The first is the superior vena cava and the interior vena cava carry oxygen poor blood into the right atrium. Then the right atrium sends the blood through the atrioventricular valve to the right ventricle. Next the right ventricle sends blood through the pulmonary semilunar valve into the trunk, the trunk then carries the oxygen poor blood and divides between two pulmonary artries to go to the lungs. Next the four pulmonary veins carry the oxygen rich blood to the left atrium. The left atrium sends the blood through the biscuspid valve to the left ventricle. Finally the left ventricle sends the blood through the aortic semilunar valve into the aorta and then into the body.
Oxygen rich blood and oxygen poor blood never come in contact with each other. The oxygen rich blood goes through the body and the oxygen poor blood goes through the lungs. Which is the purpose of the process of blood to keep circulating.
Now lets talk about the heart. The heart consists of the myocardium. This is the major portion of the heart and is composed of mostly cardiac muscle tissue. The pericardium is a thick membranous sac that supports and protects the heart. The septum is a wall in the heart that divides it into the left and right sides. The heart has four chambers. Two upper walls that are thin called the left and right atrium and the two lower walls that are thick called the left and right ventricles.
Coronary arteries - serve the heart
Hepatic vein - leaves the liver and enters the inferior vena cava
Aorta - receives blood from the heart
Superior and inferior venae cavae - return blood to the heart
Pulmonary circuit - circulates blood through the lungs
Systemic circuit - serves the body tissues
The body contains five liters of blood. Blood has three functions transporting, defense, and regulation. Blood is the primary transport medium for oxygen, CO, waste, etc. Blood defends the body against pathogens. It has regulatory functions such as temperature, water-salt balance, etc. Blood is a liquid tissue that contains cells, they are formed elements which consists of cells and cell fragments and plasma which are liquid formed elements.
Formed elements are red blood cells, white blood cells, and platelets. Formed elements are produced in the red bone marrow. Red bone marrow contains stem cells. Red blood cells (RBC) are two to three times smaller than white blood cells (WBC). The body contains millions of RBC's and thousands of WBC's. Plasma is the liquid medium the carries various substances in the blood. It is 91% water and 9% various salts and organic molecules. The salts in plasma help maintain pH in the blood. The organic molecules are plasma proteins they help maintain homeostasis. Some orgainc molecules are albumins, globulins, and fibrinogen. Albumins are the most abundant and contribute to the osmotic pressure. Globulins are alpha, beta, and gammas. Fibrinogen form blood clots. Osmotic pressure is a force that prevents excessive loss of plasma from the capillaries into the tissue fluid.
Red blood cells are small bioconcave disks that do not have a nucleus. There are four to six million in the body. RBC's are specialized to carry oxygen. They contain hemoglobin, which carries four oxygen per molecules and 280 million hemoglobin in red blood cells. RBC's only live 120 days.
Oxyhemoglobin is when oxygen binds to heme in the lungs. Deoxyhemoglobin is when heme gives up oxygen and hemoglobin resumes it's shape. Erythropoietin or EPO stimulates stem cells in the bone marrow to produce more red blood cells. When the oxygen in the blood in low the kidneys increase production of erythropoietin. Stem cells increase RBC's production. Oxygen level in the blood then returns to normal.
Anemia is the insufficient number of red blood cells or not enough hemoglobin.
Hemolysis is the rupturing of red blood cells.
White blood cells are larger and contain a nucleus. They lack hemoglobin and are translucent. They are regulated by protein colony-stimulating factor (CSF). White blood cells fight infection and are an important part of the immune system. If needed they can double within hours. There are five types of WBC's neutrophils, eosinphils, basophils, lymphocytes, and monocytes.
Neutrophils make up 50-70% of all white blood cells. They are the first responders to a bacterial infection. They are like vacuum cleaners. Eosinphils increase if a parasitic worm, infection, or allergic reaction occurs. Basophils release histamine during an allergic reaction. Lymphocytes make up 25-35% of white blood cells and is responsible for immunity to specific toxins and pathogens. There are two types of lymphocytes T cells and B cells. B cells or plasma protect the body by not letting the pathogen produce antibodies. T cells directly destroy pathogens. Monocytes are the largest of all five types. They are found in tissue and they stimulate the other white blood cells to defend the body.
There are 200 billion platelets produced daily. Platelets are a fragmentation of larger cells megakaryocytes in the red bone marrow. The process of blood clotting is: the blood vessel is punctured, platelets congregate and form a plug, platelets and the damaged tissue release prothrombin activator which iniates the cascade of enzymatic reactions, fibrin threads form and trap red blood cells.
Homeostasis is only possible if the cardiovascular system delivers oxygen from the lungs and nutrients from the digestive system to and takes metabolic waste from the tissue fluid that surrounds the cells. Lastly the lymphatic system returns the tissue to the fluid to the bloodstream. All systems must work together to maintain homeostasis.
Microbes are microscopic organisms like bacteria. Bacteria are single celled prokaryotes the don't have a nucleus. There are three common shapes. Bacillus which are rod shaped, coccus which are spherical shaped, and spirillum which are curved. Bacteria has a cell wall that contains a unique amino disaccharide. The cell wall is surrounded by a capsule which prevents white blood cells from destroying them. Bacteria have flagella. Flagella have a long thing appendage that rotate 360 degrees and make the bacteria move backwards. Fimbriae are fibers on the outside of bacteria that allow it to adhere to surfaces. Pilus is an elongated hollow appendage used to transfer DNA from one cell to another. Plasmids are accessory rings of DNA that carry resistant genes to antibodies. Bacteria double every 12 minutes. Process called binary fission is how bacteria reproduce. First a single chromosome attach to plasma membrane is copied, then chromosomes are seperated and the cell enlarges, and finally the new plasma membrane and cell wall seperate the cell into two cells.
The body has three lines of defense against pathogens. The first is barriers to entry like the skin and mucous, first responders which are white blood cells, and specific defenses overcome infection by killing particular disease causing agent that's entered the body. They protect against cancer.
Viruses bridge the gap between the living and the nonliving. They are acellular which means that are not composed of cells. Viruses are four times smaller than bacteria. They consist of two parts the outside capsid which is composed of protein units and the inner core composed of nucleic acid. Viruses carry genetic information needed to reproduce. They are microspic pirates that adhere to a host cell, they relie on the host cells enzymes and ribosomes to reproduce. Viruses are transported from one location to another and are transmitted by vectors. They can emerge because the immune system isn't able to recognize a change in the virus.
Prions cause mad cow disease, this occurs when certain proteins change shape into rogue form. This disease is very low in humans.
The lymphatic system contributes to homeostasis. There are four functions. The first is the lymphatic capillaries absorb excess tissue fluid and return to the bloodstream. The next is in the small intestines lymphatic systems absorb fats and transport them to the bloodstream. The lymphatic system is responsible for production, maintenance, and distribution of lymphocytes. Lastly the defend the body against pathogens.
The lymphatic vessels are a one way system that contain capillaries, vessels, and ducts. The fluid in the lymphatic vessels is called lymph. The vessels take lymph to the cardiovascular veins in the shoulders. The movement of lymph is dependent upon skeletal muscle contraction. There are two types of ducts the thoracic duct and the right lymphatic duct. The thoracic duct returns lymph collected from the body below the thorax, left arm, and left side of the head and neck into the sebclavian vein. The right lymphatic duct returns lymph from the right arm and right side of the head and neck to the right subclavian vein.
Lymphatic organs consist of primary and secondary organs. The primary organs are red blood marrow which produces blood cells and the thymus gland. The thymus gland produces thymic hormones. Immature T lymphocytes migrate from the bone marrow through the bloodstream to the thymus where the mature. Only 5% every leave. The secondary organs are the spleen and the lymph nodes. The spleen filters blood, it has connective tissue that divides into the white pulp and red pulp. Blood entering the spleen must pass through the sinuses before exiting. The lymph nodes filter lymph. The connective tissue form a capsule. The lymph nodes fight infection and attack cancer cells. The lymphatic nodules are concentrations of lymphatic tissues that are not surrounded by a capsule. The tonsils are patches of lymphatic tissues in a ring shape, the tonsils perform the same functions as the lymph nodes.
Immunity is the ability to combat diseases and cancer, this includes the lines of defense. There are two lines of defense they are barriers to entry and inflammatory response. Barriers to entry are built in they can be chemical or physical. This is the first line of defense. The physical is the skin and mucous membrane. These are very effective in preventing infection. These membranes line the respiratory, digestive, reproduction, and urinary tracts. The chemical barrier includes the oil glands, perspiration, saliva, and tears. They contain an antibacterial enzyme called lysozyme. The acid pH in the stomach. The normal flora are microbes in the mouth, intestine and other areas. Inflammatory response is reddness, heat, swelling, and pain. When this happens histamine is released by cells and mast cells that cause the capillaries to dilate and become permeable. Cytokines are chemical mediators that attract more white blood cells to the area like monocytes. Monocytes are longer lived cells that turn into macrophages. Macrophages are more powerful phagocytes than neutrophils.
The complement system is composed of blood plasma proteins. It complements certain immune responses. It binds to the surface of pathogens that are already coated with antibodies. The also can form a membrane attack complex that puts holes in the surface of bacteria and viruses. Interferons warn noninfected cells of a virus, it can be used to treat viral infections.
Specific defenses work when nonspecific defenses have failed. Here is how it works. Activated B cells undergo clonal selection with production of plasma cells and memory B cells after a B cell receptor combines witha specific antigen. Then the plasma cells secrete antibodies and undergo apoptosis. The plasma cells are responsible for the antibody mediated immunity. Apoptosis is the process of programmed cell death. The antibody is usually a y-shaped molecule that has two binding sites for specific atnigens. Memory B cells remain in the body and produce antibodies if the same antigen enters the body later. For the T cell to recognize an antigen the antigen must be presented by an antigen presenting macrophage along with HLA. Activated T cells undergo clonal expansion until illness has been stemmed. Most activated T cells undergo apoptosis, a few cells remain as memory T cells. The two types of T cells are cytotoxic and help T cells. Cytotoxic cells kills virus infected/cancer cells on contact because they have a nonself protein. Helper cells produce cytokines and stimulate other immune cells.
Microbes are microscopic organisms such as bacteria. A bacterium is a single celled prokaryote that does not have a nucleus. There are three common shapes of bacteria:
bacillus which are rod shaped
coccus which are spherical shaped
spirillum which are curved
Bacteria have a cell wall that contains a unique amino disaccharide. The cell wall is surrounded by a capsule that prevents white blood cells from destroying them. Flagella have long thin appendages that allow the bacteria to move backwards. Fimbriae are the fibers that allow the bacteria to adhere to surfaces. The pilus is an elongated hollow appendage that is used to transfer DNA from one cell to another cell. Independent bacteria cells are metabolically competent. Plasmids are the accessory rings of DNA that carry the resistant genes to the antibodies. Bacteria reproduce very quickly. They can double every 12 minutes; the process is called binary fission. First a single chromosome is attached to the plasma membrane and is then copied. Then the chromosomes are separated and the cell enlarges. Finally the new plasma membrane and cell wall separate the cell into two separate cells.
Pathogens are like viruses. The body has three lines of defense against them. The first line of defense is barrier to entry such as the skin and the mucous. If this doesn’t work than there is the first responder which are the white blood cells. And if that doesn’t work there are specific defenses. These overcome infections by killing the particular disease causing agent that has entered the body. Specific defenses can protect us against cancer. We will talk more about these later.
Viruses are acellular which means that they are not composed of cells. They are four times smaller than bacteria and they obligate parasites that are not independent. They also bridge the gap between living things and nonliving things. Viruses consist of two parts: the outside capsid which is composed of protein units and the inner core of the nucleic acid. Viruses carry all of the genetic information they need to reproduce. Microscopic pirates are what viruses are called because they adhere to a host cell and they relie on the host cells enzymes and ribosomes to reproduce. Viruses emerge by being transported from one location to another where the virus hasn’t been before. Viruses can also emerge because the immune system doesn’t recognize the change in the virus.
There are four functions for the lymphatic system to maintain homeostasis. The first one is the lymphatic capillaries must absorb excess tissue fluid and return it to the bloodstream. The next one is in the small intestines the lymphatic capillaries to absorb the fats and transport them to the bloodstream. Next the lymphatic system is responsible for the production, maintenance, and distribution of the lymphocytes. Lastly the lymphatic system helps defends the body against pathogens.
The lymphatic vessels are a one way system that includes the capillaries, the vessels, and the ducts. These take lymph to the cardiovascular veins in the shoulders. Lymph is the fluid in the lymphatic vessels. The movement of lymph is dependent on the skeletal muscle contractions. There are two ducts in the lymphatic vessels. The first one is the thoracic duct. This one returns lymph collected from the body below the thorax, left arm, and left side of the head/neck into the left subclavian vein. The second duct is the right lymphatic duct. This one returns lymph from the right arm and right side of the head/neck to the right subclavian vein.
There are primary and secondary lymphatic organs. The primary organs include the red bone marrow whose job is to produce blood cells and the thymus gland. The thymus gland produces thymic hormones. The immature T lymphocytes migrate from the bone marrow through the bloodstream to the thymus where they mature. Only about 5% of the lymphocytes ever leave the thymus. The secondary organs include the spleen which filters blood. The connective tissue divides it into the white and red pulp. The blood entering into the spleen must pass through the sinuses before exiting. The lymph nodes are the other organ. They filter lymph, fight infection, and attack cancer cells. Lymphatic nodes are a concentration of lymphatic tissues that are not surrounded by a capsule; where as lymph nodes are connective tissue that form a capsule. The tonsils are patches of lymphatic tissues located in a ring. They perform the same functions as lymph nodes.
Barriers to entry are the first line of defense. They are built into the body and can be chemical or physical. The skin and mucous membranes are very effective in preventing infection. They line the respiratory, digestive, reproduction, and the urinary tracts. They are the physical barriers. The chemical barriers are the oil glands, perspiration, saliva and tears. They contain an enzyme called lysozyme that is antibacterial. Some other chemical barriers are the acid pH in the stomach and the normal flora which are microbes that are found in the mouth, the intestine, and other areas throughout the body.
Inflammatory response is what happens when a person is injured. The person may experience redness, heat, swelling or pain around the injured area. This works when a histamine is released by the cells and the mast cells which cause the capillaries to dilate and become permeable. The cytokines are the chemical mediators that attract more white blood cells to the injured area. They are like monocytes. Monocytes are cells that have a longer life span and eventually turn into macrophages. The complement system is composed of blood plasma proteins. The C system complements certain immune responses. They bind to the surface of pathogens that are already coated with antibodies. They form a membrane attack complex and put holes in the surface of the bacteria and viruses. Interferons warn the non-infected cells of the virus.
Specific defenses are the secondary line of defense, they work when the nonspecific defenses have failed. They include T cells and B cells we will first talk about the B cells. First the activated B cells undergo clonal selection with the production of the plasma cells and the memory B cells, after the B cell receptor combines with the specific antigen. The plasma cells secrete antibodies and undergo apoptosis. Apoptosis is the process of programmed cell death. The plasma cells are responsible for the antibody mediated immunity. An antibody is usually a y-shaped molecule that has two binding sites for specific antigens. The memory B cells remain in the body and produce antibodies just in case the same antigen enters the body later.
Next I will go over T cells. For the T cells to recognize the antigen the antigen must be presented by the antigen presenting macrophage along with the human leukocyte antigen or HLA. Activated T cells undergo clonal expansion until the illness has been stemmed. The most activated T cells undergo apoptosis a few of the cells remain as memory T cells in case the antigen enters the body again. There are two types of T cells the cytotoxic and helper T cells. The cytotoxic cells kill the virus infected and cancer cells on contact. The helper cells produce cytokines and stimulate the other immune cells.
There are two types of immunity active and passive immunity. Immunity occurs naturally and artificially with medical intervention. Active immunity is usually long lasting. A person produces antibodies against an antigen. Active immunity depends on the memory T cells and the memory B cells. Passive immunity is when a person is given prepared antibodies with an injection. This immunity is temporary. One example is a gama globulin injection. The monoclonal antibodies are produced by plasma cells that are made from the same B cell. This is used to diagnosis certain conditions, to identify infections, and to carry drugs to tumors.
Hypersensitivity reactions are when the immune system responds in a manner that harms the body. Some examples are allergies, tissue rejection, and various immune system disorders. Allergies are hypersensitivities to substances. You usually have some tissue damage with allergens. Immediate allergic reactions can occur, this can happen within minutes. Anaphylactic shock happens when an allergen immediately enters the bloodstream. With this there is a sudden and life threatening drop in blood pressure. There can also be delayed allergic response. Examples of this are TB tests, poison ivy, jewelry, etc. This is initiated memory T cells at the site where the allergen comes in contact with the body.
Next is tissue rejection. The tissue rejection is when the body recognizes that a transplant is not it’s self. Immunosuppressive drugs can reduce the organ rejection. A very common trend is xenotransplantation which is the use of animal parts instead of human parts. Lastly is disorders of the immune system. Some examples are immune deficiency which is when the immune system cannot protect the body against diseases. And autoimmune disease; this occurs when cytotoxin T cells attack the bodies own cells.
The digestive organs are located in the gastrointestinal tract or GI tract. Digestion can be chemical or mechanical. Mechanical digestion is when the food is divided into pieces that can be acted on by digestion enzymes. This type of digestion occurs in the mouth and the stomach. The chemical digestion begins in the mouth and does not end until the food reaches the small intestine. When the mouth takes in food it is called ingestion. The movement of food along the GI tract is very important in order to fulfill the other functions of the body. Absorption of the food happens when molecules, which are produced by the digestion cross wall in the GI tract, enter the cells lining tract. The nutrients then enter the blood to be delivered to the cells for use. Molecules are eliminated when they cannot be digested, this process happens in the intestines.
The GI tract has four layers the mucosa, the submucosa, the muscularis, and the serosa. The mucosa or the mucous membrane produces mucous that protects the wall from the digestive enzymes. The submucosa is a broad band of loose of connective tissues that contain blood vessels, lymphatic vessels, and nerves. These carry the nutrients that are absorbed by the mucosa. The muscularis contains two layers of smooth muscle. The contractions of the muscle causes the movement of the digested food to the anus. The serosa is the serous membrane layer secretes serous fluid. The serosa is part of the internal lining of the abdominal cavity. The appendix is a worm shaped tube projecting from the first part of the large intestine on the right side of the abdomen.
The first part of the digestive tract starts with the mouth. The roof of the mouth has two parts the hard palate and the soft palate. The hard palate is toward the front and the soft palate is toward the back and ends with the uvula. The tonsils help protect against diseases. The tonsils are made of lymphatic tissue. Salivary glands are a big part in digestion, they send the juices. There are three pairs of salivary glands. The first pair of glands are at the sides of the face immediately below and in front of the ears. The second pair of glands are underneath the tongue. The third pair of glands are at the bottom of the oral cavity. Salivary amylase is an enzyme that begins the digestion process for starches.
The mouth and the nasal passages lead to the pharynx and esophagus. The esophagus is a long narrow tube that takes the food to stomach. Peristalsis is a contraction that pushes food along the esophagus. The sphincter is a muscle that acts as a valve. When it is relaxed food is allowed to pass into the stomach.
The stomach is a thick walled J-shaped organ that is located on the left side of the body, just below the diaphragm. The stomach does not absorb nutrients, but it does empty in two to six hours depending on the food eaten. The stomach has four layers. The rugae disappears when the stomach fills up to one liter. The gastric glands produce the gastric juices. The gastric juices contain an enzyme called pepsin that digest proteins and also contains HCl. HCl kills bacteria in the food and activates the pepsin. When the food leaves the stomach it is in a thick liquid form called chyme. Only a small amount of chyme enters into the small intestine at one time.
The small intestine is 18 feet long. It contains enzymes that digest food. The duodenum is the first 25 cm of the small intestine. It acts as a duct by bringing enzymes from the pancreas. The small intestine is where bile breaks down fat from food. The nutrients are absorbed by the villus.
Next we will talk about accessory organs. This includes the pancreas, the liver, and the gallbladder. The pancreas is a fish shaped organ. It is a spongy organ that stretches across the back of the abdomen behind the stomach. It has pancreatic amylase which digests starch, trypsin which digests protein, and lipase which digest fat. The pancreas lets insulin into the blood. The liver is the largest gland and a major metabolic gland. It is located in the upper right section of the abdominal cavity, underneath the diaphragm. The liver removes poisonous substances from the blood and detoxifies them. It removes iron and vitamins A, D, E, K, B12 and stores them for later use. The liver also makes plasma proteins that help regulate cholesterol. The gallbladder is a pear shaped organ that is located below the liver.
The large intestine is larger in diameter but shorter in length than the small intestine. It contains the cecum, the colon, the rectum, and the anal canal. The cecum is the blind end of the large intestine. It has the vermiform appendix which helps fight infections. The colon has the following parts: the ascending which goes up the right side to the liver, the transverse which crosses the abdominal cavity, the descending that passes down the left side, and the sigmoid which enters the rectum. The large intestine absorbs water to help prevent dehydration. It also absorbs vitamins that are produced by bacteria. One of the biggest jobs for the large intestine is to break down indigestible materials.
There are many disorders of the colon and the rectum. Diarrhea is an infection of the lower intestinal tract, constipation, diverticulosis, irritable bowel syndrome, inflammatory bowel disease, and polyps/cancer just to name a few.
Obesity is a very big problem in the United States. Obesity has doubled in the last 20 years, about 1/3 of all adults in the U.S. are obese. Obesity is defined by the body mass index or BMI. A healthy BMI is 19.1 to 26.4, an overweight BMI is 26.5 to 31.1, an obese BMI is 32.3 to 39.9, and a morbidly obese BMI is 40 and over. In order to keep from becoming obese or overweight we just need to eat healthy. We need to have a good balance of carbohydrates, proteins, lipids or fats, vitamins, and minerals.
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