3 Intracranial compartment, Cellular base of nervous system Intracranial compartment, Cellular base of nervous system2 Compartmentalization • Cellular specialization leads to compartmentalization on several levels – Tissue level – Organ level – Organ system level • There are barriers in between compartments • Properties/content may vary among different compartments Intracranial compartment, Cellular base of nervous system3 Compartmentalization • Cellular specialization leads to compartmentalization on several levels – Tissue level – Organ level – Organ system level • There are barriers in between compartments • Properties/content may vary among different compartments Intracranial compartment, Cellular base of nervous system4 Compartmentalization • Cellular specialization leads to compartmentalization on several levels – Tissue level – Organ level – Organ system level • There are barriers in between compartments • Properties/content may vary among different compartments Intracranial compartment, Cellular base of nervous system5 v v Intracranial compartment Intracranial compartment, Cellular base of nervous system6 ✓ „Very specific region“ ✓ Brain ✓ Cerebrospinal fluid ✓ Blood (intravasculary) ✓ Barriers • Meningeal • Hematoliquor • Hematoencephalic http://edutoolanatomy.wikispaces.com http://www.corpshumain.ca/en/Cerveau3_en.php Meningeal and hematoliquor barrier Intracranial compartment, Cellular base of nervous system7 https://sisu.ut.ee/histology/meninges https://sisu.ut.ee/histology/meninges Hematoencephalic barrier • Highly organised structure – Endothelial cells (low permeability thanks to zonlua occludens) – Basal membrane – Astrocytes – Pericytes Intracranial compartment, Cellular base of nervous system8 https://upload.wikimedia.org/wikipedia/commons/1/12/Blood_vessels_brain_english.jpg Hematoencephalic barrier 9 FSM (basic artwork: wikimedia commons) Intracranial compartment, Cellular base of nervous system Circumventricular organs • Rich vascularisation • Modified hematoencephalic barrier • Sensors • Secretion Intracranial compartment, Cellular base of nervous system10 http://www.neuros.org/index.php?option=com_photos&view=photos&oid=hafizbilal Cerebrospinal fluid • Content ✓ High levels of Mg+ and Na+ ✓ Low levels of K+ and Ca2+ ✓ Almost no cells (max 5/ml) • Function ✓ Protection ✓ Microenvironment of neurons and glia – Metabolic function – Immunologic function – Transport function and so on Intracranial compartment, Cellular base of nervous system11 http://www.control.tfe.umu.se PCh AG Cerebrospinal fluid • Clear fluidproduced by active secretion • Liquor space ➢ lined by ependymal cells ➢ 150-250 ml • Production ✓ Plexus choroideus (PCh) -70% ✓ Cell metabolism ✓ Cappilary filtration ➢ 450-750 ml/day • Resorbtion ✓ Archnoid granulations (AG) Intracranial compartment, Cellular base of nervous system12 http://www.control.tfe.umu.se PCh AG Cerebrospinal fluid • Clear fluidproduced by active secretion • Liquor space ➢ lined by ependymal cells ➢ 150-250 ml • Production ✓ Plexus choroideus (PCh) -70% ✓ Cell metabolism ✓ Cappilary filtration ➢ 450-750 ml/day • Resorbtion ✓ Archnoid granulations (AG) Intracranial compartment, Cellular base of nervous system13 http://www.control.tfe.umu.se PCh AG New insight into the production and resorbtion of CSF Intracranial compartment, Cellular base of nervous system14 • CSF – cerebrospinal fluid • ISF – interstitial fluid • VRS – Virchow Robin space (space between the pia mater and an artery or a vein, but not capillaries) Ducros A, Biousse V. Headache arising from idiopathic changes in CSF pressure. The Lancet Neurology. 2015;14:655–668. http://visnu528.blogspot.cz/2014/09/glymphatics-and- virchow-robin-space.html Intracranial compartment Intracranial compartment, Cellular base of nervous system15 • Brain • Cerebrospinal fluid • Blood (intravasculary) • Intracranial pressure (ICP) • Critical determinant of cerebral perfusion • Cerebral perfusion pressure (CPP) pressure gradient driving blood flow intracranialy http://edutoolanatomy.wikispaces.com !!! CPP = MAP – ICP !!!!!! CPP = MAP – ICP !!! Cerebral perfusion pressure Mean arterial pressure Intracranial pressure Cellular base of nervous system • Neuronal cells – Reception, integration and propagation of information – Unique, irreplaceable • Neuroglial cells – Support for neuronal cells – Easily replacable • The total amount of neuronal cells - 100 billions (1011) • Neruon/glia ratio – 1/10 - 50 (Principles of Neural Science, 4th ed., 2012) – 1/2 – 10 (Principles of Neural Science, 5th ed., 2012) – 1/1 (Nolte´s Human Brain, 7th ed., 2015) Intracranial compartment, Cellular base of nervous system16 Cellular base of nervous system • Neuronal cells – Reception, integration and propagation of information – Unique, irreplaceable • Neuroglial cells – Support for neuronal cells – Easily replacable • The total amount of neuronal cells - 100 billions (1011) • Neruon/glia ratio – 1/10 - 50 (Principles of Neural Science, 4th ed., 2012) – 1/2 – 10 (Principles of Neural Science, 5th ed., 2012) – 1/1 (Nolte´s Human Brain, 7th ed., 2015) Intracranial compartment, Cellular base of nervous system17 Neuroglial cells Intracranial compartment, Cellular base of nervous system18 Central nervous system Peripheral nervous system • Astrocytes – Hematoencephalic b. – Homeostasis maintaining – Metabolism of neurotransmitters – Important during brain development • Oligodendrocytes – Myelin sheat • Microglia – Immune funtion • Ependymal cells – Choroid plexus – (hemato-liquor barrier) – Ventricular lining (liquro-encephalic barrier) • Satelite cells – Support functions in PNS • Schwan cells – Myelin sheat Neuroglial cells Intracranial compartment, Cellular base of nervous system19 Central nervous system Peripheral nervous system • Astrocytes – Hematoencephalic b. – Homeostasis maintaining – Metabolism of neurotransmitters – Important during brain development • Oligodendrocytes – Myelin sheat • Microglia – Immune funtion • Ependymal cells – Choroid plexus – (hemato-liquor barrier) – Ventricular lining (liquro-encephalic barrier) • Satelite cells – Support functions in PNS • Schwan cells – Myelin sheat Neuroglial cells Intracranial compartment, Cellular base of nervous system20 Central nervous system Peripheral nervous system • Astrocytes – Hematoencephalic b. – Homeostasis maintaining – Metabolism of neurotransmitters – Important during brain development • Oligodendrocytes – Myelin sheat • Microglia – Immune funtion • Ependymal cells – Choroid plexus – (hemato-liquor barrier) – Ventricular lining (liquro-encephalic barrier) • Satelite cells – Support functions in PNS • Schwan cells – Myelin sheat Neuroglial cells Intracranial compartment, Cellular base of nervous system21 Central nervous system Peripheral nervous system • Astrocytes – Hematoencephalic b. – Homeostasis maintaining – Metabolism of neurotransmitters – Important during brain development • Oligodendrocytes – Myelin sheat • Microglia – Immune funtion • Ependymal cells – Choroid plexus – (hemato-liquor barrier) – Ventricular lining (liquro-encephalic barrier) • Satelite cells – Support functions in PNS • Schwan cells – Myelin sheat Neuroglial cells Intracranial compartment, Cellular base of nervous system22 Central nervous system Peripheral nervous system • Astrocytes – Hematoencephalic b. – Homeostasis maintaining – Metabolism of neurotransmitters – Important during brain development • Oligodendrocytes – Myelin sheat • Microglia – Immune funtion • Ependymal cells – Choroid plexus – (hemato-liquor barrier) – Ventricular lining (liquro-encephalic barrier) • Satelite cells – Support functions in PNS • Schwan cells – Myelin sheat Neuroglial cells Intracranial compartment, Cellular base of nervous system23 Central nervous system Peripheral nervous system • Astrocytes – Hematoencephalic b. – Homeostasis maintaining – Metabolism of neurotransmitters – Important during brain development • Oligodendrocytes – Myelin sheat • Microglia – Immune funtion • Ependymal cells – Choroid plexus – (hemato-liquor barrier) – Ventricular lining (liquro-encephalic barrier) • Satelite cells – Support functions in PNS • Schwan cells – Myelin sheat Neuroglial cells Intracranial compartment, Cellular base of nervous system24 Central nervous system Peripheral nervous system • Astrocytes – Hematoencephalic b. – Homeostasis maintaining – Metabolism of neurotransmitters – Important during brain development • Oligodendrocytes – Myelin sheat • Microglia – Immune funtion • Ependymal cells – Choroid plexus – (hemato-liquor barrier) – Ventricular lining (liquro-encephalic barrier) • Satelite cells – Support functions in PNS • Schwan cells – Myelin sheat Neuron Intracranial compartment, Cellular base of nervous system25 http://www.slideshare.net/drpsdeb/presentations Neuron Intracranial compartment, Cellular base of nervous system26 http://www.slideshare.net/drpsdeb/presentations The inside of the cell ✓ … ✓ Synthesis ✓ Transport ✓ … ✓ Signal reception ✓ Signal integration ✓ AP generatin ✓ AP propagation ✓ Signal transmission The membrane Background Activity Intracranial compartment, Cellular base of nervous system27 https://upload.wikimedia.org/wikipedia/commons/e/ed/Neuron_Cell_Body.png Background Activity Intracranial compartment, Cellular base of nervous system28 https://upload.wikimedia.org/wikipedia/commons/e/ed/Neuron_Cell_Body.png Background Activity Intracranial compartment, Cellular base of nervous system29 http://www.oapublishinglondon.com/images/article/pdf/1397255957.pdf Membrane potential • Due to differences in the concentrations of ions on opposite sides of a cellular membrane Intracranial compartment, Cellular base of nervous system30 http://www.slideshare.net/drpsdeb/presentations Resting membrane potential of a neuron • Highly instable state of membrane • Why? – Speed! • High energetical demands ✓ Oxygen - 20% of total body consumption ✓ Glucose – 25% of total body consumption Intracranial compartment, Cellular base of nervous system31 http://assassinscreed.ubi.com Action potential • Quick voltage change on the membrane • Spreads along the axon • All or nothing principle Intracranial compartment, Cellular base of nervous system32 http://www.slideshare.net/drpsdeb/presentations Action potential spreading • Local currents • Anterograde Intracranial compartment, Cellular base of nervous system33 http://www.slideshare.net/drpsdeb/presentations Saltatory conduction • Myelin sheat • Nodes of ranvier • Economy • Speed of conduction • Speed of conduction also dependent of nerve fibre diameter – the electrical resistance is inversly proportional to area of cross- section Intracranial compartment, Cellular base of nervous system34 http://www.slideshare.net/drpsdeb/presentations • In humans mostly myelinated • All fibers are myelinated in CNS • Non-myelinated are evolutionary old ones Intracranial compartment, Cellular base of nervous system35 Classification of nerve fibers http://neuroscience.uth.tmc.edu/s2/chapter04.html Neuronal classification 36 http://www.slideshare.net/CsillaEgri/presentations Intracranial compartment, Cellular base of nervous system Neuronal classification Intracranial compartment, Cellular base of nervous system37 http://www.slideshare.net/CsillaEgri/presentations Neuronal classification Intracranial compartment, Cellular base of nervous system38 http://www.slideshare.net/CsillaEgri/presentations 68. Cellular base of nervous system Intracranial compartment, Cellular base of nervous system39 ✓ Neuroglial cells • Classification and functional overview ✓ Neuronal cells • Characterization, classification, anatomy • Functions of neurons • Background activity (cytoplasm) • Synhtesis (soma) • Transport (categorization, characterization) • Information processing and transmission (membrane) • Main points of question No. 70 69. Intracranial compartment, intracranial pressure Intracranial compartment, Cellular base of nervous system40 ✓ Content of intracranial compartment (brain, blood, CSF) ✓ Barriers among compartments (meningeal, hematoencephalic, hematoliquor) • HEB description • Circumventricular organs ✓ CSF • Function • Production, circulation, absorption ✓ Intracranial pressure • Definition, equation, implications 70. Membrane voltage, action potential – generation and propagation through nerve fibers Intracranial compartment, Cellular base of nervous system41 ✓ Membrane potentials • General characteristics and ionic mechanisms description ✓ Resting potential in neuron (characteristics) ✓ Action potential • Characteristics • Ionic mechanisms • Signal conduction • Role of myelin, saltatory conduction ✓ Classification of nerve fibres