Describe the cardiovascular implications of hypokalemia and hyperkalemia with reference to the physiology of myocardial cells and the cardiac cycle. Provide examples that illustrate the impact of hypokalemia and hyperkalemia. short and sweet. .© BrainMass Inc. brainmass.com October 10, 2019, 8:11 am ad1c9bdddf
Please find below a guide solution on the significance of potassium in the cardiovascular system and the clinical implications of hypokalemia(low potassium levels) and hyperkalemia(high potassium levels).
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Pathophysiology: cardiovascular implications of hypokalemia and hyperkalemia
Potassium works in conjunction with sodium, magnesium and calcium in muscle cells (including those of the heart) to generate the electrical signals that stimulate movement.
About 90% of total body potassium is intracellular and 10% is in extracellular fluid (Teo et.al 2010)
The ratio of intracellular to extracellular potassium determines neuromuscular and cardiovascular excitability
Because the cell has potassium through which potassium (K+ ) can move in and out of the cell, K+ diffuses down its chemical gradient (out of the cell i.e. from high concentration to low)) because its concentration is much higher inside the cell than outside.
This leads to a separation of charges across the membrane and therefore a potential difference across the heart cell membrane
An action potential is then created whereby an electrical stimulation created by a sequence of potassium ion movement through these channels across cardiac cells leads to cardiac contraction.
The Sinoatrial (SA) node normally generates the action potential, i.e. the electrical impulse that initiates heart muscle contraction.
The impulse travels through pathways to the atrioventricular (AV) node.
From the AV node, the impulse then travels through the bundle of His and down the bundle branches, fibers specialized for rapid transmission of electrical impulses, on either side of the ...
Potassium plays a very key role in the electrical signals that generate movement of heart muscle that eventually facilitate the pumping of blood to and from the various body tissues. The differential concentration of potassium outside and inside the myocardial (heart muscle) cells create an electrical gradient that facilitate this process.
This solution which is in point form guides the student on the physiology of the myocardial cells with respect to potassium concentrations, the cardiac cycle and the clinical implications of hypokalemia and hyperkalemia including examples of diseases associated with these potassium abnormalities.