What are four characteristics of the skin that make it a good “wall” to prevent the invasion of pathogens such as viruses and bacteria?

What are four characteristics of the skin that make it a good “wall” to prevent the invasion of pathogens such as viruses and bacteria?

What are four characteristics of the skin that make it a good “wall” to prevent the invasion of pathogens such as viruses and bacteria? 150 150 Nyagu

BIOLOGY 21 ON-LINE LAB 8: THE IMMUNE RESPONSE We’ve spent several weeks discussing the amazing process of homeostasis in the human body. These systems have been evolving for millions of years, allowing humans (and other species) to adapt and function in different internal and external environments. As you’re no doubt aware, we’re under constant siege from bacteria, viruses, and other infectious organisms which, were it not for the body’s immune system, would disrupt homeostasis in the body, causing disease and certain death. If you’re getting over a cold, or holding the latest flu virus at bay, you can thank your body’s immune response for helping you out. In this lab, we also consider limitations of the immune response; namely, what happens when we intentionally introduce foreign tissue to the body, as in blood transfusions or organ transplants. Understanding when and why the body accepts (or rejects) these introductions is also the domain of the immune response. ACTIVITY 1: LEUKOCYTES UP CLOSE Recall that there are three types of blood cells: red (erythrocytes), white (leukocytes) and platelets (thrombocytes). Here we will concentrate on leukocytes, cells that play an important role in our body’s response to disease. Using the glossary in the back of your textbook, answer the following: Eosinophil 1. What is the function of the eosinophil? _________________________ _________________________________________________________ Callista Images / Creative RF / Getty Images _________________________________________________________ Neutrophil 2. What is the function of the neutrophil? _________________________ _________________________________________________________ _________________________________________________________ Lymphocytes 3. What is the function of the lymphocyte? ________________________ _________________________________________________________ _________________________________________________________ _________________________________________________________ Human Biology: Lab 8 8.1 ACTIVITY 2: INFECTIOUS DISEASES OF THE BLOOD: MONONUCLEOSIS Mononucleosis is a viral infection causing high temperature, sore throat, and swollen lymph glands, especially in the neck. It is typically caused by the Epstein-Barr virus (EBV) which is a member of the herpes virus family. Mononucleosis caused by EBV is the most frequently encountered type and is responsible for approximately 85% of infectious mononucleosis cases. The infection is probably transmitted by saliva. While peak incidence occurs in 15- to 17-year-olds, the infection may occur in any age, typically from 10 to 35 years. “Downey Cells” are lymphocytes infected by Epstein Barr virus. 1. On the right, the top image is a blood smear from someone with the Epstein-Barr virus; the bottom image is a normal blood smear. What is unusual about the white blood cells in the top image compared to the normal white blood cells? Downey Cells Normal _____________________________________________ _____________________________________________ _____________________________________________ _____________________________________________ ACTIVITY 3: BOZEMAN SCIENCE’S “THE IMMUNE SYSTEM” (~14 minutes) Go to www.youtube.com/watch?v=z3M0vU3Dv8E (also on Canvas under Lab 8). As you view this short video, answer the following: Non-specific Immune Responses 1. What are four characteristics of the skin that make it a good “wall” to prevent the invasion of pathogens such as viruses and bacteria? 2. What happens if a virus or bacteria gains entry to your body through, say, a cut? Specific Immune Responses 3. The body fights antigens with ____________________________. 8.2 MORE Human Biology: Lab 8 4. What are antibodies? What is important about the different shapes of antibodies? 5. Where are B-lymphocytes made? 6. How do B-lymphocytes produce antibodies? 7. What are T-lymphocytes? How do they work? There’s a lot of detail from ~8:40 minutes to 12:15 minutes. You do not need to know the specifics of the information presented here, but you can watch this section if you want an indepth explanation of how the immune response works. 8. At the ~12:15 minute mark, Mr. Andersen talks about our body’s ability to “learn” specific immune responses. Pay attention to the information from this point to the end of the video. Why do you think we haven’t been able to develop an effective vaccine for the flu? ACTIVITY 4: BLOOD IS THICKER THAN WATER (AND MORE CLUMPY, TOO) The body’s most powerful and important line of defense against infection is the immune response. The immune system can recognize foreign substances in the body (pathogens) and destroy or inhibit them. This is what keeps bacteria and viruses from overwhelming us. What allows our immune system to distinguish between body cells (self) and foreign invaders (non-self)? ANTIBODIES! Antibodies (what our bodies produce to destroy or inhibit invaders) lock onto antigens. As a result, antibodies and antigens clump together. This process is called agglutination. These big clumps are then too big to enter the body’s cells. These clumps also attract white blood cells, which engulf and digest the clumps. Human Biology: Lab 8 8.3 In humans, two of the most important types of antigens on red blood cells are Antigen A and Antigen B, and there are four types of blood: A, B, AB, and O. • • • • If you have type A blood, you have Antigen A. If you have type B blood, you have Antigen B. If you have type AB blood, you have both Antigen A and Antigen B. If you have type O blood, you don’t have either the A or B blood antigen. You can also have ANTIBODIES that recognize foreign blood proteins (antigens). • • • • If you have type A blood, you have anti-B antibodies. If you have type B blood, you have anti-A antibodies. If you have type AB blood, you have neither anti-A nor anti-B antibodies. If you have type O blood, you have both anti-A and anti-B antibodies. What to do We’ll use a blood type testing demonstration called “The case of the missing sandwich” to better understand antigens and antibodies. Go to https://www.youtube.com/watch?v=iDUJ1-GQqzw (also on Canvas under Lab 8). 1. What is the blood type of the blood left behind at the “crime scene”? _________________ 2. How many blood types (according to this video) do humans have? 1 __________________ 3. What does “Rh” stand for? __________________________________________________ 4. What does it mean if someone is Rh+? What does it mean if someone is Rh negative? _________________________________________________________________________ _________________________________________________________________________ 1 Note: human blood is actually a lot more complicated than this. If you do a quick Google search “how many antigens in human blood” you see that there are over 300! ABO and Rh are the two most important blood systems and are present in all humans in some combination, and so they are the ones commonly mentioned when talking about blood types. 8.4 MORE Human Biology: Lab 8 5. How do we detect the presence of the ABO and Rh antigens? (described from 3:45 minute mark to 4:00 minute mark in the video). __________________________________________ _________________________________________________________________________ _________________________________________________________________________ _________________________________________________________________________ 6. What happens when a serum containing a specific antibody comes in contact with its corresponding antigen? ______________________________________________________ _________________________________________________________________________ As the narrator tests the blood from different suspects, enter the observations and/or conclusions in the table below for each suspect. Blood Typing Suspect 1 (S1) Suspect 2 (S2) Suspect 3 (S3) Suspect 4 (S4) Anti-A antibodies Anti-B antibodies Anti-Rh antibodies Blood type 7. Which of the four suspects could possibly have taken the sandwich? _________________ 8. Why can’t we say definitively that the suspect you identified in #7 took the sandwich? (Based on the blood analysis, that is.) ___________________________________________ _________________________________________________________________________ _________________________________________________________________________ 9. What individuals does this exercise exonerate on the basis of the blood analysis? _______ _________________________________________________________________________ Human Biology: Lab 8 8.5 ACTIVITY 5: Hand Hygiene in a time of COVID-19… Go to https://www.unicef.org/coronavirus/everything-you-need-know-aboutwashing-your-hands-protect-against-coronavirus-covid-19 (also on Canvas under Lab 8) and read UNICEF’s guidelines for handwashing – an essential tool in our fight against COVID-19 and other infectious diseases. 1. What is one of the cheapest and easiest ways of preventing the spread of a virus? 2. How long should you wash your hands for? Identify a favorite song or verse of a song that you can sing to yourself while washing your hands. Be creative! 3. When using hand sanitizer, how long should you rub the gel into your hands? What is the minimum percent alcohol the hand sanitizer should have? 4. The article mentions 5 instances when you should wash your hands to prevent the transmission of COVID-19. List them all (this is important – for you, for your loved ones). 5. True or False: you must use warm or hot water when washing your hands to ensure the virus is completely washed away. 6. True or False: you must dry your hands completely. 7. Which is better – washing your hands or using an alcohol-based hand sanitizer? 8.6 MORE Human Biology: Lab 8 Now go to https://www.smithsonianmag.com/science-nature/five-reasons-whyyou-should-probably-stop-using-antibacterial-soap-180948078/ (also on Canvas under Lab 8). Read this short article and answer the following: 8. What are the 5 reasons why we shouldn’t use antibacterial soaps? 1. 2. 3. 4. 5. 9. What two alternatives are suggested to using antibiotic soaps? Human Biology: Lab 8 8.7
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