Electric potential
... is the energy required to move a unit charge between two specified points. An electric field has the special property that it is conservative, which means that the path taken by the test charge is irrelevant: all paths between two specified points expend the same energy, and thus a unique value for ...
... is the energy required to move a unit charge between two specified points. An electric field has the special property that it is conservative, which means that the path taken by the test charge is irrelevant: all paths between two specified points expend the same energy, and thus a unique value for ...
Checklist unit 7: membrane structure and function
... Transport is active when ATP fuels the movement of substances against their electrical or concentration gradients. Ion pumps and co-transport are two mechanism of active transport. Materials may also be moved across the cell membrane by means of exocytosis and endocytosis. These are usually used for ...
... Transport is active when ATP fuels the movement of substances against their electrical or concentration gradients. Ion pumps and co-transport are two mechanism of active transport. Materials may also be moved across the cell membrane by means of exocytosis and endocytosis. These are usually used for ...
Chapter 48: Nervous Systems Overview: Command and Control
... • A neuron that is not transmitting signals contains many open K+ channels and fewer open Na+ channels in its plasma membrane • The diffusion of K+ and Na+ through these channels leads to a separation of charges across the membrane, producing the resting potential Action potentials are the signals c ...
... • A neuron that is not transmitting signals contains many open K+ channels and fewer open Na+ channels in its plasma membrane • The diffusion of K+ and Na+ through these channels leads to a separation of charges across the membrane, producing the resting potential Action potentials are the signals c ...
Functional Organization of Nervous Tissue Chapter 11
... outside cell- negative proteins in also, Na+ higher outside than inside – At equilibrium there is very little movement of K+ or other ions across plasma membrane ...
... outside cell- negative proteins in also, Na+ higher outside than inside – At equilibrium there is very little movement of K+ or other ions across plasma membrane ...
Babylon university Medical physics exam
... Neuron is to be polarized, the inside of the cell is 60-90 mV more negative than out side and this represent the resting potential . if stimulation heat, cold, light, sound cause change in action potential Fig a : resting potential of axon= - 80mV ...
... Neuron is to be polarized, the inside of the cell is 60-90 mV more negative than out side and this represent the resting potential . if stimulation heat, cold, light, sound cause change in action potential Fig a : resting potential of axon= - 80mV ...
MEMBRANE STRUCTURE AND FUNCTION
... Big Idea 4: Interactions - Biological systems interact, and these systems and their interactions possess complex properties. ...
... Big Idea 4: Interactions - Biological systems interact, and these systems and their interactions possess complex properties. ...
Slide 1
... Some neurotransmitters are inhibitory whereas others are excitatory, so the postsynaptic cell may be stimulated or it may be inhibited depending on the neurotransmitter. ...
... Some neurotransmitters are inhibitory whereas others are excitatory, so the postsynaptic cell may be stimulated or it may be inhibited depending on the neurotransmitter. ...
State that the nervous system consists of the central
... 7. The sense of taste is normally caused by the stimulation of chemoreceptors in the taste buds of the tongue. There are four main 'tastes': sweet, salty, bitter and sour. The tongue also has receptors for temperature. It is known that the taste of food can vary according to whether it is cold, warm ...
... 7. The sense of taste is normally caused by the stimulation of chemoreceptors in the taste buds of the tongue. There are four main 'tastes': sweet, salty, bitter and sour. The tongue also has receptors for temperature. It is known that the taste of food can vary according to whether it is cold, warm ...
The Cell Membrane
... Water molecules move from a region of high concentration to a region of low concentration. Direction depends on the relative concentration of water molecules on either side of the cell membrane. Isotonic: Water inside the cell equals the water outside the cell and equal amounts of water move i ...
... Water molecules move from a region of high concentration to a region of low concentration. Direction depends on the relative concentration of water molecules on either side of the cell membrane. Isotonic: Water inside the cell equals the water outside the cell and equal amounts of water move i ...
Diffusion/Osmosis/Homeostasis
... 14. What is osmotic pressure? 15. Which way water will move in each of the following situations: a. Salt inside the cell 65% and outside the cell 40%. ___________________________________ b. Sugar inside the cell 27% and outside 80%. ...
... 14. What is osmotic pressure? 15. Which way water will move in each of the following situations: a. Salt inside the cell 65% and outside the cell 40%. ___________________________________ b. Sugar inside the cell 27% and outside 80%. ...
BGYB30 Mammalian Physiology • Today: • Next Lecture:
... Membrane Proteins Mediate Transport Across the Plasma Membrane 1A ...
... Membrane Proteins Mediate Transport Across the Plasma Membrane 1A ...
Chapter 11: Fundamentals of the Nervous System and Nervous Tissue
... area of high concentration to an area of low concentration 2. Ions flow along their electrical gradient when they move toward an area of opposite charge 3. Electrochemical gradient a. the electrical and chemical gradients taken together Resting Membrane Potential (Vr) 1. The potential difference (–7 ...
... area of high concentration to an area of low concentration 2. Ions flow along their electrical gradient when they move toward an area of opposite charge 3. Electrochemical gradient a. the electrical and chemical gradients taken together Resting Membrane Potential (Vr) 1. The potential difference (–7 ...
Central Nervous System
... After inside flooded with Na+, K+ gates open (they are slower to respond) and let K+ out which are repelled by + inside Na+ gates remain closed The inside becomes negative while outside become positive and this repolarizes membrane ...
... After inside flooded with Na+, K+ gates open (they are slower to respond) and let K+ out which are repelled by + inside Na+ gates remain closed The inside becomes negative while outside become positive and this repolarizes membrane ...
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.