Kerala Syllabus 10th Standard Biology Guide Chapter 5 Soldiers of Defense
What are the uses of wearing masks in situations where epidemics spread out?
- Prevent the entry of germs.
- Prevent the entry of pathogens from one person to another.
What do you mean by the term defence?
Defence is the ability of the body to prevent the entry of pathogens and to destroy those that have already entered the body.
What are the defense mechanisms of the body?
Body coverings like skin, mucous membrane and body secretions like mucous, saliva and tear are the defence mechanisms of the body. Body fluids like blood and lymph also play an important role in defence mechanism.
What is the role of skin in defense?
A protein called keratin present in the epidermis prevents the entry of germs. Sebum produced by the sebaceous gland makes the skin oily and waterproof. The disinfectants present in the sweat produced by sweat gland destroy the germs.
What is mucous membrane?
The mucous membrane is protective covering of body parts.
What is the function of mucous membrane?
Pathogens trapped in the mucus produced by mucous membrane, get destroyed. The destroyed germs are expelled out by the cilia cells of the mucous membrane.
What is the role of useful bacteria seen in skin and mucous membrane?
Coverings of the body act as a habitat for many useful bacteria. The germs that enter the body need to compete with such useful bacteria for shelter and nutrients. A great number of germs get destroyed in this competition.
How the body secretions help to defend pathogens?
- The disinfectants present in the sweat produced by this gland destroy the germs.
- Pathogens trapped in the mucus produced by this membrane, get destroyed. The destroyed germs are expelled out by the cilia cells of the mucous membrane.
- The wax in the ear prevents pathogens.
- The enzyme lysozyme present in tear and saliva fights against germs.
- The hydrochloric acid present in the stomach has the ability to destroy germs. It kills the germs that reach the stomach along with food.
- Lysozyme present in the urine kills the germs.
What are the defense strategies of body fluids?
Body fluids like blood and lymph play an important role in defense mechanism. These body fluids follow different defense strategies like controlling the entry of germs into the body, neutralising germs and the toxic substances they produce, preventing their multiplication, etc.
What are the defense action of white blood cells?
- Neutrophil – Engulfs bacteria, synthesizes chemicals that destroys bacteria.
- Basophil – Stimulates other white blood cells. Dilates the blood vessels.
- Eosinophil – Synthesizes chemicals that destroy foreign bodies. Synthesizes chemicals required for
the inflammatory responses.
- Monocyte – Engulfs and destroys germs.
- Lymphocyte-Identifies and destroys germs specifically.
Explain inflammatory response.
The cells that get damaged by a wound or an infection produce certain chemical substances. These substances dilate the blood vessels thereby increasing the blood flow. Blood plasma and white blood cells reach the wound site. This is the reason for the swelling of the wound site. This defense mechanism is known as inflammatory response.
What is the advantage of the dilation of blood vessels at the wound site?
The cells that get damaged by a wound or an infection produce certain chemical substances. These substances dilate the blood vessels thereby increasing the blood flow. Blood plasma and white blood cells reach the wound site. The white blood cells destroy germs.
What is the role of white blood cells in the inflammatory response?
White blood cells reach the wound site through the walls of the capillaries. Neutrophils and monocytes engulf and destroy germs.
Is inflammatory response a defense activity? Why?
Yes. Inflammatory response is a defense activity. It is the mechanism that destroys the germs that have entered the body. This is a second-level defense mechanism.
Prepare a flowchart showing the stages of inflammatory response.
Germs enter through wounds → Produces chemical messages → Blood vessels dilate → White blood cells reach the wound site through the walls of the capillaries → Neutrophils and monocytes engulf and destroy germs.
What is phagocytosis?
Phagocytosis is the process of engulfing and destroying germs. The cells engaged in this process are called phagocytes. Monocytes and neutrophils are phagocytes.
Prepare a flowchart show the stages in phagocýiosis.
Phagocytes reach near the pathogen → Engulfs pathogen in the membrane sac → Lysosome combines with membrane sac → The pathogens are degenerated and destroyed by the enzymes in lysosome.
Prepare a note on blood clotting.
Blood clotting is a defense mechanism to prevent the loss of blood through wounds. Wounds cause loss of blood. Tissues degenerate to form the enzyme called thromboplastin. Thromboplastin converts prothrombin in the plasma to thrombin in the presence of calcium ions and vitamin K. Thrombin converts the fibrinogen in the plasma to fibrin. Blood clot is formed by the entangling of platelets and red blood cells in the fibrin network.
Explain the situation in which wound scar remains.
Healing of the wound is a stage after inflammatory response and blood clotting. When wound occurs, new tissues are formed in the place of the tissues damaged by the wound.
In such situations, the wound scar does not remain. In cases when new tissues cannot be formed, the connective tissue heals the wound. In such situations, the wound scar Remains.
Fever is a defense mechanism. Why?
Pathogens enter the body. Then the presence of toxins produced by the pathogens stimulates the white blood cells. The chemical substances produced by the white blood cells raise the body temperature. The rise in body temperature reduces the rate of multiplication of pathogens and increases the effect of phagocytosis. So fever is a defense mechanism.
If the rise in body temperature persists for a long time, it is necessary to seek medical assistance immediately. Why?
When infection becomes uncontrollable, the body temperature may rise very high. We take medicines to reduce the body temperature. But it is advisable to treat after diagnosing the exact reason. If the rise in body temperature persists for a long time, it may badly affect the internal organs including the brain. Hence it is necessary to seek medical assistance immediately.
Define non – specific defense.
Non-specific defense mechanism is a mechanism that protects us from all pathogens without considering their characteristic features.
Define specific defense.
Foreign bodies or pathogens that enter the body and stimulate the defense mechanism are called antigens. The defense mechanism that identifies the structure of each antigen and destroys it specifically is called specific defense.
Prepare a short note on lymphocytes.
In certain situations, pathogens enter the body and multiply by overcoming the immune system. Specific defense is the system which identifies and destroys such pathogens. White blood cells known as lymphocytes are capable of destroying the pathogens in this way. Lymphocytes are of two types, namely B lymphocytes and T lymphocytes. B lymphocytes mature in the bone marrow. T lymphocytes mature in the thymus.
How do B lymphocytes act?
Foreign bodies or pathogens that enter the body and stimulate the defense mechanism are called antigens. B- Lymphocytes produce certain proteins that act against antigens. These are called antibodies.
Antibodies destroy the pathogens in three different ways.
- Destroy the bacteria by disintegrating their cell membrane.
- Neutralise the toxin of the antigens.
- Destroy the pathogens by stimulating other white blood cells.
How do T lymphocytes act?
T lymphocytes stimulate other defense cells of the body. Moreover, these cells are capable of destroying cancer cells and cells affected by virus.
Why is the defense mechanism of lymphocytes known as specific defense mechanism?
Lymphocytes become activated in the presence of j certain particular types of antigens. Lymphocytes can defend only such antigens. Hence, this; defense mechanism is known as specific defense mechanism.
What are the defense mechanisms of blood?
Raising body temperature, production of antibodies, healing of wound, blood clotting, inflammatory response, phagocytosis.
How does lymph help in defense mechanisms? j
The lymph, formed from the blood and reabsorbed into blood has a prominent role in defense j mechanisms, like the blood itself. Lymph contains plenty of lymphocytes. They destroy the disease causing bacteria in lymph nodes and spleen.
What is immunization?
Defense mechanisms become slow when germs enter the body. This causes the spread and multiplication of germs. Immunization is the artificial method to make the defense cells alert against the attack of pathogens.
What are vaccines? What are the component of vaccines?
Vaccines are the substances used for artificial immunization. Any one of the components from alive or dead neutralised germs, neutralised toxins or cellular parts of the pathogens will be the component of each vaccine.
What is the role of Edward Jermer in immunization?
Edward Jenner, an English doctor started immunization. He observed that people affected by cowpox escaped from the attack of smallpox. He injected the pus taken from a cowpox patient into the body of an 8-year-old boy. The boy was affected by cowpox and recovered.
After two months the pus taken from a smallpox patient was injected into the boy. He was not affected by smallpox. The immunization programmes got the name vaccination from the Latin word ‘vacca’ meaning cOw, in memory of the cowpox experiments of Jenner.
How vaccines help in immunization?
Vaccines are the substances used for artificial immunization. These act as antigens that stimulate the defense mechanism of the body. Antibodies are formed in the body against them. These antibodies are retained in the body which in future protect the body from the pathogen responsible for the same disease.
Prepare a table related to vaccines and diseases.
||Diphtheria, tetanus, pertussis (whooping cough), hepatitis B and Haemophilus influenza type b
||Measles, mumps, and rubella (German measles)
Prepare a note on the various systems of medicine.
Medical treatment becomes necessary when we are affected by diseases, crossing all obstacles of our immune system. We depend on the various systems of medicine to recover from diseases.
In various parts of the world, methods of treatment have evolved in accordance with the lifestyle of the people, their culture and available natural resources. These methods are the result of long periods of experience and observation.
Ayurveda: It is a system of treatment which prevailed in India from the ancient times. Beyond being an urgent treatment measure against some diseases, Ayurveda gains acceptance as a lifestyle to maintain the body fit. The speciality of Ayurveda is the medicine, taken from nature.
Homoeopathy: The main principle behind homoeopathy is that the causative factor of the disease can itself effect the cure. This is a system of treatment introduced by Samuel Haniman, a German doctor. Homoeopathy gives great importance to the symptoms in each individual since it aims at treating not the disease but the patient. Another significant principle of this system of treatment is that the more the medicine is diluted the more is its potency.
Unani: The treatment in Unani is based on some principles put forward by Hippocrates. The diagnosis of a disease is done by checking pulse.
Allopathy: This is a cosmopolitan medical practice widely used all over the world. This branch of medicine, introduced by the ancient Greek physician Hippocrates, gives much importance to diagnosis, treatment, medicines, etc.
Question 36. Prepare a table containing the equipment for diagnosis and their use.
|Equipment for diagnosis
||Measuring blood pressure
||To record electric waves in the brain
||To record electric waves in the heart muscle
||To understand the structure of internal organs using ultrasonic sound waves.
|C.T. Scanner(Computed Tomography Scanner)
||To get three-dimensional visuals of internal organs with the help of computer, using X-rays
|MRI Scanner (Magnetic Resonance Imaging Scanner)
||To get three-dimensional visuals of internal organs.
What are the different factors in blood?
||12-17 gm/100 ml of blood
|Number of White Blood Cells
||5000- 10000/ml of blood
|Number of Red Blood Cells
||45 lakhs to 60 lakhs/ml of blood
|Number of platelets
||2.5 lakhs to 3.5 lakhs/ml of blood
Prepare a lubie containing the specializations in medicine ami the related areas.
||Treatment of heart
||Treatment of eye
||Treatment of disorders of the nervous system.
||Treatment of ear, nose, and throat disorders.
What are antibiotics?
Medicines that are extracted from microorganisms like bacteria, fungi. etc. and used to destroy bacteria are called antibiotics. They can be used externally and internally.
Explain the role of Alexander Fleming in the discovery of antibiotics.
It was Alexander Fleming who first discovered antibiotics in 1928. He accidentally discovered that the fungus Penicillium notatum has the ability to destroy bacteria. But it took several years to extract medicine from it.
What are the side effects caused by the regular use of antibiotics?
Antibiotics are used to resist bacterial diseases. Though antibiotics are effective medicines, their regular use brings many side effects.
Some important side effects of regular use are it develops immunity in pathogens against antibiotics, destroys useful bacteria in the body,
reduces the quantity of sorne vitamins in the body.
Observe figures A, B and C and identify the instances in which the following type of first aid is given.
A – Giving artificial respiration – Artificial respiration, breathing induced by some manipulative technique when natural respiration has ceased or is faltering. Such techniques, if applied quickly and properly. can prevent some deaths from drowning, choking, strangulation, suffocation, carbon monoxide poisoning, and electric shock.
B – Arm supported by sling – During bone fracture
C – Removing objects stuck in trachea – Block in trachea
What is blood transfusion?
The transfer of blood from one person to another is called blood transfusion.
What all things should be taken care of while transfusing blood?
- People in the age group 18-60 can donate blood.
- Blood donation can be done once in three months.
- Blood donation causes no problem to the donor’s health.
- Pregnant women and breastfeeding mothers should not donate blood.
- Persons with communicable diseases
(transmitted through blood) should not donate blood.
What are the different types öf blood groups?
A, B, AB, O
What is the basis of blood grouping?
The basis of blood grouping is the presence of antigen A and antigen Binredbloodcells. The blood group of a person is named according to the antigen present in that person’s blood.
Write the importance of antibody in blood groups.
In blood transfusion, antibodies present in the blood plasma are of special importance. In blood group A, antibody b and in group B, antibody a are present.
What is antigen D?
In addition to antigens A and B, another antigen called D or Rh factor is present in the cell membrane of red blood cells of certain persons.
The blood groups in hich Rh factor is present are known as positive blood groups and those without Rh factor are called negative blood groups.
What is the importance of blood group in blood transfusion?
When a foreign antigen reaches one’s blood, it stimulates the defense mechanism. On receiving unmatching blood, the antigen present in the donor’s blood and the antibody present in the recipientes blood will react with each other and form a blood clot. Hence, everyone cannot receive blood from all blood groups.
For example, in blood group A, antigen A and in group B, antigen B are present. If a person with blood group A receives blood from a person with B group blood, the recipient’s blood does not contain B antigen. So it stimulates defense activity of the body. As a result, antigen B in blood group B forms a clot with antibody of A group blood.
What are the structural methods in the defense of plants?
The characteristics in their body structure and the specific molecules produced by plant tissues protect the plants from diseases. Wax covering, cuticle, bark of plant and cell wall are the structural methods in the defense of plants. Waxy covering and cuticle prevent the entry of germs through leaves. The bark of plants protects inner cells from the direct contact of pathogens. Cell wall is a well equipped resistant coat.
What are the biochemical methods in the defense of plants?
Chemical substances such as lignin, cutin, suberin, etc., provide rigidity to the cell wall. A polysaccharide called callose prevents the entry
of germs which have crossed the cell wall, through the cell membrane.
Let Us Assess
Which among the following is not included in non-specific body defense?
a. production of sebum.
b.action of hydrochloric acid in the stomach.
c. action of B lymphocytes.
d. action of lysozyme in saliva.
c. action of B lymphocytes.
Write the functions of blood cells in the defense mechanism of the body.
Neutrophil – Engulfs bacteria, synthesizes chemicals that destroys bacteria.
Basophil – Stimulates other white blood cells. Dilates the blood vessels.
Eosinophil – Synthesizes chemicals that destroy foreign bodies. Synthesizes chemicals required for the inflammatory responses.
Monocyte – Engulfs and destroys germs.
Lymphocyte – Identifies and destroys germs specifically.
What is the basis of grouping blood into different types? Everybody cannot receive blood of all blood groups. Why?
The basis of blood grouping is the presence of antigen A and antigen B in red blood cells. The blood group of a person is named according to the antigen present in that person’s blood. In blood transfusion, antibodies present in the blood plasma are of special importance. In blood group A, antibody ‘b’ and in group B, antibody ‘a’ are present.
When a foreign antigen reaches one’s blood, it stimulates the defense mechanism. On receiving unmatching blood, the antigen present in the donor’s blood and the antibody present in the recipient’s blood will react with each other and form a blood clot.
Hence, everyone cannot receive blood from all blood groups. For example, in blood group A, antigen A and in group B, antigen B are present. If a person with blood group A receives blood from a person with B group blood, the recipient’s blood does not contain B antigen. So it stimulates defense activity of the body. As a result, antigen B in blood group B forms a clot with antibody ‘a’ of A group blood.
Kerala Syllabus 10th Standard Biology Guide