Immune System
2nd Sign of Inflammation .......
2. Loss of Function This is more of an indirect outcome of inflammation. When there is swelling and pain, that part of the body becomes less usable. For example, when people suffer from arthritis (inflammation of joints), they can't really walk normally. This has a beneficial effect of causing disuse of the injured area, aiding in healing.
3rd Sign of Inflammation .......
3. Increased Heat Heat is a result of dilation of capillaries. When there is increased blood flow, the tissue gets warmer.
4th Sign of Inflammation .......
4. Pain There are two types of pain when you get hurt: a sharp pain that happens right at the time of injury caused by nerve endings, and a slower, throbbing pain that you feel afterwards, which is caused by inflammation. For the pain from inflammation, it is because the swollen areas exert pressure on free nerve endings, which causes a continuous pain (that's why it hurts even more when you press a swollen ankle!)
5th Sign of Inflammation .......
5. Redness Redness is also a result of dilation of capillaries. More blood=redder color.
The Thymus....
A primary lymph organ where T-cells mature Found immediatelty beneath the breastbone at the level of the heart. After puberty it begins to shrink. Removal of this organ in adult has little effect, but it is vital for making immune cells in newborns!! It produces several "growth factors" which are proteins that stimulate the proliferation and the differentiation of T-Lymphocytes. Makes the hormone thymosin which helps the T-Lymphocytes develop, among a few other thymic hormones such as thymopoietin and thymulin. By age 75, this gland turns into fatty tissue. Luckily for us...all or nearly all of our T-cells are made before puberty.
ANTIGEN PRESENTING CELLS include.....
ANTIGEN PRESENTING CELLS - Macrophages, Dendritic Cells & B cells these are the three kinds of antigen-presenting cells (APCs) that act as a bridge between the innate and adaptive response — macrophages and dendritic cells as well as B cells
Acquired Immunity...
Acquired Immunity: Acquired (adaptive or specific) immunity is not present at birth. It is learned. The learning process starts when a person's immune system encounters foreign invaders and recognizes non-self substances (antigens). Then, the components of acquired immunity learn the best way to attack each antigen and begin to develop a memory for that antigen. Acquired immunity is also called specific immunity because it tailors its attack to a specific antigen previously encountered. Its hallmarks are its ability to learn, adapt, and remember.
Acquired Immunity.....
Acquired Immunity: Acquired (adaptive or specific) immunity is not present at birth. It is learned. The learning process starts when a person's immune system encounters foreign invaders and recognizes nonself substances (antigens). Then, the components of acquired immunity learn the best way to attack each antigen and begin to develop a memory for that antigen. Acquired immunity is also called specific immunity because it tailors its attack to a specific antigen previously encountered. Its hallmarks are its ability to learn, adapt, and remember. Acquired immunity takes time to develop after first exposure to a new antigen. However afterward, the antigen is remembered, and subsequent responses to that antigen are quicker and more effective than those that occurred after the first exposure. Acquired immunity is more specialized than innate, and works with the protection of the innate immune system. You are born with the capacity to mount an immune response, but only when there is direct contact with the pathogen is immunity acquired. Initial contact leads to white blood cell activation and the synthesis of proteins that exhibit specific reactivity against the invader.
After APCs phagocytose the pathogen and break off the antigen, APCs will load the antigen on the MHC I or MHC II molecule and present it to immune cells....
After APCs phagocytose the pathogen and break off the antigen, APCs will load the antigen on the MHC I or MHC II molecule and present it to immune cells. Note here that antigens can be presented on either MHC I or MHC II If Antigen Present on MHC II Complex, the Immature T Cell Will Differentiate into CD4 Helpter T Cell ; If Antigen Present on MHC I Complex, the Immature T Cell Will Differentiate into CD8 Cytotoxic T cell
After the capillaries become permeable under the influence of histamine...
After the capillaries become permeable under the influence of histamine, immune cells rush to the site of injury and begin the battle against pathogens. The process of cells moving from capillaries to tissues is called diapedesis.
The 30 proteins in the complement system communicate and activate each other through....
Although proteins are much smaller in size compared to cells, they can generate a big effect by 'turning each other on' through a cascade series of activation. They activate each other through the release of cytokines (intracellular signaling molecule). Cytokines are cell signaling molecules that aid in cell to cell communication in immune responses and stimulate the movement of cells towards sites of inflammation, infection, and trauma. Cytokines also work in the adaptive immune response by compelling T-Lymphocytes and B-Lymphocytes to quickly proliferate in times of action and they also quickly attract the innate immune cells.
An antigen....
An antigen is a marker from a foreign molecule that is able to trigger an immune response. Antigens serve as a target, and our body will mark the cells bearing the antigen as non-self.
Interferons...
Another important molecule that links the innate and adaptive immune systems is interferon. Interferon is secreted by virus-infected cells to warn nearby non-infected cells. Interferon will act as a messenger and bind to non-infected cells to help them be prepared for a viral attack. Interferons also help activate dendritic cells, which helps kickstart the adaptive immune response.
B cells are born and mature in....
B cells are born and mature in the bone marrow
B-Lymphocytes...
B-Lymphocytes are made in the bone marrow and mature in the bone marrow. They differentiate into plasma cells that make antibodies: responsible for humoral immunity... PART OF ADAPTIVE IMMUNE RESPONSE
Both B cells and T cells are lymphocytes, which means that they are produced from the bone marrow. Their differences is.....
Both B cells and T cells are lymphocytes, which means that they are produced from the bone marrow. Their differences is that afterwards B cells stay and mature in the bone marrow, while T cells go and mature in the thymus.
CD4 T Cells (Helper T Cells)...
CD4 T Cells (Helper T Cells) - which release cytokines to boost both innate immunity and adaptive immunity. These cytokines help attract innate immune cells and increase proliferation of other T and B cells. Cytokines are cell signalling molecules that aid cell to cell communication in immune responses and stimulate the movement of cells towards sites of inflammation, infection and trauma.
CD8 T Cells (Cytotoxic T Cells)...
CD8 T Cells (Cytotoxic T Cells) - which directly kill infected cells through perforin (poke holes) and granzymes (cause apoptosis). However T cells are different from natural killer cells because they are more specific and require antigen presentation.
Cell-mediated immunity.....
Cell-mediated immunity can be acquired through T cells from someone who is immune to the target disease or infection. "Cell-mediated" refers to the fact that the response is carried out by cytotoxic cells. Much like humoral immunity, someone who has not been exposed to a specific disease can gain cell-mediated immunity through the administration of helper T-Cells and Cytotoxic T Cells cells from someone that has been exposed, and survived the same disease. The Helper T Cells release cytokines to boost both innate immunity and adaptive immunity. These cytokines help attract innate immune cells and increase proliferation of other T and B cells. The Cytotoxic T Cells assist with the elimination of pathogens and infected host cells.
Cell-mediated immunity is mediated by ......
Cell-mediated immunity is mediated by T lymphocytes
NK cells also secrete cytokines...
Cytokines are cell signalling molecules that aid cell to cell communication in immune responses and stimulate the movement of cells towards sites of inflammation, infection and trauma.
Cytotoxic CD8 T cells....
Cytotoxic CD8 T cells carry out their killing function by releasing two types of preformed cytotoxic protein: the granzymes, which induce apoptosis in any type of target cell, and the pore-forming protein perforin, which punches holes in the target-cell membrane through which the granzymes can enter. These properties allow the cytotoxic T cell to attack and destroy virtually any cell that is infected with a cytosolic pathogen. Cytotoxic T cells assist with the elimination of pathogens and infected host cell by granzymes (these induce apoptosis in any type of target cell) and through perforins (a pore-forming protein which puncture holes in the target cell membrane through which the granzymes can enter)
DiGeorge's syndrome...
DiGeorge's syndrome Did you know that congenital failure of the thymus to develop results in DiGeorge's syndrome? T cells can't be made; thus, a horrible fate awaits. Their cell-mediated immune system is nonfunctional and death results early in life. (congenital=present at birth but not necessarily hereditary; acquired during fetal development)
Major-Histocompatibility Complex II...
Earlier, we talked about three kinds of antigen-presenting cells (APCs) that act as a bridge between the innate and adaptive response — macrophages and dendritic cells as well as B cells. In addition to MHC I molecules that all nucleated body cells bear, APCs specifically also have another type of MHC — MHC II on their cell surface. So Antigen-presenting cells are the only ones that carry MHC II on their cell surface as well as MHC I. So, the Class I MHC molecule are found on all nucleated cells in the body (including cells expressing Class II MHC which are antigen presenting cells-dendritic cells, macrophages, and B cells), but are not found on non-nucleated cells such as red blood cells.
4. Eat = Eosinophils
Eosinophils are also part of the innate response. Their cytoplasms are filled with granules that contain proteins that can be released into the surrounding tissue to kill pathogens. They are especially active against parasites. They are involved in destroying parasitic worms and participate in allergic reactions. However, they have very low phagocytic activity.
5. Bananas = Basophils..
Finally, basophils are the least numerous kind of leukocytes. Their main job is to initiate the process of inflammation. This cell can do phagocytosis. Indeed, a key "player" in asthma, anaphylaxis, and hay fever. They only make up less than 1% of all leukocytes. Similar to eosinophils, basophils also contain granules that can be released to nearby tissues. Two important contents of the granules are histamine and heparin. We are familiar with the functions of histamine — vasodilation and making capillaries more permeable. Heparin, on the other hand, is a type of anticoagulant that prevents blood from clotting too quickly. Basophils are similar to mast cells, but they come from different cell lineages. The difference is that basophils leave bone marrow (site of blood cell production) as mature cells and remain circulating in the blood, whereas mast cells leave the bone marrow and circulate the blood as immature cells, only maturing when they enter the tissue.
3. Stomach Acid..
Gastric acid kills many microbes with its low pH
Helper CD4 T cells are....
Helper CD4 T cells are there to assist both innate and adaptive immunity. They release cytokines to ramp up the immune response by: 1) Attracting innate immunity cells, like dendritic and macrophage cells to where the identified antigen is present. 2) Stimulate clonal selection and proliferation of B cells and T cells The helper T cells release cytokines to 1) attract innate immune cells to where the antigen is and 2) stimulate clonal selection and proliferation of B cells and T cells. Clonal selection is a process proposed to explain how a single B or T cell that recognizes an antigen that enters the body is selected from the pre-existing cell pool of differing antigen specificities and then reproduced to generate a clonal cell population that eliminates the antigen.
Heparin...
Heparin is a anticoagulant (blood thinner) that prevents the formation of blood clots.
Histamine has two main functions:
Histamine has two main functions: 1. Dilate (to make wider) nearby capillaries → increase blood flow 2. Make capillary walls more permeable → fluid and immune cells such as clotting proteins (platelets aka thrombocytes) and phagocytes leak out to the site of injury
AutoImmune Disease — Type 1 Diabetes....
However, there are also cases of autoimmune diseases when the immune system mistakenly attacks self cells, such as in type I diabetes when the pancreatic cells are destroyed by the immune system and lose their functions. An autoimmune disease results when the body's system for fighting infection (the immune sysem) turns against a part of the body. In diabetes, the immune system attacks the insulin-producing beta cells in the pacreas and destroys them. The pancreas then produces little or no insulin. A person who has type 1 diabetes must take insulin daily to live.
Humoral immunity ....
Humoral immunity is immunity from serum antibodies produced by plasma cells. More specifically, someone who has never been exposed to a specific disease can gain humoral immunity through the administration of antibodies from someone who has been exposed and survived the same disease. "Humoral" refers to the bodily fluids where these free-floating serum antibodies bind to antigens and assist with elimination.
Humoral immunity mediated by....
Humoral immunity mediated by B Lymphocytes which produce Antibodies - Antibodies on the move are called Immunoglobins.
If Antigen Present on MHC II Complex....
If Antigen Present on MHC II Complex, the Immature T Cell Will Differentiate into CD4 Helpter T Cell
Note here that antigens can be presented on either MHC I or MHC II
If Antigen Present on MHC II Complex, the Immature T Cell Will Differentiate into CD4 Helpter T Cell ; If Antigen Present on MHC I Complex, the Immature T Cell Will Differentiate into CD8 Cytotoxic T cell
If innate immunity isn't sufficient to protect us from pathogens....
If innate immunity isn't sufficient to protect us from pathogens, the adaptive immunity joins the battle. The adaptive immunity is a specific immune response because it targets specific antigens.
If the protective wall is penetrated...
If the protective wall is penetrated, innate immunity continues with the inflammatory response. This is why when you accidentally cut yourself, the injury site reddens and swells up after a few minutes.
Organ Transplantation...
In cases of organ transplantation, the donor organ will bear a different MHC I molecule which will be labelled as an antigen by our immune system. As a result, our immune system will attack the "enemy" organ. This will lead to organ failure and transplant rejection. This is why transplant patients need to take immunosuppressants on a life-long basis to lower/eliminate the immune system's response towards the foreign organ. However, lowering the immune system also makes these patients more susceptible to general infections.
In the inflammatory response, many white blood cells are drawn to the site of injury via __________
In the inflammatory response, many white blood cells are drawn to the site of injury via chemical signals.
Inflammatory Response → SLIPR
Inflammatory Response → SLIPR Swelling Loss of function Increased heat Pain Redness
Innate Immunity.........
Innate Immunity: You are born with it... always present and available at very short notice to protect against invaders. Components include fever, interferon ( a protein that is made by body cells with numerous functions such as helping nearby cells resist viral infection after it has been infected). Other elements of the innate immunity are cells like neutrophils, macrophages, and microglia in the CNS.
Leukocytes....
Leukocytes: These are white blood cells (WBCs)
Leukotriene...
Leukotriene are one of the inflammatory molecules that stimulates the contraction of smooth muscles which enhances vascular permeability. If a person gets an asthma attack and has a hard time breathing, it is beacause leukotrienes caused tightening of the airway muscles and production of excess mucus which all causes bronchoconstriction.
Lymphatic veins do not connect directly to the heart; instead, they dump lymph into specific circulatory veins, which then connect with the heart....
Lymph from the right upper torso drains into the right lymphatic duct and then into the subclavian and jugular veins which connect to the heart. Lymph from the rest of the body drains into the thoracic duct (aka left lymphatic duct) before entering the subclavian and jugular vein which connects to the heart.
Lymph nodes ....
Lymph nodes are basically police stations with a bunch of immune cells (lymphocytes) that look at the lymph to make sure it is safe. These cells trigger immune responses whenever they come across 'bad guys' in the lymph - like harmful bacteria, for example.
Lymph nodes contain cells such......
Lymph nodes contain cells such as T and B- lymphocytes, plasma cells, macrophages, and dendritic cells.
2. Let = Lymphocytes
Lymphocytes are your artillery units, the ones who identify and acquire a target before killing it. The lymphocytes are B cells, T cells, and natural killer cells. Lymphocytes can be small, medium, or large, and actually constitute an entire family that can live for years! The B cells and T cells are part of the adaptive immune response, whereas the natural killer cells are part of the innate immune response. Naturak Killer cells use perforin (create holes) and granzyme (stimulate apoptosis) to lyse cells.
Lymphocytes...
Lymphocytes: These are a type of leukocyte which originate from the bone marrow but end up concentrating in lymphatic organs (ex. lymph nodes, spleen, and thymus)
Lymphoid aggregates known as Peyer's Patches....
Lymphoid aggregates known as Peyer's Patches are found throughout the small intestine ileum and monitor intestinal bacterial populations as well as defending us against pathogenic and intestinal bacteria. Gut-associated lymphoid tissue such as Peyer's Patches is sometimes called GALT. Similar to Peyer's Paches (GALT), we have BALT. This is bronchus-associated lymphatic tissue located in the walls of the bronchi.
Major Histocompatibility Complex I Molecule.....
Major Histocompatibility Complex I Molecule- All nucleated body cells bear MHC class I molecules on their cell surface Our immune system is normally programmed to recognize its own cells and not attack them. How does it distinguish between self and non-self cells? It accomplishes this through the major histocompatibility complex (MHC) molecule found on the surface of cells. All nucleated (cells with a nucleus) body cells bear MHC class I molecules on their cell surface. Every genetically unique individual will have his/her own unique set of uniform MHC I molecules. This means that identical twins (which are genetically identical) will have the same MHC I expression on their cells. When our immune system sees its own MHC I molecule, it will recognize these cells as allies and spare them from death. The MHC molecule is made up of alpha, 1, 2, 3, and beta-microglobulin protein chains.
Major-Histocompatibility Complex II...
Major-Histocompatibility Complex II THAT ARE ONLY PRESENT ON ANTIGEN PRESENTING CELLS - Macrophages, Dendritic Cells & B cells
T-Lymphocytes....
Make up the Cell-Mediated Immune System which functions to kill foreign or intracellular infected cells. T Lymphocytes—(Born in bone marrow and matures is Thymus)—Produce Cell Death
B-Lymphocytes...
Make up the Humoral Immune System, which functions to produce antibodies. *Antibodies on the move are called immunoglobins B -Cells make antibodies! If activated, those antibodies move out of the lymph nodes. B Lymphocytes — Born and mature in Bone Marrow —(Produce Antibodies)
Mast Cell...
Mast cells produce histamine, heparin, and leukotrienes. Main function of mast cells is to store the mediators of the inflammation process.
3. Monkeys = Macrophages/Monocytes
Monocytes are also part of the innate response. They are called monocytes when they are in their immature state in blood vessels. After they cross into the infected tissues through diapedesis, monocytes mature into macrophages. They are similar to neutrophils in that they are also phagocyted, they also "eat things" that should not be in the body in a nonspecific way. Later on, macrophages function as antigen-presenting cells to activate adaptive immunity. You can think of an antigen as the unique ID of the enemy. Macrophages act as messengers that carry vital information about the enemies from the frontline soldiers (innate immunity) to the backup troops (adaptive immunity). So whatever the macrophage ate, they present that antigen to the adaptive immunity so they can use it to make future antibodies against this antigen.
Natural killer (NK) cells....
Naturak Killer cells use perforin (create holes) and granzyme (stimulate apoptosis) to lyse cells. Natural killer (NK) cells attack and kill virus-infected cells or cancerous body cells. They are part of the innate response because they do not require activation, unlike B cells and T cells — they are always "on". NK cells fight enemies with two main weapons: • Perforin, which perforates (poke holes in) pathogenic cell membranes, causing cell lysis (cell breakdown). •Granzymes, a protease which stimulates a target cell to undergo apoptosis (programmed cell death)—useful for killing cancerous cells.
Natural Killer Cells are born in ___________but mature in___________
Natural Killer Cells are born in bone marrow but mature in many immune sites in the body, and eventually stay in the bloodstream.
Never = Neutrophils...
Neutrophils are usually the "first responders" to appear in acute bacterial infections, and are very active in phagocytosis! As you can imagine...this neutrophil is the most abundant phagocytic cell. Neutrophils are your infantry-units, the most numerous and common type of leukocytes. About 40-70% of leukocyte are neutrophils! Neutrophils are phagocytes — they eat (phagocytosis) and destroy pathogens. They are part of the innate response because they are not picky eaters — they engulf all kinds of pathogens.
4. Symbiotic Bacteria..
Not all bacteria are bad! Symbiotic bacteria are our allies and out-compete their more hostile relatives. We naturally have bacteria in our mouths (some of which are benign( not dangerous to our health) and don't cause an issue). If you take a steroid inhaler that kills those naturally occurring bacteria, you can end up with an opportunistic yeast infection (oral thrush).
Pathogens...
Pathogens: These are all kinds of harmful microscopic enemies (virus, bacteria..etc) that can cause diseases.
Phagocytosis
Phagocytosis - cell eating
Pinocytosis...
Pinocytosis = cell drinking
Plasma cells....
Plasma cells are fully differentiated B-cells that produce a single type of antibody. Antibodies on the move are known as immunoglobulins. B-cells differentiate into plasma cells that produce antibody molecules closely modeled after the receptors of the precursor B-cell. Once released into the blood and lymph, these antibody molecules bind to the target antigen (foreign substance) and initiate its neutralization or destruction.
third type of lymphocyte in the innate immune system, called .....
Remember, there is a third type of lymphocyte in the innate immune system, called the natural killer cells. They originate from the bone marrow but mature in many immune sites in the body, and eventually stay in the bloodstream.
Sometimes a dendritic cell presents itself on the surface of other cells to induce an immune response, thus functioning as antigen-presenting cell.......
Sometimes a dendritic cell presents itself on the surface of other cells to induce an immune response, thus functioning as an antigen-presenting cell. How this works is that the dendritic cell acts as an immune cell that detects, engulfs, and informs the adaptive immune response about infections. When a pathogen is detected, these APCs will phagocytose the pathogen and digest it so that it can form many different fragments of the antigen. The antigen fragments will then be transported to the surface of the antigen-presenting cell, where they will serve as an indicator to other immune cells by migrating to lymph nodes along with macrophages to activate the adaptive immune response. So in this way, the dendritic cell which is part of the innate immune system detects potentially harmful antigens and then informs the adaptive immune response about the presence of these antigens.
fever...
Sometimes, fever can result from an inflammatory response. Fever is turned on and off by the brain. It is not a local response anymore— it becomes systemic (body-wide). When our body's temperature increases, it helps to hinder the growth of pathogens, and may sometimes kill the temperature sensitive ones as well.
Now we can explain the five signs associated with inflammation: Inflammatory Response → SLIPR 1st Sign of Inflammation .......
Swelling Swelling is a result of permeable capillaries. When blood vessels become leaky, fluid starts accumulating in nearby tissues, causing swelling.
T Suppressor Cells...
T Suppressor Cells - involved with regulation of both humoral and cell-mediated response
T cells are born in ________ but mature in _________
T cells are born in bone marrow but mature in Thymus
T-Killer Cells - Natural Killer (NK)....
T-Killer Cells - Natural Killer (NK) Cells are PART OF INNATE IMMUNE RESPONSE NK cells attack and kill virus-infected cells or cancerous body cells. They are part of the innate response because they do not require activation, unlike B cells and T cells, the NK cells are always "on". NK cells can kill cancer cells. In just hours, these NK cells can kill tumor cells, infected by a virus. NK cells also secrete cytokines which are peptides or glycoproteins of low molecular weight. They act on cells that have receptors for them. Cytokines boost both innate and adaptive immunity. These cytokine cells help attract innate immune cells and increase proliferation of other T and B cells NK cells fight enemies with two main weapons: Perforin, which perforates (pokes holes in) pathogenic cell membranes, causing cell lysis (cell breakdown) Granzymes, a protease which stimulates a target cell to undergo apoptosis (programmed cell death) — useful for killing cancerous cells
T-Lymphocytes .....
T-Lymphocytes are made in the Bone Marrow and mature in the Thymus, they differentiate into T-Killer cells (Natural Killer Cells), CD8 Cytotoxic T Cells, CD4 Helper T Cells, and T-suppressor Cells and are responsible for cell-mediated immunity PART OF ADAPTIVE IMMUNE RESPONSE
The B cells and T cells are.........
The B cells and T cells are lymphocytes.
The B cells and T cells are part of the ________immune response, whereas the natural killer cells are part of the ________immune response.
The B cells and T cells are part of the adaptive immune response, whereas the natural killer cells are part of the innate immune response.
primary immune organs....
The bone marrow and thymus = primary immune organs
What can activate the complement system......
The complement system is activated by complement regulatory proteins Thus, the inactivation of the complement system would be caused by a deficiency in complement regulatory proteins. After antibodies are released into the humor, THE ANTIBODY IgM and igG is the one that activates the complement system!!!!!!
complement system
The complement system is part of the innate immune response. They are a group of about 30 blood proteins that may amplify the inflammatory response, enhance phagocytosis, or directly lyse extracellular pathogens. They are produced in the liver that works with antibodies to destroy antigens proteins in the blood that help antibodies kill their target
Some proteins can form a membrane attack complex (MAC)....
The complement system proteins can form a membrane attack complex (MAC) which specifically functions to poke holes in pathogen membranes. Once holes are created, fluid and salts can go into the pathogen and make the cell burst and die. The way this works is that membrane attack complex proteins group on the membrane of a pathogen which hence allows salts and fluids to enter the pathogen. This causes swelling within the pathogen, causing the pathogen to burst.
The first layer of the innate immunity are outer walls-physical and physiological barriers that prevent infection from entering the body. It includes....
The first layer of the innate immunity are outer walls-physical and physiological barriers that prevent infection from entering the body. This is also the body's very first line of defense. It includes the Skin, mucous, oil gland, acid, antimicrobial enzymes (lysozymes), cilia, symbiotic bacteria
The first part of the inflammatory response is rally signaling...
The first part of the inflammatory response is rally signaling. The mast cells are responsible for this, which is a type of leukocyte that sits in tissues. As soon as there is an injury, the injured tissue and mast cells work together to release the mediators of the inflammatory response such as: 1. Histamine: 2. Heparin 3. Leukotriene
The immune response can be divided into 2 categories......
The immune response can be divided into 2 categories-innate and adaptive.
The immune system..
The immune system is what protects us against hostile microbes that we are in contact with everyday. It consists of a protective outer wall and a team of well-versed soldiers who fight together to protect their kingdom—our body.
Skin....
The layers of skin are the outer thick epidermis, the dermis, and the hypodermis. Pathogens are unable to penetrate through intact skin. If any pathogen does end up entering the body through a laceration/cut then the body traps the pathogen by secreting lysozyme from mucous membranes. Lysozymes are antimicrobial proteins found in secretions such as tears, saliva, and mucous which is an enzyme that non-specifically breaks down bacterial cell walls. Sebaceous glands on the skin secrete oil (sebum) which serves as an additional physical barrier. The fatty acids contained in sebum also possess antimicrobial properties.
The lymph nodes are the major sites of ....
The lymph nodes are the major sites of B and T cell lymphocytes. These nodes can act as "filters" for foreign particles and even malignant cells! They are also encapsulated.
secondary immune organs...
The lymph nodes, spleen, and certain cells of respiratory & gastrointestinal tract = secondary immune organs
The lymphatic system.....
The lymphatic system is a network of tissues and organs that help rid the body of toxins, waste, and other unwanted materials. The primary function of the lymphatic system is to transport lymph, a fluid containing infection-fighting white blood cells, throughout the body. The lymphatic system primarily consists of lymphatic vessels, which are similar to the circulatory system's veins and capillaries. The vessels are connected to lymph nodes, where the lymph is filtered. The lymph nodes are a number of small swellings situated throughout the body in the lymphatic system where lymph is filtered and lymphocytes are formed. The lymphoid organs assist the lymphatic system. They include the thymus, spleen, tonsils, and appendix. The system consists of many tubes that will collect and deliver water and solutes from the interstitial fluid to the circulatory system ducts. Lymphatic vessels are found all throughout the body except in areas such as: the Central Nervous System, bone, cartilage, and epidermis. This is an open system....hence there is no pump for circulation. Unlike the cardiovascular system, the lymphatic system is not closed (meaning it is an open circulatory system that releases and collects fluids) and has no central pump (or heart). Lymph moves slowly in lymph vessels. Fluid from tissue spaces is returned to the blood by this system. This fluid (lymph) moves in only one direction-toward the heart. This fluid movement is due to contraction of the surrounding skeletal muscle. This is an important point, since unlike the circulatory system there is no pump!!! Lymph is very simiar to blood plasma, and it is clear-to-white fluid (the white color is due to its lipid content when in GI tract) Lymphatic vessels have walls similar to veins: 3 layers and have valves which prevent lymph backflow. Lymphatic vessels lead to specialized structures called lymph nodes (about an inch in diameter). Lymph nodes are filled with white blood cells. When you get sick, you might have "swollen glands"...these are your lymph nodes that have filled up with these immune-fighting cells called white blood cells. Hundreds are present in the human body. Sometimes a person not ill has "swollen glands", this means it is time to see an M.D. since many cancers can cause the lymph nodes to become swollen. Primary cancers of the lymph tissues are called lymphomas. Bottom Line: The lymphatic system brings lost protein and fluid to the blood. It also takes part in immune system surveillance.
The lymphatic system....
The lymphatic system removes excess fluid pathogens, dead blood cells, and cellular debris from the cells and the tissues spaces between them. The lymphatic system aids the immune system in destroying pathogens. The human body has approximately 650 lymph nodes which filter the lymph ( a tissue fluid containing water, salts, proteins, etc.) before returning to its circulation. "Swollen glands" are actually lymph nodes filled with white blood cells. Like veins, lymphatic vessels have a one-way valves. At the base of the neck, lymph enters the subclavian veins and becomes plasma in the blood.
chemotaxis....
The process of moving to a location in response to a chemical signal is called chemotaxis. Chemo= chemicals, and taxis= movement.
The Spleens main functions...
The spleen is an organ that makes lymphocytes, filters blood, stores blood cells, and destroys old red blood cells.
The Spleen...
The spleen is in the upper left part of the abdomen. It stores reserves of bood, "blood reservoir". It has the largest accumulation of lymph tissue in the body. It is the site of the "graveyard" of old, worn out red blood cells (they lost sialic acid residues on their surface and expose their galactose sugars! Which allows for phagocytosis) It produces B and T lymphocytes Think of this organ as a large lymph node (T-cell, B-Cell, and macrophages are ready to fight off invaders!) Many platelets are stored here which are involved with blood clotting. If you lose your spleen either by pathology or accident, the liver, lymph nodes, and bone marrow can complete its function. Tonsils are also aggregates to lymphoid tissue (lingual, pharyngeal, and palatine) that help guard against pathogens.
There are five main types of leukocytes.......
There are five main types of leukocytes. Here is an acronym for remembering the relative number of leukocytes circulating in the blood from highest number of cells to lowest number of cells in circulation: Never Let Monkeys Eat Bananas D (dendritic Cells) I (Interferon) Neutrophils > Lymphocytes >Monocytes/Macrophages > Eosinophils > Basophils
Epitope...
There is an important part of the antigen called the epitope. The epitope is important because it is the section of the antigen that is recognized by immune cells like B cells and T cells.
Cilia....
These are little hair-like projections, which are found in the respiratory tract They are like small brooms that sweep away unwanted guests that come in
Innate Immunity-If physical barries are penetrated....
These physical/physiological barriers serve as the first line of defense. However, if they are penetrated, the rest of the innate immune response kicks in. 1. Alarm, enemy detected-activation of the inflammatory response 2. Rally—recruitment of troops (aka, immune cells) to the site of injury 3. Battle—immune cells attack pathogens 4. Backup—activation of the complement system We will see these events in action in the following section. In cases when the innate immune response is inadequate, the adaptive immune response will step in to kill off the enemies.
The lymphatic system....
Thinking back to our discussion of the circulatory system, nutrient and gas exchange between blood and body tissues occur at the level of the capillaries. The arterial end of the capillary forces plasma out of the vessel because hydrostatic pressure is high. At the venous end of the capillary, fluid is reabsorbed back into the the vessel because osmotic pressure is high. However, not all of the fluid is reabsorbed. Thankfully , this remaining fluid (interstitial fluid = fluid between cells) is taken up by lymphatic capillaries. Lymphatic capillaries are extremely leaky, so the osmotic pressure at the venule end is enough to force the remaining fluid into them. When substances and fluid enter a lymphatic capillary, it is called lymph. Lymph is the circulating fluid found in the lymphatic system, consisting of interstitial fluid, bacteria, fats, and proteins. Certain lymphatic capillaries (lacteals) absorb dietary fats in the villi of the small intestine. Villi are small finger-like projections that increase the surface area of absorption in the small intestine. The lymphatic capillaries then begin to merge together, forming larger and larger vessels that travel toward the heart. Along the way, these vessels move through structures called lymph nodes. The lymphatic system has no central pump (it is not 'pumped' by the heart, like the blood circulatory system is), so it is a low pressure system. For this reason, the lymphatic system is similar to veins. Recall that veins are low pressure vessels that have valves to ensure a unidirectional flow. The skeletal muscle pump helps to push blood through the veins. Lymph is also pushed 'forward' by the skeletal muscle pump. The contraction of smooth muscle in the vessel walls also helps veins and lymph vessels to move fluids forward.
We can think of the innate immune system as our body's front line soldiers.....
We can think of the innate immune system as our body's front line soldiers. These soldiers attack whenever there is enemy invasion. They are quick to act but lack specificity. Since they do not have a specific target, we describe the innate immunity as a nonspecific immune response.
another type of cell that is crucial for the innate immune response — dendritic cells....
You can think of dendritic cells as surveillance guards roaming in tissues detecting potential threats. A dendritic cell can scan its local environment by taking a sip from its surroundings through a process called pinocytosis. Once it detects a pathogen, it will phagocytose the pathogen like macrophages and neutrophils. Dendritic cells are present in the skin (Langerhans cells) and in the lining of the nose, lungs, stomach, and intestine. Sometimes a dendritic cell presents itself on the surface of other cells to induce an immune response, thus functioning as antigen-presenting cell.
diapedesis....
diapedesis is the passage of blood cells (especially white blood cells) through intact capillary walls and into the surrounding tissues. Remember that leucocytes (WBCs) can leave the bloodstream by what is called diapedesis. Injured tissue releases chemical signals that cause vasodilation of capillary walls and postcapillary venules and allow for migration from the blood to connective tissues. This greatly increases during times of inflammation, which is a vascular and cellular defense-type reaction in response to invaders such as bacteria.
When activated, the complement system can do a lot of things, including:
the complement system can.. 1. Improves the 'eating' ability of phagocytosing cells ( ex. macrophages, neutrophils, and dendritic cells) by binding complement proteins C3b to antigens and tagging them for phagocytosis, a process called opsonization. Phagocytosing pathogens is not an immediate function of complement proteins, but rather a downstream effect. Complement proteins can tag pathogens, but do not phagocytose pathogens themselves. Opsonization is an important part of the adaptive immune system. It is a process where opsonins make an invading microorganism more susceptible to phagocytosis by binding a complement protein called C3b which tags pathogens, immune complexes, invading microorganisms, antigens, and apoptotic cells to make them more susceptible to the action of phagocytosis. 2. Amplifying inflammatory responses by allowing certain proteins to bind to mast cells in order to trigger a stronger histamine release. 3. Lyse pathogen membranes by allowing certain proteins to form a membrane attack complex (MAC) which specifically functions to poke holes in pathogen membranes and allow fluids and salts to go in and allow the cell to burst and die through cell lysis.
Complement System
we will talk about blood plasma proteins that participate in the innate immune response. There are approximately 30 proteins included in the complement system. They are called the complement system because they are a system (group) of proteins that exist as a side-kick to the immune cell soldiers, helping the immune cells to make the battle against pathogens more effective. The complement system is activated by complement regulatory proteins, which results in inflammation and the opsonization of pathogens. Thus, the inactivation of the complement system would be caused by a deficiency in complement regulatory proteins. After antibodies are released into the humor, THE ANTIBODY IgM and igG is the one that activates the complement system, they can also activate the complement system!!! Complement system proteins mainly tag pathogens for phagocytosis through a process called opsonization, amplify the inflammatory response by binding to mast cells for histamine release and create the membrane attack complex (MAC) to create holes in pathogen membranes causing them to burst and die through cell lysis.
