In footnote 32, David Shenk reiterates Michael Meaney’s words about cellular environment: “The intracellular environment is a function of the genetic make-up of the cell and the extracellular environment (e. g. hormones released by endocrine organs, cytokines from the immune system, neurotransmitter from neurons, nutrients derived from food) [which is] also influenced by the environment of the individual”. Using your knowledge of human body systems, explain what might be the consequences of being a high school student living in this environment: stress, dehydration, lack of sleep (dependence on coffee), and poor nutrition (low blood glucose). Think about the hormones the student’s body might release to try to maintain homeostasis—how will they regulate? Is there any hormones that might be inhibited in this environment—if so, consequences are? Say all American students suffer in this environment—what might be the long term effects if this environment is maintained for generations? Relate your answers to the biology theme of regulation.
-Linda Xu (lindaxu22@hotmail.com)
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ReplyDeletePart 2
ReplyDeleteAnother consequence of being in a stressful environment would be lack of sleep. With all the workload we get everyday, the amount of sleep we get is minimal. Sleep deprivation has been known to alter the production of certain hormones. For example, sleep deprivation dampened the secretion of thyroid stimulating hormone and increasing blood levels of cortisol. This increase is bad because it relates to insulin resistance (diabetes) and memory impairment (http://www.uchospitals.edu/news/1999/19991021-sleepdebt.html). The fact that researchers are finding out that sleep deprivation is linked to type 2 diabetes is very frightening to many. Also, people are tired, but they have so much work to do that they ingest caffeine to have them stay up longer. The effects of caffeine are restlessness, insomnia, heart palpitations, and headaches. Also, caffeine dehydrates the body, which leads to more problems, so the best option is to get your sleep.
If one is stressed out, he or she might result to stress eating, which most cases means overeating of food high in glucose. So, stress will lead to poor nutrition. If one ingests too many foods high is glucose, then his or her blood glucose level will raise above the homeostatic set point for blood glucose. In order to lower blood glucose level or return the blood glucose level to the homeostatic set point, insulin must be released from the beta cells of the pancreas. Insulin lowers blood glucose level by telling body cells to let “in” the glucose, and insulin also targets the liver to convert glucose into glycogen polymers (Campbell 982). If the blood glucose level passes the homeostatic set point negatively, then glucagon is released to raise the blood glucose level. If too much glucose is ingested, then one might get type two diabetes, which is when your body cells become insulin resistant and so they just ignore the insulin secreted and the glucose stays in the bloodstream. So, the long term effects of unhealthy eating can be diabetes, so the best option is to deal with a mentality that you gave it your best shot and tried your best. High school is just the beginning stretch of a long journey, so live life to the fullest and don’t stress out and ruin that journey.
Krish Desai (kjdesai5@mac.com)
Students must experience stress in order to succeed, but there cannot be an excess of stress. This condition cannot really be maintained for a lifetime, let alone generations because the cardiovascular system cannot sustain excess stress for years without consequences. The selective advantage that stress (not in excess) provides is essentially motivation; if a person lives too easy a life, then they have no motivation to excel.
ReplyDeleteAccording to Webmd, when a person is under too much stress, ARH (adrenocorticotrophic releasing hormone) is secreted by the hypothalamus, which causes the pituitary gland to produce ACTH (adrenocorticotrophic hormone). ACTH causes the adrenal gland to produce adrenaline (hence its name) and cortisol. This then results in increased blood pressure and heart rate. Maintaining high levels of stress can cause high blood pressure and cardiovascular diseases (http://www.webmd.com/heart-disease/news/20100909/stress-hormone-predicts-heart-death) .When the cardiovascular system is forced to sustain high blood pressure, a person’s chances of survival are significantly reduced because homeostasis is not achieved.
When a person is dehydrated, ADH is released by the posterior pituitary and increases water retention in the kidneys. According to Webmd, in the long- run, constant dehydration can cause decreased cardiovascular efficiency, renal impairment, and fatigue(http://www.webmd.com/a-to-z-guides/dehydration-directory).
When a person doesn’t get sufficient sleep, the hormone cortisol is produced. In high levels, cortisol will cause the body to break down muscle tissue and store more blood sugar and fat in the body. Lack of sleep also depresses levels of growth hormones, which help speed up and regulate metabolism. High levels of sleep deprivation can cause weight gain.
According to Campbell, when a person has low blood glucose, the alpha cells of the pancreas release glucagon (a hormone that targets the liver to break down glycogen and release glucose into the blood) into the blood (983). Once glucose is released into the blood, the blood glucose level rises and homeostasis is achieved. This negative feedback loop maintains homeostasis and regulates blood glucose levels. The long- term side- effects of constantly maintaining a poor diet are malnutrition and excessive weight loss because the body will most likely be burning more calories than what is being taken in.
The biological theme of regulation can work with or against an individual; being under constant stress and malnutrition can cause certain genes to “turn off”; this will lead to health complications, such as obesity and cardiovascular disease. Regulation can also lead to success, as Shenk quotes Anders Ericsson, who said “When individuals deliberately push themselves beyond the zone of relative comfort and engage in sustained strenuous physical activity…they induce an abnormal state for cells in some physiological systems…these biochemical states will trigger the activation of dormant genes within the cells’ DNA” (69). Stress is a stimulus that leads to success, but excessive stress is not the same as dedication; people must undergo stress, but not for their entire lives.
Akshay Ramachandran (ramachandran.akshay11@gmail.com)