THE NERVOUS SYSTEM
... Þ Any resulting net movement of positive or negative charge will generate a membrane potential, or voltage across the membrane Þ The concentration gradients of ions across the plasma membrane represent a chemical form of potential energy that can be harnessed for cellular processes ...
... Þ Any resulting net movement of positive or negative charge will generate a membrane potential, or voltage across the membrane Þ The concentration gradients of ions across the plasma membrane represent a chemical form of potential energy that can be harnessed for cellular processes ...
Cells and Their Environment
... Many ions are important for cell functions • Important in heartbeat and nerve cells ...
... Many ions are important for cell functions • Important in heartbeat and nerve cells ...
refractory period
... (milliseconds), long-distance (up to meters) communication in the body • As opposed to • chemical messages - which can be longdistance, but slow (seconds to minutes) • decremental electric currents - which are rapid, but can only operate over short distances (a few tens of microns) ...
... (milliseconds), long-distance (up to meters) communication in the body • As opposed to • chemical messages - which can be longdistance, but slow (seconds to minutes) • decremental electric currents - which are rapid, but can only operate over short distances (a few tens of microns) ...
9.2 Electrochemical Impulses
... 2. Na+ moves into cell following a concentration gradient (diffusion) and also an electrical potential gradient. The positive charge moving into the neuron reduces the potential difference of the membrane . This is ...
... 2. Na+ moves into cell following a concentration gradient (diffusion) and also an electrical potential gradient. The positive charge moving into the neuron reduces the potential difference of the membrane . This is ...
HONORS BIOLOGY Chapter 28 Nervous Systems
... Resting potential—voltage across the plasma membrane The resting potential exists because of differences in ion concentration inside and outside a cell ...
... Resting potential—voltage across the plasma membrane The resting potential exists because of differences in ion concentration inside and outside a cell ...
Homeostasis and Cell Transport
... membrane, which folds itself and forms a pouch. •The pouch pinches off from the cell membrane and becomes a vesicle. •Some vesicles fuse with lysosomes. •2 types: ...
... membrane, which folds itself and forms a pouch. •The pouch pinches off from the cell membrane and becomes a vesicle. •Some vesicles fuse with lysosomes. •2 types: ...
PHYS 222 Exam 1 Study Guide
... - Potential Energy vs. Potential: Potential energy exists between two particles, potential is a measure of how much potential energy a particle would have if it were there. - Work done by electric field is equal in magnitude and opposite in sign to the change in potential energy of the particle in q ...
... - Potential Energy vs. Potential: Potential energy exists between two particles, potential is a measure of how much potential energy a particle would have if it were there. - Work done by electric field is equal in magnitude and opposite in sign to the change in potential energy of the particle in q ...
Chapter 5: Cell Transport
... III. Facilitated Diffusion – diffusion assisted by specific proteins called carrier proteins Steps in Facilitated Diffusion a) Carrier protein binds to molecule b) Carrier protein changes shape, protecting molecule from the interior of cell membrane c) Molecule is released on other side, protein re ...
... III. Facilitated Diffusion – diffusion assisted by specific proteins called carrier proteins Steps in Facilitated Diffusion a) Carrier protein binds to molecule b) Carrier protein changes shape, protecting molecule from the interior of cell membrane c) Molecule is released on other side, protein re ...
Transport
... Phosphorylation occurs (from ATP hydrolysis)- to transport protein allowing it to change shape Na+K+ pump is an example (page 76) 2. Secondary active transport Single ATP pump or primary pump can drive this type of active transport As sodium is moved across its concentration gradient, ener ...
... Phosphorylation occurs (from ATP hydrolysis)- to transport protein allowing it to change shape Na+K+ pump is an example (page 76) 2. Secondary active transport Single ATP pump or primary pump can drive this type of active transport As sodium is moved across its concentration gradient, ener ...
Chapter 17 Part A
... - charge inside changes to positive as Na+ ions flood interior - increases until rising voltage opposes inward flow of Na+ (peak of the graph) - repolarization from +40 mV to –65 mV - sodium gates close and potassium gates (in addition to channels) open - axon resumes a negative charge as K+ ions mo ...
... - charge inside changes to positive as Na+ ions flood interior - increases until rising voltage opposes inward flow of Na+ (peak of the graph) - repolarization from +40 mV to –65 mV - sodium gates close and potassium gates (in addition to channels) open - axon resumes a negative charge as K+ ions mo ...
Cell Walls and Boundaries Cells protect themselves by their cell
... If the substance can cross the cell membrane, its particles will tend to move toward the area of less concentration until it is even or at a state of equilibrium ...
... If the substance can cross the cell membrane, its particles will tend to move toward the area of less concentration until it is even or at a state of equilibrium ...
Chapter 2
... Electrostatic pressure – the attractive force b/t atomic particles charged with opposite signs or the repulsive force b/t atomic particles charged with the same sign ...
... Electrostatic pressure – the attractive force b/t atomic particles charged with opposite signs or the repulsive force b/t atomic particles charged with the same sign ...
Neural_Tissue_notes
... Due to uneven distribution of Na & K, especially K, across the cell membrane: more K inside than outside. (Na is opposite: more Na outside). Membrane at rest is mainly permeable to K (although it can & does become more K-permeable during the late phase of an action potential). At rest, the transmemb ...
... Due to uneven distribution of Na & K, especially K, across the cell membrane: more K inside than outside. (Na is opposite: more Na outside). Membrane at rest is mainly permeable to K (although it can & does become more K-permeable during the late phase of an action potential). At rest, the transmemb ...
Basis of Membrane Potential Action Potential Movie
... Generate Action Potentials • Action potential (AP) is a sudden and major change in membrane potential – Lasts 1-2 milliseconds – Pulse of electric charge is conducted along the axon at speeds up to 100 meters per second – Membrane potential changes from -60 to +50 mV ...
... Generate Action Potentials • Action potential (AP) is a sudden and major change in membrane potential – Lasts 1-2 milliseconds – Pulse of electric charge is conducted along the axon at speeds up to 100 meters per second – Membrane potential changes from -60 to +50 mV ...
Membrane potential
Membrane potential (also transmembrane potential or membrane voltage) is the difference in electric potential between the interior and the exterior of a biological cell. With respect to the exterior of the cell, typical values of membrane potential range from –40 mV to –80 mV.All animal cells are surrounded by a membrane composed of a lipid bilayer with proteins embedded in it. The membrane serves as both an insulator and a diffusion barrier to the movement of ions. Ion transporter/pump proteins actively push ions across the membrane and establish concentration gradients across the membrane, and ion channels allow ions to move across the membrane down those concentration gradients. Ion pumps and ion channels are electrically equivalent to a set of batteries and resistors inserted in the membrane, and therefore create a voltage difference between the two sides of the membrane.Virtually all eukaryotic cells (including cells from animals, plants, and fungi) maintain a non-zero transmembrane potential, usually with a negative voltage in the cell interior as compared to the cell exterior ranging from –40 mV to –80 mV. The membrane potential has two basic functions. First, it allows a cell to function as a battery, providing power to operate a variety of ""molecular devices"" embedded in the membrane. Second, in electrically excitable cells such as neurons and muscle cells, it is used for transmitting signals between different parts of a cell. Signals are generated by opening or closing of ion channels at one point in the membrane, producing a local change in the membrane potential. This change in the electric field can be quickly affected by either adjacent or more distant ion channels in the membrane. Those ion channels can then open or close as a result of the potential change, reproducing the signal.In non-excitable cells, and in excitable cells in their baseline states, the membrane potential is held at a relatively stable value, called the resting potential. For neurons, typical values of the resting potential range from –70 to –80 millivolts; that is, the interior of a cell has a negative baseline voltage of a bit less than one-tenth of a volt. The opening and closing of ion channels can induce a departure from the resting potential. This is called a depolarization if the interior voltage becomes less negative (say from –70 mV to –60 mV), or a hyperpolarization if the interior voltage becomes more negative (say from –70 mV to –80 mV). In excitable cells, a sufficiently large depolarization can evoke an action potential, in which the membrane potential changes rapidly and significantly for a short time (on the order of 1 to 100 milliseconds), often reversing its polarity. Action potentials are generated by the activation of certain voltage-gated ion channels.In neurons, the factors that influence the membrane potential are diverse. They include numerous types of ion channels, some of which are chemically gated and some of which are voltage-gated. Because voltage-gated ion channels are controlled by the membrane potential, while the membrane potential itself is influenced by these same ion channels, feedback loops that allow for complex temporal dynamics arise, including oscillations and regenerative events such as action potentials.