Exam 1:Notes 1:4. The motor proteins that are mostly responsible for the retrograde movement of vesicles in the axon are called dyneins.Book: pg. 140Notes: slide 3Kinesin and Dynein motor proteins are required for axonal transport.Kinesin transport mainly occurs from the cell body towards the axon terminals (anterograde). Important in moving nutrient molecules, enzymes, mitochondria, neurotransmitter filled vesicles, and other organelles. Dynein movement is in the other direction (retrograde). Important in carrying recycled membrane vesicles, growth factors, and other chemical signals that can affect the neuron’s morphology, biochemistry, and connectivity.Retrograde transport is also how some harmful agents invade the CNS.MC 10. A postsynaptic neuron has three presynaptic inputs – from neurons X, Y, and Z. When X and Y are stimulated simultaneously and repeatedly, the postsynaptic neuron reaches a threshold and undergoes an action potential. When X and Z are stimulated spontaneously, however, there is no change in the membrane potential of the postsynaptic neuron. What can you about the presynaptic neurons Y and Z?A. They are probably both excitatory B. They are probably both inhibitory C. Y is probably excitatory and Z is probably inhibitoryD. Z is probably excitatory and Y is probably inhibitoryE. Cannot determine from information given Book: pg. 142Notes: ???MC3. Which incorrectly pairs a glial cell type with an associated function?A. Microglia; performance of immune function in the CNSB. Oligodendrocytes; formation of myelin sheaths on axons in the PNSC. Astrocytes; formation of the blood-brain barrierD. Ependymal cells; production and “mixing” of cerebrospinal fluid E. Radial glia; neuron guidance during cortex formationBook: pg. 142 and pg. 143Notes: Slide 6 and Slide 8Notes:PNS: Satellite cells Supports cell bodies Schwann cells Forms Myelin sheaths Secretes Neurotrophic factorsCNS: Oligodendrocytes Forms Myelin sheaths Astrocytes Support for CNS Helps form Blood-brain barrier Secretes Neurotrophic factors Takes up K+ and neurotransmitters Microglia Act as scavengers Ependymal Cells Creates barriers between compartments Source of neural stem cells 2. List an extracellular matrix (ECM) glycoprotein involved in growth cone guidance: Fibronectin/ Filopodia???Book: pg.143Notes: Slide 11MC5. Put the following events in order of occurrence. (Some steps may be omitted.)1. The axon is re-myelinated2. Distal portion of the axon degenerates3. Regeneration tube releases neurotrophic factors4. Schwann cells survive and multiply5. The regenerating axon extends to the synaptic site.6. Schwann cells form a tube.A. 2-6-4-3-5-1B. 4-6-2-3-1-5C. 2-4-6-3-5-1D. 2-4-6-3-1-5E. 4-6-2-3-5-1Book: pg.143Notes: Slide 21MC11. The autoimmune demyelinating disease that affects the periperhal nervous system and is characterized by the rapid onset of muscle weakness and ascending paralysis is…A. Amyotrophic lateral sclerosisB. LeukodystrophyC. Guillain-BarreD. Muscular DystrophyE. None of theseNotes 2:MC6. Which of the following statements about the phases of an action potential is/are correct?A. During the depolarizing phase, the permeability of the membrane to the sodium ion is greater than its permeability at restB. During the hyperpolarizing phase, the permeability of the membrane to sodium ion is greater than its permeability at rest.C. During the repolarizing phases, the permeability of the membrane to potassium ion is greater than its permeability at restD. A and CE. B and C Book: pg. 154Notes: Slide 61) Steady resting membrane potential is near EK, PK > PNA, due to leak K+ channels.2) Local membrane is brought to threshold voltage by a depolarizing stimulus.3) Current through opening voltage-gated Na+ channels rapidly depolarizes the membrane, causing more Na+ channels to open.4) Inactivation of the Na+ channels and delayed opening of voltage gated K+ channels halt membrane depolarization5) Outward current through open voltage-gated K+ channels repolarizes membrane back to a negative potential.6) Persistent current through slowly closing voltage-gated K+ channels hyperpolarizes membrane toward EK; Na+ channels return from inactivated state to closes state (without opening). 7) Closure of voltage-gated K+ channels returns the membrane potential to its resting value.On the following graph representing an action potential, clearly circle the part of the graph that represents the relative refractory period.In one short sentence, explain why the region you circled above is call a relative refractory period.It is possible for a second action potential to be produced here, if the stimulus is considerably greater, because the Na+ voltage-gated channels have been inactivated and the K+ voltage-gated channels remain open. Book: pg. 154 and pg. 156 Notes: Slide 6 5. Synaptotagmin is a calcium-sensitive protein that has been shown to mediate thelast step of the vestibular fusion necessary to release neurotransmitter. This protein may have a positive or negative regulatory effect.Book: pg. 162Notes: Slide 10 MC7. Temporal summation on a postsynaptic membrane…A. Inevitably leads to action potentials in the axonB. Refers to the effect on the membrane of one (or more) synaptic event before the effects of a previous synaptic event have died awayC. Refers only to addition of EPSPsD. Refers only to the effect of stimulating different synapses repeatedlyE. Is described by none of these choices Book: pg. 164Notes: Slide 12The axon is stimulated for a second time before the first EPSP has died away; the second synaptic potential adds to the previous one and creates a greater depolarization than from the first one alone. This is called temporal summation because the input signals arrive from the same presynaptic cell at different times. The potentials summate because there are a greater number of open ion channels and, therefore, a greater flow of positive ions in to the cell. 3. When the axon of one neuron (A) synapses on the axon of another neuron (B) and results in a reduction in the amount of neurotransmitter released by neuron B, presynaptic inhibition has occurred.Book: pg. 165Notes: Slide 14Match the descriptor to the correct division of the nervous system.9. A Innervates skeletal muscle10. B 2-neuron chain11. B Excitatory or Inhibitory 12. B Includes a ganglion 13. A Consists of a single neuron from CNS to target Book: pg. 179Notes: ???MC1.