human health _ human health presentation.pptx

human health human health human health human health human health

1. HUMAN HEALTH AND DISEASE What Is Health? In simple terms, Health can be defined as being free from all diseases and infections. According to the World Health Organization (WHO), health is not only the absence of disease or illness. It is a state of an active and energetic condition, including physical, mental, and social well-being. A balanced diet and regular exercise play an important role in maintaining the good health of an individual. There are many factors which affect health, such as: Poorly balanced diet Genetic disorders Stress and anxiety Infection from pathogens Intake of unhealthy and unhygienic food Lack of exercise and other physical activities

2. What Are Diseases? A disease is an abnormal condition affecting a healthy living organism. It is broadly divided into infectious and non-infectious. Infectious diseases-  These diseases are caused by the pathogens, such as bacteria, viruses, fungi, and parasites and can be easily transmitted from one person to another; hence it is also known as a contagious or communicable disease. Common Cold, Tuberculosis, flu, ringworm, and malaria are some examples of infectious diseases. Non-infectious diseases-  Diseases which cannot be transmitted from one person to another are called non-infectious disease, it is also known as non-communicable disease. These diseases can be either caused by genetic disorders, unhealthy diets, lack of physical activity and a few environmental factors.

3. Life cycle of malaria

4. Immunity Immunity is defined as the ability of the body to protect, defend and fight against invading  pathogens  like bacteria, viruses, and other foreign bodies and toxic substances. There are two types of immunity. Innate immunity – non-specific defence type of immunity present at the time of birth achieved by the provision of 4 barrier types – the physical barrier, physiological barrier, cellular barrier, and cytokine barrier. Acquired immunity – pathogen-specific immunity that is characterized by memory. Active and Passive Immunity Active immunity is where the host produces antibodies in the form of dead or living microbes when it is exposed to antigens. It is a slow process, taking time to provide its full effective response. Passive immunity, on the other hand, is the immunity where ready-made antibodies are given directly to protect the body against any foreign agents.

5. Innate immunity is the host's first line of defense and is intended to prevent infection and attack the invading pathogens. This nonspecific mechanism is fast (minutes to hours) while the adaptive response takes longer (days to weeks). T ypes of Barriers The four types of barriers are: Physical barrier These include the skin, body hair, cilia, eyelashes, the respiratory tract, and the gastrointestinal tract. These form the first line of defence . The skin does more than providing us with fair or dark complexions. Our skin acts as a physical barrier to the entry of pathogens. The mucus coating in our nose and ear is a protective barrier which traps the pathogen before it gets inside. Physiological barriers We know that our stomach uses hydrochloric acid to break down the food molecules. Due to such a strongly acidic environment, most of the germs that enter our body along with the food are killed before the further process is carried on. Saliva in our mouth and tears in our eyes also have the  antibiotic  property that does not allow the growth of pathogens even though they are exposed all day.

6. Cellular barriers In spite of the physical and physiological barriers, certain pathogens manage to enter our body. The cells involved in this barrier are leukocytes (WBC), neutrophils , lymphocytes, basophil , eosinophil , and monocytes . All these cells are all present in the blood and tissues. Cytokine barriers The cells in our body are smarter than we give them credit for. For instance, in case a cell in our body experiences a virus invasion, it automatically secretes proteins called interferons which forms a coating around the infected cell and prevents the cells around it from further infections.

7. Cells Involved In Innate Immunity Phagocytes : These circulate through the body and look for any foreign substance. They engulf and destroy it defending the body against that pathogen. Macrophages : These have the ability to move across the walls of the circulatory system. They release certain signals as cytokines to recruit other cells at the site of infections. Mast Cells : These are important for healing wounds and defence against infections. Neutrophils : These contain granules that are toxic in nature and kill any pathogen that comes in contact. Eosinophils : These contain highly toxic proteins that kill any bacteria or parasite in contact. Basophils : These attack multicellular parasites. Like the mast cells, these release histamine. Natural Killer Cells : These stop the spread of infections by destroying the infected host cells. Dendritic Cells : These are located in the tissues that are the points for initial infections. These cells sense the infection and send the message to the rest of the immune system by antigen presentation.

8. Acquired Immunity Acquired immunity or adaptive immunity is the immunity that our body acquires or gains over time. Unlike the innate immunity, this is not present by birth. The ability of the immune system to adapt itself to disease and to generate pathogen-specific immunity is termed as acquired immunity. It is also known as adaptive immunity. An individual acquires the immunity after the birth, hence is called as the acquired immunity. It is specific and mediated by antibodies or lymphocytes which make the antigen harmless. The main function of acquired immunity is to relieve the victim of the infectious disease and also prevent its attack in future. It mainly consists of an advanced lymphatic defence system which functions by recognizing the own body cells and not reacting to them.

9. Features of Acquired Immunity Specificity : Our body has the ability to differentiate between different types of pathogens, whether it is harmful or not, and devise ways to destroy them. Diversity : Our body can detect vast varieties of pathogens, ranging from protozoa to viruses. Differentiate between self and non-self : Our body has the unique ability to differentiate between its own cells and foreign cells. It immediately starts rejecting any foreign cell in the body. Memory : Once our body encounters a pathogen, it activates the immune system to destroy it. It also remembers what antibodies were released in response to that pathogen, so that, the next time it enters, a similar procedure is followed by the body to eliminate it.

10. B-cells They develop in the bone marrow. These cells are activated on their encounter with foreign agents. These foreign particles act as foreign markers. The B-cells immediately differentiate into plasma cells which produce antibodies specific to that foreign particle or so-called antigen. These antibodies attach to the surface of the antigen/foreign agent. These antibodies detect any antigen in the body and destroy it. The immunity dependent on B-cells is called humoral immunity. T-cells They originate in the bone marrow and develop in the thymus. T-cells differentiate into helper cells, cytotoxic cells, and regulatory cells. These cells are released into the bloodstream. When these cells are triggered by an antigen, helper T-cells release cytokines that act as messengers. These cytokines initiate the differentiation of B-cells into plasma cells which release antibodies against the antigens. The cytotoxic T-cells kills the cancer cells. Regulatory T-cells regulate immune reactions.

11. Types of Acquired Immune Response Humoral Immune Response The antibodies produced by B-lymphocytes are present in the blood cells and they are transported all over the body. This is why it is called the humoral immune response as it consists of an antibody produced by the lymphocytes. It depends upon the action of antibodies circulating in the body. When an antibody on a B-cell binds with an antigen, humoral immunity comes into play. The antigen is internalized by the B cell and presented on the helper T cell. This activates the B-cell. The activated B cells grow and produce plasma cells. These plasma cells release antibodies in the bloodstream. The memory B cells retain the information about the pathogen to prevent any disease caused by that pathogen in the near future.

12. Cell-mediated Immune Response Cell-mediated immunity is initiated by the T helper cells. The cytotoxic T cells eliminate the infected cells from the body by releasing toxins, thereby, promoting  apoptosis  or programmed cell death. The T helper cells help to activate other immune cells. Cell-mediated immunity becomes clear in the case of transplant patients. When any of our sense organs stop functioning, it can be transplanted to replace the malfunctioning organs. But it is not that simple with the immune response. It appears that T-lymphocytes are capable of recognizing whether tissue or an organ is from our body or foreign bodies. This is the reason why we cannot transplant and implant the organs into our body even if we find the donor with the same blood group because our body might reject the transplanted organ. The T-cells quickly recognize that the tissue or an organ as a foreign and do not allow it to become a part of the body. This is why transplant receivers have to take immunosuppressant medication for the rest of their lives. This response is controlled by the T-lymphocytes.

13. Types of Acquired Immunity Active Immunity Active immunity involves the direct response to a foreign antigen within the body. In the case of the acquired or adaptive immune system, the body remembers the pathogens it has encountered in the past. This is a direct result of the active immune system. Active immunity occurs when we are in contact with the pathogen or its antigen. Antigens stand for antibody generator. It is with the help of antigens released by the pathogen that our body tackles the pathogen. So what our body does is, it starts producing antibodies to attack the pathogen based on its antigen. When this happens for the first time, it is called a primary response. Once a body experiences a pathogen for the first time, it keeps a few of the antibodies that attacked the pathogen just in case it attacks for the second time. This is known as natural active immunity.

14. Passive Immunity Passive immunity involves the immune response by the antibodies attained from outside the body. The primary response by the body to a pathogen it encounters for the first time is rather feeble, so the first encounter is always a little harsh on the body. What if we could immunize everyone without the need for them ever getting sick? Biotechnology has grown tremendously in the last decade or two and now we are capable of manufacturing antibodies for diseases. These ready-made antibodies protect the body even if the body hasn’t yet experienced a primary response. While active immunity may protect us from a disease for a lifetime, passive immunity is the more short term. Passive immunity develops immediately and our body could begin its attack on the pathogen right away. There are two types of passive immunity: Natural Passive Immunity Artificial Passive Immunity

15. AutoImmunity Sometimes the immune system attacks its own tissues and organs instead of the foreign agents. This is called autoimmunity. Type I diabetes is an example of autoimmune disease. Vaccines A vaccine is made up of the antigens of the pathogen that cause the disease. For eg ., the smallpox vaccine contains the antigens of the pathogen causing smallpox disease. When a person is vaccinated with the smallpox vaccine the antibody-producing cells are stimulated that produce smallpox antibodies. Thus, the body is protected against the disease occurring in future. Vaccinating pathogenic  microbes  into our body deliberately produces a similar response and is termed as artificially acquired immunity. Immunization is a process providing resistant to pathogenic microbes and other infectious diseases by the administration of a vaccine into the body. By immunization, it stimulates the body’s immune system to protect against subsequent infection or disease.

16. The immune system is our body’s best defensive system. It functions against infringing microorganisms and keeps us healthy. Immunology  is a branch of biology which deals with complex body functions of the immune system. The ability to tackle antigens or pathogens and being healthy is referred to as immunity. The immune system is composed of cells, tissues, and organs that work unitedly in protecting our body. This system defends the human body from the trespassing pathogens in a variety of ways. They work based on memory, some are innate, and some are acquired. Hence, they function in allergies, autoimmunity and organ transplantation. The most important cells involved in the immune system are white blood cells (or) leukocytes, which are involved in destroying disease-causing organisms or substances. Apart from the leukocytes, lymphoid organs, tissues, and proteinaceous molecules antibodies are also involved in the defensive system.

17. Lymphoid Organs The organs of the immune system which are involved in defending the body against invading pathogens causing infections or spread of tumours is termed as Lymphoid organs. It includes bone marrow, blood vessels, lymph nodes, lymphatic vessels, thymus, spleen, and various other clusters of lymphoid tissue. Lymphoid organs are the site of origin, maturation, and proliferation of lymphocytes. They exist as primary, secondary or tertiary and these are based on their stage of development and maturation. These organs consist of fluid connective tissues with different types of leukocytes or white blood cells. The highest percentage of Lymphocytes are present in the white  blood cells  or leukocytes.

18. Primary lymphoid organs The primary lymphoid organs produce and allow the maturation of lymphocytes. It also serves by generating lymphocytes from immature progenitor cells. Therefore it is referred to as the central lymphoid organs. Examples of primary lymphoid organs include thymus and the bone marrow.3 Secondary lymphoid organs The secondary lymphoid organs are referred to as the peripheral lymphoid organs as they are involved in promoting the sites for the interaction of lymphocytes with the antigen to become effector cells. They initiate an adaptive immune response. The secondary lymphoid organs Examples of secondary lymphoid organs spleen, tonsils, lymph nodes, appendix, etc. are secondary lymphoid organs. Tertiary lymphoid organs The tertiary lymphoid organs usually contain very less number of lymphocytes. It plays an important role during the inflammation process.

19. STRUCTURE OF ANTIBODY Antibody ( Ab ) is also known as an immunoglobulin( Ig ). These are large, Y-shaped blood proteins produced by plasma cells. They bind to foreign particles and invade them. These particles are foreign bodies that get attacked by Antibody. Antigens are foreign pathogens that invade the body and have the capability to give rise to a response from our immunity system either by grouping up with a larger molecule or alone after binding with antibodies for a particular immune response. Hence, antigens stimulate the production of antibodies by the immune system.

20. Antibody Structure An antibody has a Y-shaped structure, made up of four polypeptide subunits. Each subunit has two identical light and heavy chains. The N-terminus of each heavy chain forms an antigen-binding domain with a light chain. There are two antigen-binding domains forming the arms of the “Y” shape. They are known as ‘fragment antigen-binding’ ( Fab ) domains. The C-terminus of the heavy chains forms ‘fragment crystallization’ ( Fc ) domain, which helps in the interaction with the effector cells. All four polypeptide subunits are held together by disulfide and non-covalent bonds. The heavy chains of the antibodies contain a variable region and three constant regions. Each antibody has two identical antigen-binding sites and they differ in the antibodies.

21. Types Of Antibodies Antibodies or immunoglobulins ( Ig ) are of five different isotypes . This classification is on the basis of their H chains. Let’s look at the different types of immunoglobulins and their functions. IgM IgM is the first antibody produced in response to a microbial attack by B cells. It is the largest antibody and is found in a pentameric form. It circulates in the blood and lymph and constitutes 6% of the total antibody content in the serum. It is involved in agglutination and opsonization . It has a large number of antigenic sites on its surface and therefore facilitates efficient activation of the immune system.

22. IgG Most abundant isotype in the plasma, and comprises 80% of the total antibody content in the serum. It detoxifies substances that are harmful and recognizes the antibody-antigen complex. It is transferred to the placenta through the foetus and protects the infant until its birth. IgG is divided into four subclasses- IgG1, IgG2, IgG3, and IgG4. Among these, only IgG3 and IgG4 possess the ability to cross the placenta. The heavy chains of IgG have two antigen-binding sites and are of the sub-class gamma. It facilitates the process of phagocytosis and provides immunity to the developing foetus . It neutralizes the toxins and pathogens and offers protection to the body.

23. IgA Usually found in liquids such as breast milk, serum, saliva, fluids of the intestine. IgA in breast milk protects an infant’s gastrointestinal tract from microbial activity. It constitutes 13% of the total antibody content in the serum and is divided into 2 sub-classes- IgA1 and IgA2. Among these, IgA1 is highly found in the secretions and is also called the secretory immunoglobulin. It exists in both monomeric as well as dimeric forms. It provides the first line of defence against the pathogens and limits inflammation. It also activates the complement pathway and participates in the immune response. IgD It is involved in the production of the antibody by B cells. It is present as a monomer and weighs around 1,80,000 dalton . It comprises less than 1% of the total antibody content in serum. It acts as a receptor on B cell surface and participates in B cell activation and differentiation.

24. IgE IgE is present in the least amounts, around 0.02% of the antibody content in the serum. These are present in the linings of the respiratory and intestinal tracts and respond to allergic reactions. This is found as a monomer in the body and weighs about 200,000 Dalton.

25. Functions of Antibody Following are some of the key functions of antibody: Binds to pathogens Activates the  immune system  in case of bacterial pathogens Directly attacks viral pathogens Assists in phagocytosis Antibody provides long-term protection against pathogens because it persists for years after the presence of the antigen. It neutralizes the bacterial toxins and binds the antigen to enhance its efficiency. They also act as the first line of defence for mucosal surfaces. They ingest cells by phagocytosis . Few antibodies bind the antigen present on the pathogens. These aggregates the pathogen and they remain in secretions. When the secretion is expelled out, the antigen is also expelled.