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25 Apr 2018

More specifically, is nicotine in the concentrations thatsmokers receive when smoking cigarettes toxic? I know that in greatenough concentrations it can be toxic (but then, so can just aboutanything else, including oxygen) and I know that in plants it isused as a defense against insects and can even be used as aninsecticide. However, it has always been my understanding thatnicotine is irrelevant as far as the harmful effects of smokinggo.

I recently had a conversation with another biologist who hadjust quit smoking and had done quite a bit of research on thesubject. He said that nicotine itself is in fact bad for you and,therefore, that tobacco-less alternatives to cigarettes (such aselectronic cigarettes) are still harmful because of thenicotine alone.

Does anyone have any more information on this? Perhaps somereferences? Or, even better, a detailed explanation of the pathwaysinvolved? Again, I stress, not about nicotine's toxicity in generalbut about its harmful effects on vertebrates (preferably human) atthe kinds of concentrations one could expect to ingest whensmoking.

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Keith LeannonLv2

27 Apr 2018

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Related questions

The human body is truly remarkable and is designed tofunction effectively. Organs are important structures composed ofdifferent tissues that facilitate specific functions within thebody. Organs function as part of an integrated group of structuresknown as organ systems. These organ systems form the organizationalunits that are responsible for crucial processes necessary forsustaining life.

Examples of organ systems include but are not limitedto the cardiovascular system, the digestive system, themusculoskeletal system, the nervous system, the excretory system,the endocrine system and the respiratory system. Even organ systemsdo not function alone. These systems work together, interactingwith other organs in a functional network that keeps the body inbalance. (Look up the term homeostasis in your text.) When homeostasis orthe normal functioning of organ systems is disrupted, disease maydevelop causing injury to the body, or even death. In thisassignment, you will explore organ systems, as well as associateddiseases or malfunctions.

Assignment details:

Take a look at the following casestudies that detail an outcome associated with a disease/organmalfunction. Select onestudy to investigate further for yourassignment.

Critically evaluate the information provided andcorrelate it with the organ systems that are affected in thescenario. Use the information that you have gathered to answer theassignment questions that follow the case study. For assistancewith your assignment, please use your text, the AIU Library, Webresources, and course materials.

Case Study 1:

Atherosclerosis isnarrowing of arteries caused by the accumulation of fatty depositson the arterial walls.

On June 22, 2002 the St. Louis Cardinals werepreparing for their upcoming baseball game against the Chicagocubs. Concern arose when their prized pitcher, 33-year old DarrylKile did not show up for practice. Soon after, he was found stillin his hotel room where he had suddenly died in his sleep (New YorkTimes, 2002). It was discovered that the cause of death was relatedto three of his coronary arteries being 80-90% blocked as a resultof atherosclerosis (New York Times, 2002), which ultimately causedhim to undergo a heart attack.

Answer the following assignmentquestions:

Why would atherosclerosis result in a heart attack?Provide a brief explanation based on how the heart functions.
How are arteries different from veins andcapillaries? Describe the functions of both arteries andveins.
Vertebrates and some invertebrates have a closedcirculatory system. Explain the advantage of having a closedcirculatory system over an open circulatory system?
Briefly explain how the lymphatic system isassociated with the circulatory system?
Describe one disease that affects the lymphaticvessels similarly to the way that atherosclerosis affects thearteries?

Case Study 2:

Cigarette smoking remainsthe leading preventable cause of death in the United States,causing an estimated 438,000 deaths - or about 1 out of every 5 -each year (National Cancer Institute, 2008).

Mr. Amos is now 57 years old and has been smoking forthe past 30 years of his life. A recent doctor's visit reveals thatMr. Amos has stage 3 lung cancer, characterized by his symptoms ofnagging chest pain, fatigue, coughing up blood, substantial weightloss, and increased carbon dioxide levels in his blood. The doctorinformed Mr. Amos that had he quit his smoking habit several yearsago, he would have reduced his risk for developing lung cancerlater in life. Mr. Amos immediately begins treatment for the lungcancer that has metastasized to his lymph nodes.

Answer the following assignmentquestions:

What main components in cigarettes affect therespiratory system? Explain their effects on specific organs, cellsand/or processes in the respiratory system.
There are alternate mechanisms of transportingcarbon dioxide (CO2) and oxygen (O2 ) in the blood. Explain howsmoking might lead to increased levels of carbon dioxide in theblood.
Can smoking affect other organ systems of the body?Give specific examples and briefly explain your answer.
How can you correlate cellular respiration with therespiratory system?
Does smokeless tobacco present a reduced risk forlung cancer and other smoking associated diseases? Provide evidencefor your answer.

Case Study 3:

Gigantism is abnormallylarge growth during childhood caused by excess growth hormonesecreted by the anterior pituitary gland.

Robert Wadlow, born on February 22, 1918, weighed anormal eight pounds, six ounces. However, by the time Robertreached the age of six months old, he weighed 30 pounds (Hamilton,1993). Within only a year, his weight rose to 62 pounds, more thandouble the normal weight of a baby at 18 months. Aside from hisweight, Robert continued to grow at an astounding rate, reachingsix feet, two inches and 195 pounds by the time he was eight yearsold. Robert's unique size was attributed to an over activepituitary gland, which produced much higher than normal levels ofgrowth hormone. At the time of his death in July 1940 at the age of22, Robert had reached a height of 8 feet 11.1 inches and weighed485 pounds (Hamilton, 1993).

Answer the following assignmentquestions:

How does growth hormone regulate various bodyfunctions in adults, and what could cause the excess secretion ofgrowth hormone?
Discuss the relationship between growth hormone andinsulin, and are there complications associated with theirinteraction?
Why is gigantism usually more difficult to treatthan dwarfism?
Give examples of two other hormones secreted by thepituitary, and briefly describe how they specifically affect otherorgan systems of the body?
Some athletes have resorted to the illegal use ofanabolic steroids to increase strength and muscle size. How areanabolic steroids different from growth hormone? Briefly explainyour answer.

References

Hamilton, S. (1993). Looking backand up: At Robert Pershing Wadlow, the gentle giant. Alton,IL: Alton Museum of History and Art.

National Cancer Institute. (2008). Tobacco statistics snapshot. Retrieved fromhttp://www.cancer.gov/cancertopics/tobacco/statisticssnapshot#0_references

The New York Times. (2002, July 17). Baseball: Coroner verifies the cause of Kile's death asnatural. Retrieved fromhttp://www.nytimes.com/2002/07/17/sports/baseball-coroner-verifies-the-cause-of-kile-s-death-as-natural.html?ref=darryl_kile

bluemosquito470

Some of you will have seen Starship Troopers, a moviebased upon a novel by Robert Heinlein. The film deviates from thebook in some ways, for example the book describes a visit to aplanet to resupply the dropships used in combat operations by theM.I. (mobile infantry). Heinlein describes this visit in the book;a portion of the novel is reproduced on the followingpage.

The followig passage contains two concepts we havediscussed in class in relation to the effects of mutation onpopulations, one positive and one negative. Describe the twomutation related concepts Heinlein discusses. You must describethese concepts as a biologist - you must use the technical terms wehave used in class properly and explain the positive and negativeeffect of mutation on the evolution and health of apopulation.

(a) What is the positive effect of mutation as describedby Heinlein?

(I.E., what does Heinlein describe as a benefit ofhaving more mutations)

(b) What is the negative effect of mutation as describedby Heinlein?

(I.E., what does Heinlein describe as a problem ofhaving more mutations)

I never have learned the co-ordinates of Sanctuary,nor the name or catalogue number of the star it orbits - becausewhat you donât know, you canât spill; the location isultra-top-secret, known only to shipâs captains, piloting officers,and such ... and I understand, with each of them under orders andhypnotic compulsion to suicide if necessary to avoid capture. So Idonât want to know. With the possibility that Luna Base might betaken and Terra herself occupied, the Federation kept as much ofits beef as possible as Sanctuary, so that a disaster back homewould not necessarily mean capitulation.

But I can tell you what sort of a planet itis. Like Earth, but retarded.

Literally retarded, like a kid who takes tenyears to learn to wave bye-bye and never does manage to masterpatty cake. It is a planet as near Earth as two planets can be,same age according to the planetologists and its star is the sameage as the Sun and the same type, so say the astrophysicists. Ithas plenty of flora and fauna, the same atmosphere as Earth, nearenough, and much the same weather; it even has a good-sized moonand Earthâs exceptional tides.

With all these advantages it barely got awayfrom the starting gate. You see, itâs short on mutations; it doesnot enjoy Earths high level of natural radiation.

Its typical and most highly developed plantlife is a very primitive giant fern; its top animal life is aproto-insect which hasnât even developed colonies. I am notspeaking of transplanted Terran flora and fauna - our stuff movesin and brushes the native stuff aside.

With its evolutionary progress held down toalmost to zero by lack of radiation and a consequent mostunhealthily low mutation rate, native life forms of Sanctuary justhavenât had a decent chance to evolve and arenât fit to compete.Their gene patterns remain fixed for a relatively long time; theyarenât adaptable - like being forced to play the same bridge handover and over again, for eons, with no hope of getting a betterone.

As long as they just competed with eachother, this didnât matter too much - morons among morons, so tospeak. But when types that had evolved on a planet enjoying highradiation and fierce competition were introduced, the native stuffwas outclassed.

Now all the above is perfectly obvious fromhigh school biology ... but the high forehead from the researchstation there who was telling me about this brought up a point Iwould have never thought of.

What about the human beings who havecolonized Sanctuary?

Not transients like me, but the colonists wholive there, many of whom were born there, and whose descendantswill live there, even unto the umpteenth generation - what aboutthose descendants? It doesnât do a person any harm not to beradiated; in fact itâs a bit safer - leukemia and some types ofcancer are almost unknown there. Besides that, the economicsituation is at present all in their favor; when they plant a fieldof (Terran) wheat;, they donât even have to clear out the weeds.Terran wheat displaces anything native.

But the descendants of those colonists wonâtevolve. Not much, anyhow. This chap told me that they could improvea little through mutation from other causes, from new blood addedby immigration, and from natural selection among the gene patternsthey already own - but that is all very minor compared with theevolutionary rate on Terra and on any usual planet. So whathappens? Do they stay frozen at their present levels while the restof the human race moves on past them, until they are livingfossils, as out of place as a pithecanthropus in a spaceship?

Or will they worry about the fate of theirdescendants and dose themselves regularly with X-rays or maybe setof lots of dirty-type nuclear explosions each year to build up afallout reservoir in their atmosphere? (Accepting, of course, theimmediate dangers of radiation to themselves in order to provide aproper genetic heritage of mutation for the benefit of theirdescendants.)

This bloke predicted that they would not doanything. He claims that the human is too individualistic, tooself-centered, to worry that much about future generations. He saysthat the genetic impoverishment of distant generations through thelack of radiation is something most people are simply incapable ofworrying about. And of course it is a far-distant threat; evolutionworks so slowly, even on Terra, that the development of a newspecies is a matter of many, many thousands of years.

I donât know. Shucks, I donât know what Imyself will do more than half the time; how can I predict what acolony of strangers will do? But Iâm sure of this: Sanctuary isgoing to be fully settled, either by us or by the bugs. Or bysomebody. It is a potential utopia, and, with desirable real estateso scarce in this end of the Galaxy, it will not be left in thepossession of primitive life forms that failed to make thegrade.