File Name: anatomy and physiology of immune system .zip
The role of the immune system — a collection of structures and processes within the body — is to protect against disease or other potentially damaging foreign bodies. When functioning properly, the immune system identifies a variety of threats, including viruses, bacteria and parasites, and distinguishes them from the body's own healthy tissue, according to Merck Manuals. Innate immunity is the immune system you're born with, and mainly consists of barriers on and in the body that keep foreign threats out, according to the National Library of Medicine NLM. Components of innate immunity include skin, stomach acid, enzymes found in tears and skin oils, mucus and the cough reflex. There are also chemical components of innate immunity, including substances called interferon and interleukin Adaptive, or acquired, immunity targets specific threats to the body, according to the NLM.
From the months spent in the womb to the end of his life, every individual is under constant attack from an enormous range of potentially harmful invaders. These threats include such diverse entities as bacteria, viruses, cancer cells, parasites and foreign non-self cells, e. The body has therefore developed a wide selection of protective measures, which can be divided into two categories. These are grouped together under the term immunity. Resistance is directed against only one specific invader. These are the first lines of general defence; they prevent entry and minimise further passage of microbes and other foreign material into the body.
All organisms are connected in a complex web of relationships. Although many of these are benign, not all are, and everything alive devotes significant resources to identifying and neutralizing threats from other species. From bacteria through to primates, the presence of some kind of effective immune system has gone hand in hand with evolutionary success. This article focuses on mammalian immunity, the challenges that it faces, the mechanisms by which these are addressed, and the consequences that arise when it malfunctions. The problems that the mammalian immune system solves are not restricted to higher animals; they are faced by all forms of life and are ignored by none.
T cells also called T lymphocytes are one of the major components of the adaptive immune system. Their roles include directly killing infected host cells, activating other immune cells, producing cytokines and regulating the immune response. This article will discuss the production of T cells, the different types present in the immune system and relevant clinical conditions. T lymphocytes originate from haematopoietic stem cells which are produced in the bone marrow. Some of these multipotent cells will become lymphoid progenitor cells that leave the bone marrow and travel to the thymus via the blood. T lymphocytes undergo a selection process in the thymus, which the majority of developing T cells called thymocytes will not survive.
Nonspecific im- mune responses serve as the initial line of de- fense against infection, providing humans with what is commonly referred to as natural immunity .
This tutorial provides an overview of the immune system, concentrating on the roles played by B and T lymphocytes, and on the antigen-presentation system. All animals possess a nonspecific defense system called the innate immune system, which includes macrophages in mammals. Vertebrates have an additional powerful immune response called adaptive immunity. Not all downloadable documents for the resource may be available in this format.
The immune system includes primary lymphoid organs, secondary lymphatic tissues and various cells in the innate and adaptive immune systems.
Victorian government portal for older people, with information about government and community services and programs. Type a minimum of three characters then press UP or DOWN on the keyboard to navigate the autocompleted search results. The immune system keeps a record of every microbe it has ever defeated, in types of white blood cells B- and T-lymphocytes known as memory cells. This means it can recognise and destroy the microbe quickly if it enters the body again, before it can multiply and make you feel sick.
Вглядевшись, она как в тумане увидела еще одну панель с буквами алфавита от А до Z и тут же вспомнила, что нужно ввести шифр. Клубы дыма начали вытекать из треснувших оконных рам. Сьюзан в отчаянии колотила в дверную панель, но все было бесполезно. Шифр, подумала .
Сзади его нагоняло такси. Он смотрел на приближающиеся огни центра города и молил Бога, чтобы он дал ему добраться туда живым. Беккер проехал уже половину пути, когда услышал сзади металлический скрежет, прижался к рулю и до отказа открыл дроссель. Раздался приглушенный звук выстрела. Мимо.
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