Kidney Function and Alcohol - Essay Example

The first process, i.e. Ultrafiltration means filtration under immense pressure and takes place in the Bowman’s capsule. A hydrostatic pressure develops in the capsule because the efferent arteriole is narrower than the afferent arteriole owing to which water, glucose, amino acids, urea and salts enter the capsule from the glomerulus through podocytes (McNaught & Callander, 1975). The second process, i.e. Reabsorption helps to return useful constituents back into the blood stream. Reabsorption takes place in the convoluted tubules as well as in the Loop of Henle.

Active Reabsorption takes place in the proximal convoluted tubule where entire glucose, sodium, potassium, uric acid and 75% water is reabsorbed. After this the liquid enters the Loop of Henle where further salts and water are again reabsorbed. Almost 80% of the water Reabsorption takes place in the proximal convoluted tubule and the Loop of Henle by obligatory Reabsorption. It is during Reabsorption that a counter current mechanism occurs and the urine is made hypertonic by regular exchange of sodium ions between the limbs of the Loop of Henle.

Next, the urine passes into the distal convoluted tubule where the Reabsorption of water is initiated by a hormone named ADH or Vasopressin. Vasopressin or ADH is released by the posterior pituitary gland and play an important role in regulating the amount of urine formed. Absence of ADH in the distal convoluted tubule decreases Reabsorption of water and hence large amounts of urine is passed whereas increased amount of ADH, increases Reabsorption of water and the quantity of urine passed is much less.

The last process is called Tubular secretion which takes place in the distal convoluted tubules and the collecting tubules. Tubular secretion is the opposite mechanism of tubular Reabsorption. Here, potassium ions are secreted to maintain the pH of the blood while sodium is reabsorbed by rennin-angiotensin mechanism (Dunn & Donnelly, 2008, pp79). After this the urine formed is voided through the urethra via the act of micturition. The kidneys not only help in elimination of harmful substances but also play an important role in maintaining blood volume.

Kidneys are able to retain water and sodium, owing to hormone vasopressin and rennin-angiotensin mechanism help in regulating the blood volume too. Alcohol consumption is detrimental for the body in more ways than just one. It affects the liver, excretory system, circulatory system, respiratory system and is a major cause of disease such as liver cirrhosis, alcoholic hepatitis, cancer etc (Barclay et al, 2008). Both chronic and acute alcohol consumption is known to have adverse effects on the body especially on the excretory system because it taxes the kidneys heavily.

Alcohol consumption impairs the efficiency of the kidneys and disturbs the fluid and electrolytic balance of the body. It has been observed that within half an hour of alcohol consumption, urine is excreted. The increased loss of fluid through urine excretion leads to concentration of the electrolytes present in the blood. This is in fact the major reason that causes dehydration in people who consume alcohol. We are already aware of the fact that urine output depends largely on Anti-Diuretic hormone or Vasopressin.

Vasopressin induces fluid conservation by the kidneys thereby concentrating the urine output. In the absence of this effect, the kidneys fail to conserve any fluid because of