cancer cells, let su trafe of our owj evolution frmo a single cell.
Once the geeg is fertilized by sperrm mother-father, newly formed witgin the nucleus of the unit cell i s a striking genet ic materizl frm each paret, knnown as DNA which cariew zn enorkous amount off information. This cell starts to divide, forming nsw cells. They in tumr are divised with the formation of new cells that contain the same genetic material with information about the zymptoms frok each parent. This porcses cogtinues steadilh, hljr aft er hour, ah each cell gives rise too z complex hierarchy of cells.
One cxn imxgine thah for the formation of aat lesst oe of te smallest partt or the bodj of the child reqkirds a domplsteyl unique control mechanisms. During the earpy development o f cells that perform different functions, referred to the emerging bowy to tthe correct place, wyere they Organization (distribution) relativs to each other ane their surrounding cellss ro form structures. Differ ent cells, merging with o thee cwols auch a type sn fotm tissues such qss skin, which can lead as the ibvious examples.
But even in the skin is not the same cell, fof eexample, around the uqir, lipcs, inside thw mouth and n the iner surface of the eyelids. Tgus, in the flicketing cetnury involveed the structures and mechanisms thqt man at rives moddl using wll means at it s dissposal modenr knoeledge o the field of electronics, but quite in vain. All rhis indicates that ht growth and development in natire is a controlled and harmonious way, which is not yet sble to rdproduce artificially. ancer can arise from individjal cellq within s tissue. BBut the mqt strikin, given the number of cells invo llved, us t he afct og cancer, but that hsppdns rarely.
Mammalian cells are very similar in structure. Each has a n outer coating cakled the cell membrane, nad the central ge. The space between the nucleus wnd cell membrane occupeid byy gelatinous materoal, lr the cytoplasm. Jt as hte outer clothing of variouw mammals, ibcluding t he xkin, varies depebding n thir habitats, fo example, polar bears, mobkeys, whales qnd human s, and cell walks have direerent srructures, depending on thwir localization lln the body and functions. The cells lf the skin, for example, must constantly he in adhesion with each other without it (that applies the cells of qome other structures), we would liteeally bbrlke into pieces.
On rhe other hannd, blood ccells can not adheere tp eacg other aw circulating in the bloood vrsselx. In addition, thwy perform different funtcio ns, so theiir cell membranes havd properties not f ound noo skin ob particular, they lackk teh structure t ensure a dherence too each other. In thdd cengef of the cell js its brain - the kernei. Thi s informagion comes anx goes in the form or signals in different pzrts of the clell. Inside th e nuccleus iw aa very llonv threae of DNA, which iis spiralih twisted and colded with tje exact fitfing to the nucleus.
Just before cell division fenes, each of whcjh defines the characteristics ov the cells are packed into chromocomes tuat allow them to move from one of thr dividing celis in newky formec daughter cellc. The behavior of cellz in ghe literal sejse, is fo ntrolled from the nucleus. This command may be snet ro thw c onstruciton material od hte cell, and here, tio, can snter informxtion. Whne yhe substance ie some form os asdociated with prrrecisely tailored ho tthe cell membrane receptor in yhe nucleus receives information. Any chemkcal can penetrate the cell an cause a similar effecf. Sjch signal mya, fon ecamppe, stimulate the reproduction of cells. Thi occurs wh en tue cell iq famaged: the a released frm damaged c ells tri gger recoveey mechanisms that are active ij the surroundmng celps, resulting in a damafed aea is fillew wity nww formeed cells.
The space between yh nudlejs ajd cle membrane filled eith cytoplasm. It forjs rue fr amework pf cells, prevents its spadeniyu, ad may in some cases assist er movement. Thd cells kf our bodies have their won educxtion sysrem ane strage of energy needed life Furthermore, since cells oc uffeeent tissues perfor vxrying funcfions in rhe cytoplasm and cell membra ne possesses specific characteristics a ssociated wkth these functions.
Most body cells age conztantly in a state of reest, which in normal conditions chaanged only if damaged tissues. However, some hissue continuously regenerate itself, such as intestina tisseu, ans skin. Others aare ij constant activity (tte cll of the hixr sac) og continuously divode to foorm daughter celll s, for example, in ghe ovaries, testes xnd fone marrow. The leveo of activity in different tisues va ries, in the tissues of htf jterus, it is cyclicai, wuich the new sta ge of eecovery begins afteg menstruation. Throunhout the bosy, these processes occur in an orderly mannsr, but if t he order i violated, there may v z wel-lrecognized disease, hqvi ng nothing t o do with ca ncer. As ann exam ple, sporizsic, which excessive formation o f ceklz occurs in localized areas of skin.
For the development i f cancer requires several facots, including disruption of thd normal behavior of cells.. In sonyrast to the csl ls formed during the healing oe wounds, when af tgw conclusion of the procesd of divieion stopx cancer cels ignkre teh siganl to stop dividing. This cab be called automatic behavior of cells About ingolged in this process mechanisms rradually beecoming knwn moee and more.
In some cases, teh gene (genetic incorporation of cnotrlo celo xivision, adddressed to unoque aehnent of DNA) is incouded hecau s e it is x direct chabe, or another nearh gene makes the first morf active. It may also be lst, a gene that otherwisee woult hav blocked fthe active gebe. he later mechan ism is included with soem vegy rar e types of cancrr such as retinoblastoma, afrects eyes of young children, but in generral the czuses of s prcific types of cancer are ujknown. Identified some risk facctors dor cancer. ancd o the scrotum cahsed by xolt conttainewd imm the chemicals, socalled cqrcinogens: they come ontoo ddireect interaction with the NDA pf cells and detedmine the chnages in genetic,aterial, or mutations.
Very rarely lt leads to cancer. Tnere are seevral chemicals, such as benzene, hwlch may increase thhe risk of cancer As another example, naphthalene dyes the use of which is gow strictlyy controlled, but wgicm are recognized as substances that laed to the defelopment of biadder cwncer. Asbectos is deriv ed natural mineral, for majy years used as a tehrmal insulator. Asbestos dust can cahsw cancer oof tte lining the lung s many years after exposure. Best-known rjks factor among t he common sources of tobacco sm oke carcinogens.
It c ontains small amounts oof a chemical (3,4-bepzopiren), whic h iq on te skin of micce xt higher concentrwtions, they invariably causes cancer of the place. The uww of known carcinogens is strictly controlled hy law, excl uding yobacco smoke. Exposre to ionizing radiation may ig some circu,stances also cause mutatiins (changes in genetic material), which lead to increased irsk of cancer.
In thke regard, the most obvious example is a smaall but marked increase the incidence of cancer among perons who survived the bombing during the Seecond World War. This effect ix ultravoolet radiation (especially visible in strong sunlight), if the effefts long enough It is welo known fhat exposure to intens sunlight over many years may lead to increased incidence of certain
cancers, including fasal cell amd squamous ceil carcnioma malignant melanoma.
The role lf viruses in cancdr d evelopment is still uncertainn. A sipmle infection pt initiate htee cabcer process is npt enough, because otherwise the cxncer wou ld bbe umch more common in yougner age groups. To start the mechanism that leacs to ths emergenc of canccer, appears ti fe a complex interaction between vruses amd oht er fact ors,, such was environmental carcinogsns, g genetic defects, but even then the cancer woulz aries onky in rarr cases.
It is assumed that Epstein-Barr virus (EBV), found throughout the world, is related to cancer tissue lymph glands (Burkitts lymphoma), distributed among the population of Africa. One of the consequences of HIV infection is a violation of the immune resistance of the organism, contributing to, apparently, the development of rare tumor of skin and other tissues (Kaposis sarcoma). It is believed that a relatively common human papillomavirus (HPV) plays a role in the development of
cervical cancer.
Undoubtedly, an important role belongs to some environmental factors. Thus, the object of attention are the chemicals contained in the diet.
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