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Biology 621 - Chapter 12 Midterm Exam Review
Biology 621 - Chapter 12 Midterm Exam Review

... 24.Sensory neurons carry impulses from receptors to the spinal cord. 25. What are the two major division of the peripheral nervous system? autonomic &somatic 26 Nervous system subdivision that is composed of the brain and spinal cord.CNS 27.The neuron is the basic functional unit of the nervous syst ...
Review 3 ____ 1. The cells that provide structural support and
Review 3 ____ 1. The cells that provide structural support and

... 10. Leonard's mother became dehydrated during a recent illness, and the levels of sodium in her body were significantly reduced. If enough sodium was lost you might expect that a. her nervous system would become highly activated and action potentials would be generated continuously b. fewer action p ...
Neurophysiology Worksheet
Neurophysiology Worksheet

Chapter 10
Chapter 10

... polarized = electrically charged: – Consequently, a potential difference (PD) exists across this resting cell membrane ...
Transport Review
Transport Review

... The substance that dissolves to make a solution is called the ___________________ A. diffuser B. solvent C. solute D. concentrate During diffusion molecules tend to move _____________________ A. up the concentration gradient B. down the concentration gradient C. from an area of lower concentration t ...
slides - Purdue Math
slides - Purdue Math

Ch 48-49 Reading Guide
Ch 48-49 Reading Guide

Interactions of KCNE Auxiliary Subunits with K and other Channels
Interactions of KCNE Auxiliary Subunits with K and other Channels

... subunit pore forming proteins (Figure 1). With about 40 genes encoding Kv channel subunits, which may ensemble by either homo or heterotetramerization, the molecular and functional diversity of native voltage dependent K+ currents is huge.1 In addition, several groups of proteins referred to as auxi ...
2.-1
2.-1

MOVEMENT OF SUBSTANCES
MOVEMENT OF SUBSTANCES

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3 Movement of substances across cell membrane 3.1 Cell membrane

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CP-7.4-Diffusion

... • Speeds up diffusion • Allows for larger molecules to pass through membrane • Example: glucose transport ...
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AP Chapter 7 Study Guide

... British botanists were quick to point out that in the case of plant, bacterial and fungal cells, water does not always move from areas of high water concentration to areas of low water concentration. They correctly indicated that plant cells, in distilled water, have equal amounts of water moving i ...
F214: Communication, Homeostasis and Energy 4.2.1 The Kidney
F214: Communication, Homeostasis and Energy 4.2.1 The Kidney

... association with sodium ions by facilitated diffusion • The opposite membrane is folded to increase surface area and contains sodium-potassium pumps that pump sodium out and potassium in • Cell cytoplasm has many mitochondria indicating that energy is required as ATP ...
Cell Membrane - Manhasset Public Schools
Cell Membrane - Manhasset Public Schools

... •Proteins can form channels (tunnels) for large substances to easily pass through. • Proteins can also form pumps to pump larger substances from one side of the cell to the other using energy. ...
Renal tubular transp..
Renal tubular transp..

... Na+ absorbed by active transport mechanisms, NOT by TM mechanism. Basolateral ATPases establish a gradient across the tubule wall.  Proximal tubule is very permeable to Na+, so ions flow down gradient, across membranes.  Microvilli create large surface area for absorption.  Electrical gradient c ...
S10 8.1 notes - Cochrane High School
S10 8.1 notes - Cochrane High School

... b. Regulates by particle size –molecules like oxygen and water are so small they can diffuse across the cell by slipping between the phospholipid molecules. c. Large or charged molecules can only be transported across the cell membrane by the membrane proteins. d. The cell is an OPEN SYSTEM (substan ...
Chapter 3 Biological Aspects of Psychology
Chapter 3 Biological Aspects of Psychology

... along which impulses are transmitted (axon), and the junctions across which chemical messengers carry signals to other neurons (synapses). Neurons vary considerably in size and shape and are usually densely ...
Cell Transport
Cell Transport

Cell processes to maintain Homeostasis
Cell processes to maintain Homeostasis

Ch. 4 Powerpoint Notes - Fulton County Schools
Ch. 4 Powerpoint Notes - Fulton County Schools

Acc_Bio_4_1and4_2_ws_Key
Acc_Bio_4_1and4_2_ws_Key

... concentration gradient. 3 Osmosis is a type of passive transport. 4If the solutions on either side of the cell membrane have different concentrations of dissolved particles, they will also have different concentrations of “free” water molecules. 5Osmosis will occur as water molecules diffuse into th ...
Electric Potential
Electric Potential

... sphere of radius R? l  What does the potential look like outside the sphere (r>R)? ...
Intro - Ece.umd.edu - University of Maryland
Intro - Ece.umd.edu - University of Maryland

< 1 ... 73 74 75 76 77 78 79 80 81 ... 180 >

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.
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