Defence mechanisms of the host, Biology

Assignment Help:

Defence mechanisms of the host


The healthy animal is protected from pathogenic organisms present in the environment by virtue of the effective immune mechanism present from birth. This innate resistance is non-specific in nature i.e. it is effective against most of the pathogens. The intact skin and mucous membranes of the body afford effective protection against pathogenic organism. Acidic pH of the gastro intestinal tract, lacrimation, ciliated mucous membrane of the nasal passage and sphincters of the natural orifices are some of the natural defence mechanisms. The reticuloendothelial system (RES) of an animal body provides an effective defence mechanism by engulfing and destroying the foreign particles like bacteria. Macrophages of Metchnikoff constitute the main cellular scavenging network of the body. Besides this, genetically a particular species could be resistant to a specific pathogen. This mechanism depends on many factors such as the absence of specific microbes binding receptors, body temperature and the animal habitat. Other type of resistance is acquired resistance which is acquired when an animal comes in contact with a particular organisms. It is of two types, viz. humoral immunity and cell-mediated immunity. The first one largely depends on the presence of antibodies in the tissue fluids and the later type is attributed largely by the phagocytic cells The acquired immunity also develops with the introduction of vaccines or toxoids in animal body.


Carriers:
Occasionally, a situation arises after recovery from a disease or because of the partial resistance of the host or the inability of the causal agent to produce the  disease syndrome in the host, the organism lives in the host without showing any symptoms of the disease, and the host itself is unable to completely get rid of the organism and cause disease in susceptible animals. The bacteria sometimes actively multiply and bring about a fresh outbreak of the disease as a result of breakdown in the balance between the host and the parasite under certain stress factors. The carriers could be classified as contact carriers, convalescent carriers and immune carriers.


Related Discussions:- Defence mechanisms of the host

Explain glucocorticoids, Explain Glucocorticoids The adrenal cortex se...

Explain Glucocorticoids The adrenal cortex secretes the glucocorticoids which  increase gluconeogenesis by increasing hepatic intake of amino acids accompanied by increased ac

What is intracellular digestion, Intracellular digestion, or cellular diges...

Intracellular digestion, or cellular digestion, is the breaking in the interior of the cell of big molecules coming from outside or even from the own cell metabolism into smaller m

Explain mendels law of dominance, Which one of the following cannot be expl...

Which one of the following cannot be explained on the basis of Mendel's Law of Dominance? 1. The discrete unit controlling a particular character is called a factor 2. Out o

What happens within the cell in the second interface period, What are the e...

What are the events that mark the beginning and the end of the second interphase period? What happens in the cell in this period? The second interphase period is the S. It begi

Explain yellow fever, Yellow Fever  Yellow fever vaccine, a single-dose...

Yellow Fever  Yellow fever vaccine, a single-dose attenuated live virus vaccine prepared in eggs, should be given at least 10 days before travel to endemic areas, which include

Explain nutritional biochemistry, Explain Nutritional Biochemistry A  ...

Explain Nutritional Biochemistry A  good understanding  of the  biochemical  basis  of  nutrient function  and  of  the consequence of nutrient deficiency  or excess  is  impo

Immunolocalization, uses and advantages and disadvantages of immunolocaliza...

uses and advantages and disadvantages of immunolocalization

Infective endocarditis, A) Definitive Infective Endocarditis 1) Patho...

A) Definitive Infective Endocarditis 1) Pathological Criteria • Micro organism: demonstrated by culture or histology in a vegetation; or in a vegetation that has embolize

What are blood enzymes, What are blood enzymes? Enzymes are proteins th...

What are blood enzymes? Enzymes are proteins that take out chemical reactions (as opposed to structural enzymes). Most of the detectable enzymes in the blood come from the seve

Fluorosis, Fl u o r osi s Continual ingestion of small amount of f...

Fl u o r osi s Continual ingestion of small amount of fluoride through feed or water leads to fluorosis in animals. The toxic effects are based on amount of fluorine inges

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd