21 n 22 LS Review PDF

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Professor Jordan clark ...

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21: The primary function of a lymph node is to filter foreign material from the lymph. Functions of the spleen:   

Phagocytosis of old erythrocytes Act as a reservoir for platelets Phagocytosis of bacteria

Lymph moves only 1 way through lymphatic vessels because of the presence of valves. Order of structures that lymph travels through: 1. 2. 3. 4.

Lymphatic capillaries Lymphatic vessels Lymphatic trunks Lymphatic ducts

The 2 primary lymphatic structures where lymphocytes are produced are the thymus and red bone marrow. Lacteals pick up dietary lipids. Order that lymph flows through a lymph node: 1. Afferent lymphatic vessel 2. Lymphatic sinuses 3. Efferent lymphatic vessel Lymphedema = a buildup of excess interstitial fluid The right lymphatic duct drains the:    

Right side of chest Right side of head and neck Right arm (right upper region)

MALT = multi associated lymphatic tissue Large clusters of lymph nodes are found in the following regions:   

Cervical Axillary Inguinal

Lymphatic nodules = small clusters of lymphocytes that lack a complete capsule Blood flows through the spleen in the following order: 1. Splenic artery

2. Central artery of white pulp 3. Splenic sinusoids of red pulp 4. Splenic vein - spleen filters blood and acts as a blood reservoir Lymphatic capillaries are close ended vessels. Veins and lymphatic vessels have valves. The lymphatic system aids the circulatory system by transporting excess interstitial fluid. As the interstitial hydrostatic pressure increases = more fluid is driven into the lymphatic capillaries. Tonsils = masses of lymphatic tissue that protect against inhaled and ingested materials and are found within the pharynx. Lymph is moved through lymph vessels by skeletal muscle pumps and the respiratory pump. The spleen initiates an immune response when antigens are found in the blood. This function is associated with white pulp. Types of Tonsils:   

Lingual Pharyngeal Palatine

All lymphocytes originate in the red bone marrow. Normal constituents of lymph:   

Ions Low concentration of protein Water

When excess interstitial fluid is not reabsorbed, the tissues swell causing a condition called edems. The larger lymphatic duct, the left lymphatic duct, is more commonly referred to as the thoracic duct.

Crash Course; The Lymphatic System:   

Takes up some extra fluid and runs a background check to make sure theres nothing bad in there Vital supporting role to cardiovascular and immune system Maintains homeostasis

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Series of checkpoints staffed with security officers designed to handle certain infections o Or alert whole immune system to shut it down 3 main parts o Lymph  Watery fluid that flows through the lymphatic system  Network of lymphatic vessels to help reabsorb the fluid  Lymph nodes  Checkpoints that monitor and cleanse the lymph as it filters through o Lymphatic organs Originate in capillary beds from circulatory system (transfer of nutrients and waste as blood plasma forced out into interstitial fluid, some left behind = becomes lymph) o Picked up by lymphatic capillaries (made up of endothelial cells that form minivalves that only open in 1 direction) o Flows through lymph nodes, lymph trunks, and lymph ducts Right lymphatic ducts o Drains all areas of the upper right area of the torso, arm, head and thorax, fed to internal jugular vein Larger thoracic duct o Drains other areas and dumps into subclavian vein Lymphatic vessel o Skeletal muscle movement, pressure changes in the thorax during breathing, and the pulsations of adjacent arteries help propel lymph along. Increased physical activity or passive movements really help keep that lymph flowing at a decent pace. o Smooth muscle o Valves Recovering 3 liters per day = more half of blood volume Role in function of immune system and circulatory system Lymph nodes o House T cells that directly attack intruders and manage the immune system o B cells that secrete antibodies into the blood o Macrophages that eat up foreign substances o Reticular cells that make the stroma scaffolding network that supports all the other cells in the lymphoid tissue o Close and regular inspection by resident immune cells  Lymphocytes  Trigger release of macrophages to attack or activate general immune system for extra support o Node overwhelmed by invader = becomes inflamed (early sin of disease or infection) Mucosa Associated Lymphoid Tissues

o In respiratory and digestive tracts o In mucous membranes o Tonsils  Ring around pharynx to inspect everything before they make it to the GI tract or lungs  Largest amount o 22: Part 1 Eosinophils are the immune system cells that target parasites. Benefits of fever:   

Accelerated tissue repair Inhibition bacteria reproduction Promotion of interferon activity

(fever is defined as a body temperature of 38 degrees Celsius or higher) Events of a fever:   

Onset Stadium Defervescence

Events of inflammation:    

Release of chemicals Vasodilation Recruitment of immune cells Delivery of plasma

The five major categories of infectious agents include:     

Bacteria Protozoans Multicellular parasites Viruses Fungi

Prions are the small fragments of infectious proteins that cause disease in nervous tissue. Obligate intracellular parasites = viruses must enter a cell to reproduce Natural Killer Cells secrete cytotoxic chemicals. Signs/symptoms of inflammation: 

Redness

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Swelling Pain

The 3 types of granulocytes are eosinophils, basophils, and neutrophils. Pyrogens target the hypothalamus; induce fever Antimicrobial substances released by the skin and mucous membranes:   

Sebum Lysosome Immunoglobin A

Phagocytes:  

Neutrophils Macrophages

Exudate – during inflammation, increased fluid, protein, and immune cells leave the capillaries and enter the interstitial space Lymphatic tissues:   

Spleen Lymph nodes Tonsils

Neutrophils are the first leukocytes to first arrive during the inflammatory response. Innate immunity is nonspecific. The cells that produce histamine and heparin are Basophils and Mast cells. Epidermal Dendritic Cells are located in the skin. Monocytes become epidermal dendritic cells. Pyrogens target the hypothalamus. Eosinophils = immune system cells associated with allergies and asthma. Acquired immunity = Specific immunity Cytokines = small proteins that serve as a means of communication between immune system cells. Pyrexia = presence of fever Neutrophils are the most prevalent leukocytes in the blood. Cilia are hair like extensions of plasma membranes that in the respiratory system, function to sweep mucus upward so that it can be expectorated or swallowed. Antimicrobial proteins of innate immune system:

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Interferons Complement

High fevers can cause:    

Denaturation of proteins Death Irreversible brain damage Seizures

Opsonization = the binding of a protein to a portion of bacteria. The binding protein, such as an antibody is called an opsonin. Interferons = a class of cytokines released from leukocytes; also referred to as IFN Skin secretions:    

Sebaceous gland secretions Normal flora Hyaluronic acid Sweat gland secretions

The complement system is usually activated in one of 2 ways 

Alternative pathway = bacteria or fungus binds directly to the complement protein

Chemotaxis = the process in which cells migrate along a chemical gradient, attracting immune system cells Margination = process in which leukocytes tightly adhere to capillaries Diapedesis = process by which cells squeeze out of the bloodstream ad migrate to sites of infection Complement proteins are synthesized in the liver. Complement system is made up of 30 different proteins. Cell mediated immunity = adaptive immunity Cytolysis = creation of a protein channel that allows fluid to enter the cell b various complement proteins in order to kill target cells Protein channel = a membrane attack complex

22: Part 2 Passive immunity = immunity obtained from another individual

IgG:    

It can cross the placenta It can neutralize snake venom Predominant antibody in the lymph Produced in a much higher concentration during a secondary response

Phases of an acute hypersensitivity reaction:   

Sensitization phase Activation phase Effector phase

Antibodies = tag pathogens for destruction by other cells Active immunity:  

Development of memory cells Direct contact with an antigen

Agglutination = of the wrong blood type is given to a patient, their red blood cells clump up because antibodies cross link them 

IgM is the immunoglobin that is most effective at causing agglutination of cells and binding complement

Antibody Titer = antibody concentration in the blood Vaccines produce artificially acquired active immunity. The first exposure to an antigen is called the antigen challenge. Opsonization = when antibodies coat a bacterium making it easier for the macrophages to engulf it. The Fc region of the antibody helps activate complement. A Y – shaped immunoglobin molecule is made of 4 polypeptide chains and referred to as an antibody monomer. The region of the antibody that binds to the antigen is the variable region. This is also the region of the antibody that makes it antigen – specific. Active and passive immunity:  

Naturally acquired Artificially acquired

Along with the direct contact between he plasma cell and a helper T – Lymphocyte, a specific type of cytokine is released from the helper T – Lymphocyte is necessary for class switching. Subacute hypersensitivity occurs within 1 to 3 hours of exposure.

The 2nd time you are exposed to the same antigen, the lag phase will be shorter and you will produce more antibodies. The ability of a plasma cell to produce a different type of antibody, class switching, requires direct contact between the plasma cell and helper T-Lymphocytes. When antibodies clump together viral particles, they become insoluble or precipitated.

Crash Course: Immune System 1. Detect 2. Deflect 3. Destroy Lymph nodes Lymphocytes Lymph vessels Bone marrow White blood cells Skin of mucous membrane 

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1st line of response = Innate (nonspecific) defense system o External barricades  Skin  Mucous membranes o Internal defenses  Phagocytes  Antimicrobial proteins  Attack cells Adaptive (specific) defense system o Goes after specific targets o Keeps files so they know how to deal with something = memory cells Very 1st line of defense = physical barrier o Skin o Tough keratinized epithelial membrane Mucous membranes o Respiratory o Digestive o Urinary

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o Reproductive  Acid from skin, stomach, vaginal  Mucin that forms mucus in the respiratory and digestive pathways  Enzymes found in saliva, mecums and eye fluid that fight bacteria  Defensins, or antimicrobial proteins  Other chemicals found in sweat that destroy bacteria 2nd line internal innate defenses o Fever o Chemical signals o Inflammation o Phagocytes  To eat  Neutrophils  Most abundant  Self destruct after eating pathogen  Macrophages  Free types patrol tissues  Fixed attached to organs devouring what passes by  Snares with cytoplasmic extensions and digest  Can do this over and over again o Natural killer cells  Patrol blood and lymph looking for cells  Can devour own cells if they become infected or cancerous (defective cells) = pokes with enzyme that triggers aptosis Inflammatory response o Internal fire alarm that uses chemicals instead of sirens o Redness o Swelling o Heat o Pain o Mast cells = send out histamine molecules  Great at calling cavalry  Vasodilation o Phagocytes attracted o Neutrophils are the first to arrive at the scene so by the time the other cells arrive they are dying in heaps  Leukocytosis = release of neutrophils from the bone marrow where they’re made into the bloodstream  To attract the neutrophis to the damaged area, inflamed endothelial cells in the capillaries send out chemicals that act like homing devices o Monocytes  Turn into macrophages

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Replace the first line of now dead neutrophils and eat up any lingering enemies and clean up carnage o When white blood cells and macrophages run into more foreign invaders than they can handle, they let loose pyrogen chemicals that tap the hypothalamus and raise your body’s thermostat call in in a systemic fever to BURN EVERYTHING Adaptive immune defenses o Has to be expressly introduced to a specific pathogen and recognize it as a threat before it will attack o it is acquired o vaccination o ability to remember specific pathogens o systemic (can fight through whole body at once) o humoral immunity  antibodies  patrol body’s fluids  reason why vaccinations work  antigen  bacteria  fungus  virus  toxin  diseased cell within own body  flags get adaptive immune system riled up  B lymphocyte  Originate in red bone marrow  Mature in bone marrow  Develops immunocompetence = how to recognize and bind to a particular antigen  Develops self tolerance = knowing how to NOT attack bodys own cells  Special protein receptors (membrane bound antibodies) each lymphocyte has own unique so it can bind to different antigens  Colonize 2ndary lymphoid organs  Activated once they meet the right antigen that it has antibodies of  recognizes and binds  clones itself producing an army w/ instruction to destroy that specific antigen o Effector cells(mass produce antibodies)  Opsonization  ride tides of blood and lymph binding to all the antigens they can find and marking them for death  Neutralization – physically block binding sites so they cant hook up to tissue  Agglutination – clumps

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Allows body to achieve immunity by encountering pathogens o Memory cells (ensures if pathogen returns, response will be faster than the first) o Active or passive  naturally or artificially Vaccine o Priming body to fight it hard and fast if you ever encounter it in the future

Cellular immune response o T lymphocytes  Go after cells that have been hijacked  Cause inflammation  Activate microphages  Get other T cells fried up  Regulate much of the immune response o MHC – display bits of the engulfed pathogen on the outside of the cell o MHC protein on surface = class 1 MHC  If MHC is normal the cell is healthy and will not be destroyed  If unhealthy, bits of MHC attach to those unhealthy proteins and tells immune system that there is a problem o Immune related cells – n=macrophages, dendiritc cells, and b cells  class 2 MHC (professionals) o T cells cant detect whole antigens only when diced up and presented on MHC  Mature in thymus o Helper  Activate cells that kill  Receptors that only bind to 1 specific 2 MHC and antigen  If correct it binds and copies itself and makes memory Ts and effective Ts (mostly helper t cells that raise alarms by releasing cytokines) o Cytotoxic  Kill cells  Binds to antigen MHC combination and releases special enzymes punching holes in the membrane = apoptosis  Detaches and continues on o...