Topic List for Chapter 6 Know the main divisions of the nervous system and what major anatomical structures are found in each CNS and PNS CNS Brain Spinal cord PNS sensory outside to CNS motor CNS to outside Nerves spinal cranial leaves or enters brain Know the different types of cells that are found in nervous tissue Which can be found in the CNS Which can be found in the PNS What are the functions of each Neurons functional cells that generate action potentials in CNS and PNS Generate electrical signals that travel from one part of the body to another Glial Cells aka neuroglia can regenerate PNS and CNS Provide support Regulate things In CNS DON T send signal but can affect how neuron sends signal 1 Astrocytes structure regulate BBB at capillaries provide nutrition for neurons 2 Oligodendrocytes extensions that wrap around axons create myelin insulates axon nonpolar sends signal faster white matter sheath around axons myelin sheath in CNS 3 Microglia mobile move around interstitial fluid defense against pathogens and toxins phagocytic 4 Epidemal cells line ventricles in brain and in spinal cord produce some CSF and regulate it have cilia to help move CSF In PNS 1 Schwann Cells makes myelin sheath in PNS 2 Satellite Cells surround neuron bodies in PNS Know the different parts of a typical neuron Fig 6 1 Cell body Dendrites receive signal from other cells Axon generate axon potential Initial segment axon hillock trigger zone of axon or axon Know how materials are transported within the neuron Fig 6 3 Axonal transport microtubule runs length of axon proteins that move across it kinesins and dyneins Double headed motor protein that has cellular cargo uses ATP derived fro hydrolysis to move across microtubule Kinesin transport anterograde moving nutrient molecules enzymes mitochondria neurotransmitter filled vesicles and other organelles only goes from cell body to axon terminal ONE WAY Dynine transport retrograde old used up recycled membrane vesicles growth factor and other chemical signals that can have effect on neurons morphology biochemistry and connectivity only goes one way from axon body harmful agents can invade cell bodies terminal to cell Know the different functional classes of neurons where they are found and where there cell bodies are located PNS or CNS Afferent PNS CNS and interneurons integrating center tells cell how to respond efferent Neurons PNS glands muscles Know what a synapse is Occurs at synaptic cleft gap between neuron post and pre synaptic the chemical or electrical signal that crosses a synaptic cleft to pass information can be inhibitory or excitatory Understand resting membrane potential and what factors establish it What voltage is it in a neuron What ions and membrane proteins are responsible for establishing resting membrane potential Resting potential distribution of voltage charge across whole cell net negative charge on inside positive on outside higher k concentration on inside and higher concentration of Na on outside Resting charge 70 MV Know what graded potentials and action potentials are and how they are related to one another Know all the ions membrane proteins associated with an action potential and the orders of events that occur during action potential How signal is sent 1 Reception which triggers change in membrane potential Message comes in chemical light voltage temp most influential ions sodium potassium chloride NA K pump Graded potential comes before action small signal small change always happens Na channels open very short so only small change Receptor Potential cause by sensory receptor touch smell light Synaptic Potential generated at synapse Pacemaker Potential random change in membrane spontaneous firing in heart Action potential if channel is open long enough it hits threshold and becomes action potential Threshold 55 MV opens closed sodium channels around it 2 Action potential initiated Sodium rushes into cell GP reaches threshold triggers AP All or non response if threshold not reached AP not produced If happens all same peak volume Action potential curve understand chart de re hyper polarization Depolarization AP membrane that is positively charge and increases as sodium in released goes up towards positive Repolarization goes towards negative goes down potassium released Hyperpolarization goes even more negative membrane potential goes lower than resting Refractory Absolute inactive or open so it cant fire a second AP during this time because sodium channels need to reset Relative increase a little bit past absolute still generate AP require higher voltage and output lower amp but still can fire some channels reset 3 Action potential on the move continue to move down axon Compound AP CAP summing of AP from different neurons in a nerve AP occurs in a single neuron but nerve is thousands of neurons so all signal and come together to nerve signal 4 Transmission Ranvier At axon terminal neurotransmitters released into synaptic cleft aka extracellular space Node of Released sent to other neuron or goes to effector hit target cell muscles fertilized egg neurons sensory cells endocrine cells Know the factors that affect the speed at which an action potential moves along an axon Temp higher temp faster but not too high Axon diameter smaller faster Myelinated salutatory conduction Know what synapses are and that they can be either chemical or electrical Know how each functions What causes neurotransmitter to be release by a presynaptic cell and how does release occur How does the neurotransmitter reach the postsynaptic cell and what happens when it does What happens to the neurotransmitter after the signal for its release ends What affects can the neurotransmitter have on the postsynaptic cell and how do they occur Electrical pre post synaptic cells connected by gap junctions neurons touch each other Chemical pre synaptic neurons release neurotransmitters from axon terminals so NT bind to receptor on post synaptic neuron again Once receptors let go of NT they are brought back into cell reuptake can occur NT can be used Ex SSRI s prevent reuptake so there is more serotonin in synaptic cleft Snares involved with very end of presynaptic cell Protein complex that is involved I releasing vesicles of neurotransmitters to synaptic cleft Voltage gated calcium channel opens calcium enter cell binds with snare complex causes exocytosis of vesicles of NT once they let go of NT they are into cell reuptake brought back What is synaptic