Реферат по предмету "Иностранный язык"


People With No Immune Systems Essay Research

Paper

You live in a world of germs and you’re at war. Your body’s constant, warm environment, rich in nutrients, is an ideal home, where tiny organisms can thrive. Their aim is to get in. Your body’s job is to keep them out. Through advances in cancer research, scientists now believe more than 100 million immune cells exist. For every virus or bacterium, there seems to be an immune cell specifically designed to hunt down and destroy it. But what happens when you are born without this ability?

The immune system is a network of cells and organs that work together to defend the body against attacks by foreign “invaders”. These are primarily germs-tiny, infection-causing organisms such as bacteria and viruses, as well as parasites and fungi. Because the human body provides an ideal environment for many germs, or microbes, they try to break in. It is the immune system’s job to keep them out or, failing at that, to seek them out and destroy them. Without the blood cells needed to perform this function, your body is susceptible to any disease or infection. Some of the problems associated with an improperly functioning immune system are arthritis, asthma, allergies, psoriasis, lupus, cancer, chronic fatigue syndrome, and a tendency to always be fighting some infection.

Infections are the most common cause of human disease. They range from the common cold to debilitating conditions like chronic hepatitis to life-threatening diseases such as AIDS. Microbes attempting to get into the body must first move past the body’s external armor. The skin and the membranes lining the body’s gateways not only pose a physical barrier, they are also rich in scavenger cells and IgA antibodies. In normal humans, microbes that cross the nonspecific barriers must then confront specific weapons tailored just for them. Specific weapons, which include both antibodies and cells, are equipped and with singular receptor structures that allow them to recognize and interact with their designated targets. Without these barriers to block out unwanted foreign cells, your body has no way to stop the infection from spreading.

Infants, who are born with weak immune responses, are protected for the first few months of life by antibodies they received from their mothers before birth. Babies who are nursed can also receive some antibodies from breast milk; these help to protect the digestive tract. However, babies with no immune system at birth must spend a great deal of their life, if not their entire life, building up enough of an immune system to leave a protected environment and return to the outside world where infections can be spread through the wind.




Не сдавайте скачаную работу преподавателю!
Данный реферат Вы можете использовать для подготовки курсовых проектов.

Поделись с друзьями, за репост + 100 мильонов к студенческой карме :

Пишем реферат самостоятельно:
! Как писать рефераты
Практические рекомендации по написанию студенческих рефератов.
! План реферата Краткий список разделов, отражающий структура и порядок работы над будующим рефератом.
! Введение реферата Вводная часть работы, в которой отражается цель и обозначается список задач.
! Заключение реферата В заключении подводятся итоги, описывается была ли достигнута поставленная цель, каковы результаты.
! Оформление рефератов Методические рекомендации по грамотному оформлению работы по ГОСТ.

Читайте также:
Виды рефератов Какими бывают рефераты по своему назначению и структуре.

Сейчас смотрят :

Реферат Субъекты Международного частного права. Виды правовых режимов в Международном частном праве
Реферат Fullerenes Essay Research Paper Overall View of
Реферат Sterily In Body Piercing Essay Research Paper
Реферат Застосування принципу можливих переміщень та принципу Даламбера до розв'язування задач
Реферат Scarlet LetterThe Forest Essay Research Paper The
Реферат Dandelion Wine Essay Research Paper Report The
Реферат Идейное значение картин русского пейзажа в романе Пушкина Евгений Онегин
Реферат К вопросу о конституционной юстиции
Реферат Идеологические и политические установки палестинского движения Исламский джихад
Реферат Кант и Вернадский
Реферат Cryogenics Is It Worth Waiting For Essay
Реферат Native Son By Richard Wright Essay Research
Реферат 142030, Московская область, Домодедовский р-н, с. Ям, ул. Южная,3
Реферат Night Essay Essay Research Paper The Absence
Реферат Использование элементов занимательности и игры при изучении состава слова в начальных классах