1. Biology presentation Lu Wei Chen xinlu Hu zhenzhen He shanliang Minh Tue

2. Our topic The transmission of nerve signals from one neuron to another is often mediated by chemical substances, or neurotransmitters. Explain how electrical signals arriving at the pre- synaptic neuron are converted to chemical signals and back to electrical signals at the post-synaptic neuron. In addition to chemical neurotransmitters, what other forms of signals may be transmitted between two neurons. The transmission of nerve signals from one neuron to another is often mediated by chemical substances, or neurotransmitters. Explain how electrical signals arriving at the pre- synaptic neuron are converted to chemical signals and back to electrical signals at the post-synaptic neuron. In addition to chemical neurotransmitters, what other forms of signals may be transmitted between two neurons.

3. Neurons create electrical signals across their membranes The researchers found that unstimulated, inactive neurons maintain a constant electrical difference, or potential, across the poles of a battery. As in a battery, the electrical potential across a neuron membrane stores energy. This potential across a neuron membrane stores energy, called the resting potential,that is always The researchers found that unstimulated, inactive neurons maintain a constant electrical difference, or potential, across the poles of a battery. As in a battery, the electrical potential across a neuron membrane stores energy. This potential across a neuron membrane stores energy, called the resting potential,that is always

4. negative inside the cell and ranges from-40 to-90 mV. If the neuron is stimulated, either naturally or by an experimenter, the negative potential inside the neuron can be made either more or less negative. If it is made enough less negative that it reached a level called threshold, an action potential is triggered. During an action potential, the neuron’s potential rapidly rises to about +50mV inside the cell.

5. Action potentials last a few milliseconds before the cell’s negative resting potential flows rapidly down the axon to the synaptic terminal, where the signal is communicated to another cell at a synapse. Action potentials last a few milliseconds before the cell’s negative resting potential flows rapidly down the axon to the synaptic terminal, where the signal is communicated to another cell at a synapse.

7. Neuron communicate at synapses Once an action potential reaches the synaptic terminal of a neuron, a muscle cell, or a gland. This transmission occurs at synapses. The signals transmitted at synapses are called postsynaptic potentials. At a synaptic terminal, an action potential encounters a synapse, where parts of 2 neurons are specialized to communicate with one another. Once an action potential reaches the synaptic terminal of a neuron, a muscle cell, or a gland. This transmission occurs at synapses. The signals transmitted at synapses are called postsynaptic potentials. At a synaptic terminal, an action potential encounters a synapse, where parts of 2 neurons are specialized to communicate with one another.

8. A tiny gap separates the synaptic terminal of the first neuron, the pre-synaptic neuron, from the second neuron, the postsynaptic neuron. Both the dendrites and the cell bodies of neurons are typically covered with synapses. The synapse includes the synaptic terminal of the pre- synaptic neuron, the gap, and the specialized membrane of the postsynaptic neuron, which

9. Which contains receptors for neurotransmitters. When an action potential reaches a synaptic terminal, the inside of the terminal becomes positively charged. This charge causes storage vesicle in the synaptic terminal to release neurotransmitter molecules rapidly diffuse across the gap and briefly bind to receptors in the membrane of the postsynaptic neuron before

10. Diffusing away and being taken back into the presynaptic neuron. Diffusing away and being taken back into the presynaptic neuron.

11. The other forms of signals Postsynaptic potential (PSP) Postsynaptic potential (PSP) Excitatory postsynaptic potential Excitatory postsynaptic potential (EPSP) (EPSP) Inhibitory postsynaptic potential (IPSP)

12. Thank for your kind attention