34 Year Old male patient dx AIDS.
Background
Upstream
Downstream
The lymphatic system is a body system made primarily of lymphatic vessels, organs and tissues. The two Primary functions of this system is to Transport and Store lymphocytes for immunity and return excess interstitial fluid to the bloodstream.
The Immune System is the Physiological part of the Lymphatic system. Immunity helps defend and protect the body against foreign pathogens that could be harmful.
There are 2 Primary Lymphatic Structures
Secondary Lymphatic structures are comprised of lymphoid organs and lymphatic nodules that contain lymphocytes and other immune cells
The pathways in which Lymph is carried range in size and have different names for the varying range of sizes.
Lymphatic Vessels are similar to small veins in size. They are where lymph capillaries converge. They have valves that prevent pooling of fluid and lack pumps to move the fluid thus relying on skeletal muscle to move lymph.
Lymphatic Trunks are the merging of lymph vessels and have 5 places they drain from. Jugular trunks from the head and neck, Subclavian from the upper limbs and thoracic area, Bronchomediastinal from the deep thoracic structures, Interstitial from the abdominal structures and Lumbar from the lower limbs, abdominopelvic wall and pelvic organs
Lymphatic Capillaries are found in areolar tissue throughout the body. They are made of overlapping endothelial cells and are slightly larger than vascular capillaries.
There are 2 lymphatic ducts that the trunks drain into
Lymph is the fluid that flows through the lymphatic vessels consisting mainly of water, dissolved solutes, protein and foreign materials like pathogens
Lymphatic Capillaries absorb interstitial fluid and the overlapping endothelium cells close with the interior pressure thus not letting the fluid leave
Lacteals are lymphatic capillaries found in the GI tract
Lacteals enable the absorption of lipid soluble substances
Lymph Nodes are small lymph organs along the lymph vessels
Lymph Nodes filter lymph fluid as it passes through them specifically removing harmful pathogens.
From all 5 areas the Trunks are responsible for draining lymph into lymphatic ducts
The right is located at the junction of the right subclavian vein and the right internal jugular vein.
Thoracic duct is found below the diaphragm where the left subclavian and jugular veins meet.
Collects lymph from the right upper limb, right side of the head and neck and the right thorax. It then feed into the right subclavian vein to restore fluid to the bloodstream.
Drains lymph from all the other areas and structures that the right does not.
Cisterna Chyli is a round sac like structure at the base of the thoracic duct.
This structure receives lipid rich lymph known as Chyle from the GI tract via the lacteals.
Red Bone Marrow is found in the traberculae in parts of the spongy bone in flat bones and epiphysis of the femurs.
The Thymus is a bilobed organ that is found posterior to the sternum and anterior to the heart. It is quite large in infants and begins shrinking with age and is near non exsistent in adults.
This is where hemopoiesis occurs or the formation of all blood cells
The outer portion is called the Cortex
The inner portion is called the Medulla
Contains immature T cells
Contains mature T cells
Spleen is the largest lymphatic organ and is located in the upper left quadrant of the abdomen with a Hilum where the blood vessels and nerves enter and leave. Made of two different types of tissues.
There are 3 pairs of Tonsils that are considered one of the first lines of defense in the body against foreign substances.
Lymph Nodes are small round encapsulated blobs along the lymphatic vessels often shaped like a kidney bean. Clusters of nodes are typically found in the axillary, inguinal and cervical areas. Lymph comes in and leaves through 2 separate pathways.
MALT or Mucosa Associated Lymphatic Tissue is found in the GI tract, respiratory tract, genital and urinary tracts.
Afferent lymphatic pathway is where the lymph arrives to the node and there are usually multiple per Node. The Efferent is where the lymph leaves usually 1 per node.
The outer layer is connective tissue called the capsule. Encapsulated means that the inner extensions of the capsule make subdivided compartments inside each node.
The inner regions are divided into 2 parts as well.
There are 2 Lymphatic Sinuses called the Cortical and Medullary Sinuses.
Outer most is the Cortex made of reticular fibers
Inner most is the Medulla that is supported by fibers called medullary cords.
This area houses B cells and some macrophages that is surrounded by the Mantle Zone where more macrophages, T cells and dendritic cells are found
Contains B Cells, T Cells and Macrophages
These sinuses are tiny openings that are lined with macrophages
The white pulp is spherical clusters of T and B cells and macrophages. Also Contains the central artery.
Red pulp contains Erythrocytes, platelets, macrophages and T cells in the connective tissue. Splenic cords from the cell clusters and splenic sinusoids are permeable capillaries that drain into small venules.
Through phagocytosis white pulp filters blood for pathogens
Platelets are stored here for when they are needed. Phagocytosis of old damaged erythrocytes and platelets happens here as well as monitoring for pathogens.
Palatine are found in the posterior and lateral portion of the roof of the mouth
Lingual are found in the inferior portion of the tongue
Pharyngeal are found in the posterior wall of the nasopharynx; also called adenoid when swollen
Helps the body defend against foreign substances that come into contact with the mucus membranes
Peyer's Patches are MALT found primarily in the Ileum due to it being closest to the bacteria infested Large intesine
While bacteria in many forms is needed in the body some bacteria if in a different area can cause damage and illness. Peyer's patches keep the level of bacteria from over populating and populating undesirable areas and structures
Immunity is the ability to resist particular pathogens such as bacteria with defenses called antibodies formed by the leukocytes or white blood cells. There are 2 distinct parts to immunity and the responses.
Immune cells are formed in the red bone marrow and generally called Leukocytes. There are 3 Classifications off leukocytes
Lytic vs Lysogenic Cycles: both involve pathogens that have altered the host cell to reproduce the infected DNA.
Infectious agents are organisms that invade other organisms looking for a host and causing damage and even death. These things are considered pathogenic because they cause harm. There are 5 major categories of these pathogens.
Fungi are Eukaryotic cells with a cell wall. Fungi releases enzymes to break down the host proteins for them to eat; this includes molds, yeast, and spore producing fungi
Protozoan are also eukaryotic with no cell wall and cause infections such as malaria and trichomoniasis.
Viruses are not cells and known to be "not alive" they are smaller than bacteria and made only of a protein shell with DNA or RNA. They must inject their genetic material to healthy cells to highjack the cell and reproduce the infected cells
Multicellular Parasites are small but not microscopic. worms like tapeworms are and example
Bacteria are single celled prokaryotes that have 3 categories based off of shape. The virulence or ability to make someone sick is very high.
Bacilli are rod like
Spirilla are coiled almost spiraled in shape
Cocci are spherical in shape
Monocytes settle in tissues after the exit blood vessels
Lymphocytes are found throughout the lymphatic system with 3 different types with different responsibilities. Lymphocytes life is formation and maturation, Activation where they identify pathogens and begin replication, and Effector response where T and B cells target specific pathogens and replicate to eradicate the pathogens.
Granulocytes look granular under the microscope. There are 3 types of granulocytes.
Macrophages are in all tissues throughout the body
Basophils circulate in the blood
Neutrophils are most common in circulating blood
Neutrophils are first to arrive during inflammatory response and engulf unwanted infectious agents and cell debris
Macrophages arrive at inflammation after neutrophils and stay after neutrophils have left engulfing infectious agents and cell debris that is known as phagocytosis.
Basophils secrete chemicals that promote inflammation like Histamine for vasodilation, Heparin as an anticoagulant, Eicosanoids to increase inflammation.
B-Lymphocytes mature and learn in the Bone Marrow where they are made.
Natural Killer Cells (NK Cells) are formed in bone marrow, circulate in blood, and accumulate in spleen, tonsils, and lymph nodes.
T-Lymphocytes are sent to the Thymus to mature and learn how to detect pathogens and differentiate from self cells
Dendritic Cells are cells derived from Monocytes that live in the Epidermis
Dendritic Cells engulf pathogens in the skin and mucosal barriers
MAST cells are similar to basophils and are located close to blood vessels in connective tissue
MAST cells secrete chemicals that also promote inflammation like Histamine, Heparin, and Eicosanoids.
T cells become two main different T cells marked with opposite proteins.
Cytotoxic T cells are marked CD8
Helper T cells are marked with CD4
Helper T cells directly contacts an antigen displaying foreign antigens and binds to the cells. The specific TCR on the T cell and binds to the antigen. after several hours if the antigen isn't recognized it releases it. Within 24 Hours the T cells begin to secrete cytokine interleukin that stimulates proliferation and making clones of themselves. Some of the cells become memory cells for future immunity.
Cytotoxic T cells are activated when they come into contact with MHC class 1 of an infected cell. IL-2 is released from helper T cells that stimulate cytotoxic t cells to proliferate and make more clones. Some cells become memory cells for future immunity.
B lymphocytes do not need an antigen to be presented by another cell to be activated unlike T cells. they encounter free antigens and bind to its BCR. B cells then can present to T cells. B cells stimulated by IL-4 that has been released from helper T cells, and can produce antibodies, and become memory cells.
NK cells patrol and destroy unwanted cells such as viruses or bacteria infected cells. To destroy cells 2 cytotoxic chemicals are released.
Perforin is released that makes a pore in the cell's membrane
Granzymes enter cell through a hole in the membrane and induce apoptosis in cell causing the cell to shrivel and die.
The patient contracted HIV most likely through sexual intercourse
Any foreign pathogen that enters his body would not be met with the full force of the immune system because the TH cells are not present to activate the adaptive immune response.
The patient would become extremely ill at the slightest common cold.
A slight cut or abrasion could spiral to full sepsis with no adaptive immunity.
The virus would continue to attack the immune system until the patient is considered to have AIDS. Which is the condition that is acquired from having HIV.
With little or no treatment for the HIV the disease would progress more rapidly than in patients that have surpressed the disease.
When the Helper T cells are destroyed and the HIV is replicated exponentially more rapidly the immune system will be more and more rapidly suppressed.
Helper T cells activate all of the other adaptive immunity cells so without them the immune system is limited to the innate immunity response.
Immediate symptoms of HIV could include but not limited to: fever, chills, muscle pain, sore throat, joint pain, diarrhea, rash, night sweats and mouth sores
With most of the symptoms being common cold symptoms the patient might not realize how sick he really is.
If the patient isn't properly treat for the HIV with anti viral prescriptions the virus will progress rapidly.
The patient would become increasingly more sick with acute symptoms becoming more consistent.
The patient is now in the after effects of the virus and it is now considered AIDS. AIDS is the condition after the initial Virus is contracted.
Adaptive Immunity refers to the forming of lymphocytes that are specific to certain foreign antigens and the products they secrete. there are 2 main ways of adaptive immunity.
Innate Immunity is the nonspecific immunity that has two main processes to protect the body.
The first line of defense is to prevent entry of the harmful pathogens. Physical barriers like Skin, mucous membranes, the respiratory and GI tracts. Chemical barriers like defensins, sebum, mucus, saliva and Hcl. Biological barriers like nonpathogenic microorganisms that live on the skin.
The second line of defense are internal processes carried out as general responses to potentially harmful substances who have made it past the barriers such as cells, chemicals, and physiological responses.
Chemical defenses like Interferon are released from infected cells to warn other cells and stimulates noninfected cells to prepare and put up defenses. Interferon activates the production of the enzymes that destroy viral DNA/RNA and signals NK to destroy infected cells. The Complement system is a group of 30 proteins that are named with numbers respectively. they are synthesized in the liver continuously and released into the bloodstream in an inactive form.
Physiological responses would include: inflammation that could be identified by the fever, redness, swelling and loss of function. Body fever brought on pyrogens or trauma.
Cellular defenses include: Neutrophils and Macrophages that reside in tissues and the blood to engulf pathogens and destroy them. Basophils and Mast cells that circulate in the blood and live in the connective tissue release granules to increase the inflammatory response and draw more cells in. NK cells destroy unwanted cells with chemicals that cause cell death. Eosinophils target parasites with granules and enzymes that destroy the parasite.
Complement system is activated in one of two enzyme cascades. Classical pathway is when the complement protein binds to an antibody from your body that has already identified the pathogen. The alternative pathway is when the surface polysaccharides of certain bacteria and fungal cells bind directly to the complement protein.
Humoral Immunity or antibody immunity is the immune response that involves B cells and the antibodies they produce.
Cell-Mediated immunity in which immune response involves T cells
In the Lytic cycle the viral DNA is injected in the host cell, the new viral components are constructed until the host cell lyses and the virus is released. The new viral pathogens then do the same thing to new host cells
The Lysogenic cycle differs after the virus is in the cell. The viral DNA integrates into the host chromosomes and the host cell with viral DNA replicates and divides. When triggered the virus becomes active and continues the cycle.
The patient will now have to be extremely careful of others around him as well as to not get injured because he will not have the immunity to fight off even just the common every day pathogens.
Unlike an Infection caused by bacteria a virus is not alive thus there is no killing it, only slowing it down until the body can find the proper antibody to combat it. So in the case of HIV with it being a virus there is no cure like with bacterial and being able to take an antibiotic.
The patients immune system is not entirely compromised but with the lack of adaptive immunity the innate can cause more harm than good with the initial responses such as inflammation due to histamine and the NK cells not being specific with their attacks on the harmful pathogens they often kill many healthy cells