PGY 300 1st EditionExam # 1 Study GuideCentral Nervous System (CNS) - Spinal cord & brain Peripheral Nervous System (PNS) - All nerve tissues outside of the CNS2 Major divisions: Autonomic System: transmit action potentials from CNS to cardiac m., smooth m. & glandso Sympathetic o Parasympathetic  Somatic System: transmit action potentials from CNS to skeletal m. o Sensation Organizations of Nervous Tissues CNS&PNS contain areas of gray matter & white matter o Gray matter: groups of neuron cell bodies & dendrites, where there’s very little myelin, sensory(afferent) & motor(efferent) nuclei o White matter: myelinated axons from spinal cord up to and from the brain, collection of nerve cell bodies(ganglion) outside CNSAnatomyMeningeal layers: Dura mater, Arachnoid membrane, Pia mater Meningitis: inflammation of meninges -> pia mater  Hydrocephalus: elevated CSF o Choroid Plexus-> exchange between blood and CSFInterneuron : doesn’t leave CNS, connect input&output neuron Astrocytes: makes the blood brain barriers1) Cerebellum: motor activity (evaluating motion)2) Pons: relay station between cerebellum&cerebrum (communicator)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.3) Medulla Oblongata : cardiovascular function (involuntary function)Association Areas:Wernicke’s Area: Sensory cortexBroca’s Area: Motor cortex Basal Ganglia: controlling movement, what motor activity you do/don’to Leads to Parkinson’s, Huntington’s, Tourette syndromeLimbic SystemThalamus: Involved in processing sensory info -> sends to cerebrum Hippocampus: Short term to long term memoryAmygdala: memory with emotional contentHypothalamus: Controls Autonomic system general body homeostasis, controls hunger, thirst, body temp.MRI: Clear images of brain, uses magnetic fields to move water molecules, unaffected by bone PET: Location of parts of brain that are active, observe brain activityEEG: Monitors stages of sleep , epilepsy, find origin of seizureThe NeuronDendrites: site for input to nerve cells Synapse: site of communication within cells, info is conveyedPNS: -Satellite cells CNS: -Astrocytes (K+ neurotransmitter) -Schwann cells (myelin sheaths) -Oligodendrocytes (myelin sheaths)Node of Ranvier: Boost electrical signalsVoltageResting voltage ~ -70mV Excitation: more positive=release transmitter -> Na+ in (depolarization) Inhibition: more negative-> Cl- in, K+ out (hyperpolarization)Sodium Potassium Pump (Na+/K+/ATPase): uses energy from ATP pumps K+ into cell & Na+ outEquilibrium: concentration gradient= electrical gradient Equilibrium Potential for Key Ions: K+ = -90mV -> hyperpolarize Na+ = +60mV -> depolarizationMembrane ProteinsLipid bilayer impermeable to ions Channels: pore in membrane, only moves things along energy gradient o Uses facilitated diffusion to speed up  Carriers: moves things against concentration gradiento Can be uniport or co-transport Primary Active Transport is ATP dependent  Moving against energy gradient requires energyo Ex: Sodium Potassium Pump Secondary Active Transport uses potential energy already created by primary active transport Neurotransmitter1)Voltage: Action potentials2)Ligand: Chemical neurotransmitter 3)Mechanical: Mechanical force Ex: hair cells in inner ears9 Subtype of Voltage-Gated Sodium Channels throughout the body S4: voltage sensor S5 & S6: activation gate  IG: plugs channels, can clog from inside “P Loop ”: determines selectivityo NaV 1.7 – causes nerve cells not to work, loss of pain sensation ACh Receptor – Ligand-Gated Channel (Ionotropic) Open by transmitters Neuromuscular junction Activated by 2 ACh moleculeso ACh(depolarizes), GABA(inhibitory), Glycine(inhibitory)Action Potentials Stimulus at Axon Terminal (max stimulus) Digital signal, All or None Must be at threshold at trigger zone to produce an AP  Involve Na+ and K+o Depolarizing -> voltage gated channels Graded Potential: analog signal, change in size, decay w/ distance  Large graded potential = high freqIndividual channels DO NOT have a threshold freqAP are regenerative, to stop it: Na+ channel closes and K+ channels open  Absolute Refractory: can’t produce another AP, b/c too many Na+ channels are activated Relative Refractory: Can produce AP but harder, due to hyperpolarization Myelin speeds conduction, AP goes in 1 direction  Saltatory Conduction No AP produced in myelinated regions, hops between Node of Ranvier  Hyperkalemia: hyper-excitable, elevated K+ Hypokalemia: hypo-excitable, less K+The Synapse Presynaptic cell releases neurotransmitters in response to an AP -> binds to postsynaptic receptor to open channel -> produces voltage -> graded potential  Presynaptic terminal contains many synaptic vesicles with neurotransmitter o Storage -> mobilization -> docking -> priming -> Ca+sensing -> fusion -> endocytosis ->translocation -> sorting  Ca+ entry triggers exocytosis  Neurotransmitter can be recycled or Glial cells can degrade them o ACh degraded by enzyme AChE (breaks down ACh)SNARE proteins on vesicles & presynaptic membrane  Bind with each other, combine where vesicles are located Botulinum toxin: breaks down SNARE proteins, prevents neurotransmitters to be released1)Ionotropic (Ligand-gated): opens channels directly, binds receptors with protein 2)Metabotropic (G Protein coupled): G-protein activates second messenger, can amplify signal  AMP -> cAMP -> protein kinase activation -> phosphorylation of other proteins -> responseSecond messenger IP3: release of Ca+ from sack inside cell (ER) Glutamate – excitatory  GABA – inhibitory in brain  Glycine – inhibitory in brainstem & spinal cordMemory Mechanism Spatial: No summation Temporal: time dependent summation -> bigger net depolarization  NMDA -> memory  Mg 2+ blocks channels, lets Na+ and Ca2+2 Glutamate Receptors:1) AMPA: opens quick but closes quick too (metabotropic )2) NMDA: long term potentiation (ionotropic ) Increase in Glutamate = increase # of AMPA receptorsHabituation : suppression of presynaptic Ca2+ channel  Aplysia: decrease in Ca2+ channel activity -> less transmitter releaseSensitization: decrease in K+ -> stronger Ca2+ influx Sensory SystemsReceptive fields Convergence increases receptive fields but decreases resolution  Lateral