BIOL 101 1nd Edition Lecture 34 Outline of Last Lecture I. Cell Mediated Adaptive Response II. Cytotoxic T CellIII. Self Nonself Complex Outline of Current Lecture I. Nervous SystemII. Central Nervous SystemIII. Peripheral Nervous SystemIV. Nervous TissueV. NeuronsVI. Action PotentialsVII. NeurotoxinsCurrent LectureClass DiscussionNervous SystemI. Parts of the Nervous System1. Central Nervous System (CNS): Interprets and formulates responses to signals from the body.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.a. Brain – central controller of the nervous systemb. spinal cord – sends signals to the brain and the body and vice versa.2. Peripheral Nervous System (PNS): Carries signals to and from the body and the spinal cord/brain (sends signals from sensory nerves to the brain and then the brain sends signals back)a. cranial nerves – neurons that are directly connected to the brainb. spinal nerves – connected to the spinal cord. 3. Nervous Tissuea. Neurons (aka nerve cells) – transmit electrical signals through the bodyi. At rest, the outside of the neuron is + charged, while the inside of the neuron is - chargedb. Glial Cells – support and nourish neuronsi. Myelin sheath – insulates nerves and lets the signal move faster. Myelin sheath is made up of glial cells (called Schwann cells)!II. How the Nervous System Works1. Sensory Input: where the PNS receives a signals from the outside world and sends it to the central nervous system2. Integration: brain formulates a response 3. Motor Output: the brain sends signal to the body part telling it to respond in a certain way. III. DRAW A NEURON: Try this at home!Label and define: dendrites, cell body, axon, Schwann cells, myelin sheath, synaptic terminal, synaptic vesiclesDRAW AN AXON: Try this at home!Label: ions, ion channels,what they do, direction of ion flowIV. Action Potentials – how the neuron propagates a signal down the axonV. Action Potential Diagram: GRAPH AN ACTION POTENITAL! 12345cell receives a stimulus (the dendrites receive the stimulus) the neuron will become slightly positively charged. Action potential threshold is the minimum increase in voltage required for an action potential to occur.cell receives a stimulus (the dendrites receive the stimulus) the neuron will become slightly positively charged. Action potential threshold is the minimum increase in voltage required for an action potential to occur.Threshold is reached -> sodium channels open; sodium flows into the cell, cell becomes positively charged.Threshold is reached -> sodium channels open; sodium flows into the cell, cell becomes positively charged.when neuron reaches peak positive charge. Potassium channels open and sodium channels close. when neuron reaches peak positive charge. Potassium channels open and sodium channels close. Potassium flows out of cell neuron becomes negatively charged again. This makes potassium ion channels close again. Potassium flows out of cell neuron becomes negatively charged again. This makes potassium ion channels close again. Sodium/Potassium pump resets ion concentrations cell is now ready for the next action potential. Sodium/Potassium pump resets ion concentrations cell is now ready for the next action potential.VI. How Neurons Communicate With Each Other:1. AP gets sent down 2. NT released to synaptic cleft 3. NT binds to receptor 4. NT causesions channels to open VII. Neurotoxins1. tetrodotoxin is found in puffer fish, and is also found in “Zombie Potions”2. TTX blocks the sodium channels in the axons , so the action potential cannot propagate3. This keeps signals from being sent through the
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