Fig. 1. The effect of replacing extracellular chloride, [Cl-]o with gluconate on slow wave activity recorded from mouse jejunal smooth muscle layer. Replacement of [Cl-]o by gluconate significantly altered slow wave properties in a concentration dependent manner (see Fig. 2). A1, A2-C, Representative traces of intracellular recording made in [Cl-]o: 13.3 mM (A1, A2); 39.9 mM (B); and 119.8 mM (C), respectively. In 5 out of 9 experiments, slow waves were abolished (A1). In the remaining 4 experiments, small amplitude residual slow wave activity was observed (A2). The horizontal bar over each traces indicates perfusion period of low [Cl-]o solution. Expanded time scales are shown at the bottom of A1, A2, B, and C with different time points before and after the low [Cl-]o perfusion.
Fig. 2. Measurement of electrical slow wave properties upon replacing
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6. The effect on slow wave activity of reducing [Ca2+]o in Krebs to the level of [Ca2+]o obtained by adding gluconate (A) and isethionate (B) (see Fig. 5). Lowering [Ca2+]o did not replicate the effect of replacing [Cl-]o with gluconate or isethionate on electrical activity in mouse jejunal smooth muscle layer. A-B, Representative traces of intracellular recordings upon perfusion with 0.13 mM and 0.54 mM [Ca2+]o. Expanded time scales are shown below the traces. C-I, Summarized data illustrating the effects of reduced [Ca2+]o on slow wave properties: At 0.13 mM [Ca2+]o, (equivalent to the level found in 13.3 mM Cl-, 120.3 mM gluconate Krebs) a decrease in the instantaneous frequency (F), shortening of slow wave width (G) and a decrease in the decay times from 90 to 10% of peak amplitude (I) were observed. These effects were reversible on washout. No change was observed in membrane potential (C) and the rest of the slow wave properties (E, H). No effects were observed at 0.54 mM [Ca2+]o (equivalent to 13.3 mM Cl-, 120.3 mM isethionate Krebs; panel D-I). Values are mean ± SEM (N=4-5, *P < 0.05, paired t
Table 5. The effects of Atropine measured by the ventricle of the frog’s heart by amplitude, period, and BPMs.
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.
3. Describe what would happen to the resting membrane potential if the sodium-potassium transport pump was blocked.
This experiment seeks to analyze how the resting membrane potential of Orconectes rusticus muscle cells changes in response to increasing [K+]o solution concentrations. By recording the intracellular voltage of the DEM, DEL1, and DEL2 crayfish muscle cells at six concentrations of [K+]o solution, we determined whether the observed resting membrane potentials (Vrest) were significantly different from the predicted Nernst equilibrium potential values. We hypothesized that the Vrest of the crayfish muscles at each concentration would not significantly differ from the Nernst potential, which solely considers the permeability of potassium ions to the cell membrane. However, our findings suggested differently, and results indicated that the Nernst equation did not accurately predict the obtained values of the resting membrane potential. The differences in muscle cell Vrest reveal instead that the membrane is differentially permeable to other ions.
The two drugs that have been used in this experiment to test their effects on the heart rate and depolarization rate of the P wave of the crayfish. Depolarization is defined as the contractions of heart muscle, and it is shown in P wave pattern of the ECG. Comparing the results of the trials of epinephrine drug to the resting state, it shows that this drug increases the heart rate, decreases beat period, and decreases the time that take
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
ST depression and T-wave changes may also indicate the development of a non Q-wave MI.
MH alters the calcium channel in the sarcoplasmic reticulum (SR) and this allows large quantity of calcium to be released from the SR creating hyper-action in skeletal muscle; this reaction increases oxygen consumption and increased heat production that ultimately leads to a hypermetabolic state after the inhaled Halothane has triggered the condition (Knies). The continuous elevation of calcium also causes excessive stimulation of anaerobic glycolytic metabolism. This creates respiratory and metabolic acidosis, rigidity (muscle contractions), and hyperkalemia (elevated potassium) and can ultimately lead to death
e) How would exposure to sarin affect Ca+2 levels inside the sarcoplasmic reticulum and cytoplasm? Explain. The continuous propagation of action potentials would lead to an increased release of Ca+2 from the sarcoplasmic reticulum (depletion of Ca+2 levels) and, as a result, an increase in cytoplasmic Ca+2 levels. However, when action potential propagation ceases, there can be no Ca+2 release from the sarcoplasmic reticulum (high Ca+2 levels) or increase in cytoplasmic Ca+2 levels (low Ca+2
_ The resting neuron is 4 to 5 times more permeable to K+ then to Na+ because of the leakage channels._
The findings of this experiment reinforced the hypothesis that the resting membrane potential is most influenced by the ion potassium. We were able to deduce this through the collection of a multitude of intracellular and extracellular recordings, such as the one shown below in Figure 1. This shows how this experiment was able to record every single resting membrane potential in all three different muscle groups under all six solutions.
Increasing the extracellular potassium reduces the concentration gradient, and less potassium diffuses out of the neuron and into the cell.
Three different dialysis tubing was acquired with 2mls of the different concentration of KMnO4 and then clamped the dialysis. The speed of the all three stirring plates was set to 5 and before adding the dialysis tubing; a sample of water was used for a blank. Then at the same time the dialysis tubes were put into the water and the string was taped onto the glass so it would not move around the bleaker. Lastly, the timer was started and every five minutes 1ml of solution was removed and placed in a cuvette to measure the absorbance into the data. On the second week, we experimented the varying of the temperature.
In the United States, there are several topics that are considered morally ambiguous. Among these contended topics is the death penalty. There are many arguments for and against capital punishment. One proponent for the death penalty is Ernest van den Haag, who in his article, “The Ultimate Punishment,” argues a case for the death penalty. I believe he successfully counters the arguments against the death penalty leading me to believe it is not something that should be viewed as inhumane and wrong. I will argue that the death penalty is not morally ambiguous, but a justified sentence some deserve.
Removal of lactic acid in the glycolysis system is largely impacted by blood flow and heart rate.