A. The cardiovascular system
B. Types of blood vessels
C. Double pump
D. Its features include...
E. Robert Frost, eat your heart out (two pathways)
F. Take this! Take that!
G. Disorders
II. Blood
A. Blood
B. Red Blood Cells
C. White Blood Cells
D. Platelets
E. Blood Typing
F. Homeostasis
III. Lymphatic System and Immunity
A. Microbes, pathogens and You
B. The Lymphatic System
C. Nonspecific Defenses
D. Specific Defenses
E. Acquired Immunity
F. Hypersensitivity Reactions
I. Heart and Blood
A. The cardiovascular system
The cardiovascular system is the heart and blood vessels. The heart pumps bl
ood. The blood vessels carry blood, which carry nutrients and oxygen and carry carbon dioxide and wastes to dispel. The exchange of nutrients and waste happens with the tissue fluid and not with actual cells. An overview of the functions of the cardiovascular system includes: blood pumping by the heart through contractions, vessels transporting blood from the heart to capillaries and veins then back to the heart, nutrient/waste exchange at the capillaries (the smallest of blood vessels), regulation of blood flow by the heart and vessels according to bodily need.The lymphatic system works hand in hand with the cardiovascular system in collecting and returning excess and necessary fluid to the blood.
A diagram of the cardiovascular system
B. Types of blood vesselsThere are three different types of blood vessels: arteries, capillaries and veins. Arteries are the thickest of blood vessels. There are three layers to the wall of an artery. The first is the endothelium, which is very thin. . The second is fairly thick and made of elastic tissue. The outer layer is made of connective tissue. A small version of the artery is the arteriole, which have more muscle fiber than elastic tissue. These properties help arteries to contract and dilate.
Capillaries are at the end of arterioles. They cannot be seen with the nake
d eye. They are made of only one wall of endothelium. Capillary beds, which are vast networks of capillaries, are found in every different area of the human body. Only certain beds are open at any time. When a bed is closed the precapillary sphincter contracts, shutting off and redirecting the flow of blood.Vein walls are similar to arterial walls in make up. Veins, however, have less connective tissue and less elastic tissue. Venules are small passageways that direct blood from capillaries to veins. Veins usually have valves. These valves keep blood flowing to the heart when open and stop blood from flowing backward when the veins are closed. These are necessary in veins that carry blood from the feet to the heart, for example. Veins carry most of the blood at any given time. This way blood can be "held" and redirected in times of hemorrhaging.
a cutaway of the artery wall
C. Double pumpThe heart is a large muscular organs (approximately the size of ones fist with the other hand clasping the fist.) which is found between the lungs and behind the sternum. Most of the heart consists of the myocardium. This muscular tissue pumps blood. The pericardium surrounds the heart and supports and protects it. Inside the septum separates the heart into two sides. There are four chambers to the heart. The upper two are the left atrium and the right atrium. The two lower chambers are the left and right ventricles. The valves that may between the atria and ventricles are called atrioventricular valves. Chordae tendineae, muscles attached to the ventricular walls, keep the valves from inverting when the heart contracts. The right valve is called the tricuspid, because of its three flaps. The left valve is called the bicuspid, because of its two flaps. The other valves are the semilunar valves. These go from the ventricles to their respective vessels.
There is a complex system through which blood flows through the heart. Here is a list of vessels and systems in the heart and their functions: The superior and inferior vena cava carry blood low in O2 to right atrium which sends the blood through the tricuspid to the right ventricle. It sends the blood through the pulmonary semilunar valve into the pulmonary trunk. The trunk carries the blood into two divided pulmonary arteries which carries the blood to the lungs. From the lungs the blood is carried by 4 pulmonary veins into the left atrium. From here it is sent through the bicuspid valve into the left ventricle. The blood is, then, sent throu
gh the aortic semilunar valve. into the aorta and into the body. The blood is never mixed between O2 rich and O2. This is an amazingly complex system. Because the left chambers have the harder work, they are thicker and better equipped for the harder task of pumping blood further. Blood pressure is also significantly greater on this side of the heart.Every heartbeat is called a cardiac cycle. First both atria contract, then both ventricles contract. After this all chambers relax. The contraction phase is called systole. The relaxation period is called diastole. An average amount of heart beats per minute is about 70. The sinoatrial node is what generates the heartbeat internally. It is referred to as the pacemaker. The medulla oblungata contains a cardiac control that monitors external conditions and reacts accordingly to regulate heartbeat. It will release hormones that can stimulate higher heartbeat rates. This happens during periods of activity, like exercise.
This diagram shows both ways that blood flows
D. Its features include...Blood pressure is strongest in the aorta, as this is where is first travels through when the ventricles contract. It becomes progressively weaker and is weakest in the venae cavae of the right atrium. The heart pump makes the blood vessels stretch and return in a rhythmic fashion. This is the pulse. Pulses are commonly felt in the wrist (the radial artery) and in the neck and heel (the cartoid artery.) Blood pressure is defined as the pressure blood places on a vessel wall. A device called a sphygmomanometer is used to read blood pressure. A band is tightened around an artery until its pressure is higher than the blood pressure. As pressure is released from the band the sphygmomanometer will pick up the pulse. The first jump of pressure is the systolic pressure. This is the highest point of blood pressure and is achieved when blood is ejected from the heart. The last pulse caught reads the diastolic pressure. This is the lowest point of blood pressure and occurs when the ventricles are relaxed. When blood pressure is read it is shown as systolic over diastolic. Normal blood pressure can have a systolic value of anywhere from 95-135. The diastolic norm is between 50 and 90. When the blood pressure of an individual is higher than these they have hypertension. If it is lower than it is called hypotension. Blood flows much slower in capillaries, which aids in a good exchange of substances with tissue fluid. Since blood pressure is slower in veins they depend on factors other than blood pressure to pump blood back to the heart. These are the skeletal muscle pump, the respiratory pump and valves. When pressure is released by both the skeletal muscles and the abdominal cavity (from breathing) valves close, keeping blood from flowing back down.
E. Robert Frost, eat your heart out (two pathways)
There are two circuits the blood flows in: the pulmonary circuit and the systemic circuit. The pulmonary circuit circulates blood through the lungs. When blood returns to the heart it is pumped through the right atrium into the pulmonary trunk. The blood goes into one of the two pulmonary arteries and releases CO2 through the capillaries into the lungs. The blood cells pick up oxygen and then go into one of the four pulmonary veins that lead into the left atrium. The systemic circuit includes the pathways of blood to all other parts of the body where oxygen is taken to be exchanged for CO2 with tissue fluid. Then the CO2 rich blood returns to the heart. The major artery is the aorta. The major veins are the superior and inferior vena cava. Other arteries include the mesenteric, the common iliac, femoral, renal, subclavian and the cartoid. Common veins are the internal and external jugular, renal, mesenteric, common iliac, femoral and the great saphenous vein. Coronary arteries supply the hearts blood. It is not nourished by the blood in its chambers. The coronary arteries are the first branches of the aorta. Their small diameter makes them more susceptible to clogging then other arteries. This is what cardiovascular disease is, essentially.
F. Take this! Take that!
Blood pressure moves water from capillaries to tissue fluid. Osmotic pr
essure moves water from tissue fluid to blood. Blood pressure is higher than osmotic pressure at the end of arterial vessels. This causes water to exit to tissue fluid here. Diffusion happens in the middle of the capillary where the pressures are equal. Oxygen and nutrients exit the vessel and CO2 diffuses into the vessel. At the venule end osmotic pressure is greater than blood pressure and water moves into the capillary. Lymphatic capillaries catch excess tissue fluid. The fluid is returned to the blood vessels at the subclavian veins.The order of operations in the capillaries
There are various cardiovascular disorders. Hypertension and atherosclerosis are two that affect the blood vessels, specifically. Hypertension is an abnormally high blood pressure. It can be the cause of stroke heart attacks, strokes or kidney failure. Atherosclerosis is a storing of cholesterol in the arteries. These deposits are called plaque. This will interfere with the flow of blood. Plaque can cause clots to form on arterial walls. A stationary clot is called a thrombus. When a clot moves it is called an embolus. Thromboembolism is a clot that moved but became stationary. This is a very dangerous disorder. Smoking, high-fat diets and lots of cholesterol all contribute to atherosclerosis. This can, naturally, lead to a heart attack. Anuerysms are also associated with hypertension and atherosclerosis. Anuerysms cause a blood vessels to swell. This happens mostly in the abdominal arteries and in the arteries leading to the brain.
When a person suffers a heart attack their heart is weaker. It has become saggy and/or swollen. There can be an abnormal beating. When this has happened it is sometimes necessary to put in a cardioverter- defibrillator. This will generate missing beats and, with electricity, send a jolt to slow the heart down when too fast. Heart transplants are also an option, but an unlikely one. Many more people are waiting for a heart than are hearts available. Genetically altered pig hearts are a possible avenue in the future. Other rarely-used devices are LVADs and the Jarvik 2000 which are pumps ran by external batteries. Very few people have received TAHs (total artificial hearts) these are controlled by an external battery feeds energy to an internal coil through the skin. The internal battery regulates the heart rate. The heart is an artificial pump.
II Blood
A. Blood
Humans have about 5 liters of blood. There are three functions of blood: transport, defense and regulation. Blood transport different substances to tissue fluid for cellular use throughout the body. The main commodity for transport is oxygen, absolutely necessary to cellular activity. It then takes away waste, like CO2, for expulsion. Blood also carries hormones from their area of origin to organs and tissue in need of them. Some blood cells fight and kill pathogens in the body. Some do this directly and others secrete antibodies, which render pathogens useless, making them easier to kill. Defense also includes repair. When a blood vessel is opened blood clots using platelets and plasma to seal up the wound until it heals. Blood also keeps homeostasis in the body. Blood holds heat and when it is too hot, releases it through vessels close to the skin. Blood keeps bodily pH fairly constant, as well.
Blood is considered a liquid tissue because it cells and cell fragments, known as formed elements, are engulfed in plasma. red blood cells, white blood cells and platelets are the formed elements of blood. These originate in red bone marrow. The stem cells in red marrow will eventually become specific formed elements in blood. Though red blood cells are much smaller than white blood cells there are many many more of them in any given area.
Plasma is about 91% water and 9% organic molecules and salts. Salts maintain the pH of blood. Plasma carries and distributes heat. Plasma proteins in plasma help keep the pH balance as well as keep in plasma at capillary exchange. Albumins, globulins and fibrogens are the three major types of plasma proteins. Their functions include osmotic pressure, transport and blood clotting.
B. Red blood cells
The proper name for red blood cells is erythrocytes. They are nucleus-less, biconcave (concave on both sides) and are incredibly bountiful. Their main function is carrying oxygen. Red blood cells contain a lot of hemoglobin: a compound that contains iron for oxygen pick up and release and protein. Each red blood cell carries over one billion O2 molecules. Red blood cells get their concave shape from losing their nucleus as they grow. This shape gives a larger surface area which is great for gas release and collection. They do not use any oxygen they carry and make ATP anaerobically.
The protein in hemoglobin picks up CO2 as well as the plasma, which takes it with hydrogen. Once in the lungs the CO2 is released through diffusion. As previously stated, red blood cells are produced in red bone marrow. They begin with stem cells with nuclei. When they divide they become red blood cells devoid of a nucleus. When their cycle is done they are destroyed by white blood cells in the liver and spleen. About 2 million red blood cells are created every second and 2 million are destroyed in the same time. Hemoglobin is released at RBC destruction. The proteins are broke down into amino acids and distributed. The iron is returned to the bone marrow for reuse.
Blood doping is an artificial version of the body's way of producing mo
re red blood cells when necessary. This is done when more oxygen is needed in the body. The process is this: the kidney release erythropoietin. This stimulates stem cells in marrow and catalyzes RBC production. Athletes have done this process by injecting EPO into themselves and then removing blood and concentrated before returning them to the blood. This is a dangerous process that has killed cyclists, specifically, because of the sport's preference for blood doping.There are specific red blood cell-related disorders. Anemia is a lack of sufficient RBCs of from lack of hemoglobin. One suffering from anemia feels fatigued. Often this happens from B vitamin deficiency. Hemolysis is a disorder in which red blood cells rupture. Sickle cell disease is a condition in which the oddly-shaped RBCs tend to rupture in the capillaries.
A photo of red blood cells
Leukocytes is the proper name of white blood cells. White blood cells aren't actually white, but are transparent. They are much larger than red blood cells and contain a nucleus. They do not carry hemoglobin. White blood cells are integral to immunity.There are different types of white blood cells. nuetrophils are the most abundant. They are the first response to bacterial infection. When they die their collection in an area often becomes pus. Eosinophils increase in number when an allergic reaction or a parasitic worm are present. Basophils release histamine which causes blood vessel dilation and air tube constriction. Lymphocytes make up about 25-30% of all white blood cells. They are active in immunity to poisonous substances. there are two different types of lymphocytes: b cells and t cells. B cells make antibodies. T cells destroy pathogens. Monocytes are the largest white blood cell. Their job is to act as vacuum cleaners. They phagocytize debris, dead cells and pathogens. They also send out a sort of warning signal to lymphocytes for defense.
There are different disorders of white blood cells. The lack of the enzyme adenosine deaminase causes sever combined immunodeficiency disease. There are about 100 babies born with SCID every year. The only treatments are regular injections of the lacking enzyme and gene therapy. Leukemia is an uncontrollable growth of one or more groups of white blood cells. They do not perform their normal function because of mutation. Epstein-Barr virus is responsible for infectious mononucleosis when infecting lymphocytes. EBV is a very common human virus. The symptoms of mono will disappear after a month or two, but the virus will stay dormant in a person all of their life. It is called the kissing disease because it can be passed through saliva, which definitely occurs during kissing.
D. Platelets
Thrombocyte is the proper name for a blood platelet. Platelets are not cells, but cell fragments. 200 billion platelets are produced in a human body each day. They are crucial to blood clotting. They work in conjunction with thrombin and fibrinogen (plasma proteins manufactured in the liver) to achieve clotting. Platelets clump at the sight of a break in a vessel. When the cut or puncture is large a blood clot is necessary. Platelets will release prothrombin activator. This turns prothrombin into thrombin. Thrombrin cuts fibrogin into two chains. The fragments will join end to end into a large threadlike chain called fibrin. Fibrin, then, creates a sort of web in the broken area of the vessel. Red blood cells get caught in the fibrin which gives a clot its red color.
Thrombocytopenia is a lack of sufficient amounts of platelets. Complications include bleeding in the brain, nose, gastrointestinal tract, mouth as well as rashes and bruising. Clotting can also occur around plaque, in a blood vessel. This can cause heart attacks. Hemophilia is a disorder which can cause bleeding into the joints and at worst the brain which often causes death.
E. Blood typing
There are different types of blood. The type depends on the antigens in the membranes and the antibodies of the blood. The different types are referred to as A, B, AB and O. Another property is the the Rh factor. Rh is an antigen that is present in only some individuals. Rh antigens would possibly be destroyed by Rh antibodies in Rh- blood. This is important when multiple Rh+ children are born to Rh- women. The subsequent children could have blood cells destroyed by anti Rh antibodies that developed from previous exposure to Rh antigens. If an Rh- women gives birth to an Rh+ positive child, she can be given a shot of Rh immunoglobulin within 72 hours. This prevents the damage to any subsequent Rh+ positive children. Antibodies are an important factor in transfusion because antibodies from certain types of blood would connect blood cells with the proper antigen together. This causes clumping known as agglutination. Agglutination must be avoided, which is why blood typing is important to transfusions.
F. Homeostasis
Tissue fluid is derived from blood. It is very similar to plasma, but contains no plasma proteins. Because tissue fluid is collected, transported by and distributed by the lymphatic system its relation to the cardiovascular system is intimate. The cycle for fluid goes: blood plasma, tissue fluid, lymphatic system and back to blood plasma. The cardiovascular system must deliver oxygen and nutrients to needy organs and tissue. It collects oxygen from the lungs and nutrients from the digestive system. It then must transport waste from the tissue fluid to the lungs (CO2) and kidneys. Lymphatic vessels must cycle fluid. The muscular system is important to the perpetuation of the cardiovascular system.The Heart and skeletal muscle contraction pump blood and moves lymph. The kidneys help regulate the pH balance as well as the salt-water balance of blood and tissue fluid.
III. The Lymphatic System and Immunity
A. Microbes, pathogens and you
Microbes is a term that encompasses any of the microscopic organisms. They are everywhere and on everything. Many of them exist on and in our bodies. They are not all harmful, by any means, many of them are quite helpful. Some bacteria produce food and drugs. They are elemental to decomposition. Plants use the nutrients from decompositions to create the molecules that become food for us. Of course there are some harmful microbes. Some bacteria and all viruses are infectious and cause disease. These are called pathogens.
Bacteria are prokaryotes that lack a nucleus. There are three main shapes of bacteria: bacillus (rod shape), spirillum (curved spiral), and coccus (spherical shape.) The cell wall is coated with a gel-like substance that is called the capsule. The capsule gives the ability to stick to surfaces. Flagella are a feature of moving bacteria. It is a long, tail-like appendage that rotates for movement. Another adhesive feature are the fimbriae. These little hair-like materials help bacteria stick. A pilus is a feature of some bacteria that causes them to be able to transfer DNA from one cell to another. Bacteria carry an independent ring of genetics called a plasmid. This is where the DNA for most resistance to antibiotics can be found. Bacteria reproduce through a process called binary fission. The cell replicates and splits. Bacteria can double their numbers every 12 minutes. Bacteria can cause disease, they also release byproducts called toxins. Toxins can cause particular symptoms.
Viruses are another microbe that are very peculiar. Viruses are absolutely inactive without a host. However, once inside a host they begin replicating inside cells. Since parasites do not live independently, they are called obligate parasites. They are acellular. A few examples are AIDS, chicken pox, flu and rabies. Viruses are have two parts: an outer
capsid, made of protein and an inner core of nucleic acid. Viruses lock onto a cell and from there the nucleic acid enters the cell, having itself replicated by the host. One of the most common forms of virus spread is through a vector. A vector is a carrier, like an insect, that will take the virus from an infected individual to a healthy one.Prions are proteins in the brain and nervous system of animals. When an individual is healthy the function of the prion is unknown. However prions can change their shape, and when they do, they can cause damaging nerve and brain diseases. Prions were once thought to be viral infections. Prion diseases in human are rare.
this picture shows all three shapes of bacteria
The lymphatic vessels were talked about in the last chapter. Along with them are the lymphatic organs. Its functions are: collect excess tissue fluid and return it to blood, absorb fats and transport them to blood, production of lymphocytes to aid, along with other antigens, the immune system in defense. Lymph vessels carry tissue fluid back to blood veins in the shoulders. The two main ducts are on the right and left side of the body and return fluid from their respective side to the blood vessels.
The different lymphatic organs are: red bone marrow, thymus gland, lymph nodes and the spleen. Red bone marrow produces white blood cells. They matu
re here, all except for T lymphocytes which reach maturation in the thymus gland. The lymph nodes and spleen purify, purge and protect lymph. In adults red bone marrow is only found in the sternum, ribs, pelvic girdle, humerus and the femur. The thymus gland produces a hormone called thymosin, which is thought to aid in T lymphocyte maturation. The spleen filters blood. Lymph nodes filter lymph. Lymphatic nodules are areas of concentrated lymphatic tissue that are not encapsulated like lymph nodes. The tonsils is a great example of lymph nodules.This photo show the location of the lymph nodules, tonsils.
C. Nonspecific defensesImmunity is the ability to fight and destroy cancers and diseases. nonspecific defenses are immunity features that filter without discrimination. Two of these are barriers of entry and phagocytic white blood cells through the inflammatory response. some examples of barriers of entry are: the skin and mucous membranes (which block out or guard entry ways like the respiratory and digestive system), chemical barriers (chemicals such as lysozyme are antibacterial) and resident bacteria (bacteria that are normally found in the body that leave no room for pathogens.)
The inflammatory response can be detected if the are contains: redness,heat, pain and swelling. When an area is damged capillaries dilate causing excess blood flow. This causes redness and heat. The heat can kill some pathogens. This also causes swelling. The blood brings white blood cells to fight infection and help clotting to prevent blood loss. Excess tissue fluid pressing on nerve endings causes the pain. Neutrophils go in first vacuuming up dead cells, bacteria and debris. If the work is too much for neutrophils they secrete a chemical called cytokine. Cytokines attract white blood cells such as monocytes, which are more powerful than neutrophils.
Another helpful immune feature are protective proteins. The operation and composition of these is called the compliment system. These proteins form a complex and produce and attack holes in bacteria. The These holes allow fluids and salts to enter the bacteria until the bacteria bursts. Other complement proteins trigger chemical releases and ensure phagocytosis by white blood cells.
D. Specific defenses
The immune system is able to detect foreign particles in the body, called antigens. Lymphocytes respond to antigens. There are specific lymphocytes for every antigen, because each lymphocyte has a different receptor for every different antigen. When a b lymphocyte connects to an antigen it makes many copies of itself called clones. They will either become plasma b cells which will travel in the bloodstream releasing antibodies, or memory cells, which are there to fight an invasion of the same antigen at a later time. B cell defense is called antibody-mediated immunity. This is because plasma b cells give off antibodies for defense. Antibodies' basic structures are Y-shaped. The antigens fit on the sight receptors on the ends of the light chain branches (the short Y arms.) Either the antibodies will neutralize the pathogen or call for white blood cells to destroy the antigens. There are five different types of antibodies, they are: IgG ( most common), IgM (largest antibody), IgA (main antibody in saliva), IgD (located on immature b cells) and Ige (found in basophils and on mast cells.)
Some t cell defense is called cell-mediated immunity. This is when a t cell directly attacks a pathogen. Other times they release cytokines to stimulate defenses.T cells detect antigens because a macrophage will bring a piece of it for recognition to a lymph node where t cells are concentrated. These helper cells are called antigen-presenting cells. Then the t cells are able to distinguish foreign from regular. The proteins brought for recognition by the APC are called human leukocyte antigens, or HLA. There are two types of HLA (HLA I and HLA II.) If the identified protein is HLA I then the t cells will produce cytotoxic cells, through clonal expansion. Cytotoxic cells latch on to viral infected or tumor cells. They use a chemical called perforin to create holes in the cell. Then they inject enzymes, called granzymes, to cause the cell to die. If the protein displayed in HLA II then the t cell will produce helper t cells through clonal expansion. Helper t cells release cytokines which cause a response from other white blood cells. B cells are not employed actively without helper t cells.
This diagram explains the process
of B cell activation.
E. Acquired immunityof B cell activation.
Acquired immunity is the medical intervention which causes immunity. The two types of acquired immunity are active and passive. Active immunity involves the bod's immune system to fight infection. This can happen naturally or artificially. Immunization is an artificial method of active immunity. A vaccine is given to an individual by injection or ingestion. Vaccines contain an antigen from a particular pathogen that triggers the body to fight it. One can measure the immune activity with the antibody titer. This shows the response of antibodies to a vaccination. When a second vaccination is given it is called a booster shot because it increases the response of the antibodies to the particular vaccine. Passive immunity involves the process of using prepared antibodies to combat infection. The individual does not produce these antibodies so passive immunity is not permanent. These can be injected or ingested as well. Sometimes monoclonal antibodies are used from other individuals. Cytokines can be inject to catalyze cytotoxic t cells that were not activated, like in the case of some cancers.
F. Hypersensitivity reactions
Allergies are a hypersensitivity to foreign substances. Allergic reactions are triggered, sometimes within seconds of contact with an allergen. Anaphylactic shock is an allergic reaction that occurs when an allergen has enterd the bloodstream. It is recognized by a sudden drop in blood pressure. Delayed reactions are caused by memory t cells at the contact of allergens. This often happens with allergies that affect the skin.
Another reaction is that of tissue rejection. The body can reject organ transplants. The body recognizes that these tissues are foreign and cytotoxin t cells attack the new tissue cells. Sometimes immunosuppressive drugs are used to aid in transplant success. These drugs inhibit the production of cytokines. Labs are attempting to grow organs that are HLA antigen free, which would make transplant success rates soar.
Sometimes, peoples cytotoxic t cells will attack the body's own cells, mistakenly. This is called autoimmune disease. Its cause is unknown. Sometimes people have immune deficiencies. These people are unable to protect their bodies against infection.
sources
Cardiovascular system http://academic.kellogg.cc.mi.us/herbrandsonc/bio201_McKinley/f22-1_cardiovascular_sy_c.jpg
circulatory system http://www.besthealth.com/besthealth/bodyguide/reftext/images/8747.jpg
artery http://www.csm.ornl.gov/Internships/rams_06/websites/e_lennartz/img/Layers.jpg
capillary exchange http://www.coolschool.ca/lor/BI12/unit9/U09L08/CTFEx.gif
b cell activationhttp://upload.wikimedia.org/wikipedia/commons/thumb/f/f7/B_cell_activation.png/300px-B_cell_activation.png
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