BSC 2011 Lecture Notes - Lecture 26: Sympathetic Nervous System, Autonomic Nervous System, Myelin
25 Mar 2015
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Bsc2011 - integrated principles of biology 2 - lecture 26: animal unit review. You would have to feed bigger animals more food overall but less food/gram of mass compared to smaller animals. 100 pound dog needs less food than ten 10 pound dogs. Neurotransmitters are released by ca2+ in the presynaptic cell. Neurotransmitters bind to ligand-gated channels and allow ions to pass through. Graded potentials: changes in membrane potential that do not reach threshold. All or none: if the stimulus exceeds threshold potential, there is a complete response. Strength does not matter after threshold is reached. Leaky channels: always open for k+ to flow out, explains -60 mv inside neuron. Rise in positive electrical energy: from na+ flowing in. Fall in electrical energy: from k+ leaving. It forces current to flow to the next node and not out of the axon. Sensory neuron (afferent)->cns->motor neurons (efferent)->muscles or gland. Autonomic nervous system: controls cardiac and smooth muscle.
