BIOLOGY 12 - CHAPTER 11 - BLOOD - CHAPTER NOTES

Transcription

1 BIOLOGY 12 - CHAPTER 11 - BLOOD - CHAPTER NOTES Facts Human beings are approximately 70% WATER by body weight. o Most of this water is within cells, while a smaller amount is found within: o Tissue fluid (surrounds cells) o Lymph (within lymph vessels) o Blood vessels (in our blood) Functions of Blood (an average person has 5 to 6 liters of blood) maintain homeostasis is a liquid connective tissue. transports gases, wastes, and nutrients seals injuries by flotting fights infections Questions (p. 227) 1) What are the two main components of blood? plasma and the formed elements 2) What are the 3 types of formed elements? Red blood cells, white blood cells and platelets 3) Describe plasma. Makes up 55% of blood volume. Organic and inorganic substances (proteins, gases, salts, nutrients, wastes).dissolved or suspended in water. Plasma Fill in the missing information on the table below Plasma Constituent Function Source Water Maintains blood volume and Absorbed from large transports molecules intestine Plasma Proteins All maintain blood osmotic pressure & ph Liver a. Albumin b. Fibrinogen c. Globulins Gases a. Oxygen Maintain blood volume and pressure Clotting Transport; fight Infection Cellular Respiration b. CO2 End product of metabolism Nutrients: Fats, glucose, Food for cells amino acids, etc. Lungs Tissues Absorbed from intestinal villi Salts Nitrogenous waste Urea Uric acid Maintain blood osmotic pressure/ph, aid metabolism Excretion by kidneys Absorbed from intestinal villi Liver Hormones, vitamins etc. Aid metabolism Varied Blood- Page 1 of 10

2 Formed Elements: the "solid part" of blood Formed Element AKA Function Source Red blood cell (over 95% of formed elements) Erythrocytes Transport O 2 and help transport CO 2 Red bone marrow White blood cell (granular /agranular) Leukocytes Fight infection Red bone marrow and lymph tissue Platelets Thrombocytes Aid clotting Red bone marrow Identify and Label Erythrocytes Platelets Granular Leucocytes Agranular Leucocytes Blood Proteins Are required for the transport of many molecules. E.g. Cholesterol is a lipid (non-polar) is insoluble in plasma (polar). carried by proteins. HDL (high-density lipoprotein) is better than LDL for binding with cholesterol, according to some studies, in the prevention of atherosclerosis. Blood proteins also contribute to the viscosity of blood ( blood is thicker than water ), which aids in transport. Blood proteins also contribute to osmotic pressure, which maintains blood volume. 8.2 BCNotes - Blood - Teacher - Page 2 of 10

3 Hemoglobin (p. 228) transporter of O 2 Hemoglbin(Hb) is made of 4 polypeptides (2 alpha (α) and 2 beta (β)). Each polypeptide has an iron-containing heme group which attaches to oxygen Hb weakly binds with O 2 in the cool, neutral conditions (lungs), and easily gives up O 2 in the warmer and more acidic tissues. Hb is contained within red blood cells. Hb is a red pigment, red blood cells appear red (When O 2 is attached). OXYHEMOGLOBIN (Hb bound to oxygen, abbreviated as HbO 2 ) is bright red, while REDUCED HEMOGLOBIN (hemoglobin that has lost its oxygen) is dark purple. Carbon Monoxide (CO) is a poison found in car exhaust. CO binds better than O 2 to Hb CO stays bound for several hours to Hb,regardless of the environmental conditions. CO poisoning can lead to death because O 2 cannot be transported. Hemoglobin picks O 2 up in the lungs and releases O 2 in tissues. Meanwhile, CO 2 and wastes diffuse out of cells. Exchange at the Capillaries Recall: Blood pressure (BP) is greatest in arteries and decreases in the vessels as it moves away form the heart. BP is a force (push) against the walls of the blood vessels Osmotic pressure (OP) is the force from the fluid between cells and the blood vessels. At the arterial side of a capillary, BP > OP and therefore water, oxygen and glucose tend to leave the bloodstream (small molecules). At the venous end of a capillary, the OP > BP and, therefore, water, ammonia, and carbon dioxide tend to enter the bloodstream (small molecules). Somewhere in the middle BP is equal to OP. At this point small molecules move in and out by diffusion. Net pressure is the difference between BP and OP. Reduced hemoglobin can pick up some CO 2 to form carbaminohemoglobin (HbCO 2 ) but most CO 2 combines with water to form carbonic acid which then dissociates to form the bicarbonate ion (HCO 3 -), the enzyme carbonic anhydrase speeds up this reaction. CO 2 + H 2 O <--->H 2 CO 3 <--->H+ + HCO 3 - How most CO 2 is transported dissociation T H + form the above reaction is picked up by the globin portion of hemoglobin to become HHb thus ph is maintained (homeostasis). 8.2 BCNotes - Blood - Teacher - Page 3 of 10

4 Red Blood Cells (p.228) There are close to 30 trillion blood cells in an adult. Each mm 3 of blood contains from 4 1/2 to 5 1/2 million red blood cells and an average total of 7,500 white blood cells. In humans, red blood cells are small, biconcave, disk-shaped cells without nuclei. Red blood cells are made by cells called STEM CELLS in red bone marrow (over 2 million per second!) of the skull, ribs, vertebrae, and ends of the long bones. Here, Stem Cells continuously divide. During the maturation process, a red blood cell loses its nucleus and gets much smaller. Oxygen levels in blood determine the rate of RBC formation. o If O 2 is low, the kidneys produce renal erythropoietic factor (REF) REF combines with globulin from the liver bone marrow produces more RBC. RBC live for 120 days then destroyed in the liver and spleen. The iron is recovered from the hemoglobin and sent to the bones, while the heme portion is chemically degraded and is excreted by the liver in the bile (disgestive function) as bile pigments. White Blood Cells (p. 229)) White blood cells (WBC aka leukocytes) are usually larger than RBC (8-20 µm), have a nucleus, and appear white (if not stained -- when stained, they appear bluish). Number comparison: 600 RBC: 1WBC (leukocytes). Two main types of Leukocytes: 1) Granulocytes: have granules (or grains) in the cytoplasm and a multi-lobed nucleus joined by nuclear threads (called "polymorphonuclear"). The granulocytes include: a) Neutrophils (phagocytizes primarily bacteria), b) Eosinophils (phagocytizes and destroys antigen-antibody complexes) c) Basophils (congregates in tissues, releases histamine when stimulated). Formed in the red bone marrow. The granules of a neutrophil are lysosomes. 2) Agranulocytes (no granules): Include Lymphocytes and Monocytes. Have a circular (lymphocytes) or indented (monocytes) nucleus. Lymphocytes are produced in lymphoid tissue found in the spleen, lymph nodes, and tonsils. a) Type B lymphocytes produce antibodies in blood and lymph, b) Type T lymphocytes kill virus-containing cells. c) Monocytes become macrophages. WBC Functioning Fight infection, develop immunity and fight disease Neutrophils ( 60-70% of WBC) lymphocytes ( 25 to 30%) main contributors to fighting infection Phagocytic (engulf invaders at infection site) WBC s: neutrophils, monocytes, and eosinophils are Lymphocytes secrete a type of gamma globulins (proteins) called immunoglobulin (antibodies). Antibodies combine with foreign substances to inactivate them. Lymphocytes (smallest WBC). When microbes invade the body, lymphocytes begin to multiply and they become transformed plasma cells. Specific microbe results in a specific type of plasma cell. This plasma cell produces a specific antibody to destroy the particular microbe. 8.2 BCNotes - Blood - Teacher - Page 4 of 10

5 Red bone marrow continually produces WBC s except lymphocytes and monocytes (produced when needed) When a parasite or virus invades and begins to colonize, the reserves of white blood cells are released and the production of large quantities of the appropriate white cells begins. It is this increased production that causes fever. WBC s are very specific for various illnesses, their count can help doctors diagnose patients. Blood Clotting (p.230) After an injury, coagulation "or clotting" takes place to prevent excessive blood loss. This requires the action of 1) platelets 2) prothrombin, and 3) fibrinogen. Megakaryocytes fragment to become platelets (thrombocytes). Fibrinogen and prothrombin are plasma proteins produced by the liver (vitamin K is needed for the production of prothrombin) Steps involved in clot formation: 1.Platelets clump at the site of the puncture and partially seal the leak P r o t h r o m b i n A c t i v a t o r 3. Prothrombin activator converts c a t a ly z e s t h e c o n v e r s i o n o f prothrombin P r o to t h rthrombin. o m b t o T hca r o m +2 b i n. ( C a + + i s n e c e ss a r y f o r t h i s s t e p ) needed P r o t h r o m b i n A c t i v a t o r 2. Platelets and injured tissues release the enzyme prothrombin activator In j u r e d t i s su e s a n d p l a t e le t s r e l e a se P r o t h o m b i n A c t i v a t o r ( a n e n z y m e ) ( v i ta m i n K r e q u i r e d f o r th e p r o d u c t i o n o f P r o t h o m b i n ) + C a + + T h r o m b i n P r o t h r o m b i n F i b r in o g e n F i b r i n F r a g m e n t T h r o m b in i s a n e n z y m e t h a t a c ts l ik e a p a ir o f s c i s s o r s, c u t ti n g sh o r t a m i n o a c i d e n d s o f f F ib r i n o g e n m o l e c u l e s 4. Thrombin acts as an enzyme and cuts two short a.a. chains from each fibrinogen molecule. 5. Fibrinogen fragments join end to end to form long fibers of fibrin. F i b r i n F r a g m e n ts j o i n t o g e t h e r 6. Fibrin e n d threads to e n d t o join f o r m together l o n g f i b e r s and. F ib r i n f ib e r s f o r m th e form the framework of the clot. f r a m e w o r k o f t h e c l o t. RBC s and platelets gets trapped and contribute to the clot Other Clotting Facts RBC s trapped in the clot give it its red colour. 8.2 BCNotes - Blood - Teacher - Page 5 of 10

6 B ra dykinin: Clotting takes place faster at warmer temperatures than cold. Why? because clotting is controlled by enzymes which work better at warmer temperatures. Serum is plasma from which the fibrinogen has been removed due to clotting. Once blood vessels are healed, plasmin (an enzyme) breaks down the fibrin network and restores the fluidity of plasma. Haemophilia a genetic disorder. Persons do not produce a necessary clotting protein. Clotting proteins can be produced using recombinant DNA Infection Fighting: another major function of blood The skin - body's first line of defense against invading pathogens like bacteria and viruses - major burn victims may die because of infection that follows not the burn itself The blood - The second line of defense: white blood cells and gamma globulins. Antibodies (p.246) Antibodies are very specific proteins that attach to invading pathogens Lymphocytes produce antibodies in response to invading pathogens. Each lymphocyte produces only one type of antibody that is specific for one type of antigen. An antigen is a foreign substance (usually a protein, sometimes a carbohydrate) an antigen could be protein coat of a virus antigens stimulates the release of antibodies Antibodies bind with antigens causing antigens to become harmless. An antibody fits a specific antigen like a lock and key. Light chain Heavy Chain STRUCTURE OF A A TIBODY Variable Region Constant Region Antibodies binding to antigens (proteins on surface of a cell) An individual is immune to an antigen if he/she has antibodies to that particular antigens. The blood in the individual contains lymphocytes that can remain in the system for years, ready to produce antibodies if that antigen is detected. Exposure to the antigen (naturally or by vaccine) can cause active immunity to develop. Diseases will often cause an increase in a particular type of white cell. e.g. mononucleosis characterized by greater #'s of dark staining lymphocytes. Leukemia is a form of cancer characterized by uncontrolled production of abnormal white cells, which accumulate in the bone marrow, lymph nodes, spleen, and liver, causing them to malfunction. Leukemia patients often have severe anemia, clotting difficulties, and succumb to many infections. The Inflammatory Reaction p Whenever the skin is broken due to a minor injury, a series of events occur that are known as the inflammatory response because there is swelling and reddening at the site of the injury. This response is designed to get the body's defenses assembled as quickly as possible at the site where they are needed. Steps in the Immune Response Injure 1. Injured d tissues blood a nd vessels c apillaand ries re lease tissue fa ctors cells tha release t for m precursors B RADY of bradykinin KI I. 8.2 BCNotes - Blood - Teacher - Page 6 of 10

7 2. Bradykinin 2. Bradykinin initiates nerve impulses PAIN causes mast cells to release histamine, Fact: Mast cells are a type of cell that resides in tissues that are derived from Basophils 3. Histamine causes redness, localized heat and capillaries to dilate and enlargen 4. Enlarged capillaries increase permeability allowing proteins and fluids to escape swelling. 5. Lymphocytes release antibodies that attack any invading pathogens (remember, bacteria are everywhere), preparing them for phagocytosis by neutrophils or monocytes. 6. Monocytes become macrophages (p.229) Macrophages are large phagocytic cells (5 to 10 X larger than monocytes) that are able to devour a hundred invaders and still survive. Bacteria BLOOD TYPING p BCNotes - Blood - Teacher - Page 7 of 10

8 ABO Grouping. 4 possibile blood types: i. type A ii. type B iii. type AB iv. type O These blood types are due to 2 antigens (A or B) that may be present on the surface of the RBC s. Plasma of individuals also contain antibodies to the antigens they are lacking. If the same antigen and antibody are present, agglutination (or clumping) of red cells will occur (may cause death). Blood recipients may only receive donated blood for which they have no antibodies in their plasma. Fill in table with this last point in mind Blood Type A B AB O Can receive a blood transfusion A or O B or O All 4 types O from what blood types? Cannot receive a blood transfusion from what blood types? B or AB A or AB A, B or AB Question: Explain why people with O type blood are termed universal donors, yet are limited in the blood they can receive. (2 marks) blood type O is accepted by all blood types therefore it is the universal donor blood type O can only receive blood type O because it produces anti-a and anti-b antibobodies The Rh System Another important antigen in matching blood types is the Rh factor (another antigen found on red blood cells) 8.2 BCNotes - Blood - Teacher - Page 8 of 10

9 People that have this antigen on their RBC s are termed Rh positive; those without the antigen are Rh negative. If you are blood type AB from the ABO system and do not have the RH antigen you re blood type is AB- Therefore there are 8 blood types when the 2 systems are combined Rh - individuals do not normally make antibodies to the Rh factor, unless they are exposed to the Rh factor. The Rh factor and Pregnancy. If the mother is Rh - and the father is Rh +, the child may be Rh +. During gestation, it is normal that a few red cells from the child will find their way into the mother's system -- she will then produce Rh antibodies. If the mother becomes pregnant with another Rh positive baby, Rh antibodies may cross the placenta and destroy the child's red cells. This is called fetal erythroblastosis (or hemolytic disease of the newborn). Antibody Current treatment: prevent the mother from producing Rh antibodies. How? give Rh- women an Rh immune globulin injection (like an injection of antibodies) called RhoGAM just after the birth of any Rh + child. This injection will destroy any RBC s left over from the baby, before the mother s immune sytem has a chance to start producing her own antibodies. The injection won't work if the woman has already started to produce her own antibodies. Determining Blood Type 8.2 BCNotes - Blood - Teacher - Page 9 of 10

10 Recall: agglutination is the clumping of blood when an antibody that is specific to its antigen combine. (e.g. combining antibody A and blood type A will agglutinate) Blood types can be determined by observing this change. Example: The blood of 4 students was placed on separate slides with the the specified antibodies. Square W is prepared with anti-a solution which causes agglutination in blood containing the A antigen. Square X is prepared with anti-b solution which causes agglutination in blood containing the B antigen. Square Y is prepared with anti-rh solution which causes agglutination in blood containing the Rh antigen. Blood which contains the Rh antigen is said to be Rh+, while blood without the Rh antigen is said to be Rh-. Square Z is a control (no solutions added). What conclusion can be made about each student from the above observations? Student 1 is Blood type O - Student 2 is Blood type A - Student 3 made a mistake control should not have antibodies agglutination should not have occurred Student 4 is Blood type AB BCNotes - Blood - Teacher - Page 10 of 10