01:119:116 Lecture Notes - Lecture 19: Polyspermy, Axon Hillock, Membrane Potential

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lemonyellowjacket537

28 Mar 2017

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Conduct messages as electrical signals and integrate information. A neuron is: cell body-contains all organelles: neuron anatomy. Axon: transmits neural impulse away from cell body to: Usually just one long axon > 1m in a giraffe. End of axon divides (usually) into many branches. Nerve=axons of many neurons, held together with connective tissues. Result is that there is a difference in % ions inside (cytosol) and outside (extra- cellular fluid) of a membrane. Only excitable cells can rapidly generate changes in membrane potential. Resting potential (rp) between -60 and -80 mv. -70mv = maintained by the sodium-potassium pump & ion channels. Sodium-potassium pump 3na+ out, 2 k+ into cell. Each pump requires atp to pump against the gradient. Ion channels-ions defuse across membrane as they move, they carry an electrical charge. Any net movement of + or generates membrane potential (the possibility of doing some work) The membrane is 100x more permeable to k+ than na+

Related Questions

Nerve cells that conduct messages are called (1) ____. (2) _____ cells, which support and nurture the activities of neurons, make up less than half the volume of the nervous system. (3) _______ neurons respond to specific kinds of environmental stimuli, (4) ______ connect different neurons in the spinal cord and brain, and (5) ______ neurons are linked with muscles or glands. All neurons have a (6) _______ ________ that contains the nucleus and the metabolic means to carry out protein synthesis. (7) _______ are short, slender extensions of the (6), and together these two neuronal parts are the neuronsâ âinput zoneâ for receiving (8) _____. The (9) _____ is a single long, cylindrical extension away form the (10) ______; in motor neurons, the (11) ______ has finely branched (12) ________ that terminate on muscle or gland cells and are âoutput zones,â where messages are sent on to other cells. A neuron at rest establishes unequal electric charges across its plasma membrane, and a(n) (13) ____ ____ is maintained. Another name for (13) is the (14) _____ _____ _____; it represents an ability for the membrane to be disturbed. Weak disturbances of the neuronal membrane might set off only slight changes across a small patch, but strong disturbances can cause a(n) (15) _______ ______, which is an abrupt, short-lived reversal in the polarity of charge across the plasma membrane of the neuron. For a fraction of a second, the cytoplasmic side of a bit of membrane becomes positive with respect to the outside. The (16) ______ that travels along the neural membrane is nothing more than short-lived changes in the membrane potential. A. Neurons H. Sensory B. Motor I. Endings C. Interneurons J. Disturbance D. Cell body K. Signals (stimuli) E. Axon L. Voltage differential F. Dendrites M. Resting membrane potential G. Neuroglial N. Action potential

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01:119:116 Lecture Notes - Lecture 19: Polyspermy, Axon Hillock, Membrane Potential

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