Slide 13-1 Cells of the nervous system3-1 Cells of the nervous systemSlide 4Slide 53-1 Cells of the nervous system3-1 Cells of the nervous systemSlide 83-1 Cells of the nervous system3-1 Cells of the nervous system3-1 Cells of the nervous system3-1 Cells of the nervous systemSlide 133-1 Cells of the nervous system3-1 Cells of the nervous system3-1 Cells of the nervous system3-1 Cells of the nervous system3-1 Cells of the nervous system3-1 Cells of the nervous systemSlide 20Slide 213-1 Cells of the nervous system3-1 Cells of the nervous system3-1 Cells of the nervous system3-1 Cells of the nervous system3-1 Cells of the nervous system3-1 Cells of the nervous systemSlide 283-1 Cells of the nervous system3-1 Cells of the nervous system3-1 Cells of the nervous system3-1 Cells of the nervous systemSlide 333-1 Cells of the nervous system3-1 Cells of the nervous systemChapter 3:What Are the Functional Units of theNervous System?3-1 Cells of the nervous system•The neuron–Golgi stain–Cajal–Golgi thought they were all connected–Cajal proposed that they were individual neurons3-1 Cells of the nervous system•The neuron–Communicates–Cell body•Like other cells–Dendrites•Receive information–Axon•Sends information3-1 Cells of the nervous system•Visualization–Stains–Brainbow•Genes introduced into mice that express blue, green, and yellow fluorescent proteins•https://www.youtube.com/watch?v=IZCZV5-v3S4https://www.youtube.com/watch?v=c-NMfp13Uug3-1 Cells of the nervous system•Neurons: the basis of information processing–We have about 100 billion neurons–Typically, large numbers of neurons work together to produce behavior–Most CNS neurons are never replaced•But some types of behaviors depend the production of new neuronsA) Golgi StainB) Typical neuronC) Electron micrographD) Light microscope3-1 Cells of the nervous system•Structure and function–Dendritic spines•Small protrusions on dendrites •Point of contact between cells–Axon•Fiber that carries messages from one neuron to the next–Axon Hillock (little hill)•At the beginning of the axon•Many voltage-gated Na+ channels–Terminal Button•At the end of each axonal branch•Projects to dendrites of other cells–Synapse•Space between cells (between terminal and dendrite)•Sight of information transfer between neurons3-1 Cells of the nervous system•Dendritic spines3-1 Cells of the nervous system•Axon Hillock•Terminal button3-1 Cells of the nervous system•Synapse–Chemicals across synaptic clef3-1 Cells of the nervous system•Communication–Stimulation results in changes in ion concentrations•Excitatory: more positive–Action potential•Series of channels open and let in positively charged ions; this propagates down the axon–Synapse•Electrical changes result in the release of chemicals•These chemicals cross from axon terminals of one cell to dendrites of the nexthttps://www.youtube.com/watch?v=oLSmNcem2X0https://www.youtube.com/watch?v=p5zFgT4aofA3-1 Cells of the nervous system•3 types of neurons–Sensory neurons•Receive and transmit sensory information–Motor neurons•Transmit motor commands–Interneurons•Everything in between•Most neurons (in humans) are interneurons3-1 Cells of the nervous system•Sensory Neurons–Convey sensory information3-1 Cells of the nervous system•Motor Neurons–Send motor commands to muscles3-1 Cells of the nervous system•Interneurons –Link up sensory and motor signals–Ofen branch extensively–Most of the neurons in our brains are interneurons3-1 Cells of the nervous system•Language of neurons: Excitation and inhibition –Networks with elaborate interconnections–Communication is the result of excitatory and inhibitory signaling•Neurons send “yes” or “no” signalsto one another•Cricket robothttps://www.ted.com/talks/heather_knight_silicon_based_comedy3-1 Cells of the nervous system•Glial Cells–Support cells of the nervous system–Aid neurons–Do not transmit information themselves, but help neurons do so•Bind, insulate, support, provide nutrients, protection3-1 Cells of the nervous system•5 types of glial cells–Ependymal Cells–Astrocytes–Microglia–Oligodendroglia–Schwann cells3-1 Cells of the nervous system•Ependymal Cells–Line the walls of the ventricles–Secrete cerebrospinal fluid (CSF)–CSF is constantly formed and flows through ventricles to the base of the brain where it is absorbed by blood vessels•CSF–Shock absorber, waste elimination, assists in maintaining temperature, provides nutrients to areas around ventricles3-1 Cells of the nervous system•Hydrocephalus–Results from a blockage in the 4th ventricle in newborns–CSF builds up and expands the ventricles–Baby’s head swells (skull bones not fully formed)–Can cause severe mental retardation and even death3-1 Cells of the nervous system•Astrocytes (astroglia)–Star-shaped cells that provide support–Provide scaffolding that hold neurons in place–Secrete chemicals to keep neurons healthy and help them heal if injured–Dilate blood vessels to allow more glucose and oxygen to get to neurons for fuel–Form a scar to seal off damaged brain tissue•This can also prevent regrowth of damaged neurons–Create the blood-brain barrier3-1 Cells of the nervous system•Blood-brain barrier–Astrocyte processes attach to blood vessels causing them to bind tightly together–Prevents toxic molecules from entering the brain–Also blocks useful drugs, like penicillin•Brain infections are very hard to treat3-1 Cells of the nervous system•Microglia–Monitor the health of brain cells and play a role in its immune system–Engulf foreign tissue and dead brain cells•Phagocytosis–Remove waste–Provide growth factors that aid in repair•Alzheimer’s–Associated with plaques –Microglia consume plaques3-1 Cells of the nervous system•Microglia–Phagocytosis•When full, take on a distinctive appearance, which can be seen near damaged brain regionsA) Red nucleusB) Stained neurons in the red nucleusC) After exposure to a neurotoxin. Only microglia are present3-1 Cells of the nervous system•Oligodendroglia and Schwann cells–Myelinate axons–Myelin: glial coating that insulates neurons•Electrical signals travel down axons as part of neural communication3-1 Cells of the nervous system•Neuronal repair–PNS axons can regrow if cut•But slowly–Microglia remove debris lef by dying