Understanding Obesity, Cellular Respiration, And Electrolytes In Human Body
Body Mass Index and Obesity
Obesity is the medical condition in which the individual suffers poor health outcomes as a result of excess body fat. An individual is considered to be obese when the body mass index (BMI) is over a certain range, as derived from the weight and height of the person. BMI is expressed as the body mass divided by the square of the body height. It has been well recognized that body mass index is the key predictor of morbidity as well as mortality caused as a result of different chronic conditions such as cardiovascular disease, stroke and type 2 diabetes. Further, it has been indicated that abdominal obesity which is assessed by waist circumference is a predictor of health risks related with obesity. A mounting pool of evidence highlight that waist circumference when coupled with BMI is a better predictor of health risks (Thibodeau & Patton 2010).
In the present case study, Brodie is a 55 year old male, with a height of 185 cm and weight of 95 kilograms. Further, he has a waist circumference of 100cm. calculating the BMI for Brodie it can be stated that his BMI is 27.8 with a waist circumference of 100 cm. Typically a person having a BMI below 18.5 is considered to be overweight while a BMI of 18.5-24.9 is considered to be healthy (Ratan, Sellner & Hollier 2018). In case a person is having a BMI of 25 or above it, the person is to be considered as overweight. A BMI of 30 or more is categorized as obese (Ashwell & Gibson 2016). As per the US National Institute of Health (NIH), a person having a waist circumference excess of 102 centimeters for men is to be considered as a high risk of developing hypertension, cardiovascular disease and diabetes as a result of excess visceral body fat. Brodie is therefore overweight since his body fat is more than what is optimally healthy. Further, he has an oval body shape. For achieving decrease in health risks, Brodie must be having an ideal rectangular body shape while his waist circumference must be less than 90 cm and weight must be in the range of 65 to 85 kilograms (Pouzesh, Mohammad & Poozesh 2015).
2. Performing exercises helps in maintaining health and improving the range of motions of different body parts, improving balance and supporting functions. During exercise, muscle motion is fueled when there is breakdown of ATP that occurs in a constant manner. Utilization of ATP in a rapid manner can lead to fast muscle contraction that is followed by a period of exhaustion. Muscle movement at the time of exercise is a result of the incessant instantaneous breakdown and reconstitution of ATP. ATP must be rebuilt as fast as if fracture. The process by which skeletal muscles build up energy is cellular respiration. Cellular respiration can bee of two types; aerobic and anaerobic. While the aerobic respiration takes place in the mitochondria, anaerobic respiration takes place in the cytoplasm.
Types of Cellular Respiration
Lipids, proteins and carbohydrates, used for performing muscular work are required to be oxidized after there if chemical breakdown through the metabolic pathway of glycogenolysis and the citric acid cycle. Electrons in the form of hydrogen ions are transported into the mitochondria by the nicotinamide adenine dinucleotide system (Hughey et al. 2017). This ultimately provides 39 moles of ATP per mole of glucose while the rest of the energy is lost when there is production of carbon dioxide, water and heat. ATP is thereafter used for performing muscle work through the aerobic process. When adequate amount of oxygen is delivered to the working muscle cells the process is fueled up. The mitochondria uses the oxygen to accept the hydrogen electrons formed at the time of organic fuel breakdown. The pattern is prominent when there is balance between oxygen demand and supply. As work intensity increases, the balance is broken and energy is to be obtained in an anaerobic manner through glycolysis and glycogenlosysis.
The second form of cellular respiration is anaerobic respiration in which sugar is broken down. The method permits muscles to borrow the stored form of glucose for generating ATP. Through a rapid process, and different steps, multiple enzymes transform glucose into pyruvic acid, and produce 3 moles of ATP. In case a muscle fiber has adequate oxygen, the generated pyruvic acid moves to the mitochondria where further aerobic pathway can follow. In case of absence of oxygen, pyruvic acid is to remain outside of the mitochondria wherein successive activity of enzymes transforms pyruvic acid into lactic acid. Anaerobic respiration is the preferred type of respiration since exercise demands faster ATP generation which can be possible only through anaerobic respiration (Ravcheev & Thiele 2014). Further, anaerobic process is solely dependent on carbohydrates for making energy while the aerobic process depends on both fats and carbohydrates for producing energy.
3. It is known that multiple body systems normally work together for oxygen to enter the body and reach cells. The systems involved in this process are the respiratory system, the autonomous nervous system, the circulatory system and the muscular system. The respiratory system plays the primitive role in allowing oxygen to enter the body. The mouth, nose, trachea, lungs and diaphragm participate in the absorption of oxygen from the surrounding air. Oxygen is known to enter the body through the nose and mouth after which it passes through the larynx and the trachea (Mohanty, Nagababu & Rifkind 2014). Thereafter, the trachea splits into two bronchial tubes that lead to smaller tubes. These smaller tubes carry the oxygen into 600 million alveoli that are small sacs and surrounded by capillaries.
The Link between Muscular System and Respiratory System
The link between muscular system and the respiratory system is to be discussed in here. The respiratory system works in conjunction to the muscular system so that oxygen can be inhaled. The muscular system is the organ system consisting of the smooth and skeletal muscle. For oxygen to be inhaled, cooperation of a number of muscles near the lungs is required (Xing et al. 2016). The diaphragm is situated above the ribs and is made up of a thin sheet of muscles. These muscles help in breathing as they pull and push the lung up and down for expansion or contraction.
The nervous system comprises of two major types of cells namely, the nerve cells or neurons and the glial cells. The neurons are responsible for communicating between brain cells to carry out the normal functioning of the brain. On the other hand, the specialized glial cells support the neuron’s functioning. The primary electrolytes that are present in the physiological system are potassium (K+), sodium (Na+), magnesium (Mg2+), calcium (Ca2+), hydrogen phosphate (HPO42−), hydrogen carbonate (HCO3−), and chloride (Cl−). Na+ is the chief electrolyte that is found in the extracellular fluid. Conversely, K+ is the chief intracellular electrolyte and both of these play an essential role in maintaining blood pressure and fluid balance. The human body comprises of a large variability of electrolytes and ions that are entitled with the responsibility of performing a range of physiologic functions (Herlihy 2017). While some of the electrolytes help in the process of conduction of electrical impulses, all along the cell membrane, in the neurons and muscles, other electrolytes are responsible for maintaining a stability in the structure of proteins and enzymes. Additionally, other electrolytes aid in the release of hormones from the endocrine glands. All of the aforementioned electrolytes that are present in the plasma play a major role in maintaining the osmotic balance of the neurons, by controlling the net movement of water between the external environment and the cells.
Sodium is considered as the major cation that is present in the extracellular fluid. It is primarily responsible for more than a half of the gradient of osmotic pressure that is present between the environment and the interior of the cells. Adherence to a typical western diet, results in an intake of 130-160 mmol/day sodium. However, 1-2 mmol/day sodium are required by humans. The excess sodium acts as a major contributing factor to hypertension (high blood pressure). Na+ electrolytes, that are present in the form of dissolved salts in the fluid, play a vital role in controlling brain function (Biet et al. 2015). The neuronal cells comprise of proteins, referred to as ion pumps that allow the free flow of sodium in and out of the cells. A quick influx of Na+ electrolytes sets up an electrical charge inside the nerve cells, thus triggering an electrochemical nerve impulse, commonly known as action potential.
The Role of Electrolytes in Human Body
Potassium acts as an important intracellular cation. Potassium plays a fundamental role in the second phase of the action potential. Following the influx of sodium into the neurons, K+ electrolytes undertake an efflux for neutralising the charged cell, thus helping the cell to re-establish the resting state. Without presence of suitable K+ levels, a neuron fails to send more than one electrochemical impulse. Following the beginning of the first action potential, the cell that is deficient in K+ fails to return to the resting phase, thus failing to initiate succeeding action potentials. K+ is imperative for establishing a resting membrane potential inside the muscle fibres and neurons, after action potential and membrane depolarization (Calloe et al. 2017). Low levels of K+ in the CSF and the blood can be attributed to the presence of sodium-potassium pumps inside the plasma membranes that are responsible for maintaining a normal concentration of K+ between the ECF and ICF.
Calcium ions are essential for enzyme activity, muscle contraction, and blood coagulation. Besides, Ca2+ also helps in cell membrane stabilisation and has been identified crucial for neurotransmitter release from the neurons and hormone release from the endocrine glands. Action potentials result in the opening of Ca2+ channels that are located in the membrane of synaptic knobs, thus resulting in an influx of Ca2+ ions. These ions lead to the release of neurotransmitters from synaptic vesicles present in the pre-synaptic membrane to the synaptic cleft (Kanaporis & Blatter 2015). Following this release, the neurotransmitter binds to and brings about an activation of the receptors located in the post-synaptic membrane.
Venous return refers to the blood flow rate back to the heart, and usually limits the cardiac output. In other words, it is the flow of blood from the peripheral regions back to the right auricle and is often considered equivalent to cardiac output. Under conditions that involve a steady-state, owing to the fact that the cardiovascular system represents a closed loop, the cardiac output (Q) equals to the venous return, once averaged over time. Else, this would result in accumulation of blood in either the pulmonary or the systemic circulation. Although venous return and cardiac output are interdependent, they can be independently controlled as well. Each time the heart beats, the left ventricle undergoes contraction and pushes blood in the arteries, which are responsible for delivering blood rich in oxygen to different cells present in the body (Magder 2016). Heart function primarily comprises of two different phases, namely systole and diastole. While systole represents the contraction phase, which makes the heart chambers push blood, diastole represents the relaxation phase, during which the heart chambers get filled with blood. Upon restricting venous return, the left ventricle collects less amount of oxygenated blood, thus ensuing in low-end diastolic volume (Yonezawa et al. 2015).
During low end-diastolic volume, there occurs failure of the ventricles to stretch, which is considered as an essential precursor to strong contraction and expulsion of blood. Little EDV together with weak cardiac muscles and extreme peripheral resistance restrict the capacity of the heart to meet the body’s oxygen demands. While performing exercise, the rhythmic pump of cardiac muscles simplifies venous return. This is principally accomplished by pushing blood via the valves that are connected to the heart. Furthermore, exercise also increases the lung activity and results in an alteration in the thoracic pressure, thereby drawing blood towards the heart (Kropp et al. 2018). Upon performing regular exercise, the venous return also increases by an elevation in the total blood volume. This is followed by an increase in the EDV, and contractile strength of cardiac muscles. Exercise also results in an increase in the capillary number, in the muscles that facilitate gaseous exchange, thus dropping peripheral resistance (Joseph et al. 2016). Thus, Brodie’s mean arterial pressure is likely to influence his venous return.
Oxygenation refers to the addition of oxygen to the human body and also encompasses the process of treating a person with supplemental oxygen. Acute infection in the respiratory tract requires supplemental oxygen therapy as the mainstay treatment. The symptom acquired by Brodie of a cold has possibly occurred due to bacterial infection that has resulted in an obstruction of the airways and inability to cough up the mucous. Respiratory compensation refers to the mechanism by which the respiratory centre alters the plasma pH by altering the respiratory rate (Fontana et al. 2015). This compensation for the cold acquired by Brodie will mainly occur in the lungs that retains carbon di oxide by slowing down the breathing rate and triggering hypoventilation. This will be followed by consumption of CO2 for the development of carbonic acid intermediates, thereby resulting in a decrease in pH (Broxterman et al. 2015). The reduction in the H+ ions will lead to a suppression of the peripheral chemoreceptors that are sensitive to pH changes. However, due to a slowdown in the respiratory process, an increase might occur in the pCO2. Upon entry of the blood in the pulmonary capillaries, the hydrogen and bicarbonate ions will convert to carbonic acid, and back to CO2 and water. Removal of the hydrogen ions will impart a neutral pH to blood, thus facilitating binding of oxygen and haemoglobin.
If Brodie developed coronary artery disease, the arteries responsible for delivering blood to the cardiac muscles would have become narrowed and hardened. Owing to the fact that cholesterol is a lipid and does not usually dissolve in the bloodstream, higher levels of LDL act as significant risk factors and contribute to the onset of coronary artery disease (Levine et al. 2016). Build-up of cholesterol in the form of plaques in the inner arterial walls would result in atherosclerosis, due to which his heart would become deprived of the oxygen that is required for its normal functioning. Lack of oxygen in the heart muscles would also have resulted in death of the cells, thus causing a condition commonly referred to as myocardial infarction. It would eventually result in cardiac muscle scarring, and subsequent death (Arbab-Zadeh & Fuster 2015). Deposition of calcium phosphate in the muscular layers of the arteries would play a vital role in hardening them and inducing early atherosclerosis.
However, in absence of adequate oxygen, the cardiac cells would demonstrate a shift towards anaerobic respiration of glucose. This would result in the production of lactic acid, as a primary by-product. This lactic acid would subsequently stimulate the pain receptors and lead to a painful sensation in the chest, commonly manifested in the form of a condition called Angina Pectoris. The condition can also be observed when Brodie engages in vigorous exercise. Anaerobic respiration and subsequent accumulation of lactic acid would also contribute to a decline in the capability of the muscles to generate some force. This can be attributed to the fact that lactic acids have been found responsible for increasing the muscular intracellular acidity (Lund et al. 2018). This in turn will reduce the contractile apparatus’s sensitivity to Ca2+, in addition to reducing inhibition of chloride ions present in the muscles to contraction.
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