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What effect does potassium have on the resting potential of a cardiac cell?
Hyperkalemia is an increase in extracellular K. Driving force of an ion depends on two factors, voltage and concentration gradient. For K voltage gradient is pushing K into the cell but the concentration gradient is driving K out of the cell. However, the total driving force for K is out of the cell because the concentration gradient is that strong. When there is an increase in K on the outside, the driving force for K decreases.The equilibrium potential for K is -95mV. This means if K was freely permeable to the cell's membrane, it would reach equilibrium at -95mV. Another way to look at this is that efflux of K is the same as influx of K and the cell's new resting membrane potential would increase from a normal value of -70mV to -95mV. Note that I said it would increase even though the value became more negative. This is because the change in membrane potential has increased.Since the driving force of K has decreased, the equilibrium potential has also decreased. From a value of -95mV it is decreased to let's just say -80mV. Since a normal resting membrane potential is regularly -70mV, the decrease in equilibrium potential of K has decreased this resting membrane potential to say -60mV now. This is a depolarization of the cell.If this process happens quickly, it will depolarize the cell to the threshold value and you will have an action potential. However, if the hyperkalemia is severe, the cell will stay depolarized because the K equilibrium has decreased to a point where the cell cannot hyperpolarize back to threshold or resting membrane potential.If this process happens slowly, the inactivation gates of the sodium voltage-gated channels will automatically shut and the cell cannot depolarize even if it reaches threshold values. It must hyperpolarize back to resting membrane potential and the inactivation gates of the sodium voltage-gated channel will reopen.
Excess blood potassium hyperkalemia is removed by increasing secretion of the hormone which stimulates an increase in the secretion of potassium by cells within the?
Excess blood potassium (hyperkalemia) is typically removed by increasing the secretion of aldosterone. Aldosterone stimulates the kidneys to increase the secretion of potassium by cells within the kidney nephrons, promoting the excretion of excessive potassium from the body through urine.
Stimulation of the aortic baroreceptors results in what?
Stimulation of the aortic baroreceptors results in an increase in action potential frequency, which sends signals to the brain to decrease sympathetic activity and increase parasympathetic activity. This leads to a decrease in heart rate, vasodilation, and a decrease in blood pressure.
What is the result of intrapulmonary volume increase?
An increase in intrapulmonary volume leads to a decrease in air pressure within the lungs. This decrease in pressure creates a pressure gradient, causing air to flow into the lungs during inhalation.
Does potassium increase blood flow?
Potassium itself does not directly increase blood flow. However, maintaining proper potassium levels is important for overall cardiovascular health, as it helps regulate blood pressure and fluid balance in the body. Adequate potassium intake can support healthy blood flow by promoting proper function of the heart and blood vessels.
