The Effect Of Pef On Biological Cells

1. ECF potassium levels affect resting membrane potential. Hyperkalemia (excessive levels of potassium in the blood) and hypokalemia (abnormally low blood potassium levels) both affect the function of nerves and muscles.

The purpose of this experiment was to indirectly study the effects of environmental stress on cell membranes. Watercourses have been with discarding of domestic and manufacturing, for centuries. Alarms have only escalated about the ecological alterations in the recent years of what would be the consequences. Scientists have developed a thorough investigation in search of various man harmful waste that is damaging the environment of watercourses.

A voltage-gated sodium ion channel opens when there is a change in the voltage of the membrane and allows sodium ions to flow across its electrochemical gradient. These voltage-gated channels are made up of amino acids and they aid in generating and moving an action potential down a membrane or axon (Brooker, Robert, 106).

Next, to determine if contraction via the EMC pathway requires extracellular or intracellular calcium, the second type of stimulus was used and the tissue was stimulated using calcium free K+-depolarising solution. The bathing solution in this experiment was calcium free solution to make sure all extracellular calcium was eliminated, as without calcium, the EMC pathway is expected to produce no response.

A major determinant of diffusion in a biological system is membrane permeability. Small, uncharged molecules pass through cellular membranes easily, while most and/or charged molecules cannot pass through the membrane. The movement of water across a selectively permeable membrane, like the plasma membrane

This stage is called repolarisation. The K+ channels then close, the sodium-potassium pump restarts, restoring the normal distribution of ions either side of the cell surface membrane and thus restoring the resting potential. In response to this the Na+ channels in that area would open up, allowing Na+ ions to flood into the cell and thus reducing the resting potential of the cells. If the resting potential of the cell drops to the threshold level, then an action potential has been generated and an impulse will be fired.

A lesser amount of Potassium ions diffuse out across the membrane, leaving behind a less negative charge. The

Both electrical and chemical forces combine to determine the resting membrane potential of the cell. Although the resting membrane potential of most cells is normally negative, the selective permeability of the membrane allows certain ions in and out, causing the neuronal membrane voltage to become depolarized (more positive), or hyperpolarized (more negative). Key ions involved in muscle membrane potential are sodium, potassium, and chloride, which move via passive or active diffusion through ion channels and transporter pumps (Baierlein et al. 2011). The Nernst equation predicts the membrane voltage based on the assumption that the membrane is only permeable to one type of ion. In this investigation, we are seeking to understand the basis for how different ions interact to produce the membrane potential of DEM, DEL1, and DEL2 crayfish muscle

My prediction was that the membrane potential will not change and that was wrong because the resting membrane potential changed from -40V to 0V. This happened because K+ diffuse out across the membrane and they leave a net negative charge behind. ___

Voltage gated channels are necessary components of life processes, in many organisms. One in particular, is the calcium voltage gated ion channel. Often lodged within the phospholipid bilayer, the imbalance of the calcium, or, the inside vs outside concentration, creates a gradient. The channel proteins often undergo conformations, states that which allow or block calcium ions from passing through. As ions move inside the cell, this creates a depolarization, or surge in the voltage. Clinically, this is associated with the heart and how it allows the heart to contract, which can be read in the

A nerve cell has a negative charge at a resting state due to negatively charged proteins within the cell.[3] Although the inside of the cell contains positively charged potassium ions as well, overall the charge is still negative. Along with potassium on the inside of the cell, positively charged sodium ions are located around the exterior of the cell.[3] When an action potential occurs, the cell becomes even more negatively charged. In turn, this causes sodium transport molecules in the membrane of the cell to open.[3] Sodium will then enter the cell during active transport. The positively charged sodium will cancel out the negatively charged active potential which will depolarize the cell. This allows neurotransmitters to transfer from cell to cell.[3] These neurotransmitters are what allows the body to feel pain. Local anesthetics work by diffusing through nerve fibers. Once they’ve reached the cells, they block the sodium transport molecules in the cell.[2] Therefore neurotransmitters cannot transfer information from cell to cell and the feeling of

The establishment of electrochemical gradient is one of the driving forces for ion movement across the cell membrane. Cells are usually negative and surrounded by positively charged extracellular fluids. All transport processes across cells impact the chemical gradients. There are two primary transport processes that affect electrical gradients, electroneutral carriers and electrogenic carries. Electroneutral carries transport uncharged molecules or exchange an equal number of particles with the same charge across the membrane, ultimately not changing the overall elecrtochemical gradient. Electrogenic carriers result

are pore forming proteins which allow the passage of ions that are charged into and out of the cell

I. Description: Congestive Heart Failure is more of a syndrome than a disease. Heart failure may be classified according to the side of the heart affected, (left- or right-sided failure), or by the cardiac cycle involved, (systolic or diastolic dysfunction). (Schilling-McCann p. 176). The word "failure" refers to the heart's inability to pump enough blood to meet the body's metabolic needs. (Schilling-McCann p. 176). When the heart fails to deliver adequate blood supply edema may develop. (Cadwallader p. 1141). Where edema occurs depends on what side of the heart is failing.

When a membrane is excited depolarization begins. When the membrane depolarizes the resting membrane potential of -70 mV becomes less negative. When the membrane potential reaches 0 mV, indicating there is no charge difference across the membrane. the sodium ion channels start to close and potassium ion channels open. By the time the sodium ion channels finally close. The membrane potential has reached +35 mV. The opening of the potassium channels allows K+ to flow out of the cell down its electrochemical gradient ( ion of like charge are repelled from each other). The flow of K+ out of the cell causes the membrane potential to move in a negative direction. This is referred to as repolarization. ( Marieb & Mitchell, 2009). As the transmembrane potential comes back down towards its resting potential level and the potassium channels begins to close, the trasmembrane potential level goes just below -90mV, causing a brief period of hyperpolarization (Martini, Nath & Bartholomew, 2012). Finally, as the potassium channels close, the membrane turns back to its resting potential until it is excited or inhibited again.