Physioex 3 Essay

On a larger scale, the example of a Lego made motors efficiency can relate to that of a modern day car and the efficiency / energy waste that comes from it. The internal combustion engine is an engine in which the combustion of a fossil fuel mixes with air in a chamber of the operational fluid flow circuit.

Potassium works with sodium to regulate the body’s water balance. The kidneys help to control the blood pressure by controlling the amount of fluid stored in the body. Therefore, the more fluid then the higher the blood pressure is. The kidneys do this by filtering out the blood and extracting any extra fluid, which then is stored in the bladder as urine. This is done very delicately as both sodium and potassium pull the water across the wall of the cells from the bloodstream into a collecting channel that leads to the bladder. When eating to much salt, the amount of sodium in the bloodstream will be imbalanced compared to the amount of potassium and thus reducing the ability of the kidneys remove the extra fluid. Eating more fruit and vegetables, the potassium levels increase and can help restore the chemical imbalance. However, there is a possibility of too much potassium, also known as hyperkalemia, which can lead to other issues like renal failure.

However, when the membrane was changed to from 20 MWCO to 50 MWCO, the Na+ Cl- molecules were able to diffuse through the membrane, the equilibrium would be reached and no osmotic pressure was generated. If the concentration of Na+ Cl- of both size are equal, the osmotic pressure would be zero.

3. What would happen to the amount of H+ secreted into the renal tubule if the activity of the Na+ /K+

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.

3. A nerve is a bundle of axons, and some nerves are less sensitive to lidocaine. If a nerve, rather than an axon, had been used in the lidocaine experiment, the responses recorded at R1 and R2 would be the sum of all the action potentials (called a compound action potential). Would the response at R2 after lidocaine application necessarily be zero? Why or why not?

What effect will opening more of these channels have on the excitability of a neuron?

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

We experience each of Sir Isaac Newton's laws everyday. In a car, pushing a car, or even in a fight. All of these laws have to do with motion. You can experience the first law in a stopping car, the second when you are a pushing a shopping cart, and the third one in the water.

1. The force of the window on the bug because the bug is just flying, but the force of the window at a given speed is much greater creating the force to splatter the bug.

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.

The action potential at R1 (or R2) stayed the same as I increased the stimulus above the threshold voltage. My results did not compare well with my prediction because I predicted that the peak value of the action potential would increase.

Hence, this would allow for an influx of sodium into the cell down its electrochemical gradient. It would also allow for the flow of potassium outward, as it has a 140mM concentration inside the cell and wants to shift down its concentration gradient to 5.4mM. Therefore, this great driving force for the influx of sodium and efflux of potassium helps to explain the findings at this point. As Table 1 shows, the findings within this figure are statistically supported. The fact that there is not significant difference between the findings of this experiment and the calculated Nernst at the 10, 20 and 40mM of potassium is an indicator that sodium is the largest determinant of the resting membrane potential. However, some findings defy the expectations, as the last two concentrations elicit a resting membrane potential significantly more negative than expected. This can be explained by the fact that at this point, each muscle at their respective muscle groups has been protruded many

1. Why does the force begin to decrease with time? Note that a decrease in force indicates muscle fatigue.

Just about everything you do from moving to eating to listening to music involves physics. Now that I have really explored them I think it is hard to go about our day and not do something that involves physics. Some of the things I will talk about are getting out of bed, the eye and how eye glasses help a person see better, speakers, the Frisbee, sailing, and the pulleys I use to get my jeep unstuck in the mud when I ride in the woods.