Week 6 Critical Thinking Exercise Blood and sea water are analogous in the way t
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Question
Week 6 Critical Thinking Exercise Blood and sea water are analogous in the way they serve and support the organisms (or cells) they contact. In this line of thinking, blood is an extension of the ocean in the bodies of land animals in providing the needs of cells deep in the body Examine this analogy in relation to problems in acid-base homeostasis and oxygen availability. In what ways are sea organisms and our body cells affected in a similar manner? . Task 1: Create a new discussion post on or before Friday at 11:55 p.m. by clicking the ""REPLY HERE" post and reply with your answers to the Week 6 Critical Thinking Exercise questions. Your response to the exercise questions should be a minimum of 5 sentences Going over the minimum sentence requirement is acceptable; however, I am not looking for an essayExplanation / Answer
The blood has a pH range of 7.4-7.5. Therefore, this is the general pH level in the body which may be altered in the individual organ (for example Saliva: 6.4-7.4, Gastric juice: 1.5-1.8, Duodenal fluid: 5.5-7.5, Pancreatic juice: 7.5-8.2) to meet the needs of special functions of that organ.
Similarly ocean has different elements and substances with diversified living organisms. The exact pH and its composition is dependent on the source and the composition of the living organisms in that area of ocean. Marine plants and animals take up the nutrients required for their metabolism and excrete the waste products into the sea water altering the 'microenvironment' of the sea
On the other hand, The metabolic processes of the body cells produce acids or acidic substances(Ex. Carbonic acid from CO2 and water, sulphuric acid, phosphoric acid from proteins and phosphoproteins etc) and alkalies(Ex. Bicarbonate ions from salts of organic acids like citrates, lactates etc) which tend to alter the pH of the tissue fluid and the blood.
The sea waters constantly are replenished by the tides, wind currents, ocean currents set up by differntial temperatures. They are also churned by the constant human activities like sea transport, oil spillages, ocean mining, fishing etc. These are analogous to the various metabolic processes that occur in the human body which will tend to alter the normal pH of the body
Body cannot rely upon the environment for restoring the altered pH levels like sea waters which rely upon winds and tides. There are active regulatory mechanisms (unlike passive mechanisms) in the body to maintain the pH of the body fluids (Homeostasis) and the different tissues fairly constant and in equilibrium with one another. The ability of the complex buffer systems of the blood tobind H+ ions or neutralize acids is called the alkali reserve of the blood. If the pH of the blood falls below 7.4, the reserve of alkali has been decreased by an increase in production of H+ ions and the condition of acidosis exists.
Conversely, when the pH is raised above 7.5, the increased alkali produced has used up the acid reserve a nd astate of alkalosis exists.There are mainly three regulatory mechanisms which maintain the Homeostasis (pH of the each system and equilibrium withone another).
They are:
i. Buffers of Body Fluids ii. Respiratory mechanism iii. Renal regulation
(Similar to winds and currents in oceans)
i. Buffers: (Analogous to mineral reserves in the oceans) Buffers are the chemical systems capable of mai ntaining a constant pH ex. Phosphates, bicarbonates and some proteins which are able to bind free H+ ion or OH ion and so prevent a change in pH. The major buffer systems existing in the body fluids are as follows:
a. Carbonic acid-Bicarbonate buffer system: It occurs in plasma and kidneys. It is considered to be an important regulator of blood pH. If there occurs an excess of H+, the bicarbonate ion (HCO3-) ion acts as a weak base and accepts H+ to form Carbonic acid.
While if there occurs shor tage of H+, the carbonic acid (another component of buffer system) ionizes to release more H+ions and maintains the pH.
H2CO3 <----------------> H+ + HCO3-
Normal metabolism gives rise to more acids than bases, but the blood is made more acidic. Therefore the body needs more bicarbonate salt than it needs carbonic acid. Hence at physiological pH 7.4, the plasma is having about 24mEq/lit of bicarbonate in comparison to about 1.2mEq/lit of carbonic acid (ratio of 20:1)
b. Phosphate buffer system: It is able to maintain physiological pH at 7.4. As the phosphate concentration ishighest in intracellular fluid, t he phosphate buffer system is considered to be an important regulator of pH in the
cytosol. This system occurs in the cells and kidneys. The system consists of monohydrogen phosphate/dihydrogen phosphate (HPO42-/ H2PO4-) anions. It is known to act in the same manner as the carbonic acid-bicarbonate buffer system acts.
If there occurs an excess of H+, the monohydrogen phosphate ion acts as the weak base by accepting the proton. While the dihydrogen phosphate ion acts as the weak acid and is able to neutralize the alkaline condition
c. Protein (Haemoglobin) Buffer system: It is considered to be the most abundant buffer in body cells a nd plasma. Proteins are composed of amino acids that are having at least one carboxyl group (COOH) and at leastone amino (NH2) group. When there occurs an excess of Hydrogen ions, the amino group acts as a base andaccepts the proton. While the free carboxyl group can release protons so as to neutralize an alkaline condition.
Thus protein is able to serve both the functions of acid and base components of a buffer system because of its
amphoteric nature.
ii. Respiratory mechanism: (Analogous to aeration in the sea water) When respiration is decreased, there is an accumulation of CO2 in the body which us es up the alkali reserve of the blood resulting in acidosis. On the other hand, if there is over breathing, it results in excessive excretion of CO2, the condition of alkalosis may develop. Thus acidity and CO2 increased levels are both powerful stimulants of respiratory mechanisms and cause an increase in the rate and depth ofrespiration. The H2CO3 is converted to CO2 and water and the CO2 is rapidly breathed out. On the other hand, an increase in base, leads to a decrease in acidity and H2CO3 content. Respiratory rate and depth, both are depressed, resulting in retention of CO2 and thus an increase in H2CO3 till the normal ratio of MHCO3/H2CO3 is reached
iii. Renal Mechanism: (Analogous to volcanic eruptions and floods that completely eliminate the existing life forms and renew the environment in the oceans) Kidneys have the ability to form ammonia which combines with the acids produced during the protein metabolism and is excreted in the urine. The pH of urine is highly variable between 4.8-8.0. Normally it is acidic side but varies with the nature of diet, exercise etc. While unstable H2CO3 is removed mainly by respiratory mechanism, the fixed acids like Phosphoric acid, sulphuric and hydrochloric acids have to beremoved through kidneys.
Similarly high concentrations of minerals and salts in the sea water can also cause cell shrinkage in the marine organisms whereas hypotonic sea water may lead to cell death affecting the life in the oceans. Several marine organisms have developed unique ways acquired by years of evolution to compensate to the fluctuations in marine environment.
Apart from the analogy sea water is also having a similar composition as that of sea water but with more concentration of sodium chloride and devoid of oxygen carrying cells like RBC and other macromolecules which offer complexity in the multicellular organisms.
Sea water takes away the excess waste products and replenishes them with fresh minerals for the thriving of organisms. Thus, sea water is almost analogous to the blood in the organisms. These conclusions not only ended up with drawing conclusions and comparisions, Some researchers also conducted experiments which are even successful testifying this analogy.
One such successful research is Dr. Renne quinton's work
Dr. Rene quinton used this sea water which is diluted several times and well treated to replace plasma during the times of blood transfusion and successful in the experiments.
But still sea water is not a potential therapeutic agent because the purity and sterility of the sea water depends on the area of collection. Rene quinton collected sea water which is away from the shore and several feet deep enough and pretreated it through a patented process to get successful.
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