BIOL 100 Section 4

Carbon Dioxide

(CO2) is achieved through the terrestrial biosphere and the ocean. burning coal, oil, natural gas, and wood and since the industrial revolution began in the mid 1700s, each of these activities has increased in scale and distribution. Carbon dioxide was the first greenhouse gas demonstrated to be increasing in atmospheric concentration Today, they are around 370 ppm, an increase of well over 30 percent. In 2010, CO2 accounted for about 84% of all U.S. greenhouse gas emissions from human activities.

Diabetes Mellitus

(DM) is a condition in which the body either does not produce enough, or does not properly respond to, insulin, a hormone produce in the pancreas. In diabetes, the body either fails to properly respond to its own insulin, does not make enough insulin, or both. This causes glucose to accumulate in the blood, often leading to various complications. DM causes irreversible physiological damage, and over time it can disable the patient. DM disease is a worldwide problem and it is the leading cause of death. In the United States, over a million people are affected and this number continues to increase. Several forms of the disease: • Type 1 Diabetes: insulin dependent diabetes mellitus, irreversible • Type 2 Diabetes: insulin independent diabetes mellitus, reversible,affects both obese and nonobese • Malnutrition related: very rare • Gestational Diabetes: reversible, 2-7% of pregnant women develop it -A disease characterized by a chronic high blood glucose concentration and is caused by lack of insulin or insulin resistance.

Macrovascular Disease

(large vessels) disease leads to strokes, cardiovascular disease, renovascular, and peripheral vascular disease. Macrovascular disease is not specific to diabetic patients. -Effects the large vessels; leads to strokes, cardiovascular disease, renovascular disease, and peripheral vascular disease; not specific to diabetic patients.

Microvascular Disease

(small blood vessels) system are affected and cause three common complications: blood supply to the nerves (neuropathy), retina (retinopathy), and renal glomerulus (nephropathy). Some of these complications can be prevented by good medical care, particularly control of blood glucose levels and early detection of health problems.

Diabetes and Obesity

-Blood glucose levels regulated by catabolic hormones (i.e. glucagon): increase blood glucose; & anabolic hormones (i.e. insulin): decrease blood glucose -Obesity can be explained by imbalances between energy intake & expenditure -Diabetes/Obesity treated by pharmacologically (glucose stabilizer), behavioral changes (diet & exercise), or surgically (lapland, gastric bypass, etc) -Diabetes is divided into Type 1 (no insulin production) & Type 2 (cells are not responsive to insulation

Greenhouse Gases

-Global Warming is caused by increases in greenhouse gases -Methane is produced in biosphere -HFCs, PFCs, & SF6 are man made -Carbon dioxide is produced biologically & industrially

HIV/AIDS

-RNA retroviruses use reverse transcriptase to make a DNA copy of their RNA genome -Prevention and testing try to limit spread of HIV -Collapse of immune system (or immune deficiency) allows for opportunistic infections -Collapse of immune system caused by infection and death of CD4 "helper" T cells HIV/AIDS has become a pandemic because it has spread all over the world. 25 to 30 million people have died from AIDS to date. In fact, 5000 people die from AIDS every day, and currently, 1 out of 7 of those deaths are children. This means that 30 children die of AIDS every 30 minutes HIV final stage is known as AIDS (Acquired Immune Deficiency Syndrome) "quiet epidemic" because it affects primarily people in sub-Sahara Africa where the support for prevention and medical care of these millions of afflicted men, women, and children is not available

Drought

-Water Cycle has various components: condensation, precipitation, infiltration, evaporation, transpiration -CO2 & H2O affect pH of ocean -Population depletes limited water sources -Climate Change will cause famine & global migration

Human Activities that Have led to the Emergence of New Diseases

1. Construction of new villages and housing developments in rural areas forces animals to live in dense populations, thus, creating opportunities for microbes to mutate and emerge (antigenic shift). 2. Changes in agriculture such as new crops in certain terrains attract new pests and bring new microbes to farmers. 3. Modern transportation systems harbor unintended passengers that can spread diseases to faraway destinations.

Obesity Treatments

1. Eat sensible portions 2. Eat slowly and stop when you are full 3. Eat whole foods (i.e. apples instead of drinking apple juice) 4. Recognize and control your environment (do not buy large bags of M&Ms and leave them next to you when you are reading this module) 5. Make sure you get at least 30 minutes of physical activity every day 6. Snack between meals (fruits and nuts, not chips and candy) 7. Do not eat in the car or in front of the computer. Sit at a table and look at your food. Do not clean the plate if you are full, save it for later. 8. Keep a record of your food intake and do not skip meals 9. Do not eat out of desperation before finals, instead, study daily, and think twice before overeating.

Steps in HIV Replication Cycle

1. Fusion of the HIV cell to the host cell surface. 2. HIV RNA, Reverse Transcriptase, Integrase, and other viral proteins enter the host cell. 3. Viral DNA is formed by reverse transcription. 4. Viral DNA is transported across the nucleus and integrates into the host DNA with the help of the viral Integrase protein. 5. This viral DNA is then used as a template to make new viral RNA and to make viral proteins. 6. New viral RNA and proteins move to the cell surface and a new, immature, HIV virus forms. 7. The virus matures by protease releasing individual HIV proteins.

Effects of Population Growth

1. It is one of the major drivers for the growth of greenhouse gases. More people more demands on everything run on energy: water, food, clothing, housing, transportation, etc. If the population does not grow too fast, agricultural production loss and an increase in prices will put 90-125 million people at risk of hunger by 2080. 2. The poorest countries and the poorest groups within this population are most vulnerable to climate related hazards such as floods, droughts, and landslides. 3. Poor people will play a major role in deforestation. People need to stay warm, cook their food and possibly sell the timber for food and shelter. Examples are Sierra Leone, Solomon Islands, Rwanda, Uganda 4. Population will impact the world's limited water supply. Experts point to Africa as being one of the continents most impacted by water scarcity. However in the United States, the southwest drought will impact as well 5. Global warming will bring about sea level increase and those change will have a significant effect on the high population density near coastlines. Low elevation zones account for two percent of the worlds land area but contain 10% of the worlds population which is growing fast. 6. Global warming and increase in population will affect women the most. In many societies, women are the providers for water, food, and fuel.

Major Contributions to Carbon Dioxide

1. The carbon cycle as photosynthesis, plants, algae, and cyanobacteria absorb carbon dioxide, light, and water to produce carbohydrates, energy, and oxygen as a waste product. But in darkness, photosynthesis cannot occur, and during the resultant respiration small amounts of carbon dioxide are produced; 2. Carbon dioxide is also produced by combustion of coal or hydrocarbons; 3. The fermentation of liquids (wine!); 4. The respiration of humans and animals; 5. In addition it is emitted from volcanoes, hot springs, geysers and other places where the earth's crust is thin; 6. CO2 is also commingled with oil and gas deposits. -ocean acidification is CO2 which dissolves in water forming carbonic acid, which is a weak acid, because CO2 molecule ionization in water is incomplete.

Predictions

1. Water supplies are projected to become increasingly scarce, calling for trade-offs among competing uses, and potentially leading to conflict. Large reductions in spring precipitation are projected for the Southwest. Continued temperature increases combined with river flow reductions and rapid population growth will increase competition for water supplies. 2. Increasing temperature, drought, wildfire, and invasive species will accelerate transformation of the landscape. 3. Unique tourism and recreation opportunities are likely to suffer. Decreases from 40 to almost 90% are likely in end-of-season snow pack under high emissions scenarios in states with major ski resorts from New Mexico to California. 4. Cities and agriculture face increasing risks from a changing climate. With more intense, longer-lasting heat waves projected to occur over this century, demands for air conditioning are expected to deplete electricity supplies, increasing risks of brownouts and blackouts. Much of the region's agriculture will experience detrimental impacts in a warmer future, particularly specialty crops in California such as apricots, almonds, artichokes, figs, kiwis, olives, and walnuts.

Sources of Methane

1. Wetlands account for 20% of atmospheric methane 2. Ruminant animals such as sheep and cows contain bacteria that break down plant material. As a consequence of this activity, when the animals burps or defecates, methane is produced. 3. Permafrost, which releases methane when it is heated. 4. Rice cultivation, rice is grown in swamp like conditions and contributes, to a large extent, methane production. 5. Landfills (AKA dumps), in the United states are the largest source of methane. 6. Biomass burning, such as burning to clear out land. 7. Natural Gas: Methane is a component of natural gas.

Televisions

A large-screen plasma can produce as much carbon dioxide as a big refrigerator. A plasma TV can draw 400 watts of power which equivalent to about 1,500 pounds of carbon dioxide over the course of a year.

Sedentary Lifestyles

A sedentary lifestyle plays a significant role in obesity. Worldwide there has been a shift towards less physically demanding work, and currently 60% of the world's population gets insufficient exercise. This is primarily due to increasing use of mechanized transportation and a greater prevalence of labor-saving technology. In children there appears to be declines in levels of physical activity due to less walking and physical education. In both children and adults there is an association between television viewing time and the risk of obesity. A study done in 2008 showed that 86% of people studied showed an increased rate of obesity with increase media exposure, with rates increasing proportionally to time spent watching television.

Latency

A strong immune defense reduces the number of viral particles in the blood stream, marking the start of the HIV infection's clinical latency stage. Clinical latency can vary between two weeks and over 20 years. During this early phase of infection, HIV is still active within lymphoid organs. If an activated T cell happens to be infected by HIV, it also is more likely to die by apoptosis but a few of these cells become memory cells. In their resting state, these memory cells do not replicate the virus, but still harbor it as a DNA copy integrated into the chromosomes, the provirus. Latency is broken when the virus starts to proliferate and this occurs when the T cells are stimulated during an antigenic response.

3 Methods of Vaccination

Active artificial (immunization), Passive natural (mother to child), Passive artificial (injection of gamma globulin) -Some individuals develop natural serum antibodies to the surface of some pathogenic agents although they have had little or no contact with the agents, these natural antibodies confer specific protection to adults and are passively transmitted to newborns.

Diabetic Diet ("Plate Diet")

Adherence to a diabetic diet is an important aspect of controlling elevated blood sugar in patients with diabetes. The American Diabetes Association (ADA) has provided guidelines for a diabetic diet. The ADA recommends a "plate approach" to meal planning. Here's how it works: draw a line down the center of your plate. One side of the plate is for "non-starchy vegetables" and the other half is then divided again into two sections, starchy foods and protein foods

Proliferative Retinopathy

After several years, retinopathy progresses to a more serious form called proliferative retinopathy (figure 16). In this form, the blood vessels are so damaged that they close off, and in response, new blood vessels start growing in the retina. As new blood vessels form at the back of the eye, they can bleed (hemorrhage) and blur vision. The new blood vessels can also cause scar tissue to grow, which later shrinks and distorts the retina (retinal detachment). The retina can be badly damaged before the patient notices any changes in vision. Most people with nonproliferative retinopathy have no symptoms and even patients with proliferative retinopathy have sometimes reported no symptoms until it is to late to treat them.

Immunoglobin Proteases

Another group of virulence factors possessed by bacteria are immunoglobulin (Ig) proteases. Proteases are enzymes that break down specific proteins. Remember that Immunoglobulins are antibodies expressed and secreted by hosts in response to an infection. Bacteria such as Streptococcus pyogenes (scarlet fever) are able to break down the host's antibodies by using proteases. These virulence factors allow the bacteria to successfully succumb the host's immunity.

Antibodies

Antibodies constitute about 20% of total protein in blood plasma. Antibodies do not destroy a microbe directly, but bind to a specific antigen on the microbe and signal its presence to the innate immune system. Effectors of the innate immune system (phagocytes and natural killer cells) react to this signal by targeting the specific microbe or infected cell. This cooperation between the adaptive and innate immune systems leads to efficient elimination of the infection -Secreted B-cell receptors that will bind a specific antigen on the surface of a microbe thus marking the microbe for more efficient destruction by effectors of the innate immune system.

Immunosuppressant

Any substance that performs immunosuppression of the immune system such as immunosuppressive drugs taken daily.

Atmosphere

As a gas, it has compressibility and great mobility. It extends well above topographic barriers and can sustain global-scale circulations. A number of forcing factors including radiative heating and cooling, latent heat sources and sinks (reservoirs) due to phase change of water, and variations in Earth's surface temperature give rise to significant temperature variations in all three space dimensions and in time. These temperature variations give rise to horizontal pressure gradient forces approximately consistent with the hydrostatic relationship, which are the basis for horizontal atmospheric motions.

Shortwave & Longer-wave Energy

As the sun's shortwave energy (the visible and ultraviolet portion of the spectra) heats the surface, longer-wave (infrared) energy (heat) from the earth is re-radiated to the atmosphere. Greenhouse gases absorb this energy, thereby allowing less heat to escape back to space, and "trapping" it in the lower atmosphere.

Pathogen Cell Structure

Bacteria are prokaryotes (meaning before a nucleus)and their cells lack internal membrane-bound structures. Fungi and protozoa are eukaryotes (meaning true nucleus) and their cells contain a membrane-bound nucleus as well as other membrane bound structures called organelles. Viruses are acellular (meaning not containing any cells), it is only nucleic acid wrapped in a coat (typically a protein). Multicellular parasites are multicellular organisms that benefits from a host and typically, the parasite is smaller than the host.

Automobiles

Burning one gallon of gas creates approximately 20 pounds of carbon dioxide, and the average car emits about six tons of carbon dioxide every year

Water Cycle & CO2 Cycle

Carbon dioxide can change the pH of water. Recall that pH determines the rate at which chemical reactions can occur. If the pH becomes too alkaline or acidic the reactions stop. Carbon dioxide dissolves slightly in water to form a weak acid called carbonic acid, H2CO3, according to the following reaction: CO2 + H2O --> H2CO3 After that, carbonic acid reacts slightly and reversibly in water to form a hydronium cation, H3O+, and the bicarbonate ion, HCO3-, according to the following reaction: H2CO3 + H2O --> HCO3- + H3O+ This chemical behavior explains why water, which normally has a neutral pH of 7 has an acidic pH of approximately 5.5 when it has been exposed to air. If the carbon dioxide level increases the consequence is that the pH will change influencing the life in the sea.

Respiratory Tract & Bacteria

Cells lining our upper respiratory tract secrete sticky mucus that traps microbes before they can reach the warm, moist areas deep in our lungs that make such ideal breeding grounds. Cilia on the cells lining sweeps the mucus and any microbe upwards where it can be removed through coughing, sneezing, or swallowing (where the acidic medium of the stomach will eliminate them).

Antigen Presenting Cells (APCs)

Cells such as macrophages that present a fragment of microbial antigen on their cell surface in order to activate B and T cells.

CDC

Centers for Disease Control and Prevention (http://www.cdc.gov/).

Medical and Psychiatric Illness

Certain physical and medical illnesses and the pharmaceutical substances used to treat them can increase the risk of obesity. Medical illnesses that increase obesity risk include several rare genetic syndromes as well as some congenital or acquired conditions, such as hypothyroidism (which produces low thyroid hormone which leads to lower metabolic rate), Cushing's syndrome (which exposes body tissues to high levels of hormone cortisol), and the eating disorders, such as binge eating and night eating syndrome. Certain medications may cause weight gain or changes in body composition, these include antipsychotics, antidepressants, steroids, anticonvulsants, and some forms of hormonal contraception.

Kaposi Sarcoma

Classic Kaposi's sarcoma is typically limited to elderly men from the Mediterranean region, or of Eastern Europe descent. However, in 1981 an unusual cluster of Kaposi Sarcoma in young homosexual men was observed and this event brought AIDS to clinical attention. These are diseases that people with a normal immune system can also get, but with HIV they occur at a much higher rate. It also takes longer for a person with HIV to recover than it takes for someone with a healthy immune system.

Climate System

Climate system is affected by Ocean, Biosphere, Land/Ice/Snow surface, & Atmosphere. The predictions are that the heating of the globe will cause climate change throughout the world. The climate system is similar to any other system you have studied and it have has five major components. (a) Atmosphere; (b) Ocean; (c) Land surface; (d) Ice and snow surfaces (both land and ocean areas); (e) Biosphere (both terrestrial and marine).

Turbulent Combustion (Gas Turbines)

Combustion resulting in a turbulent flame is the most used for industrial application (e.g. gas turbines, gasoline engines, etc.) because the turbulence helps the mixing process between the fuel and oxidizer.

Hypoglycemia

Develops when the blood glucose level falls extremely low.

Hyperglycemia

Develops when there is an excess amount of glucose in the blood.

Natural Immunological Tolerance

During development, T and B cell clones that would respond to self-antigens are eliminated or suppressed. Thus, the only clones that circulate are those that are directed at non-self antigens. Sometimes natural tolerance breaks down spontaneously, allowing B and/or T cells to attack unnecessarily. -A process when the body does not mount an immune response to self antigens.

Phagocytosis

During phagocytosis, flowing cytoplasmic extensions engulf the microbe. Then, the phagocyte uses lysozyme and other chemicals to destroy the microbe.

Sun/Radiation

Electromagnetic wave energy transfer (radiation) accounts for nearly all energy transfer from the sun, and is the primary source of energy for the atmosphere and the entire climate system. For energy to reach the world it has to be radiant. The other means of heat transfer are conduction and convection both of which would not work in outer space. For the earth to maintain a steady climate the radiant heat from the sun must equal the radiant heat emitted by the globe. Incoming radiant heat must equal outgoing radiant heat.Such transfer is also the only way in which significant amounts of energy can leave the climate system. The primary human impact on the energy balance is to alter the radiative properties of the atmosphere with respect to these two energy streams. This effect far out-shadows other anthropogenic (human) energy sources and sink effects such as the heating due to combustion and nuclear processes. There are two primary forms of radiation relevant to the energy balance properties of the climate system: solar or short-wave form predominant in the radiation from the sun & terrestrial or long-wave type predominant in the radiation emitted by matter in the climate system

Endothelial Cells

Endothelial cells that make up the capillary walls will capture immune cells such as phagocytes as they pass by a site of tissue infection.

Epidemiology

Epidemiologists attempt to determine what factors are associated with diseases (risk factors), and what factors may protect people or animals against disease (protective factors). The science of epidemiology was first developed to discover and understand possible causes of contagious diseases like smallpox, typhoid and polio. Diagnosis of an infectious disease involves identifying the infectious agent either directly or indirectly. -is the study of diseases in populations of humans or other animals, specifically how, when and where they occur.

Stratosphere

Even if it is not destroyed in the troposphere, methane can usually only last 12 years before it is eventually destroyed in Earth's next atmospheric layer: the stratosphere. Destruction in the stratosphere occurs the same way that it does in the troposphere: methane is oxidized to produce carbon dioxide and water vapor.

Consequences of Obesity

Excessive body weight is associated with various diseases, particularly cardiovascular diseases, type 2 DM, obstructive sleep apnea, certain types of cancer, and osteoarthritis. As a result, obesity has been found to reduce life expectancy. Studies have shown that obese men have a greater risk of developing colon, rectum, and prostate cancer and obese women are more likely to develop gallbladder, uterus, cervix, and ovarian cancer. Other diseases associated with obesity are gallbladder disease, gallstones, fatty liver disease, gastroesophageal reflux, gout, and reproductive problems in women. Obesity does not only cause physiological disorders, but also psychological and social disorders. Obesity can have a devastating psychological impact, especially in children. As a technology-advanced society, we are obsessed with perfection and the media reminds us of it constantly. We associate beauty and perfection with physical appearance: slimness and genetic makeup. Obese and overweight people are often discriminated and ridiculed. Obese individuals complain they are treated differently, ridiculed in public, perceived as dumb, lazy, and not accepted as a normal citizens. Depression, shame, and feelings of rejection are the typical symptoms of psychological damage. Unfortunately, these feelings can make it more difficult to lose weight since they eat more food to comfort themselves and become more secluded.

Primary Forcing of the Ocean

First, the primary forcing of the ocean is at the upper boundary, whereas the primary forcing for the atmosphere is at its lower boundary. Atmospheric winds above the ocean are a major factor in causing ocean surface currents through surface friction processes. In contrast, for the atmosphere frictional conditions at its lower boundary tend to reduce atmospheric motion.

Travel

Flying non-stop round trip from Boston to Wichita creates about 1,400 pounds of carbon dioxide emissions, but the total impact is actually twice that, due to other gases, the contrails, and the altitude at which the carbon dioxide is emitted. Since the plane is already at high altitudes, the carbon dioxide that it emits is directly injected into the atmosphere.

Gastrointestinal Diseases

Gastrointestinal diseases are often acquired by ingesting contaminated foods.

Lentivirus

HIV is a Lentivirus (a specific type of Retrovirus). Lentiviruses have biological properties that are responsible for long-duration illnesses with a long incubation period. This means that symptoms of the disease may not become evident for years after the initial infection.

Retrovirus

HIV is a Retrovirus, which means that it is a virus with an RNA genome that uses Reverse Transcriptase to make a DNA copy of its RNA genome (This is the opposite of the first step of the Central Dogma). This DNA copy of the genome is then integrated into the host's cells DNA.

Heating a House

Heating a house produces about four tons of carbon dioxide per year on a national average, in addition to eight tons for electricity use.

Humans Interfere in Water Cycle

Human activities interfere with the water cycle in the three following ways: by drawing large amounts from surface sources and groundwaters, by polluting water, and by removing or damaging the world's forests. Water covers 71% of the Earth and makes up at least 60% of living cells, but only 0.014% is available for people's use. Yet humans continue to waste water, pollute it, or otherwise treat it as if it were free.

Family Planning

In the long run, it would be cheaper to finance family planning rather than inventing or enhancing technological changes to generate solar energy, capture and store carbon dioxide. As a consequence it would also be more effective in minimizing global warming. However, religious, cultural, and social norms will make it very difficult to slow the human population explosion, especially in developing countries.

Incomplete Combustion (in Thermal Power Plants)

Incomplete combustion will only occur when there isn't enough oxygen to allow the fuel to react completely to produce carbon dioxide and water. It also happens when the combustion is quenched by a heat sink such as a solid surface or flame trap. For most fuels, such as diesel oil, coal or wood, pyrolysis (thermo-chemical decomposition of organic material) occurs before combustion. In incomplete combustion, products of pyrolysis remain un-burnt and contaminate the smoke with noxious particulate matter and gases. The quality of combustion can be improved by design of combustion devices, such as burners and internal combustion engines. Further improvements are achievable by catalytic (change in rate of a chemical reaction) after-burning devices (such as catalytic converters) or by the simple partial return of the exhaust gases into the combustion process. Such devices are required by environmental legislation for cars in most countries, and may be necessary in large combustion devices, such as thermal power plants, to reach legal emission standards.

Drought & Population Growth (Biological concept: Reproduction)

Interestingly most articles that deal with global warming do not address the issue of reproduction. If the conditions become too harsh than the rate or reproduction may decrease; however in poor countries, the rate of reproduction is high.

Genetics

Like many other medical conditions, obesity is the result of an interplay between genetic and environmental factors. Polymorphisms in various genes controlling appetite and metabolism predispose to obesity when sufficient calories are present.

Major Histocompatibility Complex (MHC)

MHC molecules play a crucial role in the response of T cells to antigens that penetrate or live inside cells of the body. MHC molecules bind to amino acids derived from proteins and present them to T cells with the appropriate receptor. Thus, T cells responses are said to be MHC restricted. The MHC codes for two major categories of cell surface transmembrane molecules, MHC class I and class II molecules. (both of these are known as APCs-antigen presenting cells) Each person has unique & distinct array of MHC class I and class II molecules. This diversity comes about because different individuals within a species have a range of slightly different forms of MHC class I, and class II genes. However, an individual expresses the same MHC class I and II molecules in all his/her cells, and expresses them at the cell surface.

Microphage

Macrophages will engulf anything that is not normal including cell debris, dust particles, invading microbes, and cells infected by microbes. Macrophages are motile and can move through your blood and tissues searching out and destroying invading microbes -phygocytic cell, antigen presenting cells

Microbes

Microbes that enter the bloodstream stimulate an immune response in the spleen.

Microscopy

Microscopy may be carried out with the compound light microscope. Microscopy is often also used in conjunction with biochemical staining techniques. Biochemical tests used in the identification of infectious agents include the detection of metabolic or enzymatic products characteristic of a particular infectious agent. The isolation of enzymes from infected tissue can also provide the basis of a biochemical diagnosis of an infectious disease. For example, humans do reverse transcriptase so the presence of this enzyme is characteristic of specific viral infection.

Nitrous Oxide

Natural sources of N2O (Nitrous oxide) are estimated to contribute about 64% of the total inputs to the atmosphere. The largest sources of natural N2O emissions are soils (contributing 6.6 Tg N/yr) and oceans, rivers, and estuaries (contributing 5.4 Tg N/yr). However, there is some controversy as to what fraction of the emissions associated with rivers and estuaries should be considered natural source emissions, as they are driven primarily by anthropogenic contributions of nitrogen to the water bodies (e.g., from agricultural runoff) Global average atmospheric concentrations of N2O have increased from about 270 parts per billion by volume (ppbv) in 1750 to 314 ppb in 1998, which equates to a 16% increase for the period.

Population & Global Warming

One of the great drives for biological systems is to reproduce. Humans have the means to control their rate of reproduction but many factors influence their decision. In 2012, the population passed 7 billion. In thirty eight years we have more tripled the entire world population with people producing carbon dioxide from the Krebs Cycle, their cars, their industries, and cattle. What is interesting is that the nations continued to grow. By the year 2043, the world population will be billion. (what number do you want to put here?) Part of the reason that the societies did not collapse was due to more scientific ways to raise crops and population control. Birth control in poor countries is not administered well, cultural differences, etc. for example, Nigeria only 8% of the women use birth control vs 72% in the USA. By 2050, Nigeria might exceed the United state in terms of population. According to some experts, three billion people are under the age of 25 and are entering child bearing year. China is #1 with 1.339 Billion, India is #2 with 1.184 Billion, USA is 309,975 Million.

Forests & Transpiration

Plants and trees possess special cells on the underside of their leaves, called guard cells, that release water vapor from the plant into the atmosphere. The transpiration process begins when trees draw water from the soil through their roots and transport it upward in vessels—xylem carries water and nutrients upward and phloem distributes water and nutrients throughout the plant. Trees, depending on size and species, transpire from 5,000 gallons to almost 50,000 gallons of water per year, more in warmer weather and less in colder weather. Low relative humidity and increased air movement caused by wind or breezes also increase the transpiration rate. During drought or in the desert where only drought-tolerant plant life lives, a tree's transpiration rate decreases so that it can conserve water. When soil moisture levels are low, as in drought, trees slow their transpiration rate to conserve water. Trees undergoing the normal aging process, called senescence, give way to new trees ready to take their place. Prolonged drought, however, puts all trees into a premature senescence, an event that may eventually kill a forest.

Types of Combustion

Rapid (explosive weapons), Complete (industrial applications), Incomplete (in thermal power plants), Smoldering (in residential fire), Turbulent (gas turbines)

Antibiotics

Since then wound infections, gonorrhea, tuberculosis, pneumonia, septicemia, and childhood ear infections have been treated with antibiotics, but in response these pathogens have become resistant to a lot of antibiotics and are becoming more difficult to treat. One part of the problem is that bacteria and other microbes that cause infections are remarkably resilient and have developed several ways to resist antibiotics and other antimicrobial drugs. Another part of the problem is due to increasing use for unnecessary health problems and misuse in veterinary medicine and in agriculture. The top 3 disease killers are HIV, Tuberculosis (TB), and malaria. Although, the overall number of deaths due to nearly every disease has decreased, deaths due to HIV/AIDS have increased fourfold. HIV is considered a pandemic.

Carbon Offsets

Since we cannot completely reduce our carbon dioxide production (aka carbon footprint) by reducing the amount of fuel and energy we consume we can compensate for this production by having offsets. A carbon offset is a reduction of carbon dioxide or other greenhouse gases made in order to compensate for or to offset a greenhouse gas emission made elsewhere Carbon offsets are measured in metric tons of carbon dioxide-equivalent (CO2e) and may represent six primary categories of greenhouse gases which include: Carbon dioxide (CO2), Methane (CH4), Nitrous oxide (N2O), Perfluorocarbons (PFCs), Hydrofluorocarbons (HFCs), and Sulfur Hexafluoride (SF6). One carbon offset represents the reduction of one metric ton of carbon dioxide or its equivalent in other greenhouse gases.

Smoldering Combustion (in Residential Fire)

Smoldering is the slow, low-temperature, flameless form of combustion, sustained by the heat evolved when oxygen directly attacks the surface of a condensed-phase fuel. Common examples of smoldering phenomena are the initiation of residential fires on upholstered furniture by weak heat sources (e.g., a cigarette, a short-circuited wire), and the persistent combustion of biomass behind the flaming front of wildfires.

Waterless Toilet

Some countries have already entered a dangerous condition known as water stress, meaning their water requirements exceed the water they have available. A solution that addresses this issue is the waterless toilet. Toilets require a huge infrastructure of water, sewage treatment plants and electricity. The Melinda Gates Foundation awarded a major grant to University of California which demonstrated a prototype waterless toilet that generated hydrogen gas and electricity every time it was flushed. It might not be the most creative solution to water shortage but consider that 2.5 billion people in the world do not have access to toilets which lead to major illness.

Civilizations & Drought

Some scientists contend that climate changes may have had a more profound effect on the stability of past societies. Climate change may not have been the only force that caused the toppling of old societies but it played a critical role.

Atmospheric Methane

The 100-year global warming potential of methane is 29[3] (i.e., over a 100-year period, it traps 29 times more heat per mass unit than carbon dioxide and 32 times the effect when accounted for aerosol interactions.[4]) Global methane levels, had risen to 1800 parts per billion (ppb) by 2011, an increase by a factor of 2.5 since pre-industrial times, from 722 ppb, the highest value in at least 800,000 years

Body Mass Index (BMI)

The BMI compares a person's weight and height. Though it does not actually measure the percentage of body fat, it used to estimate a healthy body weight based on how tall a person is. BMI is defined as the individual's body weight divided by the square of his or her height. This is a widely used diagnostic tool to identify weight problems within a population, usually whether individuals are underweight, overweight or obese. A typical BMI chart, which display BMI as a function of weight (horizontal axis) and height (vertical axis) using contour lines for different values of BMI or colors for different BMI categories.

Albedo

The albedo (reflectivity) of sunlight from the Earth's surface is indicative of (inversely related to) the absorption of radiation by that surface. A surface with a high albedo (high visible brightness) is heated much less than one with a low albedo (low visible brightness). At the Earth's surface, the albedo ranges from about five percent for ocean surfaces (with the sun high in the sky) and the top surface of dark thick coniferous forests to 90% for fresh snow.Thick clouds in the atmosphere can also have an albedo nearly as high as fresh snow. Since much of the reflected and back scattered solar radiation travels back out to space, it is never converted to heat in the climate system.

Hot Tub

The average hot tub, uses about 2,300-kilowatt hours per year, producing more than 3,000 pounds of carbon dioxide.

Electricity

The combustion of fossil fuels to generate electricity is the largest single source of CO2 emissions in the nation, accounting for about 40% of total U.S. CO2 emissions and 33% of total U.S. greenhouse gas emissions in 2009. The type of fossil fuel used to generate electricity will emit different amounts of CO2. To produce a given amount of electricity, burning coal will produce more CO2 than oil or natural gas.

Transportation

The combustion of fossil fuels. such as gasoline and diesel to transport people and goods is the second largest source of CO2 emissions, accounting for about 31% of total U.S. CO2 emissions and 26% of total U.S. greenhouse gas emissions in 2010. This category includes transportation sources such as highway vehicles, air travel, marine transportation, and rail.

Penicillin

The first antibiotic was discovered in 1929 by Sir Alexander Fleming, who observed inhibition of staphylococci on an agar plate contaminated by a Penicillium mold (Fig.15). Fleming called it penicillin. He noticed that a patch of the mold Penicillium notatum had grown on a plate containing the bacterium Staphylococcus and that around the mold there was a zone where no Staphylococcus could grow. After more research, he was able to show that culture broth of the mold prevented growth of the Staphylococcus even when diluted up to 800 times.

Reverse Transcriptase

The function of Reverse Transcriptase is to synthesize DNA, using HIV's RNA genome as a template after cell infection has occurred.

Drought & Energy (Biological Concepts: Comfort, Business, Temperature regulation)

The human race needs energy to power its current culture. Cars need gasoline, houses need air conditioning, computers need electricity. From a biological point of view, water is used to generate electricity along with nuclear power. Without electricity and gasoline, our culture would collapse The biological basis of energy demand in a hot environment is to maintain the human body in a range of normal. Cold air and cold water are essential for minimizing hyperthermia.

Inhaled Insulin

The insulin is packaged and then inserted into an inhalation device. The device lances the powder packs allowing the insulin to enter a chamber that has a mouth piece through which the user can inhale the insulin. This type of insulin is very short acting and thus in patients with type 1 DM, the insulin should be combined with a longer acting basal insulin.

Glucose Metabolism

The liver is responsible for glucose metabolism. It absorbs, and produces/stores glucose in the form of glycogen, which is released into the blood stream slowly between meals and this process is known as gluconeogenesis The liver produces more than 90% of the needed glucose and the remainder comes from renal gluconeogensis (in the kidneys). The rate of glucose utilization by peripheral tissues must match the rate of glucose production to maintain homeostasis. The average person produces about 200g glucose daily and the brain alone utilizes about 100 g every day. The uptake of glucose by the brain is mandatory and does not seem to directly depend on insulin

Troposphere

The most effective sink of atmospheric methane is the hydroxyl radical in the lowest portion of the earth's atmosphere, known as the troposphere. As methane rises into the air, it reacts with the hydroxyl radical to create water vapor and carbon dioxide. The lifespan of methane in the atmosphere was estimated at 9.6 years as of 2001; however, increasing emissions of methane over time reduce the concentration of the hydroxyl radical in the atmosphere.

Diet

The per capita dietary energy supply varies markedly between different regions and countries and has changed significantly over time. From 1971 to 2000, obesity rates in the US increased from 14.5% to 30.9%. During the same period, an increase occurred in the average amount of calories consumed. As societies become increasingly reliant on energy-dense, big portion, fast-food meals, the association between fast-food consumption and obesity becomes more concerning. In the US alone, consumption of fast-food meals tripled and calorie intake from these meals quadrupled between 1977 and 1995.

CD4

The primary target cell of HIV are cells that express the CD4 (complementary determinant 4) protein on their cell surface, mainly cells of the immune system such as 'Helper' T cells (also known as CD4 T cells) and some brain cells. CD4 interacts with the gp120 protein on the virus to create a firm attachment of the virus to the host cell.

Neuropathy

The term refers to pain in the nerves or damage to the nerves.

Forests & Water Storage

Trees act as a watershed by absorbing water during floods and storing and slowly releasing water in times of low rainfall. Surface waters, groundwaters (or aquifers), and plant life comprise the Earth's total watershed. Part of trees' role in the watershed involves regulation of the water table, which is the area underground where water has completely filled the spaces between rocks and soil particles. Beneath the water table lies an area of higher density where all the air has been squeezed out to make room for water. This location, called the zone of saturation, holds water undisturbed for longer periods than the water table. Therefore, water moves through three layers in the earth: the upper unsaturated zone, where soils hold varying amounts of moisture (also called the soil zone); the water table, where water exchanges from the saturated layer below to the unsaturated layer above; and the zone of saturation. Tree roots pull water from either the unsaturated zone or the water table. If the water tables are decreasing, then the plants that depend on that source of water will die.

DM Treatments

Type 1 DM is treated with insulin, exercise, and a diabetic diet. Type 2 DM is treated first with weight reduction, a diabetic diet, and exercise. When these measures fail to control the elevated blood sugars, oral medications are used. If oral medications are still insufficient, treatment with insulin is considered. Weight reduction and exercise increase the body's sensitivity to insulin, thus helping to control blood sugar elevations.

Biosphere

Vegetation on the land surface and both plant and animal life in the oceans are all relevant elements of the biosphere component that interact with the atmosphere. Climate conditions of the atmosphere have a direct effect on the type of terrestrial plant growth at the Earth's surface. The nature of the plant cover in turn feeds back on the atmospheric condition by influencing the sensible and latent energy transfers from a land surface, as well as surface layer turbulence in the atmosphere (through its roughness properties). Furthermore, land vegetation is a significant reservoir for carbon with a total carbon content nearly equal to that in the atmosphere. Changes in the amount of land vegetation due, for instance, to forest cutting and burning or simply seasonal changes have a direct impact on the carbon dioxide concentration in the atmosphere. Along with dissolved inorganic carbon and calcium carbonate solids, plant and animal life have key roles in the ocean, in the carbon cycle which influences the concentration of the greenhouse gas, and carbon dioxide in the atmosphere and results in a loss of carbon due to sedimentation of carbonates at the ocean bottom.The interactions between the biosphere and atmospheric climate have produced a record of past climate conditions. Tree rings, fossil patterns, pollen counts in ocean and lake bottom sediments, and coal and oil deposits are records which give us information on past climates. Humans, themselves, are members of the biosphere. Humans alter the biosphere directly by agricultural and forestry activities and indirectly by altering the climate system in which the biosphere exists. It is important to understand these various impacts of human activity in order to understand climate change. The biosphere must be included in the climate system analysis in order to understand climate change. It is a component that interacts with other climate system components, and is the component where the effects of climate change will be clearly evident to people.

Viruses

Viruses are microscopic parasites that can reproduce only inside a host cell. Some consider viruses amazing cellular "terrorists" since they infect and kill the cell by taking over the DNA molecular systems in the infected cells. They can infect all types of organisms: animals, plants, and bacteria. Consist of two basic components: the genome, a core of genetic material (DNA or RNA), and the capsid, a surrounding protein coat that protects the genome

Water Vapor

Water vapor is the most abundant greenhouse gas, followed by carbon dioxide,methane, nitrous oxide and synthetic ones. The synthetic ones are chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs) and Perfluorocarbons (PFCs), as well as sulfur hexafluoride (SF6). -by-product of respiration in plants and animals. - 4% over oceans. Approximately 99.13% of it is contained in the troposphere. Water vapor is also the most potent greenhouse gas owing to the presence of the hydroxyl bond which strongly absorbs in the infra-red region of the light spectrum.

Drought & Transportation (Biological concepts: comfort, business)

We have designed better ways to carry our goods, ourselves, and our family.

Cytokines

White blood cells cells communicate and coordinate their actions through the release of chemical signals called cytokines. signaling molecules (a type of hormone) that coordinate the other immune system cells' response, without this coordination, the immune system would not be able to function correctly

WHO

World Health Organization (http://www.who.int/en/).

Type 1 DM

a chronic progressive autoimmune disease that leads to the lack of insulin production. This type of DM is most common in children and identification of autoantibodies in the general population can predict type 1 diabetes. The following symptoms are signs of type 1 DM: 1. polyuria (frequent urination) 2. Thirst (due to loss of fluids) 3. Weight loss (due to rapid breakdown of fat and muscle) -A chronic progressive autoimmune disorder that leads to lack of insulin production.

Microbial Culture

a growth medium is provided for a specific agent.

Gluconeogenesis

a metabolic pathway that results in the generation of glucose from non carbon sources, such as fat, glycogen, and protein.

Nephropathy (The Diabetic Kidney)

a progressive kidney disease caused by blockage of capillaries in the kidney glomeruli. Kidney failure provoked by these blockages leads to fluid filtration deficits and other disorders. There is an increase in blood pressure and fluid retention in the body. Proteinuria, or high amounts of protein in the urine, is the hallmark of diabetic nephropathy. These symptoms eventually lead to renal failure. Patients with type 1 DM develop nephropathy more frequently than type 2 DM patients. It is important for DM patients' urine to be tested annually for protein since at the beginning of the disease there might be no symptoms. Renal transplant is the treatment of choice and usually the donor is a relative. However, a transplant is not possible for many patients, and the usual method continues to be ambulatory peritoneal dialysis (CAPD). The patient receiving dialysis needs it 3 to 5 times a week depending on their condition. The procedure takes about 3-5 hours, and it is slightly painful, but patients become accustomed to it. -The term that describes kidney disease or damage to the kidney.

Endotoxin

a toxic heat-stable lipopolysaccharide substance present in the outer membrane of gram-negative bacteria that is released during lysis of bacteria. -are toxins associated with certain bacteria. Typically and endotoxin is not secreted by live bacteria, but is a structural component of the bacteria, which is released mainly when bacteria are lysed.

Epidemic

affecting a disproportionately large number of individuals within a population.

Immunological Memory

after T-cells have been activated and proliferate in an immune response to a particular antigen, most die by apoptosis as the response to that antigen wanes. However, some of the cells do not die, instead they remain for a long time in the body so that they can respond promptly to a second exposure to the same antigen. This is called immunological memory and is why the response to the second encounter with an antigen is more rapid than the primary response. The T cells that remain after the antigen are called memory T cells. Memory T cells can survive for decades.

Water Cycle

also called the hydrologic cycle, operates similarly to other biogeochemical cycles in which the chemicals associated with plant and animal nutrients move through the atmosphere, the earth, and through living things and repeat the cycle. The water cycle includes water in the forms of solid, liquid, and gas with the Sun providing the energy to power the continuous cycle of water among these three forms. The largest component of the water cycle occurs in oceans, bays, lakes, ponds, rivers, and streams. The ocean covers most of the Earth's surface and so contributes the largest share to the water cycle; more than 85% of the water that evaporates from the Earth's surface into the atmosphere does so from the ocean. About 80% of the world's precipitation enters oceans.

Blood Glucose Levels

amount of glucose present in the blood of a human. Normally in mammals the blood glucose level is maintained at a reference range between 3.6 and 5.8 mM. It is tightly regulated as a part of metabolic homeostasis. Glucose levels rise after meals for an hour or two by a few grams and are usually lowest in the morning, before the first meal of the day. Transported via the bloodstream from the intestines of liver to body cells, glucose is the primary source of energy for body's cells, fats and lipids being primarily a compact energy store.

Glucose

an important molecule needed for human survival. Glucose is our source of energy and several body organs are involved in its regulation to maintain homeostasis.

Autoimmune Disorders

arise when the immune system attacks its own body. While the embryonic immune system will respond to both self and nonself molecules, as the individual matures, the immune system learns to recognize the difference between self and nonself markers. i.e.: type I diabetes mellitus, rheumatoid arthritis, multiple sclerosis, lupus, allergies, and myasthenia gravis. Exactly what triggers an autoimmune disease is not known, but women are more often affected than men. -Failure of an organism to distinguish between self and non-self so that the immune system attacks its own body.

Greenhouse Effect

cause of global warming is the greenhouse effect which is the heat absorption by certain gases in the atmosphere which effectively "trap" heat in the lower atmosphere and re-radiation downward of some of that heat. Without a natural greenhouse effect, the temperature of the Earth would be about 0°F (-18°C) instead of its present 57°F (14°C).

Retinopathy (The Diabetic Eye)

causes abnormality in the tiny blood vessels nourishing the retina. As the vessels weaken, they leak fluid and blood, failing to provide nutrients necessary for good health in the retina. This damages the retina, which can eventually lead to blindness. It affects up to 80% of all patients who have had DM for 10 years or more. Despite these intimidating statistics, research indicates that at least 90% of these cases could be reduced if there was proper and vigilant treatment and monitoring of the eyes. two forms of diabetic retinopathy: nonproliferative and proliferative. -A complication that causes abnormality in the tiny blood vessels nourishing the retina.

Megadroughts

changes in Colorado River flows indicate that drought is a frequent feature of the Southwest, with some of the longest documented "megadroughts" on Earth.

Warming Trend

climate models point to a warmer planet due largely to greenhouse gases. This warming trend will create extremely dry conditions across western North America as global winds and atmospheric pressures respond to the warming. Scientists have detected a relationship between warming and drought in western North America by analyzing trends over the last 100 years. From a common sense point of view, they documented that frequent drought and low precipitation events observed are associated with increasing temperatures across the Northern Hemisphere. More heat, less water due to evaporation and human use.

Causes of Obesity

combination of excessive caloric intake and a lack of physical activity is thought to explain most cases of obesity. A limited number of cases are due primarily to genetics, medical reasons, or psychiatric illnesses. A recent review article identified other possible contributors to the recent increase of obesity: (1) Insufficient sleep (2) Endocrine disruptors (environmental pollutants that interfere with fat metabolism) (3) Decrease variability in ambient temperature (4) Decreased rates of smoking (smoking suppresses appetite) (5) Increased use of medications that cause weight gain

Insulin Pump

composed of a pump reservoir similar to that of an insulin cartridge, a battery operated pump, and a computer chip that allows the user to control the exact amount of insulin being delivered. Currently, pumps on the market are about the size of a pager or beeper. The pump is attached to a thin plastic tube that has a cannula (like a needle but soft) at the end through which insulin passes. The cannula is inserted under the skin, usually on the abdomen and is changed every two days. The pump is used for continuous insulin delivery, 24 hours a day. It allows the user to program many different basal infusion rates to allow for variations in lifestyles. In addition, the user can program the pump to deliver additional insulin during meals to cover the excess demands for insulin caused by the ingestion of carbohydrates with the meal.

Ocean

covers approximately 71 percent of the Earth's surface and thus has a dominant role for transfers of energy and other properties between the atmosphere and the Earth's surface. Its large heat capacity, made accessible for surface energy transfers by circulations within the ocean, provides a moderating effect on temperature variability in the atmosphere. Oceanic currents transfer large amounts of heat energy away from equatorial regions. Finally, the ocean is an important source for atmospheric water vapor, as well as a source and sink for other greenhouse gases.However, the oceanic condition is different from the atmosphere in two fundamental ways.

Ocean Density

density of the ocean water is determined primarily by its salinity and temperature instead of pressure, temperature and water vapor content as in the atmosphere.The oceans play a significant role as a source and sink for atmospheric gases, including greenhouse gases. Changes in ocean temperature can change the holding capacity for gases and can result in a net outflow or intake from the atmosphere. Particularly noteworthy is the case for carbon dioxide. It is estimated that the carbon dioxide dissolved in the upper layers of the ocean is nearly 50 percent more than the total amount in the atmosphere (1020 versus 750 gigatons of carbon content). Thus, there is much potential for effects on the atmospheric carbon dioxide concentrations and the resulting radiation impacts due to changes in the ocean.

Passive Artificial (Injection of Gamma Globulin)

develops immediately, is temporary, and affects all antigens to which the donor has immunity.

Passive Natural (Mother to Child)

develops immediately, is temporary, and affects all antigens to which the mother has immunity.

Active Artificial (Immunization)

develops slowly, lasts for several years, and is specific to the antigen for which the immunization was given.

Diabetic Foot

diabetic neuropathy disorder symptoms may include: • Decreased sensitivity to pain • Hypersensitivity to pain • Numbness • Tingling • Shooting, burning or electric pains •Cold feet/ inability to judge temperatures •Foot ulcers •Infections •Muscle and bone deformities The diabetic foot is caused by damage to blood vessels and impairment of the immune system, which makes it difficult to heal these wounds. Bacterial infections can develop into gangrene. Because of poor blood flow, antibiotics cannot get to the site of the infection easily. Often, the only treatment for this is amputation of the foot or leg. For this reason DM patients must be fully aware of how to examine their own feet in order to prevent foot problems.

Alexander Fleming

discovered the world's first antibiotic Penicillin in 1928 and discovered the lysozyme in 1923.

Endemic

disease usually found in a particular people or country.

Helper T Cells

do not have cytotoxic or phagocytic activity. Instead, they are helpers to the immune response by directing other cells to perform these tasks. This management is absolutely critical. Without helper T cells, an individual cannot mount an adaptive immune response. As with B-cells and cytotoxic T-cells, helper T-cells become activated once they find and bind their matching antigen. However, helper T-cells usually find their antigen through the assistance of macrophages. Helper T cells bind their matching antigen presented on the macrophage and secrete cytokines.

Drought in Southwest America

droughts of this length and severity will be commonplace through the end of the century unless human-induced carbon emissions are significantly reduced. Indeed, assuming business as usual, each of the next 80 years in the American West is expected to see less rainfall than the average of the five years of the drought that hit the region from 2000 to 2004. The report puts the increase in global warming as a function of mankind- calling it anthropogenic climate change along with natural variability. Anthropogenic means that it was caused by humans.

Methane

effective absorber of radiation, though its atmospheric concentration is less than CO2 and its lifetime in the atmosphere is brief (10-12 years), compared to some other greenhouse gases (such as CO2, N2O, CFCs). Methane (CH4) has both natural and man made (anthropogenic) sources. It is released from swamplands or in rice production. Over the last 50 years, human activities such as growing rice, raising cattle, using natural gas and mining coal have added to the atmospheric concentration of methane. Natural sources of CH4 are estimated to produce 37 percent of the total CH4 flux into the atmosphere every year. The largest source of natural CH4 emissions is natural wetlands, which contribute 170 Tg CH4/yr (per year). Several other sources contribute substantially as well, including geologic emissions (now estimated at 42 to 64 Tg CH4/yr), lakes (estimated at 30 Tg CH4/yr), and vegetation (which potentially contributes 20 to 60 Tg CH4/yr)

Terrestrial (Long-Wave) Radiation

emitted and absorbed by material substances in the climate system. The Earth's surface and clouds have radiative properties that tend to produce the maximum amount of terrestrial radiation given by "black body" values and to absorb incident terrestrial radiation completely. On the other hand, the radiation emission and absorption characteristics of atmospheric gases have a large variability depending on wavelength. The strongest effects are exhibited by minor constituents in the atmosphere: water vapor, carbon dioxide, ozone, nitrous oxide, and methane. These gases occur naturally and are known as "greenhouse gases". The "greenhouse gas" radiative properties just noted are much more pronounced for terrestrial radiation than for solar radiation.On a globally-averaged basis the observed surface temperature is about 33K above the 255K expected with no atmosphere at all. This enhancement value would be even greater (over 80K) if radiative effects for the clear atmosphere were the only modifying factors [Manabe and Strickler, 1964]. Sensible and latent heat fluxes from the Earth's surface to the atmosphere along with atmospheric convection partially offset the surface temperature enhancement due to radiation transfer back from the atmosphere.A basic aspect of radiation forcing is the systematic variation with latitude. There is generally an overall reduction with distance from the equator in the daily total solar radiation coming into the Earth-atmosphere system, being more extreme in the winter season and nearly absent at the time of the summer solstice. Seasonal and annual means for solar radiation absorbed in the Earth-atmosphere system show poleward decreases in both the summer and winter hemispheres.The resulting net radiation forcing for the Earth-atmosphere system has a net excess in the tropical latitudes and a deficit in the polar latitudes. If radiation transfer were the only process occurring, the equatorial regions would be hotter than observed and the polar regions colder than observed. However, the transport of heat from the equatorial to polar regions by atmospheric and oceanic circulations offsets this radiation imbalance and provides an overall energy balance at each latitude. In conclusion and as stated before, the primary connection between human activity and climate change is the alteration of the radiation transfer characteristics of the atmosphere. The change in greenhouse gas concentration and the addition of other gases with similar characteristics will change the terrestrial radiation transfer. In addition, a change in aerosol concentration and perhaps related change in cloud cover will change the solar radiation transfer. Except on a very local scale, the energy transferred by radiation is far greater than any production rate of energy due to human activity.

Insulin

enables cells to absorb glucose in order to turn it into energy. Key regulator of glucose. Its action is predominant after a meal and the receptors mediate its broad range Once glucose is released from the liver, it is regulated by insulin that is discharge from the pancreas and it can be delivered to muscle or adipose tissue, or any of the other organs. Insulin binds to receptors on target cells throughout the body and only when bound can glucose get inside the cells Insulin binds to its receptor, and as a result, turns on various signaling cascades. One of which, causes glucose-4 transporter (GLUT-4) to translocate to the plasma membrane and leads to an influx of glucose into the cell. Glycogen, lipid, and protein synthesis can now take place. -Helps transport glucose inside the body's cells so it can be used for energy.

MHC Class I

expressed on all nucleated cells

Rapid Combustion (Explosive Weapons)

form of oxidation otherwise known as a fire, in which large amounts of heat and light energy are released, which often results in a flame. This is used in a form of machinery such as internal combustion engines and in thermobaric weapons. Sometimes, a large volume of gas is liberated in combustion besides the production of heat and light. The sudden evolution of large quantities of gas creates excessive pressure that produces a loud noise. Such a combustion is known as an explosion.

3 Important features of HIV Virus

he first two are the glycoproteins gp120 and gp41. These two proteins allow the HIV virus to attach to and penetrate into the host cell. The third important feature of the HIV virus is the enzyme, Reverse Transcriptase.

Regulation of Blood Glucose Levels

homeostatic mechanism which keeps the blood value of glucose in a remarkably narrow range is composed of several interacting systems, of which hormone regulation is the most important. There are two types of mutually antagonistic metabolic hormones affecting blood glucose levels •catabolic hormones-such as glucagon, which increase blood glucose •anabolic hormones- such as insulin, which decreases blood glucose Insulin and glucagon are produced in the pancreas (in the pancreas, the beta cells produce insulin and the alpha cells produce glucagon.)

Hydrofluorocarbons, Perfluorocarbons, Sulfur hexafluoride

hydrofluorocarbons and perfluorocarbons are emitted in relatively small quantities, they have a disproportionate effect on the greenhouse effect. As a greenhouse gas, the most potent hydrofluorocarbons and perfluorocarbons are 11,700 times and 7,000 to 9,000 times per molecule as effective as a molecule of carbon dioxide, respectively. perfluorocarbons have relatively long atmospheric lifetimes (up to 50,000 years). Rated as the most powerful greenhouse gas ever released to the atmosphere, sulfur hexafluoride is used as an electric insulator, heat conductor, and a freezing agent. In comparison to one molecule of carbon dioxide, the global warming potential of one sulfur hexafluoride molecule is approximately 24,000 times greater. Sulfur hexafluoride has now been banned from use due to its global warming potential. Chlorofluorocarbons (CFCs) are nontoxic, nonflammable chemicals containing atoms of carbon, chlorine, and fluorine. They are used in the manufacture of aerosol sprays, blowing agents for foams and packing materials, as solvents, and as refrigerants. They have been banned since they contribute to Ozone depletion -Chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and aerosols are very important greenhouse gases. CFCs, HFCs, and PFCs are all human made and are not produced by any other process but our activities. Chlorofluorocarbons (CFCs) are nontoxic, nonflammable chemicals containing atoms of carbon, chlorine, and fluorine. They are used in the manufacture of aerosol sprays, blowing agents for foams and packing materials, as solvents, and as refrigerants. CFCs owe their existence to accidents that occurred in the early 1900s. Refrigerators in the late 1800s and early 1900s used the toxic gases, ammonia (NH3), methyl chloride, and sulfur dioxide, as refrigerants

Hydrological System

important part of the atmospheric system. Evaporation and condensation of water can transfer considerable amounts of energy by both vertically and horizontally. The cloud component of the hydrological cycle strongly affects transfers of both solar and terrestrial radiation. The precipitation is the source of fresh water needed for life on land surfaces.The circulation in the atmosphere is sufficiently vigorous that material injected into one part of the atmosphere can be spread quickly over broad regions. It may take just days for a volcanic smoke plume or radioactive products to circle the Earth. Constituents with sufficiently long lifetimes, such as carbon dioxide, would be expected to have relatively uniform concentration throughout the atmosphere. The large-scale north-south circulations are less vigorous than those in the the east-west direction. Vertical motions generally are much smaller than horizontal motions so the vertical transport of atmospheric constituents may be quite limited. This accentuates the buildup of atmospheric pollutants in the lower layers of the atmosphere especially in local areas with large sources of the pollutants.

Industry

industrial processes emit CO2 through fossil fuel combustion. Several processes also produce CO2 emissions through chemical reactions that do not involve combustion, for example, the production and consumption of mineral products such as cement, the production of metals such as iron and steel, and the production of chemicals. Various industrial processes accounted for about 14% of total U.S. CO2 emissions and 20% of total U.S. greenhouse gas emissions in 2010.

Pathogen

infectious agent or germ, a biological agent that causes disease to its host.

Pandemic (Global Epidemic)

is a disease that affects people over an extensive geographical area.

Exotoxin

is a toxin excreted by a microorganism (bacteria, fungi, algae, and protozoa. An exotoxin can cause damage to the host by destroying cells or disrupting normal cellular metabolism.

Skin Defense & Bacteria

keep water in, and keep microbes out. This is very important when you consider the fact that one square inch of skin contains around 50 million bacteria that no amount of cleaning can completely remove. Skin keeps these microbes on the surface by providing a nearly impenetrable physical barrier that is supplemented with chemical weapons. Oil and sweat glands within the skin lower the pH to a level that inhibits microbial growth. Sweat and oily secretions produce hydrolytic enzymes such as lysozyme that digest the cells walls of many bacteria.

Solar Radiation

leads to heating as it is absorbed by gases, aerosols and clouds in the atmosphere, and by the ocean, land, ice and biosphere elements at the Earth's surface. The absorption is proportional to the intensity of the solar radiation and depends on the properties of these substances. As the solar radiation is absorbed, there is less radiation available to be absorbed at lower levels. Although the radiation is initially in a narrow beam traveling in one direction from the sun, reflection at surfaces and scattering within the atmosphere sends the solar radiation all directions. For this reason, when one looks outdoors in the daytime one sees light coming from all directions.The intensity depends on the temperature of the sun and the distance from the sun to the Earth. The angle of the solar beam to the local vertical varies according to a number of astronomical factors: latitude on Earth (distance from the equator), longitude on Earth (time of day), and the orientation of the Earth's axis with respect to the sun (the solar declination angle) which varies according to the time of year. Variations in these factors lead to large variations in heating from day to night, from equatorial to polar regions, and from summer to winter. The atmosphere (gases, aerosols, and clouds) absorbs less of the incident radiation than the Earth surface, so that solar heating effects are greater at the Earth surface than in the atmosphere.

Adipose Tissue

loose connective tissue composed of adipocytes (fat cells) and its main role is to store energy in the form of fat, but it also cushions and insulates the body. There are two types of adipose tissue: white adipose tissue and brown adipose tissue. Adipose tissue serves as an important endocrine organ by producing hormones such as leptin, resistin, and the cytokine TNF alpha. Leptin and resistin are believed to regulate body fat, energy balance, and feeding behavior and cytokine TNF alpha is involved in inflammation responses. -Loose connective tissue composed of adipocytes (fat cells).

Obesity

medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems. Current national statistics show that 65% of adults are overweight or obese and 30% of children are overweight/obese. These statistics are alarming because obese individuals are at a higher risk of chronic diseases such as heart disease type 2 DM, high blood pressure, stroke, and cancer. Obesity in humans and most animals is not dependent on the amount of body weight but on the amount of body fat.

DM Treatment Medications

medications for type 2 diabetes are designed to: 1. Increase the insulin output by the pancreas 2. Decrease the amount of glucose released from the liver. 3. Increase the sensitivity (response) of cells to insulin 4. Decrease the absorption of carbohydrates from the intestine 5. Slow emptying of the stomach to delay the presentation of carbohydrates for digestion and absorption in the small intestine. Oral treatment is the preferred method for type 2 DM. The administered medications are hyperglycemic agents, such as Metformin, Sulphonyurea, and Acarbose. All of these drugs may act through different mechanisms but their goal is to reduce increasing blood glucose and minimize hyperglycemia. Weight gain plays an important role in the progression of DM, and Orlistat (weight loss drug) is commonly prescribed to patients to help them achieve healthy weights. -Insulin therapy

Drought & Public Health (Biological Concepts: Bacteria, Viruses, Infectious Diseases, Unsanitary conditions)

models of global warming suggest that there will be areas of extreme drought and other areas of extreme rainfall. Cholera, the bacteria that invades the intestinal tract and can cause diarrhea by causing the intestinal solution to have a hypertonic solution relative to the cells became a major problem.

Insulin Therapy

not a cure for DM, but it is a requirement for patients with type 1 DM or those with type 2 DM who do not respond to oral medications. Insulin is destroyed in the gastrointestinal tract so it must therefore be given subcutaneously, intravenously, or intramuscularly. Insulin can be injected in three places in the body: the upper arms, the inner/outer thighs, and the abdomen. Some of the complications associated with insulin injections are wrong dose/timing, poor injection technique, and injection in the wrong place. Insulin regimen and dosing is individualized because every person's body is different. Usually medical doctors can estimate depending on age, weight, and diet, it typically requires a trial period.

Consequences of DM

not able to use glucose efficiently because they make very little to no insulin to meet their metabolic needs. The body, therefore, cannot use glucose for energy without enough insulin. If glucose builds up in the bloodstream because it cannot get inside the cells, it can damage the heart, kidneys, eyes, and feet. causes both macrovascular and microvascular disease. After development of diabetes, an individual will suffer from tissue damage that can lead to the following problems, limb amputation, blindness, and kidney disease. DM also shortens lifespan by up to 1/3, it triples the risk of heart disease, and it increase infection susceptibility. Minor symptoms: lack of energy, visual blurring, fungal infections, and bacterial infections.

Diabetic Neuropathy (Neuropathy Disorder)

one of the most common diabetic disorder. A diabetic neuropathy can affect nearly any part of the body, but the feet are typically affected first. Do not affect the central nervous system, but the peripheral nerves, which transmit signals to the brain via the spinal column can be acute sensory nerve, involving asymmetric transient pain, chronic sensory nerve disorder involving symmetric pain, or autonomic neuropathy causing erectile dysfunction -Effects the small vessels; specific to diabetic patients.

MHC Class II

only found on B cells and macrophage or dendritic cells

Land Surface

overs 29% of the Earth's surface. Significant exchanges of heat, moisture, and momentum occur between the atmosphere and the land surface, including its biosphere. It is also the surface on which people live. The heat storage factor of land surface with respect to atmospheric temperature variations is much less than that for the oceans. Land has a lower specific heat than the ocean, and its rigidity restricts heat transport to deeper levels. As a result, the depth of the soil layer which is important for energy exchange interactions with the atmosphere is only several meters for the annual-cycle time scale. A cave 20 meters underground will remain at the same temperature all year round. Because of the small heat capacity of the land surface, variations in atmospheric temperature just above the surface are much larger over the land than over the ocean.Topography of the land surface has a pronounced effect on large-scale atmospheric circulations. particularly in the Northern Hemisphere. The Rocky Mountains, which are oriented north-south transect the Northern Hemisphere westerlies, and the Tibetan Plateau with its extreme height and aerial extent affects flow over a large area. Topography is a factor in the wave patterns in the upper tropospheric horizontal wind flow, and also has major effects on surface temperature and rainfall.Alteration of land surface by human activity is an important factor in climate change that adds to the effects of human-produced changes in the radiative characteristics of the atmosphere. Urbanization, cultivation for agriculture, irrigation, and deforestation change the albedo of land surfaces and the surface sensible and latent heat transfers. These factors can also greatly influence the local aspects of climate change.

Transition from HIV to AIDS

people with advanced HIV infection are vulnerable to infections and malignancies that are called "opportunistic infections" because these infections take advantage of the opportunity offered by a weakened immune system. This is a key characteristic of AIDS.

CO2 & the Environment

plants convert carbon dioxide and water into food compounds, such as glucose, proteins, lipids, and oxygen. This process is called photosynthesis. The overall reaction of photosynthesis is as follows: 6 CO2+ 6 H2O --> C6H12O6+ 6 O2 Plants and animals, in turn, convert the food compounds by combining it with oxygen to release energy for development of ATP which is used to power anabolism and catabolism. This is the respiration process which is the reverse of photosynthesis. The respiration reaction is as follows: C6H12O6+ 6 O2--> 6 CO2+ 6 H2O Carbohydrates are oxidized in the cells and the resulting chemical is carbon dioxide. We are using carbohydrates as an example of a compound that can be oxidized to produce energy in the form of heat and ATP. However any compound that can be oxidized can produce heat

Terrestrial (Long-Wave Form of Radiation) (Invisible)

predominant in the radiation emitted by matter in the climate system The primary wavelength range for this form is from 4 to 60 microns which is entirely in the invisible infrared part of the spectrum.

Solar (Short-Wave Form of Radiation) (Visible)

predominant in the radiation from the sun This is primarily in the wavelength range from 0.2 to 4.0 microns (a micron is one-millionth of a meter, .000001 m) which encompasses the visible part of the spectrum. This short-wave radiation provides a source of energy for the climate system as it is absorbed in the atmosphere, clouds, ocean, land surface, and by living matter.

Louis Pasteur

proved beyond doubt that certain diseases are caused by infectious agents and developed a vaccine for rabies.

Pus

pus is often seen within an infected area, and pus is comprised of dying phagocytes, broken down tissue cells and dead microbes.

Type 2 DM

refers to a chronic progressive disease with either decreased insulin secretion, or insulin resistance. The risk of type 2 DM and glucose intolerance has been associated with obesity. Type 2 DM is becoming a worldwide problem since obesity has become a global epidemic. Type 2 DM is the most common type of diabetes (90-95% of diabetic patients). Research has demonstrated that genetic factors are also associated with Type 2 DM. Nearly 6 million people in the US have type 2 DM and do not know it. Many have no signs or symptoms. Symptoms can also be so mild that you might not even notice them. The following symptoms are good indicators of type 2 DM: 1. increased thirst 2. increased hunger 3. fatigue 4. polyuria 5. weight loss 6. blurred vision 7. Sores that do not heal -Refers to a chronic progressive disease with either decreased insulin secretion or insulin sensitivity, or both.

Cell-Mediated Immunity

refers to macrophages engulfing antigens, processing them internally, and then displaying parts of them on their surface. This sensitizes the T cells to recognize these antigens.

Antigenic Shift

refers to the genetic strain that enables a flu strain to jump from one animal species to another, including humans.

Insulin Pen

similar to an ink cartridge in a fountain pen. A small pen-sized device holds an insulin cartridge. The amount of insulin to be injected is dialed in by turning the bottom of the pen until the required number of units is seen in the dose-viewing window. The tip of the pen consists of a needle that is replaced with each injection. A release mechanism allows the needle to penetrate just under the skin and deliver the required amount of insulin.

Specificity

the ability to discriminate among different molecular entities, and to respond to only those uniquely required (non-self)

Adaptiveness

the ability to respond to previously unseen molecules that may in fact never have naturally existed before.

Cryosphere

the ice component — has significant impacts on the climate system in several ways. It affects radiative and sensible heat transfers at the Earth's surface. It influences temperatures in the ocean and at the Earth's surface due to transfers between latent and sensible energy during melting and freezing.Finally, its melting and freezing influences water runoff from land and ocean salinity. Ice and snow exist primarily in the latitudes poleward of 30 degrees latitude and are thus are unfamiliar to the majority of the world's human population. Although only about two percent of all the water on Earth is frozen, it covers an average of 11% of the world's land surface and seven percent of its oceans. Note that although Antarctica and Greenland between them account for 98% of the world's land ice, the total area covered by ice and snow can be much larger in the Northern Hemisphere winter. The Northern Hemisphere has a much larger seasonal range than the Southern Hemisphere because of the larger amount of land area. Cryosphere conditions may not be directly evident to most people of the world. However, because of the global nature of the climate system, the cryosphere component also influences lower latitudes.

Nonproliferative Retinopathy

the most common form. It usually has no effect on vision and needs no treatment after diagnosis. However, as it continues it can get worse because the capillary walls may lose their ability to control the passage of substances between the blood and retina. As a result, the retina becomes swollen and fatty deposits form within. If this swelling affects the center of the retina, the problem is called macular edema.

Complete Combustion (Industrial Applications)

the reactant burns in oxygen, producing a limited number of products. When a hydrocarbon burns in oxygen, the reaction will only yield carbon dioxide and water. When elements are burned, the products are primarily the most common oxides. Complete combustion is almost impossible to achieve. In reality, as actual combustion reactions come to equilibrium (constant), a wide variety of major and minor species will be present such as carbon monoxide and pure carbon (soot or ash). In a complete combustion reaction, a compound reacts with an oxidizing element, such as oxygen , and the products are compounds of each element in the fuel with the oxidizing element. For example: CH4 + 2 O2 = CO2 + 2 H2O + energy. In most industrial applications and in fires, air is the source of oxygen (O2).

5 Components of Water Cycle

transfer moisture either from the Earth's surface to the atmosphere or from the atmosphere back to Earth • Condensation—conversion of water vapor into droplets of liquid water • Precipitation—water that falls from the atmosphere to land or to surface waters as rain, snow, sleet, or hail • Infiltration—downward movement of liquid water through soil • Evaporation—conversion of liquid water into gas, or water vapor • Transpiration—movement of liquid water from plant roots, upward in vessels, and into the atmosphere from the leaves as water vapor

Vector

transmission of infectious diseases may also involve a vector (a carrier). There are two types of vectors: mechanical and biological. An effective strategy used to control vector transmitted infectious diseases is to kill the vector since the vector is required in the life cycle of the pathogen

Forests & Water Cycle

transpiration and water storage

Humoral Immunity

typically refers to an immature B-lymphocyte is stimulated to maturity when an antigen binds to its surface receptors and an observant T helper cell releases a cytokine. This reaction signals to the B cell to undergo clonal selection-asexual reproduction by mitosis. Most of the family of clones become plasma cells. These cells, after an initial lag, produce highly specific antibodies at a rate of as many as 2000 molecules per second for four to five days. The other B cells become long-lived memory cells. -Is the type of immunity that is mediated by secreted antibodies produced by B cells.

Drought & Water (Biological Concepts: All biological chemical reactions require water. We are 80% water; thirst).

water is the solvent involved in all chemical reactions. Without water, chemical reactions will not occur and plants will die. Water is the unifying theme from a biological point of view as you study global warming. Plants require to water to produce ATP and both plants and animals require it for their chemical reactions.

Drought & Agriculture (Biological Concepts: Carbohydrates, Proteins and Lipids, Hunger)

we depend on photosynthesis to produce the heat, rice etc. Without photosynthesis, life as we know it would not exist. Photosynthesis depends on water for growth and development. The hydrogen ion from water is key for producing the ATP that the plant needs to develop its own protein, carbohydrates and lipids. Without water, there is no photosynthesis and the end result is a desert.

Disease Prevention

•Wash your hands before eating or touching your face •Cook meats thoroughly •Do not have unprotected sex •Make sure you have been properly vaccinated •If you work in a public place get a flu shot that includes the swine flu vaccine •When taking antibiotics, make sure to finish your prescribed medication

Primary Lymphoid Organs

(bone marrow and thymus) are those in which the maturation of T and B lymphocytes into antigen-recognizing takes place. Antigen-shifting is the term used for one of the direct weapons used by microbes against the immune system. Mature B and T lymphocytes migrate from the primary lymphoid organs through the bloodstream to the secondary lymphoid organs

Secondary (Peripheral) Lymphoid Organs

(lymph nodes, the spleen, and gut-associated lymphoid tissues such as the tonsils) are those organs in which antigen-committed lymphocytes are stimulated by antigens to undergo further division and differentiation. The adaptive immune response occurs mainly in the secondary lymphoid organs. Pathogens and their secreted antigens are trapped in these secondary lymphoid tissues, and presented to the native lymphocytes that constantly pass through. Microorganisms that enter the body through the skin or the lungs drain to the regional lymph nodes where they stimulate an immune response. Microorganisms and food antigens that enter the gastrointestinal tract are collected in the gut-associated lymphoid tissue.

Most Common STDs Pathogenic Causes

-Bacterial: Chancroid (Haemophillius ducreyi); Chlamydia infection (Chlamydia trachomatis); Donovanosis (Granuloma inguinale); Gonorrhea (Neisseria gonorrhoeae); Lymphogranuloma venereum (Clamydia trachomatis); Syphilis (Treponema pallidum) -Viral: Cytomegalovirus; Hepatitis B; Herpes (Herpes simplex virus); Human Immunodeficiency Virus (HIV); Human Papilloma Virus (HPV); Molluscum (MC). -Parasites: Pubic Lice or crabs (Phthirius pubis); Scabies (Sarcoptes scabiei). -Fungal: Candidiasis (Candida albicans). -Protozoal: Trichomoniasis (Trichomonas vaginalis)

Innate Immunity

-Innate immune system are the white blood cells that circulate in the blood -Secondary defense mechanism includes inflammation -Macrophages fight microbial infection by phagocytosis -Primary defense mechanism composed of physical barriers and surface bacteria. Cells of the immune system are derived from white blood cells. All the cells of the immune system are initially derived from the bone marrow. They form through a process called hematopoiesis.

Adaptive Immunity

-Key elements of successful immune defense are recognition, activation, and response -Cell mediated immunity works via T cell mediation (active morphages) -Humoral immunity works via B cell activation natural (self-antibodies) and acquired (vaccines) -Organs of the immune system divided into primary lymphoid & secondary lymphoid organs More specialized than innate immunity and it supplements the protection provided by innate immunity. Only present in vertebrates. A major difference between the innate and adaptive immune system is the ability to recognize specific pathogens. In other words, while the innate immune system may recognize bacteria in general, the adaptive immune system will recognize a specific bacterium. The adaptive immune system can respond rapidly after coming in contact with a microbe because it can remember prior encounters. This is the reason why you might develop an infection the first time you come across a specific microbe such as the chickenpox virus, but you will not get sick the second time you contact it. The ability of the adaptive immune system to remember a microbe is also why vaccination works. -The second component of the immune system capable of recognizing and remembering specific microbes in order to eliminate them from the body in future attacks.

Infectious Diseases

-Pathogenic microbial agents are bacteria, viruses, protozoa, and prions -Sexually transmitted diseases are successful infections such as HPV/HIV -Disease treatment and prevention depends on vaccination and antibiotics -Results of host-microbe interaction depends on virulent factors and immunity Human illnesses caused by the presence of pathogenic microbial agents such as bacteria, fungi, protozoa, viruses, multicellular parasites, and proteins known as prions Infectious disease results from the interaction between those few pathogens and the immune system of the hosts they infect.

Biological Vector

A biological vector harbors pathogens within its body and delivers them to new hosts in an active manner. Some examples of biological vectors are arthropods (mosquitoes, ticks, lice, etc.), which are responsible for many blood-borne diseases such as malaria, viral encephalitis, Lyme disease, and African sleeping sickness.

Mechanical Vector

A mechanical vector picks up an infectious agent on the outside of its body and transmits it in a passive manner. An example of a mechanical vector is a mosquito/fly that touches a contaminated surface and the insect touches your food prior to consumption. The pathogen never enters the insect's body, only the human body.

Immunoglobulins (Igs)

Antibodies, constitute part of the blood proteins These are the ways antibodies work or inactivate antigens: (a) complement fixation--proteins attach to antigen surface (causing cell lysis) (b) neutralization-- bind to specific sites to prevent antigen attachment (c) agglutination—they just clump with each other (blocking antigen) (d) precipitation: force insolubility and settled out of solution along with antigens In the absence of B cells, life is possible as long as infusions of immunoglobulin IgG are maintained.

Herd Immunity

As long as most people are vaccinated, it is much more difficult for an outbreak of a disease to spread. This effect is called "herd immunity", and it provides protection to unvaccinated individuals. In other words, if most people are immune to a disease, it is very difficult, although not impossible, for a susceptible person to even come in contact with the disease because no one has it. -Occurs when vaccination of the majority of a population protects the unvaccinated individuals because there are so few individuals who can actually spread the disease.

Plasma Cells

B-cells dedicated to producing copies of the B cell receptor, which are secreted into the bloodstream as antibodies. During its short lifespan, one plasma cell will typically secrete around 2,000 antibodies per second.

Botulinum

Botulinum toxin is a lethal naturally occurring substance, but since 2007 has become known to women as botox injections that will render the muscle unable to contract for 3-4 months (keeping you looking younger). -is a lethal naturally occurring substance, when carefully isolated and purified, it can be used as an effective and powerful medication.

Cervical Cancer

Cervical cancer does not have symptoms until it is quite advanced. For this reason, it is important for women to get screened regularly for cervical cancer. Genital HPV is passed on through genital contact, most often during vaginal and anal sex. Approximately 20 million Americans are currently infected with HPV and it is estimated that 6.2 million people become newly infected each year. At least 50% of sexually active men and women acquire genital HPV infection at some point in their lives. The American Cancer Society estimates that in 2008, 11,070 women were diagnosed with cervical cancer in the U.S. A vaccine can now protect females from the four types of HPV that cause most cervical cancers and genital warts. The vaccine is recommended for females age 13-26. Condoms may lower the risk of contracting HPV.

Clonal Selection Theory

Clonal selection theory has become a widely accepted model for how the immune system responds to infection and how certain types of B and T lymphocytes are selected for destruction of specific antigens invading the body. About 52 years ago, Australian immunologist Frank Macfarlane Burnet developed this theory. Burnet explained this theory as the cloning of two types of lymphocyte. One clone acts immediately to combat infection while the other is longer lasting, remaining in the immune system for a long time, which results in immunity to that antigen. For instance, B-cells will undergo about 8 cell divisions which will take approximately 5 days and will lead to a large population of identical B-cells. Many of these B-cells will stop dividing and will become plasma cells. -Burnet explained this theory as the cloning of two types of lymphocyte. One clone acts immediately to combat infection whilst the other is longer lasting, remaining in the immune system for a long time, which results in immunity to that antigen. Clonal refers to asexual reproduction by mitosis

Cytotoxic T Cells

Cytotoxic T-cells bind and kill infected host cells that are displaying the specific antigen by punching holes in their cell membranes. This is essential for the destruction of host cells that have been infected with viruses or intracellular bacteria or host cells that have become abnormal such as cancer. Foreign antigens do not necessarily have to come from a harmful source such as a microbe. Tissues that are taken from one individual and placed in another (organ transplant) will also be recognized as foreign. Cytotoxic T cells will attack these foreign cells leading to transplant rejection or graft rejections.

Dendritic Cells

Dendritic cells are long-lived phagocytic cells and reside in an immature state in most tissues, where they recognize and phagocytize pathogens and other antigens. They are important in both innate immunity and the initiation of adaptive immune responses.

Hematopoiesis

During hematopoiesis, bone marrow-derived stem cells differentiate into either mature cells of the immune system or into precursors of cells that migrate out of the bone marrow to continue their maturation elsewhere. The bone marrow produces B cells, natural killer cells, granulocytes, and immature thymocytes in addition to red blood cells and platelets. The function of the thymus is to produce mature T cells (thymus cells). Immature thymocytes leave the bone marrow and migrate into the thymus. Through an interesting maturation process in which the first positive selection process weeds out only those T cells with the correct set of receptors that can recognize the MHC (Major Histocompatibility Complex) molecules responsible for self-recognition. Then a negative selection process begins whereby T cells that can recognize MHC molecules complexed with foreign peptides are allowed to pass out of the thymus. The mature T cells are then released into the bloodstream.

Exotoxins

Exotoxins (meaning inside the cell) are actively secreted by some bacteria and have a wide range of effects including inhibition of certain biochemical pathways in the host. The most potent exotoxins known are the tetanus toxin (tetanospasmin) and the botulinum toxin.

Genital Warts

Genital warts usually appear as small bumps or groups of bumps, usually in the genital area in men and women (Fig. 13). Warts may appear within weeks or months after sexual contact with an infected person. If left untreated, genital warts may go away, remain unchanged, or increase in size/number. They will not turn into cancer. About 1% of sexually active adults in the U.S. have genital warts.

HIV

Human Immunodeficiency Virus (HIV) kills its victims slow by attacking their immune system. This mechanism allows a lot of its victims to transmit the virus to many others before even realizing that they are carrying the disease. This relatively low virulence allows its victims to travel long distances, increasing the likelihood of an epidemic.

Clonal Expansion

If you are infected with a virus for the first time and you innate immune system cannot contain the infection, your adaptive immune system will be activated. Since each B or T cell can only recognize one microbial antigen, and the receptors to these antigens are randomly generated, it can take awhile for those T and B cells to find their antigen. Once they do, those T and B cells will begin to divide and make more copies of themselves. This is called clonal expansion

Autoimmune Disease

If your immune system loses the ability to recognize itself, your immune system can attack your own healthy cells resulting in an autoimmune disease such as allergies.

Infectious Microorganisms

Infectious microorganisms can be classified as either primary pathogens or as opportunistic pathogens according to the status of host defenses.

2 Branches of Immune System

Innate immunity & adaptive Immunity

Microbiological Culture

Microbiological culture is a principal tool used to diagnose infectious diseases. A sample taken from potentially diseased tissue or fluid is then tested for the presence of an infectious agent able to grow within that medium. Most pathogenic bacteria are easily grown on nutrient agar, a form of nutrients that allows a bacterium to grow into a visible mound on the surface of the plate called a colony. The size, color, shape, and form of a colony is characteristic of the bacterial species, its specific genetic makeup (its strain), and the environment which supports its growth. Culture techniques rely on microscopic examination for definitive identification of the infectious agent.

Antigens

Molecules (proteins, sugars or lipids) located on a microbe's surface that can bind to B and T cell receptors leading to activation of the immune system

Natural Killer Cells

Natural killer cells differ from phagocytes in that they do not kill invading microbes, but rather the host cells that are infected with them. In viral infections, this prevents the infected host cell from producing more viral progeny and infecting neighboring cells. Recognize altered features of the membranes of abnormal cells such cancer cells and get rid of them. Natural killer cells kill by the release of various cytotoxic molecules. Some of these molecules cause the formation of pores in the membrane of the target cell, leading to cell destruction

Bacterial Toxins

One important group of virulence factors is bacterial toxins (algae, fungi, and protozoa also produce them). These toxins are divided into two groups: endotoxins and exotoxins.

Inflammation Response

One of the first responses to infection is the generation of an inflammatory response by the innate immune system. The symptoms of inflammation include redness, a sense of heat, swelling (edema), and throbbing pain. Although the inflamed tissue may feel uncomfortable, these reactions are a critical step in controlling an infection. Inflammation at the site of infection speeds up the killing of invading microbes by the front-line microphages and causes changes in the walls of local blood vessels that enable additional molecules and macrophages to enter the infected tissue from the blood. expansion of capillaries increases the flow of blood to the site of infection/injury. The increased blood flow results in the characteristic redness and increased heat at the site of inflammation. Capillaries are leakier, an increase in fluid, along with phagocytes, will leak into the tissue--> swelling of the area. Pain is caused by compression of nerves due to the swelling. blood clotting, making a physical barrier to the spread of infection through the bloodstream Fever contributes to your body's defenses by creating a temperature that is less favorable to microbial growth. Fever also stimulates phagocytosis and causes the body to reduce blood levels of iron, which bacteria need to grow. Fever is caused by chemical signals called pyrogens that are released by macrophages that have encountered invading microbes. Pyrogens travel to the hypothalamus, and signal for an increase in body temperature. The hypothalamus acts as the body's thermostat.

Opportunistic Pathogens

Opportunistic pathogens are organisms that cause an infectious disease to an immunocompromised host (newborn, sick person, etc.). Opportunistic disease is typically caused by microbes that are in contact with the host for example bacteria found in the gastrointestinal tract that would be controlled by a good immune system. However, there are some instances when these pathogens can be acquired from other hosts (a flu-virus carrier kisses a newborn) or introduction during surgery via nonsterile needless. It may also occur as a result of genetic defects, or exposure to antimicrobial drugs/immunosuppressive drugs.

Allergies

Our immune system can also mount a major defense against a harmless antigen such as plant pollen. These are called allergies, which usually result in sneezing, runny nose, and fever. More dangerous is when allergic reactions are so strong that they can be life threatening. This is called anaphylactic shock and symptoms include respiratory distress, swelling and decreased blood pressure. -An exaggerated immune response to a harmless antigen such as pollen or other environmental triggers.

Primary Pathogens

Primary pathogens cause disease as a result of their presence or activity within a healthy host because of the severity of the disease they cause. Many common primary pathogens of humans only infect humans and they do not cross species. However, many serious diseases are caused by organisms that jumped to our species from non-human hosts.

Receptors

Proteins often found on the surface of a cell that can bind a specific molecule, allowing for cell communication.

Cell Mediated Immunity

Refers to an immune response that does not involve antibodies, but rather involves the activation of macrophages, natural killer cells (NK), antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen

Respiratory Diseases

Respiratory diseases are commonly acquired by contact with aerosolized droplets spread by sneezing, coughing, talking, or kissing.

STDs

Sexually transmitted diseases are acquired from sexual activity through body fluids. STDs incidence rates remain high worldwide despite diagnostic and therapeutic advances. STDs are transmitted from one person to another by certain sexual activities rather than being actually caused by those sexual activities. STDs are transmitted through the mucous membranes of the penis, vulva, rectum, urinary tract, and mouth. Mucous membranes differ from skin in that they allow certain pathogens into the body. Pathogens are also able to pass through breaks or abrasions of the skin during sex, for example the shaft of the penis is particularly susceptible due to the friction caused during penetrative sex. Depending on the STD, a person may still be able to spread the infection even if no signs of the disease are present. A person can spread HIV infection at any time, even if he/she has not developed symptoms of AIDS. All sexual behaviors that involve contact with body fluids of another person should be considered to be a risk of pathogen transmittance. Sexual norms and condom use can prevent the spread of these pathogens.

Contaminated Fomites

Some infectious agents may be spread as a result of contact with a contaminated fomites (inanimate objects) such as a dollar bill passed from one person to another.

Normal Microbes

Staphylococcus epidermidis (S. epidermidis) and Staphylococcus aureus (S. aureus) are normal flora of the skin (Fig. 3). S. aureus tends to be found in moist environments such as the nostrils and armpits, whereas S. epidermidis is usually found in drier areas of the skin. S. epidermidis is rarely pathogenic, whereas S. aureus is widely known as a troublesome opportunistic pathogen.

Suppressor T Cells

Suppressor T cells inhibit the production of cytotoxic T cells once they are unneeded, lest they cause more damage than necessary.

Tetanus

Tetanus is a highly fatal disease in humans. Recorded mortality rates vary from 40% to 78%. The disease develops when the potent neurotoxin spores germinate after gaining access to wounds. The use of the tetanus toxoid for immunization (as part of the DPT vaccine) allows for fewer than 100 cases annually in the U.S., but the disease is a significant problem worldwide.

Endotoxins

The endotoxin (refers to bacterial toxin) is the lipopolysaccharide (LPS) which is part of Gram-negative bacteria release upon bacterial lysis.

3 Lines of Defense

The first and second lines of defenses are associated with innate immunity and the third one with adaptive immunity. The first line of defense consists of nonspecific surface defenses, which are physical barriers (structural/mechanical) along with a broad array of chemicals/proteins (biochemical) that prevent pathogens from entering deeper tissue. The second line of defense occurs in the interior of the tissue and refers to inflammation, which leads to phagocytosis. These two lines of defenses are considered nonspecific because they act in the same way against all microbes. The third line of immune defenses (Fig. 2) is adaptive immunity, which is activated when innate immunity is not successful at combating the infection. All three lines of defense are essential parts our response to microbial infection.

Ebola

The human strains of the Ebola (Fig. 5) virus kill their victims extremely quickly and as a result, the victims of this disease do not have the opportunity to travel very far from the initial infection zone. Additionally, this virus spreads through skin lesions or permeable membranes so the initial stage of Ebola is not very contagious since its victims experience only internal hemorrhaging. Usually the spread of Ebola stays within a relatively confined geographical area. High virulence.

Primary Immune Response

The immune response that this first encounter sets off is called the primary immune response. It will take several days for these cells to form a clone of cells that will secrete antibodies, and it is likely that by the time the immune system can mount an effective response, the infection will progress to the point where you will become sick. However, not all B and T cells become plasma cells or cytotoxic T cells. -Adaptive immune response generated upon the first encounter with a microbe. It takes much longer for the adaptive immune system to mount a response and the microbe may cause disease before it can be eliminated.

Constitutive Immunity

The innate immune system is also called constitutive immunity because it is always active and will respond to any invading microbe without prior exposure to it. The innate immune system is often the initial line of defense against a pathogen.

Lysozyme

The lysozyme is abundant in a number of secretions such as tears, saliva, and mucus. It is responsible for breaking down the polysaccharide walls of many kinds of bacteria and thus it provides some protection against infection. Bacteria found in the foods we eat, are typically removed by the lysozyme produced in saliva, stomach acid, and/or digestive enzymes in the small intestine.

Normal Flora

The mixture of organisms regularly found at any anatomical site is referred to as the normal flora. The normal flora of humans consists of a few eukaryotic fungi and protists, but bacteria are the most numerous microbial components. Normal flora has formed a symbiotic relationship with your body and provides another protective barrier to illness causing bacteria by producing secondary metabolites that inhibit adhesion, and growth of the attacking microbes.

Diseased Pathogens

The pathogens that cause disease in animals and/or plants are not closely related to each other. The only single property that links them is their small size (Fig. 1). A primary distinction between these entities is cell structure. Infectious pathogens are usually qualified as contagious agents because they can be transmitted from one person or species to another. Once the agent comes in contact with a host, the pathogen can enter and multiply using the host's resources, or it can die if the host has a good vigilant immune system.

Lymphocytes

The peripheral blood contains 20-50% of circulating lymphocytes; the rest move in the lymph system. Roughly 80% of them are T cells, 15% B cells and remainder are undifferentiated cells. Lymphocytes constitute 20-40% of the body's White Blood Cells. Their total mass is about the same as that of the brain or liver.

Virulence

The relationship between virulence and transmission has important consequences for the long term evolution of a pathogen. It takes many generations for a microbe and a new host species to co-evolve, that is why an emerging pathogen may hit its earliest victims hard. However, if a disease is rapidly fatal, the host may die before the microbe can get passed along to another host, killing the pathogen as well. -the relative capacity of a pathogen to overcome body defense.

Transmission

Transmission of an infectious agent can occur through various mediums such as liquids, food, body fluids, contaminated objects, and airborne inhalation.

Vaccines

Vaccines work by exposing the immune system to microbial antigens to generate a primary immune response. The antigens use in preparations of vaccines have been altered so as not to cause disease (typically they are only a small part/or an inactive form of the pathogen so that it should not cause infection). However, if the person later comes in contact with the fully pathogenic microbe, the body will already have memory cells that recognize the antigen. The secondary immune response will be strong and quick enough to destroy the microbe before it can cause disease. Immunological memory provides the basis for the use of vaccines. -typically contains a small amount of an agent that resembles a microorganism. The agent stimulates the body's immune system to recognize the agent as foreign, destroy it, and "remember" it, so that the immune system can more easily recognize and destroy these microorganisms if encounters them later.

Virulence Factors

Virulence factors are molecules expressed and secreted by pathogens that enable them to adhere to a host, evade the host's immune response, and feed from a host. These factors are often responsible for causing disease in the host because they have the ability to inhibit certain host's functions.

T Cells

When children are born without T cells, they appear normal for the first few weeks. Then, they begin to acquired opportunistic infections and die in infancy. This ailment is called severe combined immunodeficiency (SCID)--> It is called severe because it is fatal and called combined because, in humans, B cells cannot function without help from T cells, so that even if the B cells are not directly affected by the defect, both humoral and cell-mediated immunity are lost. Two important types of T-cells are cytotoxic T-cells and helper T-cells -Are cells of the adaptive immune system. The abbreviation "T" stands for thymus where they mature. They include helper T-cells that help manage the immune response, cytotoxic T-cells that kill infected host cells, and memory cells that remember specific antigens.

Phagocytes

White blood cells of the innate immune system are phagocytes and natural killer cells. Phagocytes are a type of cell that kills microbes by ingesting them through a process called phagocytosis. There are different types of phagocytic cells that your body uses to fight infection, but one of the most important phagocytic cells is called a macrophage.

White Blood Cells

White blood cells, along with red blood cells, are formed from the cells in the bone marrow called hematopoietic stem cells. An average adult human has about 1-2% white blood cells in his/her total blood volume. White blood cells of the adaptive immune system are T and B cells.

B Cells

Y-shaped molecule is composed of two identical light chains (shorter, outer structure) and two identical heavy chains (longer structure and therefore "heavier"). The antigen binding sites are located at the end of each arm of the Y and are formed by the pocket between the heavy and light chains. The antigen binding sites at the tip of the receptor are highly variable with each receptor having a slightly different antigen binding site. Each of these receptor variants will therefore bind a different antigen. we cannot encode each T and B cell receptor variant as an individual gene. Instead, the variable antigen binding site of the heavy and light chains is composed of a random combination of DNA segments that are stitched together to form this region of the receptor. Since there are different versions of these DNA segments, the many possible combinations literally generate millions of different antigen binding sites. -Are cells of the adaptive immune system. The abbreviation "B" comes from the bursa of Fabricius, where they mature in birds. In mammals, immature B cells are formed in the bone marrow. They include plasma cells that produce antibodies and memory cells that remember specific antigens.

Memory

a property shared with the nervous system, is the ability to recall previous contact with a foreign molecule and respond to it in a learned manner.

2 Fundamental Adaptive Mechanisms

cell-mediated immunity and humoral immunity

Innate Defenses

considered non-specific because they target all microbes in the same general manner. These innate defenses cannot recognize or distinguish one microbe from another and they do not remember specific microbes or the most effective way to get rid of infection.

Capillaries

continuous movement through the body ensures that the T and B cells will be exposed to foreign antigens. Capillaries are particularly important because these are the smallest of the blood vessels where the interchange between oxygen and carbon dioxide between blood and tissue cells occurs. This means that capillaries have access to all tissues of the body and can aid in monitoring those tissues for signs of infection.

LPS

endotoxin LPS is a very potent antigen and stimulates an intense host immune response. If purified LPS is administered to laboratory animals, it results in imminent death. However, in humans, it is responsible for septic shock which, in severe cases, can lead to death as well.

H. Pylori

half of the world's population is infected with H. pylori. Helicobacter pylori (H. pylori) is the bacteria responsible for most ulcers and many cases of stomach inflammation (chronic gastritis). The bacterium only grows in the stomach and is usually contracted during childhood through food or water. The bacteria can weaken the protective coating of the stomach, allowing digestive juices to irritate the sensitive stomach lining. If you are a carrier of H. pylori, you may have no symptoms, but some of the symptoms are abdominal pain, belching, bloating and fullness, feeling very hungry 1 to 3 hours after eating. Patients who have H. pylori are treated with a 10-14 day antibiotic regimen. Those living in developing countries or crowded, unsanitary conditions are most likely to contract the bacterium, which is passed from person to person. Simple blood, breath, and stool tests can determine if you are infected with H. pylori. A clean and germ-free environment may help decrease your risk of H. pylori infection.

Antigen Presenting

helper T-cells usually find their antigen through the assistance of macrophages. Once macrophages have "eliminated" a microbe or a cell infected with a microbe, they display the microbial antigens on their surface. This is called antigen presentation

Cells of the Immune System

lymphatic organs are those in which lymphocyte maturation, differentiation, and proliferation take place. These organs are divided into primary lymphoid organs -thymus and bone marrow, and secondary lymphoid organs - spleen and lymph nodes. Cells of the innate immune system are phagocytes and natural killer cells.

Spleen

lymphoid organ, the spleen filters the blood to remove aged or abnormal red cells and invading microorganisms. immunologic filter of the blood. It is made up of B cells, T cells, macrophages, dendritic cells, natural killer cells, and red blood cells. In addition to capturing foreign materials (antigens) from the blood that passes through the spleen, migratory macrophages and dendritic cells bring antigens to the spleen via the bloodstream. An immune response is initiated when the macrophage or dendritic cells present the antigen to the appropriate B or T cells. You can picture this organ as an immunological conference room where important people meet to make sure the body is safely guarded. In the spleen, B cells become activated and produce large amounts of antibody. Also, old red blood cells are destroyed in the spleen. This brings us to the lymph nodes

HPV

most deadly STD Genital human papillomavirus (HPV) is the most common sexually transmitted infection. The virus infects the skin and mucous membranes. There are more than 40 HPV types that can infect the genital areas of men and women, including the skin of the penis, vulva (area outside the vagina), and the linings of the vagina, cervix, and rectum. HPV is not visible to the naked eye and a lot of infected individual do not even know they have it. Most people with HPV do not develop symptoms, but certain types of HPV can cause genital warts in men and women, cervical cancer and other less common cancers, such as cancers of the vagina and penis. HPV types are divided into two groups: low-risk (wart-causing) and high-risk (cancer-causing). Most of the time, the body's immune system clears the HPV infection naturally within two years.

Antigen Shifting

most people have gotten the flu more than once. This is due to a technique employed by the influenza virus called antigen shifting. Every few years a major new strain of flu is generated with a rearranged surface antigen that human antibodies no longer recognize. While immunity to this new version builds up, people may get sick and the whole process will repeat within a few years. Although we normally think of the flu as more of an annoyance, it can fatal to the elderly and immunocompromised individuals. However, the greatest fear is that a truly deadly strain will emerge.

Pathogen Removal Mechanisms

our body has an efficient method of getting rid of microbes in the event that your hydrolytic enzymes do not kill the ingested bacteria, you would vomit or develop diarrhea. These processes are necessary pathogen removal mechanisms employed by our bodies. Although unpleasant, it can be beneficial to allow the body to purge these microbes rather than to try to stop it through the use of anti-vomiting/anti-diarrhea medication.

Immune Cells

protect the bloodstream and tissues from invading microbes as well as host cells that have been infected by microbes. Immune system cells are not located in one particular tissue as in other body systems, nor are the immune system controlled by a central organ. Rather, the immune system is composed of a host of individual cells that rush to the site of infection upon request. The various components of the immune system are combined in an exquisitely complex communications network that functions as an effective defense against foreign microorganisms and against body cells that have become abnormal.

Secondary Immune Response

some activated B and T cells become memory cells that will survive for decades. If the body encounters this microbe again, then the memory cells recognize the antigens on the intruder and immediately initiate an immune response. This is called the secondary immune response, and because of the pre-existing population of memory cells, it is much quicker and stronger than the first one. In most cases, the microbe will be eliminated before it can cause disease. -Adaptive immune response generated upon subsequent encounters with a microbe. Pre-existing memory cells result in a fast and strong response that usually eliminates the microbe before it can cause a disease.

Lymph Nodes

the lymph nodes which function as an immunologic filter for the bodily fluid known as lymph. Lymph nodes are found throughout the body (see diagram). Composed mostly of T cells, B cells, dendritic cells and macrophages, the nodes drain fluid from most of our tissues. Antigens are filtered out of the lymph in the lymph node before returning the lymph to the circulation.

B & T Cells

the white blood cells that comprise the adaptive immune system. These cells can remember the microbes they encounter by recognizing very specific cell surface markers on those microbes. B and T cells can bind to antigens through specific receptors located on the surface of the B and T cells. Each B or T cell expresses only one kind of receptor and therefore can bind only one type of antigen (see figure 2). While T-cell receptors are only found bound to the surface of the T-cell, B cell receptors can be bound to the surface of the B-cell or secreted into the bloodstream. B-cell receptors are also known as antibodies. High degree of specificity is a necessary property of the immune system because otherwise the distinction between foreign molecules and self-molecules would not be possible. This specificity is also what makes antigen recognition different from the more general recognition systems employed by phagocytes and natural killer cells. The distinction between the foreign antigen and the organism's own molecules is so subtle that only the highly specific receptors on the T and B cells can make the distinction.

Lymphatic Organs

those organs in which lymphocyte maturation, differentiation, and proliferation take place. They are divided into two categories: Primary (thymus & bone marrow) & Secondary (lymph nodes, the spleen, and gut-associated lymphoid tissues such as the tonsils)