Blood and Body Defenses Honor

Science & Health

Requirements

1. Name the 2 components of blood. What is the percentage of each?

   Answer: You name: 1) Plasma — the yellowish liquid part (about 55% of blood, containing water, proteins, hormones, salts, and nutrients); 2) Formed elements — the cellular part (about 45%, made up of red blood cells, white blood cells, and platelets). — The hematocrit (percentage of red blood cells) ranges between 38-50% for men and 35-45% for women. Anemia is diagnosed when the hematocrit is low (few red blood cells). Plasma is 92% water — the only liquid connective tissue, classified as such by the German histologist Theodor Schwann in 1839.

2. Draw or paste photos of the following blood cell types, identifying all of them: red blood cell, platelet, neutrophil, lymphocyte, eosinophil, basophil, and monocyte. What is/are the main function(s) of each one?

   Answer: You identify functions: Red blood cell (transports O₂ and CO₂); Platelet (coagulation); Neutrophil (phagocytosis of bacteria); Lymphocyte (adaptive immunity, antibodies); Eosinophil (combats parasites and allergies); Basophil (releases histamine in allergies); Monocyte (large-scale phagocytosis, becomes a macrophage in the tissues). — Red blood cells have a lifespan of ~120 days; other cells from minutes to years. B lymphocytes make antibodies; T cells attack infected cells. Neutrophils are the first responders in infections (~60% of leukocytes). The blood count differentiates these types for diagnosis — leukocytosis with neutrophilia indicates a bacterial infection.

3. Do 2 of the following options:
   • Observe a healthcare professional drawing blood from someone and describe the necessary precautions.
   • Visit a laboratory where blood tests are performed. Find out which tests are carried out there and the procedures required for at least 3 of them.
   • Visit a blood bank. Ask how blood is stored, what its shelf life is, and which types are in shortest supply.

   Answer: You choose 2 of the 3 options: 1) Observe a professional drawing blood (note precautions such as asepsis, sterile needle, tourniquet); 2) Visit a clinical analysis laboratory and describe 3 tests (complete blood count, blood glucose, cholesterol). — A blood bank needs donors: type O- (the universal donor) is in high demand. Whole blood has a shelf life of 35 days; platelets only 5 days. Blood lasts longer as separated red blood cells (42 days) — which is why laboratories fractionate donated blood into components for different treatments.

4. Which gases are transported by red blood cells? Explain why the blood in your veins appears blue/green, but if you cut yourself it is bright red. Explain why a lack of iron in the diet causes the blood to have a less reddish tone.

   Answer: GASES: red blood cells transport O₂ (oxygen, from the lungs to the tissues) and CO₂ (carbon dioxide, from the tissues back to the lungs), both bound to hemoglobin. COLOR OF THE VEINS: blood is always red; veins appear blue/green because the skin and tissue absorb and reflect light differently — blue wavelengths penetrate less and are more reflected, giving that appearance. When you cut yourself, the blood comes out and we see its real color, red (bright red if arterial and rich in O₂; dark red if venous, with more CO₂). LACK OF IRON: the red color comes from hemoglobin, and hemoglobin needs IRON at its center (heme group) to form and bind to oxygen. With little iron in the diet, the body produces less hemoglobin and fewer red blood cells (iron-deficiency anemia); with less hemoglobin bound to O₂, the blood takes on a less reddish/paler tone — and the person also becomes paler and more tired. — Hemoglobin contains Fe²⁺ that binds to O₂. Each red blood cell carries ~280 million molecules. The blue color of veins is an optical illusion: the skin filters more red light; deep veins reflect blue/green. Without iron, hemoglobin does not form, red blood cells become small, and the blood pale — a diagnosis of iron-deficiency anemia.

5. Explain how a blood clot is formed. What is the first aid used to help in this process?

   Answer: You explain that a clot forms like this: the injured vessel exposes collagen → platelets adhere and form a plug → coagulation factors activate fibrin (a protein network) → fibrin traps more cells and forms the final clot. — The coagulation cascade has 13 factors numbered in Roman numerals. A lack of factor VIII causes hemophilia (a genetic disease). Direct pressure works in 90% of bleeding cases. A tourniquet is only for severe emergencies — it can cause amputation if done improperly. Aspirin inhibits platelets (a mild anticoagulant).

6. What is required to be a blood donor? What are the main precautions and recommendations? Who cannot donate blood?

   Answer: You need: age 16-69 years (16-17 with authorization), minimum weight 50kg, good health, photo ID. Precautions: eat well (no fatty foods), sleep well the night before, stay hydrated, do not smoke 2h before. Cannot donate: pregnant women, anemic people, those with the flu/fever, recent tattoo (less than 6 months), recent drug use, travel to an area with endemic diseases within the last 30 days. — Each donation saves up to 4 lives (blood is fractionated). In Brazil, only 1.4% of the population donates, below the WHO target (3-5%). Donation takes 30 minutes and removes 450ml. Women can donate every 90 days; men every 60 days. Hemobrás (state-owned) and state blood centers are the official collection points in Brazil.

7. What is your blood type? Which blood types can you donate to? Which blood types can you receive a donation from? Why? Make a table showing the blood compatibility between all blood types.

   Answer: You present a table: A+ donates to A+, AB+; receives from A+, A-, O+, O-. B+ donates to B+, AB+; receives from B+, B-, O+, O-. AB+ is the universal recipient; O- is the universal donor. Reason: each type has specific antigens (A, B, Rh+) — antibodies in the plasma destroy different antigens, causing a fatal reaction if incompatible. — ABO system discovered by Karl Landsteiner in 1901 (Nobel 1930). Types in Brazil: O+ (36%), A+ (34%), B+ (8%), AB+ (2.5%), and the negatives (Rh-) total 12%. A wrong transfusion causes acute hemolysis. Rh- mothers carrying an Rh+ baby receive anti-D serum to prevent a reaction in the second child.

8. In addition to the cells studied in item 2, what are the other cells involved in the defense of our organism? Illustrate each one of them.

   Answer: In addition to the cells in item 2, the following act in the defense of the organism: 1) Macrophages — a large cell that phagocytizes (engulfs) bacteria, cell debris, and antigens in the tissues; derived from the monocyte; 2) Dendritic cells — antigen-presenting cells that capture the invader and show it to the lymphocytes, activating the adaptive response; 3) NK cells (Natural Killer) — destroy virus-infected cells and tumor cells without needing prior recognition; 4) Mast cells — release histamine and inflammatory mediators, acting in allergies and inflammation; 5) Helper (CD4) and cytotoxic (CD8) T cells (T lymphocytes) — coordinate the response and kill infected cells. — Macrophages come from circulating monocytes that migrate to tissues. Dendritic cells were discovered in 1973 (2011 Nobel Prize to Ralph Steinman). NK cells kill without needing to recognize a specific antigen — the first line against cancer. Mast cells cause allergies by releasing histamine, IgE-mediated.

9. What are antibodies? How do they act? By which cells are they produced?

   Answer: You define antibodies as Y-shaped proteins produced by B lymphocytes (also called plasma cells when activated). They work by recognizing specific antigens (part of the invader) and neutralizing them through tagging for phagocytes, blocking toxins, aggregating pathogens, or activating the complement system. — There are 5 types: IgG (most common, crosses the placenta), IgM (initial response), IgA (mucous membranes), IgE (allergy), IgD (B-cell membrane). Each B lymphocyte produces 1 specific type — the system generates enormous diversity via V(D)J recombination discovered by Tonegawa (Nobel 1987).

10. Name at least 5 differences between the innate immune response and the acquired immune response.

    Answer: You mention: 1) Innate is congenital; Acquired is developed throughout life; 2) Innate responds quickly (minutes); Acquired takes days; 3) Innate is nonspecific; Acquired is specific to each antigen; 4) Innate has no memory; Acquired creates immunological memory; 5) Innate uses phagocytes/NK cells; Acquired uses B/T lymphocytes and antibodies. — Innate is the first line of defense (skin, mucous membranes, phagocytes, complement). Acquired involves T and B lymphocytes with memory that lasts years. Vaccines exploit acquired memory — the first exposure teaches, the second generates a robust response. The complete system emerges between 6 months and 3 years of a child's age.

11. Cite 2 biblical texts in which blood is involved. After studying about blood, why do you think the Bible uses blood as a symbol of God's saving power?

    Answer: You cite: 1) Leviticus 17:11 — 'the life of the flesh is in the blood, and I have given it to you upon the altar to make atonement for your souls'; 2) Hebrews 9:22 — 'without shedding of blood there is no remission'. The Bible uses blood because it symbolizes life — Christ shed His blood to give eternal life to those who believe. — Blood in biblical culture was seen as the seat of life (understood scientifically today through the vital function of blood). The OT sacrifices pointed to Christ's sacrifice. 1 John 1:7 reinforces this: 'the blood of Jesus Christ His Son cleanses us from all sin' — central to Christian soteriology.

12. List 10 health habits that can help your body stay healthy and fight infection. Find a text from the Spirit of Prophecy for each one of them. Keep a record of at least 1 month in which you applied these habits.

    Answer: List of 10 health habits with a text from the Spirit of Prophecy (Ellen White) for each one (keeping at least 1 month of records applying them): 1) Healthy eating (nutrition) — 'The truly temperate man does not hesitate to lay aside everything that is harmful' / 'Grains, fruits, nuts, and vegetables constitute the diet chosen for us by the Creator' (The Ministry of Healing, p. 296). 2) Physical exercise — 'Inaction is a fruitful cause of disease. Exercise quickens and equalizes the circulation of the blood' (The Ministry of Healing, p. 238). 3) Water (drinking plenty and using it externally) — 'Pure water to drink and pure air to breathe invigorate the vital organs... Water is the beverage that God provided to quench thirst' (The Ministry of Healing, p. 237). 4) Sunlight — 'Sunlight... is one of the most efficient restoratives that nature can provide' (The Ministry of Healing, p. 274). 5) Temperance (avoiding what is harmful) — 'True temperance teaches us to abstain entirely from everything that is harmful, and to use judiciously that which is healthful' (Patriarchs and Prophets, p. 562). 6) Pure air — 'In order to have good blood, we must breathe well. Full, deep inspirations of pure air... soothe the nerves' (The Ministry of Healing, p. 272). 7) Adequate rest — 'Nature must have an opportunity to restore itself... through sleep and rest, the energy spent is recovered' (The Ministry of Healing, p. 235). 8) Trust in God (peace, faith) — 'Courage, hope, faith, sympathy, and love promote health and prolong life' (The Ministry of Healing, p. 241). 9) Hygiene / cleanliness — 'Strict cleanliness is essential to both physical and mental health... Cleanliness must be observed in the home and around it' (The Ministry of Healing, p. 276). 10) Positive attitude / cheerful mind — 'A contented and cheerful spirit is health to the body and strength to the soul. Nothing tends more to promote health of body and soul than does a spirit of gratitude and praise' (The Ministry of Healing, p. 251). Keep a daily record for at least 30 days marking the application of each habit. — NEWSTART is an acronym for the 8 Natural Remedies taught by the Seventh-day Adventist Church since the writings of Ellen White (1827-1915). Modern studies confirm: the Adventist lifestyle increases longevity by up to 10 years (Adventist Health Study, Loma Linda University). A habits journal is a validated practice for behavioral change.

13. Define the following terms
    • Immunology
    • Pathogen
    • Inflammation
    • Memory
    • Vaccine
    • Allergy
    • Histamine
    • Antigen
    • Fever

    Answer: 1) Immunology: it is the study of the immune system, that is, the body's defenses against agents that cause disease. 2) Pathogen: it is any agent capable of causing disease, such as viruses, bacteria, fungi, and parasites. 3) Inflammation: it is the body's local defense response to an injury or infection, with heat, pain, redness, and swelling in the affected area. 4) (Immunological) memory: it is the immune system's ability to "remember" an invader already faced, responding faster and stronger if it returns. 5) Vaccine: it is a preparation that presents the body with a weakened, killed, or partial form of the pathogen, stimulating the immune system to create defenses and memory without causing disease. 6) Allergy: it is an exaggerated reaction of the immune system to normally harmless substances (such as pollen, dust, or certain foods), causing symptoms such as itching, sneezing, and swelling. 7) Histamine: it is a substance released by the body during allergic and inflammatory reactions, responsible for symptoms such as redness, swelling, itching, and dilation of the blood vessels. 8) Antigen: it is any substance (generally part of a pathogen) recognized as foreign by the body that triggers the immune response, leading to the production of antibodies. 9) Fever: it is the elevation of the body's temperature as a defense of the organism, hindering the multiplication of many pathogens and activating the immune system. — These terms form the basic vocabulary of immunology. Inflammation has 5 cardinal signs (Celsus, 30 AD): heat, pain, redness, swelling + loss of function (Galen). Vaccines work with memory — Pasteur coined the term in 1881 in honor of Jenner, the first to vaccinate against smallpox in 1796.

14. Name 3 species of toxic plants found in your region. What should you do to avoid an allergic reaction to them? What should you do if you have an allergic reaction?

    Answer: You cite 3 plants common in Brazil: 1) Dumb cane (Dieffenbachia) — irritant sap; 2) Oleander (Nerium oleander) — every part is toxic; 3) Castor bean (Ricinus communis) — the seed contains deadly ricin. To avoid them: identify before touching, wear gloves, teach children. — Dumb cane is one of the most common houseplants — simply touching it and putting it in your mouth causes oral swelling. Castor bean produces ricin, a poison 6,000× more lethal than cyanide (1mg can kill an adult). Antihistamines block H1 receptors; in severe emergencies, adrenaline (EpiPen) and IV corticosteroids are used at the nearest hospital.

15. Describe how vaccines and serums work. Check your vaccination card, and if any are missing, seek a medical service and get it up to date.

    Answer: You explain that a vaccine contains a weakened or inactivated antigen of the pathogen — the immune system recognizes it, produces antibodies, and creates memory without causing disease. Serum contains ready-made antibodies (from immunized horses) — used in emergencies (snakebite, rabies). Check your SUS card and update missing doses at free public health clinics. — A vaccine is prevention (active memory); serum is emergency treatment (passive, lasts weeks). The Brazilian SUS immunization schedule includes 20+ free vaccines. Vaccines eradicated smallpox (1980) and nearly eliminated polio. Serum therapy was invented by Vital Brazil in 1901 at the Butantan Institute.

16. What is AIDS? How is it transmitted? Is there a cure? What is the difference between being HIV positive and having AIDS?

    Answer: You explain that AIDS is the advanced disease caused by the HIV virus, which destroys CD4 T lymphocytes (defense). Transmission: unprotected sex, contaminated blood, mother-to-child. There is no cure, but treatment (ART) controls the virus, making the viral load undetectable. HIV+ means a carrier of the virus. — HIV was discovered in 1983 (Montagnier and Barré-Sinoussi, Nobel 2008). ART (antiretroviral therapy) uses a cocktail of 3+ drugs. Brazil has offered free treatment since 1996 (Sarney Law). U=U: undetectable = untransmittable by sexual route. Mortality has dropped 80% since 1996 with modern ART.

17. Find 3 biblical references that talk about cleanliness and controlling the spread of diseases.

    Answer: You cite: 1) Leviticus 13 — laws on leprosy and isolation of the sick (biblical quarantine); 2) Leviticus 11 — clean vs unclean foods (sanitary protection); 3) Deuteronomy 23:13-14 — instruction on waste (basic sanitation in camps). — These Mosaic laws anticipated modern sanitary principles: quarantine (Lev 13), food inspection (Lev 11), sanitation (Deut 23). Historical studies show that populations that followed the Torah had up to 30% lower mortality during medieval plagues — empirical evidence of the sanitary value of the biblical laws.

18. Where are blood cells produced? Where are they broken down (hemolyzed)? What is the average lifespan of a red blood cell?

    Answer: You answer: Blood cells are produced in the red bone marrow (present in flat bones such as the sternum, ribs, ilium, and skull). Hemolysis (destruction) occurs mainly in the spleen and liver, where macrophages digest old red blood cells. A red blood cell has an average lifespan of 120 days — after which it is recycled and the iron returns to the body. — In adults, red marrow is in flat bones; yellow marrow (fat) occupies long bones. Every second, 2.5 million red blood cells are born to replace the 2.5 million that die. The spleen acts as the blood's 'cemetery'. Hemolytic anemias occur when red blood cells die before the expected 120 days.

19. Do one of the following:
    • (For those under 18): invite a person to donate blood and accompany the donation process.
    • (For those over 18): go to the medical system and make a blood donation (if eligible). If you cannot donate, invite a person to donate and accompany the donation process.

    Answer: You choose one of the options: 1) If you are under 18, invite an eligible adult to donate blood and accompany the process at the nearest blood center; 2) If you are over 18, go in person to donate blood after a medical evaluation. If you are ineligible (anemia, low weight, flu), invite someone eligible and accompany their donation. — Accompanying a donation teaches about screening (medical interview), apheresis, collection (450ml in 10 minutes), and post-donation rest. In Brazil, blood centers such as Hemorio (RJ), Pró-Sangue (SP), and Hemominas (MG) receive more than 1 million donations/year. Each bag can save up to 4 lives depending on the fractionation.