Question

4. After a shipwreck, Sam and Georgie wash up on the shore of a deserted island. Upon their arrival, they both weigh the same amount, but Sam is taller than average and very athletic, while Georgie is shorter than average and considered a little overweight. They quickly find a spring with plenty of fresh water, and sit down to assess their situation. Explain the consequences of each of the following three possible situations in which they may find themselves (A, B, and C) by answering the questions below.

. Situation A: They find absolutely no food on the island. What would occur metabolically in Sam and Georgie during their first day? How will their metabolic processes change as the length of their starvation increases? Based on the information provided, briefly explain which of the two castaways you would expect to be able to survive the longest without food.

Situation B: They find a steady supply of starchy tubers and small crabs. Over time, they both begin to develop skin lesions and a couple of Georgie’s teeth fall out. Give a possible explanation for the appearance of these symptoms

Situation C: They find a large supply of wild grain, but little else. Not long after, they begin to feel weak and tired. Both of their bellies begin to swell up and protrude (edema). Give a possible explanation for the appearance of these symptoms. (Hint: what is missing from their diet, and how is normal blood osmolarity primarily maintained? Why would water be retained in tissues, rather than moved into the blood and thus out via the urinary system?)

Answer 1

A. Sam and Georgie find absolutely no food on the island on the first day. There will be metabolic changes in their body because of starvation. There is an initial rise in metabolic rate, reflecting gluconeogenic activity. These metabolic processes occur in our body to get different kinds of energy--energy from macronutrients like carbohydrates, proteins etc, which gives bulk energy, and energy from micronutrients (minerals and vitamins) which is essential for maintenance of tissue function. Metabolism can be of two types--anabolism, the biosynthesis of macromolecules (glycogen, proteins, and lipids) and catabolism, the degradation of macromolecules into their simplest form- glucose, amino acids, glycerol, and fatty acids. The energy from catabolic degradation is required for the endergonic processes of anabolic biosynthesis. As length of starvation increases, gluconeogenesis is stopped and thus reduce muscle protein breakdown and ketones. Some other consequences are - the result of chronic energy deficiency will make slow growth and low adult body size. Increased in Serum rT3 and the decreased in T3 will lead to decrease in protein breakdown in the body. Adipocyte lipolysis for liver ketogenesis is the most important metabolic pathway during starvation. This adipose stores will be depleted and muscle also be degraded for gluconeogenesis if starvation is prolonged, thus it may cause to death. Therefore, the metabolic response to starvation is related with maintaining a supply of water-soluble substrates to the brain for energy supply.

Georgie will survive more since it was proved clinically that obese individuals are able to live for few months without eating. Thus, the carbohydrate reserves in their body are depleted quickly, and the survival period of starving individuals are more on fat reserves than on muscle mass. So, starvation rarely occurs in well-nourished individuals. Moreover, it was proved that shorter people can live longer than taller people on an average.

B. They both fed on starchy tubers and small crabs, and have developed skin lesions. This skin lesions are caused because of infections on the skin. Skin infection means the skin with abnormal growth or appearance. These infections may arise from the food they eat or from other sources. When they eat those crabs and tubers, they might get allergic and causes lesions. The other probable reason could be infection of the skin by bacteria, viruses, fungi or parasites through air or by touch. Warts and chickenpox are some examples of possible infections. Other reason may be allergic sensitivities or health conditions eg. diabetes or poor circulation. While Georgie’s teeth fall out may be due to continous starving (eating disorder) and purging. Purging makes our teeth weakened, brittle and sometimes it can cause tooth fall. It means that stomach acid is regularly making direct contact with teeth.

C. Both of their bellies begin to swell up and protrude (edema). These swelling is due to indigestion or a tight abdomen. Constipation may also be the cause of abdominal swelling, other reasons include stomach cancer. A swollen abdomen is mainly due to gastrointestinal issues. And Edema happens where excess fluid is stored in our body’s tissue. Due to this excess storing, swelling and puffiness of the tissue occured. This can be observed at feet, ankles and legs.