After discussing the heart and how it functions, lets learn more about blood and the pipes connecting to the heart.
First, I'd like for you to print or download the lecture notes and then watch the lecture videos. I also came up with some questions that go along with the video, which I'd like for you to answer on an email. Please make sure to send it before class to [email protected]
Watch out! There are 2 parts to this chapter: Blood & Blood Vessels.
These videos I made some years back. The quality is a bit iffy, but until I record a new version, here you go:
13.1. Blood is a fluid that guided through vessels distributes substances throughout the body. It’s roughly 8% of ones body weight. Technically, blood is connective tissue with the basic 3 components: cells, fibers, and ground substance. Remember from the tissue chapter? Blood plasma makes it liquid; that’s the ground substance part. Fibers are used in blood to patch broken vessels and prevent blood loss. Can you list the cellular components of blood?
13.2. All the cells in blood make up roughly 45% of the total blood volume. What term do we use to express that number?
13.3. Blood can pick up excess ‘heat’ produced by organs and carry it close to the skin’s surface to let it radiate off. Blood’s white cells help us defend against invaders we don’t want. What is the job of the red blood cells?
13.4. Red blood cells (RBC) were cells that have the nucleus sucked out of them. They look like discs with both sides bending in. This shape is great, because it makes them flexible, so they can squeeze through narrow vessels. Also, RBC’s are basically bags filled with the protein hemoglobin. The distance between the edge of an RBC and any given hemoglobin makes for a short diffusion span for a specific gas to attach to it. What gas attaches to hemoglobin reversibly?
13.5. RBC’s only live about 3 months before they get broken down by the liver and spleen. Since their job is so vital and we have so many of them, our body has to produce them at a rate of 160 million per minute! The RBC’s are made in the red bone marrow. However, a hormone released by the kidneys regulates the RBC production. What is that hormone called?
13.6. The White Blood Cells (WBC) are one of the main parts of the immune system. We have identified 5 different types and can group them for easier study into 2 groups, the granulocytes and the agranulocytes; the ones that show ‘granules’ (little dots) when prepared for microscopic viewing (staining), and the ones that don’t. Can you list the different WBC’s and group them?
13.7. Since the WBCs provide us with immunity, some of their numbers increase during an infection. We call that leukocytosis. You can feel that for example, when you get the flu and the lymph nodes in your neck swell up and hurt. What can leukopenia, which is when we have too few, indicate?
13.8. I know we are covering blood, and the WBCs are discussed in this chapter. However, many of them ‘live’ throughout the body in the tissues where they are needed. Others use the blood stream as a means of travel. Damage to a tissue releases chemicals that signal to WBCs in the area to squeeze through the blood vessel and move to the damaged site to help clean it up. What does the term ‘diapedesis’ mean?
13.9. WBC’s are selfless. They die defending your body, they love you that much! If there is pus in a wound, know neutrophils perished in the battle to save you. Neutrophils are the most numerous WBC and the first to arrive at the site of injury or inflammation. They are filled with little granules containing enzymes that can neutralize pathogens (foreign substances that can harm you). What is the main job of eosinophils? How about basophils?
13.10. Have you heard of B-cells and T-cells? They live in lymphoid organs such as lymph nodes, where they learn to recognize a specific pathogen once exposed to it. They then specifically, but very harshly fight that type of pathogen when encountered the next time. What do we call B & T-cells collectively?
13.11. Monocytes live in many body tissues as macrophages, which means ‘eaters of large things’. They destroy pathogens and then present parts that identify them (called antigens) on the cells surface for the B & T-cells to recognize, and fight. That makes them ___ ___ cells.
13.12. A cut in a blood vessel is a problem because blood leaks out of it. The body uses a very well thought out process to patch up a leak. What are the cell fragments that play a major role in blood clotting?
13.13. To prevent blood loss after an injury, vessels around it will tighten and narrow to minimize the loss. Platelets then deposit around the cut. That makes them sticky so they cling to one another creating a plug. The next step is the trickiest one. The fiber part of the blood gets activated, making them able to help patch up the vessel injury. Once the vessel is ‘healed’, an enzyme dissolves the plug. What is that enzyme called?
13.14. Spinning blood will push the heavier cellular components to the bottom, leaving the plasma on top. What needs to be removed to make serum? Extra question: Why could that be important?
13.15. Blood plasma is mostly water with proteins, nutrients, and salts dissolved in it. Proteins in the blood have many uses. Some help establish osmotic pressure…say what?...remember back in chemistry, we talked about osmosis. It’s the ability of a molecule to pull water towards itself. I used the example of putting salt on a cut tomato. When you let it sit for a few minutes, one can see water droplets replacing the salt crystals; the salt attracts the water and pulls it out of the tomato. In the blood vessels, we have proteins that pull liquid from tissue back into blood vessels. What are those proteins called?
13.16. Another protein function is to transport fats around in the body. Remember, fats don’t like to be in water, they are hydrophobic and aggregate, or clump together; think of oil in vinegar (if you eat salad, which you should). Well, so called lipoproteins are round, hollow spheres with an oil friendly inside. The liver is essential for fat processing (metabolism). Some lipoproteins carry the fats from the liver and distribute them to the body. Others collect them and bring them back to the liver. What are the different types called?
13.17. Another cool protein group are antibodies. They are part of the specific immunity attacking specific pathogens in part by poking holes into their walls! They also bind to antigens (pathogens) by tagging them for destruction by white blood cells. What is the ’tagging’ process called?
13.18. Each hemoglobin in RBCs contains 4 iron atoms. Each of them can pick up an oxygen atom when travelling through the lungs and release it as it passes by a tissue in need. How does the waste product CO2 travel through the body?
13.19. The challenge with giving someone in need blood is the fact that it might not be compatible and cause a bad transfusion reaction in the recipient. RBCs have markers on their surface that identify them (remember the glycocalyx as we discussed the cell membrane in the cytology chapter?). Those markers (antigens) cause an immune reaction if the recipient’s RBCs don’t have them. How many antigens does the ABO system differentiate?
13.20. A second reactive element on RBCs is the Rh factor. These antigens when given to a recipient without them will not cause an immediate reaction, but make them sensitive to another exposure. This becomes a problem when a mother without the Rh-antigen has consecutive pregnancies with babies both having it. During the second pregnancy, if not intervened, antibodies the mom’s body made after the first exposure to the Rh-antigen will spill over to the baby’s blood causing it to react and clump together. How was the Rh factor discovered?
Please email the answer back to [email protected] before class. Thank you.
13.21. Arteries carry blood away from the powerful pump in our chest, the heart. They have to withstand strong hydrostatic pressures, especially right at the beginning, the aortic arch. Those vessels have large amounts of elastic fiber in them. As this main ‘elastic’ artery travels downward through the chest and abdominal cavity, smaller ‘muscular’ arteries divert blood to organs. The amount of blood delivered to an organ depends on the tissues need and is regulated by constricting or relaxing smooth muscle inside the vessel wall. Can you list the names of all the 3 ‘coats’ or layers making up an arteries or veins wall?
13.22. Veins are thinner and function more in channeling blood back to the heart after it has fed the tissues with oxygen and nutrients, and picked up any waste products to be eliminated. The forward propelling force imposed to the blood by the heart pump (hydrostatic pressure) is not there anymore and the blood needs to find different means to get back to the heart. Veins often travel through skeletal muscles that squeeze them when they contract. What structures makes the blood travel towards the heart and not backwards?
13.23. Fluid exchange in tissues happen when the blood vessels become tiny small and leaky. They form penetrating networks called capillary beds that perfuse tissue. The amount of blood to an area depends on its need. What structure regulates blood flow through a capillary bed?
13.24. Parallel to veins runs another vessel system that helps pick up excess body fluid. It has inward slits that let fluid in, but not out. The fluid, called lymph at that point, gets filtered and cleaned through small round organs before it is returned back to the blood stream near the heart. What are those filtering organs called?
13.25. Many arteries and veins are named for the region they travel through, for the bone they run parallel to, or for the organ they feed. Can you name some examples of them?
13.26. When the heart contracts (systole), blood is ejected rapidly putting pressure onto the walls of arteries. Each heart contraction is followed by a brief moment of relaxation (diastole) that lets the heart fill back up with blood. That makes the pressure wave in the arteries rhythmic giving us a pulse. Blood pressure is when we measure the force of that pressure wave. What measures pulse pressure?
Please email the answer back to [email protected] before class. Thank you.
This video goes through the components of the lab used in the last test.