules: smallest unit of compounds. - Result from interactions between atoms. - When atoms get close to each other their nuclei and electrons interact. - Distribute themselves in such a way that the total energy is lower than it would be in any other arrangement. ### Lewis structure - Shows all valence electrons in an atom/molecule. ## Electrons & Bonds - 11/5/2024 ### Review - Molecules: result from interactions between atoms (bonding). ### Valence - 1 shell = 2e- - 2 shell = 8e- - 3 shell = 8e- ### Lewis structure - Lets us know how many valence electrons there are. ### Periods: rows - All elements in a row have the same number of shells. ### 1 shell = full with 2e- - Lewis structure: H. - Bohr model: H - Lewis structure: He: - Bohr model: He ### Li, C, N, O: - Li: 1 more electron to fill shell. - C: 4 more electrons to fill shell. - N: 3 more electrons to fill shell. - O: 2 more electrons to fill shell. ### Na, Cl: - Na: 1 more electron to fill shell. - Cl: 1 more electron to fill shell. ### Groups: columns - All elements in a column have the same valence electrons. - Group 1: have 1e- to "give". ### H - H : gives away 1e- - H+ ### Li - Li: gives away 1e- - Li+ ### Cations: positive charge ### Group 1B - "need" 2e- ### Group 17 - "need" 1e- ### Cl - Cl: 2 more electrons to fill shell. - Cl- ### Anions = negative charge