PPT 11 Your Nervous System PDF

1/5/2023 PPT 11 Your Nervous System Nervous System Fig. 16.1 1  1/5/2023 Nervous System Nervous System Fig. 12.1 2 ...

1/5/2023 PPT 11 Your Nervous System Nervous System Fig. 16.1 1  1/5/2023 Nervous System Nervous System Fig. 12.1 2  1/5/2023 Nervous System Fig. 12-3 Nervous System Fig. 12-5 3  1/5/2023 Nervous System Neuroglial cells Nervous System Fig. 12-7 4  1/5/2023 Nervous System Fig 12.8 Nervous System Na (sodium ion channels) Fig. 12-10a 5  1/5/2023 Nervous System Fig. 12-10b Nervous System Fig. 12-10c 6  1/5/2023 Nervous System Intro to Resting Potential in Neurons All potentials result from ions moving across membranes. Two forces on ions: Diffusion (from high to low concentration); Electrical (toward opposite charge and away from like charge). Each ion that can flow through channels reaches equilibrium between two forces. The difference to create the final # of -70mV is from using the Na/K pump Nervous System Concentration of Ions and State of Channels at Rest -65 mV Concentrations maintained by Na+/K+ and Ca++ pumps. 7  1/5/2023 Nervous System Pumps Exchange Ions All cells have pumps and resting potentials (The neuron will be -70mV). Pumps use ATP to exchange ions. Na+/K+ pump: 3 Na+ out and 2 K+ in. Ca++ pump: Keeps powerful Ca++ ions out. Nervous System Resting Potential Results from Passive K+ Channels and EK+ At rest, membrane potential is -70 mV in most neurons. Why? K+ is most permeable, due to leak of K+ through passive K+ channels. Therefore, K+ ions leave, making the inside more negative. 8  1/5/2023 Nervous System Membrane has more K channels than Na channels 9