Human Disease and Immunity

Human Disease and Immunity

Human Disease and Immunity

Task 1 (a)

Barriers to Invasion by Infective Organisms

Human body is composed of many types of components, including, tissues, cells and organs. Human body is vulnerable to many infective organisms, but eventually it is provided with the natural barriers. Immune system and physical barriers are two important defense providers.

Skin

Skin is considered as a largest organ of the human body. Naturally it is formed in a way that any external factor cannot produce harmful effect on our body. Skin prevents the exposure of internal organs to the external environment. Our heart, lungs, brain, vessels, and all the internal organs are covered in Skin so nicely that any external factor cannot affect them. The epidermis, which is the upper most layer of skin, does not allow any harm full thing to penetrate inside. Microorganism is the species that tries to find their way to enter inside the body in order to infect it. Most of the infectious diseases are caused by harmful microorganisms that enter into the body through various means. If the skin is burned, damaged or wounded, the microorganism can enter into the body; otherwise it is one of the great protective barriers of the human body to the invasion of infective microorganism.

Mucous Membranes

Mucous membranes are another effective physical barrier, as for example, mouth lining, eyelids and nose. The mucous membranes produce secretions that act against the microorganisms. As for example when tears moist our eyelids, an enzyme known as Lysozyme is secreted that provide defense against the microorganism that can infect the eyes. Similarly, when any microorganism enters into our nose through air inhaled, it is expelled out via mucus. Cilia, small hair like projections, assist the mucus in expelling the microorganism out. Similarly, the mucous membranes present in gastric area, urinary tract and genital area act according to their function and help to prevent the infections by the invasion of microorganisms.

Blood clotting

The blood supply increases during the process of inflammation. Porosity of the walls of blood vessels increases that allow the white blood cells and fluid to move towards the infected area. The WBCs attack the microorganisms that are invaded and substances are releases in order to continue the inflammation process. Clotting factors delay the infective microorganisms and their toxins spread by promoting the clotting of blood (Robertson et al, 2007, pp. 34-361).

Task 1 (b)

Barriers Crossed by the Pathogens

Cholera- The cholera is transmitted into the human body by eating contaminated food and drinking contaminated water, the pathogen of cholera crossed the barrier of mucous membrane.

Malaria- the pathogen of malaria crossed the skin barrier through biting of a mosquito enters to the blood and cause infection.

Tuberculosis- Tuberculosis pathogen that is bacteria crossed the barrier of mucous membrane of the nose. It is transmitted by inhaling the contaminated air, invade the mucous membrane and cause infection.

Measles-The pathogen of Measles crossed the barrier of the nasal passage as it gets transmitted by the droplets and respiratory ...