HA&P II Exam 3 Lecture Objectives
HA&P II Exam 3 Lecture Objectives Biol 2230-001
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Date Created: 03/06/16
Clemson University Spring 2016 Exam 3 Lecture Objectives Lymphatic System 1. Overview of the lymphatic system. • Relation to the circulatory system: -‐ All exchanges that occur between the circulatory system (Blood stream) and tissues have to pass through the interstitial space -‐ Fluids move out into the interstitial space from the arteriole side of the capillary bed -‐ Most fluids return to the blood stream through the venous side of the capillary bed -‐ The rest of the fluids that did not come back through the venous side are picked up by the lymphatic system • Ultimately, the lymphatic system returns the leftover fluids into circulation • Osmotic pressure is generated with the capillaries due to the proteins (Ex: Albumin) found in the circulatory system • These proteins are not able to diffuse across capillaries so the lymphatic system functions in bringing the proteins into the lymphatic vessels so that they can be put into the circulatory system • Overall: Lymphatic system functions to— a) Return fluid to the circulatory system to maintain blood volume b) Allows large molecules to pass into the circulatory system c) Filters blood fluids d) Involved with some immune function • Lymphatic system acts as a transition between the circulatory system and immune system • Lymphatic vessels: -‐ Collect interstitial fluid and ultimately return it back into the circulatory system • Lymphoid tissues and organs: -‐ Most of the lymphoid tissues are made up of reticular connective tissue -‐ Specialized organs: Lymph nodes, spleen, tonsils, thymus -‐ Lymph: o Excess fluid formed from plasma that accumulates in tissues as interstitial fluid o Fluid inside the lymphatic vessels that enters into circulation to become a part of the plasma (Again) o Fluid includes proteins that are ultimately transported to the blood -‐ Within the lymphoid tissues and organs, there are many active cells (B and T lymphocytes and phagocytic cells) that provide the immune functions for the lymphatic system • Overall: Lymphatic system has immune, blood filtration, and blood volume functions 2. Identify the lymphatic vessels, and discuss how lymph is transported through these structures. • Lymphatic Vessels -‐ Lymph flows in the lymphatic vessels one way towards the heart à Close- ended circuit -‐ Lymphatic capillaries are the smallest of the lymphatic vessels and are dead- ended structures -‐ Fluid in the interstitial space makes its way into lymphatic capillaries that travels into other lymphatic vessels until it’s dumped back into the jugular veins near the heart • Lymphatic Capillaries -‐ Smallest of the lymphatic vessels -‐ Only have one layer of tissue = endothelium -‐ Endothelial cells are anchored by connective tissue (Collagen filaments) -‐ Lymphatic capillaries are formed by loosely overlapping endothelial cells à Allows them to be able to open and close as cells get distended because of pressure difference inside and outside the capillary oSpaces are created as a result = minivalve system oMinivalves: Overlapping endothelial cells that allows fluid into lymphatic capillaries but not out -‐ Minivalve system: oHigher pressure of the fluid outside of the lymphatic capillary (Flud in the interstitial space) causes it to bed à Opens the overlapping flaps (AKA minivalve flaps) so that fluid can move in oHigher pressure of fluid inside the lymphatic capillary than outside in the interstitial space pushes the minivalves shut so that the cells overlap à Exit for fluid is shut off so that the fluid stays inside the lymphatic capillary and flows in one direction towards the heart -‐ Found throughout the entire body except in bones, teeth, and nervous system • Lacteals -‐ Lymphatic capillaries of the intestines -‐ The villi of the small intestine contains tiny capillaries that will collect stuff (lacteals) -‐ Small intestine is the site of digestion and absorption of nutrients à Some molecules are too large to go through the regular capillaries of the blood so they enter through the lacteals -‐ Lipids especially go through lacteals à circulatory system -‐ Chyle: Lymph in the small intestine lacteals à Chyle is rich in fats • Lymphatic Vasculature: a) Lymphatic Capillaries -‐ Start with tiny, dead-ended, very permeable lymphatic capillaries that are branched everywhere b) Lymphatic Collecting Vessels -‐ Some lymphatic capillaries merge into the lymphatic collecting vessel -‐ Contain tunica interna, tunica media, and tunica externa -‐ Unlike veins, lymphatic collecting vessels’ tunics are much thinner -‐ Lymphatic vessels also have valves to prevent back flow of blood (Uni directional flow) + have more valves than veins oValves are important especially because there isn’t a pump to provide pressure to push the lymph towards the heart c) Lymphatic Trunks -‐ Lymphatic collecting vessels à lymphatic trunks -‐ Lymphatic trunks: Collect and drain large regions of the body • Major Lymphatic Trunks -‐ 5 named based on areas they drain: a) Bronchomediastinal: o Located where the heart is o Drain the lungs—Middle of the thorax b) Subclavian: o Located under the clavicle o Drain upper limbs c) Jugular: o Drain from the head d) Lumbar: o Drain lower extremities or lower abdominal cavity e) Intestinal: o Drains abdominal cavity d) Lymphatic Ducts -‐ Right Lymphatic Duct: o Drains the head, upper arm, and thorax o Upper right portion of the body in general -‐ Thoracic Lymphatic Duct: o Drains the rest of the body – Lymph comes from the entire body below the diaphragm -‐ The body is divided into these two regions that are not considered to be halves—Up high = right region and down low = thoracic region -‐ Both ducts connect at the junction between the jugular and subclavian veins (The jugular connection is where the lymph goes back into the blood stream in the circulatory system) • Factors Assisting Lymphatic Flow -‐ Valves: o Support unidirectional flow of lymph towards heart -‐ Muscular pump: o Activity of skeletal muscle helps push fluid in one direction along with working with the valves o In terms of lymph filtration: § Ex: If there is a puncture wound in the skin, it is possible for bacteria to have entered the fluid in the interstitial space à It is necessary to filter this through the lymph organs (Such as spleen) § Being physically active allows the body to filter the lymph and blood even more to remove disease causing agents— muscular pump helps prevent illness as a result and speeds up recovery in -‐ Respiratory pump: o During low pressure status in the chest, the lymph is allowed to move more easily -‐ Arterial pumping: o Lymph vessels are located next to arteries so when blood has a wave pushing it through the blood vessels, the wave also helps the lymph vessel to have the same sort of effect -‐ Smooth muscle contraction: o Even though the tunica media is very small in the lymphatic arteries, the smooth muscle contraction will still help move the lymph towards the heart o Smooth muscle contraction is especially important with the lymphatic trunks and thoracic duct -‐ Gravity can also play a role in helping lymph from the top part of the body to move towards the heart 3. Differentiate the lymphoid cells. • Lymphocytes: -‐ White blood cells that are mostly composed of nucleus -‐ All made in the red bone marrow -‐ B lymphocytes: o Immune function o Lymphoid follicles of the cortex of a lymph node contain germinal centers that are dominated by B lymphocytes, which produce antibodies against antigenic agents o When encounters a pathogen such as a bacterium in a blood stream: Triggered to produce plasma which starts to produce antibodies that can attach to foreign cells with specific markers à Marks the foreign cell to be destroyed by something like a macrophage o AKA B lymphocytes do not destroy pathogens themselves (Mark them for destruction by other cells) -‐ T lymphocytes: o Immune function o Directly attacks and destroys foreign cells that have already invaded our body cells (NOT a free floating pathogen at this point) o Attaches to pathogen and through secretion of chemicals, it causes the pathogen to lyse and break apart -‐ Able to produce memory cell after interacting with a foreign substance for the first time • Macrophages: -‐ When monocytes diapedese and leave the circulatory system à Interstitial space to become a macrophage -‐ Phagocytic cell -‐ Activate T cells -‐ Take in foreign cells and starts to break it up à T lymphocyte comes and kills it -‐ Function in the stroma in lymph organs • Dendritic Cells: -‐ Phagocytic -‐ Activate T cells -‐ Take in foreign cells and then T cell comes to kill pathogen -‐ Function in the stroma in lymph organs -‐ *Macrophages and dendritic cells difference in their mechanism by which they attach to foreign cells • Lymphoid Cells: Reticular Cells -‐ Reticular cells have reticulocyte fibers that make the mesh/network to produce stroma that can house/hold other cells temporarily such as macrophages -‐ Filter the lymph à Lymph is able to pass by active cells that can detect foreign cells and get rid of them • Lymphoid Tissue -‐ Lymphoid tissue—Mainly made up of reticular cells -‐ In the lymph node, it has a nodular component that contains the stroma = germinal centers -‐ Germinal centers: o Have the reticular cells holding cells such as macrophages, lymphocytes, etc. à Everything is held in place temporarily (Some move in and out) o Proliferation for lymphocytes (Location where the other types of cells in the lymphoid organs proliferate/accumulate in the centers) o Allows detection of infection or damage: § As lymph passes through lymphoid tissue, impurities can be attacked and removed before the lymph goes back into the circulatory system -‐ Thymus does NOT contain reticular tissue o All embryonic tissue is derived from the mesoderm but the thymus isn’t o Thymus develops first though and controls the development of lymph organs 4. List the lymphoid organs, discuss their functions, identify their histological makeup and compare their modes of action. • Lymph Nodes -‐ Principal lymphatic organs of the body -‐ Accumulations of lymph nodes are found along the larger lymph vessels so that as the lymph passes through the vessels towards the heart, the lymph nodes filter it -‐ Lymph nodes possess germinal centers with accumulations of lymphocytes à Detect foreign substances and initiate immune responses • Spleen -‐ Largest lymph organ -‐ Located behind the stomach -‐ Allows lymphocyte proliferation + detection of foreign substances = immune function -‐ Site of blood cleansing too (Site of breakdown)à Removes aged and defective cells + gets rid of platelets and recycles these components -‐ The spleen contains many macrophages à phagocytosis of foreign cells -‐ Plays an important role with infants: -‐ Blood cells are produced in red bone marrow -‐ Infants are generally born without an intact skeletal system so the bone marrow isn’t fully functional -‐ Babies/embryos then obtain blood cells from the spleen -‐ Overall in adults the function of the spleen is to filter lymph, recycling red blood cells, and cleanse the blood • Lymphoid Organs: Thymus -‐ Thymus is very active in new born babies à decreases in size as get older -‐ Promotes immunocompetency in T cells à Gives the cell the ability to interact with something foreign -‐ Each class of T lymphocytes bind to specific receptors on foreign cells -‐ B lymphocytes become immunocompetent in the bone marrow • Lymphoid Organs: Tonsils -‐ Gather and remove pathogens entering the body through the food that is being consumed or air breathed -‐ Located in oral and nasal cavities • Lymphoid Organs: Peyer’s Patches -‐ Located in the distal part of the small intestine -‐ Able to destroy bacteria • Lymph Node Action -‐ A cortex and capsule surround the whole lymph node -‐ At the center is the medulla -‐ Hilum: Depression/indention of a lymph node -‐ Contains 2 different draining lines -‐ Lymph that is flowing through the lymphatic vessels enters the lymph node via afferent lymphatic vessels and passes through the cortex through the sinuses to the germinal centers where there is reticular tissue with macrophages and macrocytes that filter the lymph -‐ Next, the lymph goes to the medulla and exits at the hilum where it is then pushed out through efferent lymphatic vessels -‐ There are fewer efferent than afferent lymphatic vessels à Means that the flow of lymph is slowed down so that there is lymph filtration efficiency -‐ Efferent lymphatic vessels can lead to other lymph nodes where the lymph can be filtered again -‐ Mastering HA&P Description: Afferent vessels deliver lymph to the lymph node. The lymph then filters through the subcapsular sinus of the node and then into a number of smaller sinuses that cut through the node's cortex and lead into the medulla. Eventually, lymph exits the node via the hilum and is carried away by efferent vessels • Spleen Action -‐ Blood vessel supply goes directly to the spleen through the splenic artery -‐ White pulp: Surrounds the blood vessel -‐ Fluid in the blood is pushed through the white pulp so that it is filtered and then it gets pushed out through red pulp à splenic vein à back to circulation -‐ Red pulp: Makes up most of the spleen that surrounds the white pulp -‐ Again: Spleen gets rid of old cells, recycles, and checks fluid for impurities • Thymus Action -‐ Secretes 2 chemicals: Thymosin and thymopoietin à Can trigger white blood cell production in the red bone marrow -‐ Chemicals cause immunocompetency to occur in T lymphocytes -‐ No reticular tissue is in the thymus so no filtration of lymph occurs (Nothing is there to hold the other cells in place that function in the filtration) • Palatine Tonsils -‐ Multiple sets of tonsils are in the body -‐ Filter food and air that is breathed à Pass the pharynx where the tonsils are there to stop pathogens -‐ Tonsil names are based on where they’re located -‐ Largest tonsil: Palatine à Located in the back of the throat on each side of the oral cavity where they meet the pharynx and is the one more lastly to become infected and removed via tonsillectomy • Lingual Tonsils -‐ Two are located on each side under the base of the tongue • Pharyngeal Tonsil (Adenoids) -‐ Single one located on the posterior wall of the nasal cavity -‐ Often times when the palatine tonsils are removed, the adenoids are also removed since they’re easy to get to • Tubal Tonsils -‐ In order for hearing to work, the middle ear has to be equal to the atmospheric pressure -‐ There is the pharyngeal tube that runs down the middle pharynx and it is where the tonsils surround the tube • Tonsil Histology -‐ Follicles with germinal centers -‐ Crypts: Dead end ally ways à As swallowing or breathing the liquid or air gets into the crypts à Diffuses into lymphatic tissue à Passes through germinal centers with reticular tissue to get filtered • Tonsil Action -‐ Crypts trap bacteria and other particulates à Bacteria cross membrane and get into tonsil tissue ultimately passing through reticulocytes where all the lymphoid cells accumulated in the germinal centers that destroy pathogens – In this process, memory cells can be formed • Peyer’s Patches -‐ Isolated clusters of lymphoid follicles in the distal portion of the small intestine that destroy bacteria -‐ Contain lymphoid tissue that filters chyle -‐ Produce memory cells especially since food that is being digested and the absorbed is likely to be there again 5. Outline the development of the lymphatic system. • 5 week post-conception is when the production of lymphatic vessels begins • Lymph sacs bud off developing veins and are first to form on the jugular veins à Where the connection is going to be for the lymphatic and circulatory systems • Some lymph sacs form on the vena cava and iliac veins (Low at bottom thoracic trunk) • Lymph sacs then begin to branch: Start with the big vessels and branch down to the small ones (Different than how arteries and veins develop) • Jugular lymph sac attaches to the jugular vein to become the right lymphatic duct and thoracic duct • All organs except the thymus come from the mesodermal mesenchyme that becomes reticular tissue • Lymphoid organs develop and migrate to different parts of the body • Thymus: -‐ Endoderm derivation -‐ Outgrowth of pharynx that detaches and migrates to the thoracic cavity -‐ First lymphatic organ to form -‐ Starts to accumulate lymphocytes until after birth -‐ Secretions of thymocytes (Thymopoietin and thymosin) are important in the regulation of development of other lymphatic organs Immune System 1. Differentiate the nonspecific and specific immune pathways. • Immune System -‐ Immune system doesn’t have numerous organs working together but instead it has functions working together that bring about an immune response -‐ Immune System can: o Prevent the entry of pathogens into the body o Prevent the spread of pathogens throughout the body by keeping the pathogenic problem to one area + killing it if there was a breech -‐ Pathogen: A disease causing agent -‐ Antigen: Foreign thing that the body wants to get rid of it enters the body (Can include pathogens) • Nonspecific Immune System -‐ AKA innate immune system -‐ Part of the immune system that attacks anything foreign -‐ Consists of external body membranes and can include inflammatory response -‐ Inflammatory Response: o Ex: Cut on the body § The inflammatory response is activated since the membrane of the skin was cut and some substances were able to enter through the breech § Inflammatory response works to try to keep the foreign substances localized to that area so that they don’t spread to the rest of the body o Ex: Mosquito Bite: § Can see where the inflammatory response keeps the foreign substance localized • Immune Systems: Specific Immune System -‐ AKA adaptive immune system -‐ Individual cells respond to certain and specific foreign substances -‐ Includes B and T lymphocytes -‐ Ex: There are B lymphocytes that only respond to Staphylococcus 2. Identify the nonspecific defenses, both superficial and internal. • Superficial Nonspecific Defenses: Skin -‐ Unbroken epidermis is a great barrier to antigens/pathogens -‐ Epidermal tissue does not have a blood supply à Means that the skin is made up of squamous epithelium that is mostly dead -‐ Have protein layers stacked up on top of each other = barrier • Superficial Nonspecific Defenses: Mucous Membranes -‐ A mucosal lining can be found on all internal body cavities that is composed of epithelial tissue and also creates a physical barrier -‐ Mucous membranes also secrete mucous that act like a trap so that any foreign substances inside the body can be stuck in the cavities of the mucous membranes -‐ Mucous secretions create an acidic environment à Foreign cells can be destroyed by the acids -‐ Production of protein digesting enzymes that are able to break down foreign substances with a protein coat -‐ Some mucous membranes can produce lysozymes: Enzymes in lysosomes that are able to break apart foreign substances (Can be found in tears, saliva, etc. *Overall: Skin and mucous membranes function to keep foreign substances out of the body, but the barriers can be breeched so there is a need for additional nonspecific mechanisms • Internal Nonspecific Defenses: Phagocytes -‐ Phagocytosis: Phagocytic cells surround something that is foreign by extending their cytoplasm and bring it inside a vacuole to destroy it -‐ Free phagocytes: Found in circulation -‐ Fixed phagocytes: Found in the lymph organs that hang out in the reticular cells -‐ Phagocytes: o Macrophages: o Derived from monocytes that escaped from circulation through diapedesis o Neutrophils: o Continuously in circulation in the blood stream o Become phagocytic when they bind to a foreign cell o Eosinophils: o Continuously in circulation in the blood stream o Attack internal parasitic worms • Internal Nonspecific Defenses: Mast Cells -‐ Mast cells are somewhat phagocytic but are different than phagocytes in the way they find the foreign substance and bring it inside the mast cell -‐ Have specific receptors that are non-specific à Means that mast cells can bind to a number of different things that then digest the bound components and kill them -‐ Mostly bind to bacteria • Internal Nonspecific Defenses: Natural Killer Cells -‐ Natural killer cells are a class of lymphocytes (In addition to the T and B lymphocytes) that circulate in the blood stream so that when they encounter anything abnormal, they automatically kill it -‐ Lyse foreign substances and not phagocytize them -‐ Attack cancerous cells or cells infected by a virus -‐ Cancerous cells are abnormal cells -‐ Virus within a cell: Parts of the virus appear on the surface of the body cell so that it looks weird à Therefore, natural killer cells attack any cell that does not look normal • Internal Nonspecific Defenses: Inflammation -‐ Inflammation is the result of the dilation of capillaries that become larger and porous -‐ 4 Symptoms of Inflammation: a) Redness: o Capillaries are dilated so more blood is able to rush to the site of damage o Blood pigment is red so because there is more blood, the area will appear more red b) Swelling: o When the capillaries dilate, they become more permeable o Fluids leak out of the bloodstream and accumulate as a result to create swelling c) Heat: o Blood is warmer than the rest of the body o Therefore, when blood accumulates in one spot à That location will feel much warmer than the rest of the body d) Pain: o As fluid accumulates at the site of inflammation, it causes pressure that activates pain receptors -‐ Purpose of inflammation: By delivering more blood to the site of damage, more most mast cells, natural killer cells, phagocytic cells, etc. can be delivered to fight off foreign substances in a non-specific fashion + keeps the foreign substances from leaving that location • Internal Nonspecific Defenses: Antimicrobial Proteins -‐ Antimicrobial Protein: Attack microorganisms by destroying them or interfering with their reproduction (Like with viruses) -‐ Interferon: o Antimicrobial protein secreted by a cell infected by a virus in order to signal neighboring cells to induce changes to protect themselves form the virus o Disrupts viral replication in neighboring cells so that they can’t reproduce -‐ Complement System: o Involves more than 20 different proteins that function in complement o Blood proteins that circulate in the blood o If they become activated, complement system (proteins) promote inflammation o Some complement proteins can cause lysis to occur • Internal Nonspecific Defenses: Fever -‐ Fever: Elevation of body temperature à Systemic response -‐ Interferes with replication of foreign cells • Phagocytic Mechanism (Phagocytosis) -‐ Phagocyte recognizes pathogen’s carbohydrate surface markers o Phagocytes are able to differentiate between body cells and pathogens because “Self” markers on body cells are MHC (Major histocompatibility complex) and pathogens do not have the MHC self marker -‐ *(Phagocytes located in the body and in interstitial space and lymphatic organs are not active until they encounter a foreign cell) -‐ Opsonization: o Enhances the recognition of a foreign cell o Antibodies that attach to the foreign cell are able to flag it and make it easier to be found and destroyed -‐ Adherence: Phagocytic cells attach to the foreign cell by sending out cytoplasmic extensions that adhere to the pathogen -‐ After adherence to the pathogen, the phagocyte brings the foreign cell into its own body in vacuole à Phagocyte + pathogen inside = phagosome -‐ Phagosome combines with lysosomes (Carry lysozymes) to forms a phagolysosome so that the lysozymes break down the pathogen -‐ Lysozymes can be aided by respiratory burst (Additional chemicals) in breaking down pathogen -‐ Breakdown products: o Residual bodies still contained within the phagosome that are expelled out of the phagocyte and filtered through the blood and lymph to be expelled as waste • Natural Killer Mechanism -‐ Natural killer cells detect body cells that have become cancerous or infected through lack of “Self” (MHC) markers or by the presence of certain sugars -‐ Key that natural killer cells detect problems with body cells and NOT foreign cells -‐ Adherence of a natural killer cell to an abnormal body cell activates the natural killer cell to release perforins (proteins) that lead to a cytotoxic T cell process (Both T and catural killer cells use the same key mechanism— discussed later) à natural killer cells bore holes into the plasma membrane to disrupt the cell and cause it to become fractured -‐ Channels in the plasma membrane of the target cells result to allow the formation of holes in the nuclear membrane as well so that the nucleus disintegrates • Inflammatory Mechanism -‐ Macrophages have toll-like receptors that are non-specific on their surfaces that recognize pathogens -‐ When the toll-like receptors bind to the pathogen, cytokines are released -‐ Cytokines promote inflammation à signaling capillaries to dilate -‐ Cytokines also attract white blood cells wherever they are produced (Exhibit positive chemotaxis) -‐ Activation of the toll-like receptors on a macrophage causes other cells in the same area to release other chemicals that are inflammatory mediators such as histamines, prostaglandins, or any sort of chemical with a localized change or effect -‐ Cytokines signal blood vessels in the injured area to dilate and increase permeability à hyperemia: Excessive blood -‐ Increased permeability allows the plasma to leave the capillary and move into the interstitial space à Exudate (Fluid and clotting factors containing antibodies that have left circulation and that accumulate at the site where the capillary is most permeable) -‐ When exudate accumulates this leads to swelling, which is also known as edema -‐ Edema functions and effects: o Helps to dilute the foreign substances à more exposure for the immune system to be more efficient in detecting the foreign substances o Brings oxygen and nutrients to activate other substances like enzymes o Carries clotting proteins to plug breaks in a barrier with a clot • Results of Inflammation -‐ Injured cells release leukocytosis-inducing factors à Cause neutrophils to be released from the red bone marrow -‐ Leukocytosis: Higher than normal numbers of neutrophils in the blood -‐ Loss of fluids slows blood flow locally -‐ Flow of fluids leaking out of the bloodstream à low blood pressure à ultimately slows down blood flow -‐ Neutrophils are able to accumulate at the site of damage due to the slow blood flow -‐ Some neutrophils will be grabbed and held near the site of damage due to endothelial cells from inside the wall of a capillary secreting selectin -‐ Margination: The process of holding neutrophils at the wall of a capillary near the site of damage -‐ Neutrophils held on the cell wall of capillaries near the site of damage will then diapedese and escape the capillaries -‐ Neutrophils are phagocytic cells that attack foreign substances -‐ Inflammatory chemicals (Includes selectins and mediator chemicals) act as chemotactic agents that mostly attract neutrophils to an area of damage -‐ Once neutrophils have escaped the walls of the capillaries, monocytes follow out (Diapedese) of the capillaries as well and become macrophages -‐ Macrophages have more lysosomes (Full of enzymes that break substances apart) • Interferon Mechanism -‐ Cells infected by a virus release interferons (IFN) -‐ Interferons diffuse into neighboring cells that causes them to synthesize PKR protein that interferes with viral replication through prevention of use of the host cell’s machinery -‐ Interferons also activate macrophages and natural killer cells • Complement System Mechanism I -‐ Antibodies bind to antigens/pathogens (Opsonization has occurred) o Antibodies binding to specific antigens is part of a specific immune response that can invoke a non-specific action (Here the complement proteins) -‐ Complement proteins bind to antibody-pathogen complexes -‐ Lysis, phagocytosis, and inflammation result -‐ Complement proteins circulate in the plasma portion of the blood and wait to be called to action • Complement System Mechanism II -‐ Complement proteins bind directly to the polysaccharide molecules on the antigen/pathogen (Skip antibody attachment step) -‐ Lysis, phagocytosis, and inflammation result • Fever Mechanism -‐ Leukocytes and macrophages exposed to pathogens secrete pyrogens -‐ Pyrogens signal the hypothalamus to elevate body temperature -‐ By increasing whole body temperature, the availability of iron and zinc is reduced which are important components that bacteria used to divide à Bacteria eliminated as a result since they aren’t able to divide -‐ Pyrogens also elevate metabolic activity à One way of producing the necessary heat o Heat is produced from shivering when you feel cold even though the body temperature can be at 102+ degrees F o Then fever breaks 3. Define antigen, and describe how antigens affect the immune system. • French • Any substance that promotes an immune response (Anything foreign) 4. List and define the properties possessed by antigens. • Antigens demonstrate immunogenicity • Reactivity: -‐ Markers on the surface of cells are able to interact with antibodies or lymphocytes -‐ Antigens promote interactions with immune cells due to their reactive components (Antigenic determinants) • Antigenic determinants: Reactive parts of a an antigen that gives it immunogenicity 5. Identify the “self” antigens. • Body cells have genetically determined markers on their surface = “self” antigens that are also known as MHC markers • MHC markers are not immunogenic to us (Not reactive/immune system wouldn’t attack them) • Our own MHC markers would be immunogenic to other individuals except for those with identical twins 6. Differentiate the humoral and cell-mediated specific immune responses. • Characteristics of Specific Immunity -‐ AKA adaptive immunity -‐ Pathogen specific -‐ Specific immunity is not immediately active à When specific immune cells come in contact with the specific antigen, there is a delay before the specific immune cells become fully active -‐ Systemic with specific immune cells circulating the body all the time scanning for specific pathogens -‐ Provides memory: The activation of specific immune cells will cause the production of more of those cells that will then interact with the antigen faster the next time it encounters it (Time lag is shortened as well) • Humoral -‐ Humoral: Fluid -‐ Specific immune cells interact with antigens that are free floating (Found in the blood stream and circulating the body) -‐ Humoral pathway is an antibody-mediated pathway since antibodies detect the free floating pathogens (Uses B lymphocytes) -‐ Antigens + antigenic determinants on the surface of an antigen along with the antibodies are specific -‐ Antibodies do NOT kill the specific antigen directly à It is marked so that another immune cell can kill it, such as complement proteins or phagocytic cells -‐ In general, a specific immune response is able to activate a non-specific immune response -‐ Main point: Humoral pathway marks antigens for destruction • Cell-Mediated -‐ Pathway where one of our body cells has become infected so the T lymphocytes will attack and kill the infected body cell -‐ This process is similar to that of the natural killer cells, except that the natural killer cells attack anything à Each T lymphocyte in the cell-mediated pathway can only bind to a certain type of infectious agent -‐ Main point: Cell-mediated pathway kills infectious agents directly by cell lysis 7. Compare the origin, maturation and action of B and T lymphocytes. • Humoral: B lymphocytes • Cell-mediated: T lymphocytes • All lymphocytes are produced by stem cells in the red bone marrow • Immature lymphocytes are virtually identical until they mature • Immature lymphocytes migrate to the bone marrow or thymus (Primary lymph organs) to become immunocompetent (Point where receptors are required to interact with a specific antigen and its antigenic determinants) • T lymphocytes: Immunocompetent in the thymus • B lymphocytes: Immunocompetent in the bone marrow **Immunocompetent T and B lymphocytes still have to remain in secondary lymph organs (Spleen, lymph nodes, etc.) until they mature and even when they are mature, they are not fully functional until they bind to an antigen • Lymphocyte Production: Recap -‐ Produced by stem cells in red bone marrow -‐ T cells become immunocompetent in thymus -‐ B cells become immunocompetent in bone marrow -‐ Immunocompetent cells mature in secondary lymphoid organs -‐ Not fully functional until bound with antigen 8. Describe the role of antigen presenting cells. • Engulfs pathogen and presents its fragments as antigens 9. Define antigen challenge. • Cell-Mediated Immune Response -‐ Review: st o 1 lnde of defense (Non-specific): Protective barrier o 2 line of defense (Non-specific): Keeping the antigen in one spot + attempting to eliminate it o 3 line of defense (Specific): Specific approach where the specific immune system tries to target invaders and kill them th o 4 line of defense (Specific): After body cells have become infected, the immune system has to attack its own altered body cells and lyse them -‐ Non-specific immune system keeps working even though it may not initially solve the pathogenic problem • Antigen Challenge -‐ Antigen challenge: First encounter between a specific naïve immunocompetent lymphocyte and antigen -‐ Review: o Lymphocytes are produced in red bone marrow à lymphocyte à primary lymphoid organ (Bone marrow or thymus) à Immucompetency achieved o Cells producing proteins due to genes are expressed on the surface of the cell that become the receptors specific for their specific antigens -‐ Immunocompent lymphocyte: Can interact with specific antigens but won’t yet -‐ Naïve competent cell: Ready to interact with specific antigen but hasn’t yet 10. Differentiate primary and secondary humoral responses. • Primary Humoral Response -‐ Antigens in the humoral pathway are free floating in the fluids in the plasma and lymph -‐ Antigens bind with surface receptors on naïve immunocompetent B lymphocytes -‐ When the specific antigen and immunocompent B lymphocyte connect à B lymphocyte becomes active and the clonal sectional process is stimulated -‐ Clonal Selection: When the cell grow and multiplies to produce clones of that particular lymphocyte with identical receptors for that specific antigen -‐ Most clones produce and become plasma cells that produce antibodies (Mark specific antigen for destruction) -‐ Some clones instead of producing plasma cells and therefore antibodies are stored/remain as memory cells that wait to respond to another of the same infection in the future (Secondary humoral response) -‐ Primary Humoral Response: The very first encounter between a naïve immunocompetent lymphocyte and its specific antigen • Secondary Humoral Response -‐ Refers to any subsequent exposure -‐ Same mechanism as primary humoral response but is much more rapid and produces a lot more antibodies (Higher titer- concentration of antibodies) that last longer (For months) -‐ Figure: a) Primary humoral response to antigen X: Takes about 7-10 days for us to reach maximum titer (maximum number of antibodies) that lasts for about 4-5 days that then declines o AKA primary response characteristics include, lag, limited antibody production and short duration b) Secondary humoral response to antigen X: More rapid, more antibodies produced (higher titer) and last longer c) Exposure to antigen Y is shown along with secondary exposure to antigen X so that primary humoral response is induced again for antigen Y 11. Compare and contrast active, passive, natural and artificial humoral immunity. • Refers to how to get antibodies present in the body for humoral responses • Active Immunity: -‐ Our own system makes the antibodies due to a full-blown antigen being present -‐ AKA: Antigen activate B lymphocytes to produce plasma to produce antibodies • Passive Immunity: -‐ Obtaining antibodies from a source other than our own bodies -‐ AKA: Antibodies were produced somewhere else • Natural and artificial immunity • Combinations: a) Natural Active Immunity: -‐ Similar to active immunity in that we had to have been infected by a full- blown pathogen to induce production of antibodies by our own body b) Natural Passive Immunity: -‐ Ex: Antibodies are produced by the mother that pass across the placenta and are given to the baby -‐ Ex: Antibodies produced by the mother that are passed to the baby through breast milk c) Artificial Active Immunity: -‐ Immunizations are where an attenuated (weakened) antigen is injected so that it won’t make you sick but it still activates an immune response so that the body can make its own antibodies d) Artificial Passive Immunity: -‐ Vaccines are where antibodies (Called immunoglobulins here) are injected into another body -‐ Antibodies have been made to fight off infections for you 12. Describe the structure of an antibody. • Antibodies are complex proteins à Made up of 4 subunits • Also called immunoglobulins or gamma globulins • 2 identical light chains: Variable region à Have antigen binding sites to determine what antigen the antibody will bind to • 2 identical heavy chains: Constant region à Same in each antibody and dictates how an antigen will be destroyed • Some constant regions will bind complement proteins that will lyse cells and kill them, attract phagocytic cells, or simply mark the antigen for destruction (Ex: By phagocytosis with a dendritic cell or macrophage) • Classes of Antibodies -‐ Most antibodies are single units with light (short) chains that bind the antigen and heavy (long) chains that destroy the antigen -‐ IgD: o Receptor on the surface of a B lymphocyte o Is incorporated into the B lymphocyte to make it immunocompetent -‐ IgG: o Most abundant of all antibodies o Main antibody present in the late portion of the primary and secondary response o There is a longer lag time in the production of IgG than others because they have to get to the end of the responses before circulating in the plasma to fight off antigens o Can invoke passive immunity by crossing the placenta o Bind to specific antigen and use complement proteins and otherwise exhibit phagocytosis (On the heavy chains) -‐ IgE: o Don’t have many IgE o Increase seen with individuals with allergies o Can bind to mast cells that have engulfed a foreign substance and tells basophils to release histamine granules o Overalll: IgE cause the production of histames that causes IgE to replicate -‐ IgG:IgE à IgE should be far more numerous, but if there isn’t much for the immune system to do, the IgE will respond to allergens -‐ In order to control allergies, suppression of IgE leads to suppression of histamine response -‐ IgA: o Dimer: 2 units (monomers) are attached together à Have 4 receptor sites (Instead of the usual 2) on the variable region and constant region o Tend to accumulate in mucous and other body secretions o Binding to their specific antigens prevents the antigens from attaching to epithelial cells -‐ IgM: o Pentamer: 5 monomers are attached together à Have 10 receptor sites o First antibody secreted by plasma cells during a primary immune response to help prevent the spread of the foreign substance (IgG are produced later in the response and have more of these than IgM) o Can be used in a diagnostic test to see if an individual has had a recent infection or an older infection o Readily fixes and activates complement o Promotes agglutination: § Agglutination: Antigens bound to IgM clump together and are isolated in one spot so that non-specific cells (Ex: Natural killer and phagocytic cells) are drawn towards that area 13. Identify the general functions of antibodies. • Formation of antigen-antibody complex à Mark antigens for destruction through variable site • Provides site for binding of complement proteins through the constant region - Complement protein fixation à Secretion of perforins that cause lysis of cells (Or due to another cytolytic chemical) • Blocks sites on pathogens so they won’t be able to bind to other cells in the bodyà Neutralization process in neutralizing the antigen so it won’t attack our bodies (Ex: IgA function) • Cause clumping of antigen-containing cells that allows greater phagocytosis efficiency in keeping the antigens in one spot à Sometimes they can still be traveling throughout the body • Cause clumping of soluble antigen molecules: It’s even better to precipitate out the antigens so they don’t have to travel as much à Again, taking the soluble antigen molecules out of solution helps so that phagocytes can have better access to the antigens • Monoclonal Antibodies -‐ Commercially produced antibodies -‐ Process: o Infect another organism o Organism produces antibodies o Collect blood serum or plasma o Extract antibodies to be used for vaccines, research, cancer treatment, etc. 14. Describe the general mechanism of the cell-mediated immune response. • Part of B lymphocytes functions to attract phagocytes to infected body cells in addition to trying to eliminate free floating antigens in the humoral response • Cell-mediated response has to do with an infected body cells à A naive immunocompetent T cell is going to bind with one of the antigen infected body cells that does not have a normal MHC “self” marker • T lymphocyte with the specific receptor will bind to that infected cell (AKA T cell has bound to an antigen presenting cell) • Next, a second binding has to occur where the other arm has to bind to something else to release costimulatory signals that help activate T lymphocytes • Key: After the T lymphocyte has bound to the infected cell with one arm and the binding of something to the other arm has occurred to allow the release of costimulatory cells, the T lymphocyte has then been activated -‐ This is different than B lymphocytes where when a B lymphocytes attaches to an antigen it is activated • Activated T cell will go through clonal selection to produce more T lymphocytes with receptors for that specific antigen + some clones will remain as memory cells for future encounters of the same infection • *T lymphocytes do NOT produce antibodies but they attack altered body cells 15. List the various types of T cells, and identify the role each plays in imparting immunity. • There is more than one type of T cell • CD4 and CD8 cells differentiation is due to differences of markers (glycoproteins) on the surfaces of these T cells that ultimately affect what antigens they can bind to • T Cell Activators -‐ CD4 Cells: T C4lls à Helper T cells -‐ CD8 Cells: T C8lls à Cytotoxic T cells/Killer T cells -‐ Differences between the 2 T cells: Antigens they’ll attach to and what activates them -‐ Two classes of altered MHC “self” markers on body cells that activate T cells: a) Class I MHC Protein-Linked Antigens: CD8 o Endogenous (Produced by the body) o Antigen part comes from the body itself o A virus affects a body cell that has MHC + part of virus (antigen) present on the surface o Cancerous cells included o All body cells can produce MHC except for red blood cells o Any body cell that is infected will put antigen on surface of cell o T (CD8) or cytotoxic cells interact with class I MHC 8 b) Class II MHC Protein-Linked Antigens: CD4 o Exogenous (Antigen part is produced outside of the body and is foreign) o Found on phagocytic cells that engulf bacteria o T (CD4) or helper T cells interact with class II MHC • Cell-Mediated Immune Response (Overall) -‐ T cell antigen receptors bind to antigen-MHC complex (Infected body cell) -‐ Co-stimulatory signals are present o Then there has to be a second step where there binding to other receptors on APC (Antigen presenting cells) that causes the production of costimulatory signals such as cytokines and interleukins o Each costimulatory signal promotes a different response that either facilitates or disables activation o T lymphocyte is activated after antigen binding and constimulatory signal release -‐ T cell is activated -‐ Clones are produced -‐ Some clones become memory cells • Cytotoxic T Cells -‐ Cytoxic T cell = CD8 cell -‐ Directly attacks and kills cells with Class I MHC -‐ Therefore, once the CD8 cell attaches to the specific antigen and the costimulatory signals are present, the infected body cell is lysed and broken up • Helper T Cells -‐ Helper T Cells = CD4 cells that bind to Class II MHC (Phagocytic cell engulfed something foreign) -‐ Once the helper T cells have attached to the antigen and the co-stimulatory signals are released, the helper T cell is activated -‐ Activated helper T cells activate CD8 (cytotoxic) T cells and B cells -‐ B cells are released as a result and attach to the foreign antigens directly -‐ CD8 cytotoxic T cells are recruited to kill the exogenously infected cells (Class II MHC) -‐ Overall: Helper T cells (CD4) link the B and cytotoxic (CD8) T cell sides à Regulatory cells that regulate the activity of other cells • Suppressor T Cells -‐ One T cells are activated à Clonal selection and clones are continued to be produced until suppressor T cells shut them off -‐ Cytokines produced by costimulatory signals or lysis chemicals produced by T lymphocytes activate suppressor T cells that produce other chemicals to stop clonal selection to ultimately stop the immune response -‐ In general: Suppressor T cells are activated by chemicals that activated the T cells to begin with or the chemicals produced by T cells that are released in the process of the antigen they are trying to kill • Primary Immune Response Summary 16. List specific examples of immune disorders. • Immune Disorders -‐ Immunodeficiency: o Any condition that causes the immune cells to behave abnormally o Could be insufficient production of immune cells o Could be that there are enough immune cells that aren’t doing their proper function -‐ Autoimmune Diseases: o When the immune system attacks its own body cells (Can’t distinguish MHC “self” markers vs. the antigen markers) -‐ Hypersensitivities: o When the immune system responds to stimuli that wouldn’t normally activate the immune system (Harmless cells that are antigenic) o Ex: Allergies caused by allergens (antigens) • Immunodeficiencies -‐ Congenital Immunodeficiency: o Genetic, inborn, from birth o Ex: SCIDS (Severe Combined Immunodeficiency Syndrome) à Fails to produce enough T and B lymphocytes so that even the smallest infection can be detrimental -‐ Acquired: o Ex: AIDS (Acquired Immunodeficiency Sydrome) à HIV virus causes AIDS by destroying helpter T cells § It’s subsequent infection that kills a person with HIV since there are no helper T cells available to get rid of the infection • Autoimmune Diseases -‐ Multiple Sclerosis: o Destroys the myelin of the white matter in the brain and spinal cord o Lose conductivity and can’t send electrical signals à Loss in muscle control and movement -‐ Myasthenia Gravis: o Immune cells attack neuromuscular junction in skeletal muscle o Impairs communication between nerves and skeletal muscles o Ex: Loss of control of eye muscles as seen in picture -‐ Grave’s Disease: o Immune system attacks the thyroid gland so that it produces excessive amounts of thyroxine o Bulging eyeballs is one symptom -‐ Juvenile Diabetes: o Type I Diabetes o Immune system attacks the pancreatic cells that produce insulin o Results in insufficient insulin production -‐ Lupus: o Immune system attacks the kidneys, heart, and lungs o Skin lesions association to where someone looks like they have been bitten by a dog or wolf o Butterfly rash = distinguishing characteristic -‐ Rheumatoid arthritis: o Immune cells attack the synovial membranes o Joints destroyed à rheumatoid arthritis • Hypersensitivities: Immediate -‐ Immediate (Acute) à Anaphylaxis o Response to allergen occurs within contact -‐ Anaphylaxis: o Systemic release of histamine that causes systemic vasodilation à incredible drop in blood pressure o Often fatal -‐ EpiPen: o Someone is told to carry this after there has been a warning in an initial episode where the person’s body responds to something and loses the ability to breathe, drop in blood pressure, etc. o Epinephrine is contained in the EpiPen and causes vasoconstriction so the vasodilation is reversed temporarily (Must get to the hospital still as soon as possible) • Hypersensitivities: Subacute -‐ Subacute: o Response to an allergen occurs a few hours after the initial contact -‐ Transfusion reaction: o When the wrong blood type is injected in another individuals body à The body starts to reject the blood • Hypersensitivities: Delayed -‐ Delayed: o Response occurs 1-3 days after contact with the allergen -‐ Poison ivy reaction 17. Identify the reasons for transplant rejection. • Autograft: -‐ Transplant from one part to another part of the same body -‐ Only works in some cases -‐ Transplant won’t be rejected • Isograft: -‐ Transplant from an identical twin since twins have identical MHC markers on body cells -‐ Transplant won’t be rejected • Allograft: -‐ Key to look for closeness in relatedness in relatives (Can include strangers though too) -‐ The closer the MHC markers on body cells are, the less likely of a rejection -‐ There is still possibility of a rejection due to donor cells being foreign cells to acceptor • Xenograft: -‐ Transplant from a different species -‐ Ex: Pig heart valves Respiratory System 1. List and describe the processes of respiration. • Pulmonary respiration: - Movement of air into and out of the body • External respiration: - Once air is in the lungs, external respiration will occur - Exchange between the capillaries and lung space (Gases exchange with circulatory system) - Oxygen is going to move from the lungs into circulator and carbon dioxide will move from circulation into the capillaries to the lungs • Gaseous transport: - Deliver oxygen from the lungs to all of the tissues through circulation • Internal respiration: - Once oxygen reaches the second capillary bed at tissues à internal respiration - Exchange between the blood capillaries and the tissues in the body - Oxygen moves from the circulatory system of the blood stream into the tissue - Carbon dioxide is produced by tissues undergoing cellular respiration will move from the tissues into the blood stream • Pulmonary respiration, external respiration, and gaseous transport are all part of the respiratory system • Gaseous transport is included in the circulatory system but is considered to be a part of the respiratory system because it involves carrying oxygen 2. Trace the path air must follow from outside the body to the alveoli in the lungs. • Respiratory apparatus: Pathway air has to flow • Nose: Primary entry path for air à Nasal cavity connects to the pharynx (Throat) • Mouth: Mainly for the digestive system but can be an entryway for air since the oral cavity also connects to the pharynx • Nasal (Or oral) cavity à Pharynx (Divided into segments) à Larynx à Trachea à Splits to each lung • First split in the lungs from the trachea: Primary bronchus (2 primary bronchi overall) à Split to secondary bronchi à Split to tertiary bronchi à Bronchioles à Ultimately air reaches the terminal bronchioles à Branch in the respiratory bronchioles (Microscopic) that contain alveoli • Alveoli: Sac-like structures on the ends of the respiratory bronchioles • Sites of gaseous exchange: Respiratory bronchioles and alveoli • As continue down the line of splitting/branching, the sizes of the respiratory structures continue to get smaller 3. Differentiate the conducting and respiratory zones, including the structures and functions of each. • Entire respiratory apparatus is divided into 2 regions: a) Conducting Zone: - Moves air - All parts that are larger than the respiratory bronchioles are part of the conducting zone (Nasal/oral cavity à Terminal bronchioles) - As air passes down through the conducting zone to the respiratory zone, air is cleansed - Any particulate matter such as smog, pollen, dust, other big particles, etc. and pathogens are filtered - Air is humidified as it passes the mucous membranes that secrete mucous to add humidification to the air à Important because otherwise if the air was dry when it reached the sacs, the sacs would dry out and not function - Air is warmed as it passes by blood vessels so the heat moves from the blood vessels to the cooler air, which is important for core body temperature— Otherwise a lot of energy would be required - On very hot days, air is cooled before it reaches the lungs too b) Respiratory Zone: - Where gaseous exchange occurs between the lungs and capillaries - Includes the alveoli attached to the respiratory bronchioles 4. Identify the specialized structures involved with the respiratory passageway, and discuss their functions. • Nasal Cavity: - External nares: o Openings in the nose - Vestibule: o Immediately inside the nose o Lined with relatively stiff hair (Vibrissae) - Paranasal sinuses: o Hallowed portions of some of the bones in our skull o Help to lighten the weight of the skull o Help with resonation - Internal nares: o Exit point for air leaving the nasal cavity o Internal nares are a point of constriction at the back of the nasal cavity: Draw air in the nasal cavity but slow it down and to filter, warm, and moisten more • Nasal Mucosae: - Olfactory mucosa: o Smell receptors
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