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

What is root cap, What is root cap? Root cap is a protective structure ...

What is root cap? Root cap is a protective structure located in the tip of the growing root. It defends the meristematic tissue of the root forming a cap that surrounds the tip

Different from all the other cellular microbes, How are the bacteria and th...

How are the bacteria and the archaea different from all the other cellular microbes? -They have cell walls? -They can move? -They reproduce asexually? -They have no nucleus?

Disorder of platelets - purpura, Disorder of Platelets - Purpura Purpu...

Disorder of Platelets - Purpura Purpuras  are bleeding disorders characterised by petechiae  and ecchymosis which may be due to deficiency in either,  the number or quality of

Lungs - respiration, Lungs - Respiration Lungs can be simple, characte...

Lungs - Respiration Lungs can be simple, characterised by air exchange with surrounding environment by diffusion only. These are called the diffusion lungs and are present in

Post-operative care of cardiac surgical patients, POST-OPERATIVE CARE OF PA...

POST-OPERATIVE CARE OF PATIENTS The first few days following cardiac operations are the most critical in terms of the patient's survival. The safety with which a patient can

What do you understand by haemagglutinins, Q. What do you understand by Hae...

Q. What do you understand by Haemagglutinins? Haemagglutinins are the globulin type of proteins which are present in the seeds of plants like double bean, field bean, white be

How cells of neoplastic tumors obtain oxygen and nutrients, Q. How do cells...

Q. How do cells of neoplastic tumors obtain oxygen and nutrients and release wastes? In the neoplastic tumors a phenomenon called as angiogenesis occurs. The Angiogenesis is th

What is enzyme assay, What is Enzyme assay Enzyme assay may also be use...

What is Enzyme assay Enzyme assay may also be used to determine whether stored plant products are suitable for use as food commodities, for e.g.  α-amylase should be present

Phylum Coelenterata, What are the classes in Phylum coelenterata?

What are the classes in Phylum coelenterata?

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