Agglutination
Blood Clotting
Nuetrophil
Lymphocyte
Phagocytosis
Sickle Cells
Hemolysis
Red Blood Cells
White Blood Cells
Plasma Cell
I. Blood: An Overview
II. Red Blood Cells and Transport of Oxygen
III. White Blood Cells and Defense Against Disease
IV. Platelets and Blood Clotting
V. Blood Typing and Transfusion
VI. Homeostasis
I. Blood: An Overview
A. 3 categories for the function of blood:
1. Transport: Blood is the primary transfer medium. Delivers oxygen from lungs and nutrients from the digestive tract to the tissues, where it is exchanged for carbon dioxide and wastes that it takes away from the tissues to exchange surfaces in the lungs and kidneys.
- A variety of organs and tissues secrete hormones into the blood, and blood transports those to other organs and tissues so the hormones can send signals that influence cellular metabolism.
2. Defense: Blood defends the body against invasion by pathogens in several ways. Some blood cells can actually destroy the pathogens, while others secrete antibodies into the blood. These antibodies then "kill" the pathogens, sometimes with the help of white blood cells.
3. Regulation: Blood helps regulate body temperature by picking up heat, (mainly from active muscles), and transporting it to the body.
- Also helps regulate body pH.
B. Composition of Blood
1b. Blood is a tissue, containing cells and cell fragments, which are collectively called the formed elements.
- Formed elements: red and white blood cells, and platelets. All are produced in red bone marrow, which occurs in most of the bones of a child but only certain bones in an adult. Red bone marrow contains stem cells, which divide and give rise to various types of blood cells.
- Red blood cells are 2-3 times smaller than white, but there are many more of them than white.
C. Plasma1c. The liquid medium for carrying various substances in the blood, and also distributes heat generated as a bi-product of metabolism.
- Approximately 91% water.
- Remaining 9% consists of various salts and organic molecules.
- These formed elements are suspended in plasma (liquid), and therefore, blood is classified as a liquid tissue.
(Insert plasma cell picture / www.mcl.tulane.edu http://www.mcl.tulane.edu/classware/pathology/Krause/Blood/Blood.html)
1c. Plasma Proteins: Most abundant organic molecules in blood. Produced by liver.
- Helps maintain homeostasis. 3 major types:
- Albumins: Most abundant of plasma proteins. Contribute most to plasma's osmotic pressure. Combine with and help transport other organic molecules.
-Globulins: Three types: alpha, beta, and gamma. alpha and bets: combine with and help transport substances in the blood.
- Fibrinogens: Produced by white blood cells (lymphocytes), not by liver. Fights diseases.
(Insert white blood cells picture / www.mcl.tulane.edu / http://www.uiowa.edu/~cemrf/archive/sem/large)
2c. Osmotic Pressure: A force that prevents excessive loss of plasma from the capillaries into tissue fluid. (Mader 106-107)
II. Red Blood Cells and Transport of Oxygen
A. Red blood cells (erythrocytes) are small, biconcave disks that lack a nucleus when mature. Also lack most organelles, including mitochondria. Great quantity.
(Insert red blood cells picture / www.rochedalss.eq.edu.au http://www.rochedalss.eq.edu.au/jeopardy/slide20.htm)
- Specialized for oxygen transport.
- Hemoglobin: A pigment that makes red blood cells and blood a red color. Protein that contains four highly folded polypeptide chains.
- Each red blood cell can carry over a billion copies of oxygen.
- Oxyhemoglobin: Hemoglobin' different shape when oxygen binds to heme in the lungs.
- Deoxyhemoglobin: Heme gives up the oxygen in the tissues, and hemoglobin resumes its former shape. (Mader 108)
- Every second, three million new red blood cells are created through a specialized mitosis. (Frolich PowerPoint Slide 16)
B. How does oxygen get into the blood?
1b. Oxygen diffuses into blood in lungs. In lungs, bronchioles (air tubes) branch and branch, finally ending in tiny sacs called alveoli. Each alveolus is surrounded by capillaries. Oxygen diffuses across super-thin epithelial tissue of alveolus, across super-thin epithelial tissue of capillary, across red blood cell membrane and is held by Hemoglobin protein molecules in red blood cells. (Frolich PowerPoint Slide 15)
C. How do red blood cells help transport carbon dioxide?
- After blood picks up carbon dioxide in the tissues, approx. 7% is dissolved in plasma. 25% is directly transported, and the rest (68%) is transported as the bicarbonate ion in the plasma. (Mader 109)
D. Red blood cells are produced in bone marrow.
- The RBC stem cell in the bone marrow divides and produces new cells that differentiate into mature RBCs.
- Only live for approx. 120 days. Destroyed in liver and spleen by macrophages, white blood cells that come from monocytes.
- Approx. 2 million RBCs are destroyed per second.
E. Blood Doping: Any method of increasing the normal supply of RBCs for the deliverance of oxygen more efficiently.
1e. Erythropoeitin: Kidneys, liver, and other tissues stimulate stem cells in bone marrow to produce more red blood cells. (Mader 109)
F. Disorders Involving Red Blood Cells
1f. Anemia: An insufficient number of red blood cells, or, the cells don't have enough hemoglobin.
2f. Hemolysis: Rupturing of red blood cells.
(Insert hemolysis picture / www.marietta.edu / http://www.marietta.edu/~spilatrs/biol202/labresults)
3f. Sickle Cell Disease: hereditary. Sickle-shaped red blood cells tend to rupture as they pass through the narrow capillaries. (Mader 109)
(Insert sickle cells picture / www.dnai.org / http://www.dnai.org/media/bioinformatics/sicklecell)
- 1910: First documented case, by a cardiologist named James B. Herrick. He noted the following in the patient's blood workup: "Nucleated reds [red blood cells] were numerous, 74 being seen in a count of 200 leukocytes [white blood cells; also note: normal mature redblood cells lack a nucleus]. The shape of the reds was very irregular, but what especially attracted attention was the large number of thin, elongated, sickle-shaped and crescent-shaped forms."
- "Since there are four subunits per hemoglobin molecule, when fully saturated any hemoglobin therefore carries four oxygen molecules (or eight oxygen atoms). Saturation occurs in the lungs, and desaturation in the body tissues."
- "Hemoglobin binds oxygen when the oxygen pressure is high, and releases it when the oxygen pressure is low. In the tissues hemoglobin picks up a small percentage (25%) of the carbon dioxide released there and transports it back to the lungs where it is released. The remainder of the carbon dioxide is transported to the lungs as H2CO3, or carbonic acid, most of which dissociates into hydrogen ions and bicarbonaleration occurs in the lungs, and desaturation in the body tissues."
- Any significant decrease in amount of functional Hb is known as anemia. All forms of anemia have serious physiological effects because of reduced oxygen delivery to and reduced carbon dioxide removal from the tissues. Sickle cell anemia, in particular, creates serious depletion of oxygen through two mechanisms:
- "Because of molecule changes within the sickled cell, oxygen-carrying capacity of the blood is greatly reduced; Because of their peculiar shape, greater rigidity, and tendency to stick together, sickle cells clog smaller vessels in the circulatory system -- the arterioles and capillaries in particular --, preventing the blood from delivering oxygen and nutrients, and removing carbon dioxide and wastes from the tissues."
- Might be genetically determined.
- Effects in humans:
a. Short-Term: Because of poor oxygen delivery the individual is frequently out of breath and tires easily;
b. Long-term: Oxygen deprivation leads to poor tissue development;
c. Hemolysis and clogging of arterioles and capillaries in the lungs, kidneys and liver by sickled cells leads to malfunction of many systems and usually death by the age of 30. (ARIS Mader Text Website)
4f. Interestingly enough, patients with sickle cell anemia are more likely to survive malaria! A mutation of the sickle cell gene can provide priceless protection to those regularly exposed to malaria, ie. Africans. (ARIS Mader Text Website.)
III. White Blood Cells and Defense Against Disease
A. White blood cells (leukocytes) are different than red in that they are usually larger, they do have a nucleus, lack hemoglobin, and are translucent unless stained. Not as numerous as red, either.
- Derived from stem cells in red bone marrow.
- Can squeeze through the walls of capillaries, so they are also found in tissue fluid and lymph.
B. Colony-stimulating factor: Regulates the production of each type of white blood cell.
C. Immune System: Consists of a variety of cells, tissues, and organs that defend the body against pathogens, cancer cells, and foreign proteins. Some live for a few days, others for months or even years.
D. Phagocytosis: A projection from the cell surrounds a pathogen and engulfs it. The resulting vesicle moves toward and fuses with a lysosome where enzymes digest the pathogen to debris that leaves the cell.
(Insert phagocytosis picture / www.peterjurek.com http://www.peterjurek.com/rbv_site/web_pages/phagocytosis.html)
E. White blood cells may reduce antibodies, proteins that combine with antigens, proteins foreign to the individual, and mark them for destruction.
F. Granular and Agranular Leukocytes: The classification of white blood cells because some have noticeable granules and some do not. Granules contain various enzymes and protein. (Mader 110)
- Granular Leukocytes: Neutrophils, eosinophils, and basophils.
1f. White blood cells fight invading microbes as part of the immune system
include:
- Lymphocytes—recognize invaders.
- Monocytes and neutrophils (the most abundant of white blood cells)—actually consume or engulf microbes.
- Basophils—release substances that trigger the other cells.(Frolich PowerPoint Slide 18)
G. Agranular Leukocytes: Lymphocytes and Monocytes.
- Lymphocytes: (2nd most abundant of white blood cells.) B cells and T cells.
- Monocytes: Largest of white blood cells, and after residence in the tissues, they differentiate into even larger macrophages except in skin. (Mader 111)
(Insert lymphocyte and neutrophils pictures / www.wadsworth.org http://www.wadsworth.org/chemheme/heme/microscope/lymphocytes.htm AND faculty.une.edu / http://faculty.une.edu/com/abell/histo/histolab3a.htm)
H. Disorders Involving White Blood Cells
1h. Immune deficiencies can be inherited.
- Severe Combined Immunodeficiency Disease: Stem cells of white blood cells lack the enzyme adenosine deaminase. Without this, the body can't fight infections of any sort. Treatments: Gene therapy, or regular injections of adenosine deaminase.
- Leukemia: A goup of cancerous conditions that involve uncontrolled white blood cell proliferation. most of them are abnormal or immature, and are therefore no help in defense.
- Epstein-Barr virus: Infection of lymphoctyes causes infectious mononucleosis. The "kissing disease". Infected cells lay dormant and hidden in a few cells for the person's entire life. (Mader 111)
IV. Platelets and Blood Clotting
A. Platelets (thrombocytes) result from fragmentation of certain large cells, called megakaryocytes, in the red bone marrow.
- 200 billion produced per day.
B. Blood Clotting (coagulation): When a blood vessel is damaged, platelets clump at the site of the puncture and seal the break. Large break may also need a blood clot to stop the bleeding.
1b. Platelets and damaged tissue release prothrombin activator, which converts the plasma protein prothrombin to thrombin. Thrombin acts as an enzyme that severs two short amino acid chains from each fibrinogen molecule. When these activated fragments join end to end, they form long threads of fibrin, which winds around the platelet in the damaged area of the blood vessel to provide framework for the clot.
2b. Serum: Yellowish liquid that escapes from clot after it is finished clotting.
(Insert blood clotting picture / biomed.brown.edu / http://biomed.brown.edu/Courses/BI108/2006-108websites/group01Heparin-coatedOxygenators/pages/Heparin_pharmacokinetics.htm)
3b. Disorders:
- Thrombocytopenia: Insufficient number of platelets.
- Thromboembolism: A clot can form in an unbroken blood vessel if it is "rough" because plaque is present. If it dislodges and travels in blood, it is embolus. If thromboembolism is not treated, it can cause a heart attack.
- Hemophilia: Inherited clotting disorder due to a deficiency in a clotting factor.
(Mader 113)
V. Blood Typing and Transfusion
A. Blood transfusion: Transfer of blood from one individual into the blood of another.
B. Bloods must be types to avoid agglutination, the clumping of red blood cells.
(Insert agglutination picture / www.andrews-clinic-natural-therapies.co.uk / http://www.andrews-clinic-natural-therapies.co.uk/darkfield_microscopy.htm)
C. ABO Blood Groups: Based on the presence or absence of two possible antigens, called type A antigen and type B antigen. Depends on inheritance.
- Only certain types of transfusions are safe because the plasma membranes of red blood cells carry glycoproteins that can be antigens to others.
- Type A blood: has anti-B antibodies in the plasma; Type B blood has anti-A antibodies in the plasma, and Type O blood: has both antibodies in the plasma.
D. Blood compatibility: Antibodies in the plasma must not combine with the antigens on the surface of the red blood cells, or it will result in agglutination. (Ie., when anti-A antibodies have combined with type A antigens.)
- Type O Blood: Universal donor. Agglutination will not occur with any other type blood.
E. RH Blood Groups: Designation of blood type usually also includes whether the person has or does not have the Rh factor on the red blood cell. (Mader 114-115)
VI. Homeostasis: Only possible if:
A. The cardiovascular system delivers oxygen from the lungs and nutrients from the digestive sytem to, and takes away metabolic wastes from, the tissue fluid that surrounds cells, and second, the lymphatic system returns tissue fluid to the bloodstream. (Mader 116)
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