CaseStudy: Cell Biology and Genetics
CaseStudy: Cell Biology and Genetics
Ischemiainvolves the reduction of blood to tissues and cells of the body.This event means that the necessary components of body function suchas oxygen and nutrients are not supplied adequately to cells.Similarly, lack of sufficient blood supply directly translates to theaccumulation of metabolites due to their inadequate removal fromcells and tissues. In the case of Maria, who is overweight, ischemiawill occur due to two main reasons. First, being overweight isassociated with the accumulation of fatty plaque in the arteries.This deposition eventually leads to the narrowing of veins and thusthe volume of blood pumped to other body parts is significantlyreduced. Second, Maria will experience tissue ischemia sincedisturbed blood flow can lead to the formation of a thrombus. This isa blood clot that forms in blood and is responsible for the blockageof blood vessels in the circulatory system. These two conditions arecharacterized by the substantial restriction of oxygen and nutrientsfrom reaching the target cells hence leading to ischemia [ CITATION Ric13 l 1033 ].
Hypoxiais a disorder marked by the deprivation of oxygen to the whole bodyor certain body parts. Mostly, hypoxia occurs as a result ofischemia. As mentioned earlier, lack of enough blood supply totissues means that the cells of the body will be deprived of oxygenwhich is a necessary component for normal physiological processes.For Maria, hypoxia will occur because the conditions Maria has do notallow blood to reach all parts of the cells and tissues. Hence,oxygen deficiency occurs. In summary, hypoxic injury transpires dueto the decrease of blood flow below the critical level that isessential for the maintenance of cell viability [ CITATION Car14 l 1033 ].
Apartfrom other reversible changes that occur due to hypoxia, two of themost significant alterations include edema and limited musclecontraction. If oxygen does not reach the cells as ideally expected,energy production will be distorted. A lack of Adenosine Triphosphate(ATP) will cause the membrane disruption and eventually, theelectrolytes will be in a state of imbalance. Often, sodium andpotassium are the ions that will be affected. When high amounts ofsodium ion influx into the cell, water is subsequently drawn into thecell through the process of osmosis [ CITATION Car14 l 1033 ].
Accumulationof water is commonly termed as edema. Cellular swelling has thetendency to interfere with the operations of organelles. Likewise,muscle contraction is expected to be impaired. This is because suchcells require a lot of energy for them to function and in the absenceof oxygen, only a small fraction of energy will be generated. Also,the edema or swelling interferes with the transmission of impulsesince it requires intact cellular membranes and ion channels thatwork effectively.
Inthe absence of such, electrical impulse transmission and theassociated movement of ions (usually sodium and potassium) will notbe efficient. It is for this reason that skeletal muscles experiencefatigue and loss of function. All these changes are reversible butonly in instances where oxygen is adequately restored beforepermanent damage occurs. If the oxygen supply is reestablished, thenthese cells can continue to perform their functions purposefully. Onthe other hand, failure to provide the cells with oxygen for aprolonged period may cause severe damage including the death of theaffected tissues [ CITATION Ric13 l 1033 ].
Cellsare capable of adapting to the various changes that they are exposedto. For Maria, hypertrophy is the adaptation that has occurred. It ischaracterized by the increase in overall size of individual cellsmaking the organ in question to also increase in size. Seemingly,this is a case of pathological hypertrophy especially in the cellsthat do not typically undergo mitotic division. Myocardialhypertrophy is the term given to this condition. Also, it isimportant to note that the enlargement of the heart cannot bereverted to its original state. This occurrence is specific forpathological cases of heart enlargement or hypertrophy.
Thisconclusion has come about because from the physical and physiologicalexaminations done it is clear that Maria has high blood pressure. Itis uncommon for organs to try to put up with alterations and in thisscenario, her heart is being overworked due to the need to pump bloodagainst resistance. This phenomenon prompts the cells to increase insize to cater for the deficit by pumping blood even harder. As thedemand increases, the size of the organ also increases. At somepoint, the heart will no longer be able to adapt any further to theexigencies. Once the limit is attained, the cardiac muscles cannotundergo any further enlargement to compensate the workload.Ultimately, more severe conditions such as cardiac failure may ensue[ CITATION Ric13 l 1033 ].
Thebest prediction explaining the enlargement of Maria’s heart isbased on the high blood pressure results recorded as 184/98 mm Hg.The heart must, therefore, contract against this high pressure and inthe long run, it adjusts to this condition. Several processes areinvolved in the hypertrophy including the synthesis of moremembranes, increased levels and requirements for AdenosineTriphosphate (ATP), increased filaments, ribosomes and Golgiapparatus [ CITATION Ric13 l 1033 ].For the cardiac muscles, it represents an increase in the size ofcytoplasmic myofibrils. In summary, heart enlargement for this casestudy is mainly due to increased resistance of blood flow by theblood vessels especially the arteries.
Maria’senlarged heart is not capable of providing the same strength andendurance as a well-trained athlete this is attributed to the factthat an athlete’s heart is just responding to a physiologicalprocess which ranges from running, swimming cycling among othersport. The enlargement of the heart is, therefore, an adaptivefeature, and it is focused on the ventricles to increase the volume.The flow of blood is not obstructed. Mostly, for an athlete, theheart is adapted to provide adequate services when need be but atrest, the rate is standard. On the contrary, an enlarged heart due tohigh blood pressure means that the heart is always overworked,pumping blood against resistance. Despite how much it tries, still,the amount of oxygen and nutrients reaching the cells and tissues isnot sufficient to enable endurance and power to do work. As mentionedbefore, the increased size of an athlete’s heart increasesefficiency by pumping large volumes during physical activity whilemyocardial hypertrophy due to high blood pressure is strenuous to theheart, additionally, because the hypertrophy in athletes is notpathological, it can resume its normal size when the particularactivities are eliminated. Pathological hypertrophy, on the otherhand, is usually irreversible [ CITATION Arm13 l 1033 ].
Klabunde, R. (2013). Cardiovascular Physiology Concepts. Amazon Kindle Book.
Legge, A. (2013, January 13). Reasons Why a Large “Athlete’s Heart” is Usually Not Dangerous. Retrieved from Complete Human Performance: http://www.completehumanperformance.com/athletes-heart-2/
Porth, C. M. (2014). Essentials of Pathophysiology: Concepts of Altered States. Philadelphia: Lippincott Williams & Wilkins.