Presentation on theme: " Circulates body fluids; transports wastes, fats, etc. › Fluid inside is called lymph. Fights infectious diseases; launches attacks against foreign."— Presentation transcript:
Circulates body fluids; transports wastes, fats, etc. › Fluid inside is called lymph. Fights infectious diseases; launches attacks against foreign objects.
Lymphatic capillaries – located near and around blood capillaries. Pick up tissue fluid from the area and absorbs it into lymph.
Lymphatic capillaries merge to form lymphatic vessels › Have valves like veins. Larger vessels lead to lymph nodes. Vessels merge to form lymphatic trunks.
Lymphatic trunks join with collecting ducts before being emptied into the veins. Two collecting ducts › Thoracic › Right lymphatic
Thoracic – larger and longer › Lymph from lower limbs, abdominal region, left upper limb, left thorax, head, and neck. › Empties into the left subclavian vein. Right Lymphatic – much smaller area › Lymph from right side of the head, right upper limb, right thorax. › Empties into the right subclavian vein.
Tissue fluid › Originates from blood plasma – water and dissolved substances that are released by blood capillaries. Lymph fluid › Tissue fluid is pushed into the lymph capillaries where it becomes lymph.
Transports proteins back to the blood. Transports bacteria and other foreign objects into lymph nodes. Basically, the purpose of lymph is to cleanse the blood plasma and return it to the cardiovascular system.
Lymph is driven into capillaries by hydrostatic pressure of the tissue fluid. Once inside, it’s moved by muscle contractions (like in veins). It is also moved by pressure changes that come along with breathing. If lymph doesn’t move properly, it can back up and cause inflammation (edema).
Function: filter harmful particles; monitor body fluids; make lymphocytes. Located in groups of chains along larger lymphatic vessels.
Bean-shaped < 2.5 cm long Enclosed by connective tissue capsule. Hilum – indentation where blood vessels and nerves join a lymph node
Vessels leading in (afferent) come in at many different points. Vessels leading out (efferent) exit at one point – the hilum.
Inside: › Lymph nodules – masses of B cells and macrophages that fight disease › Lymph sinuses – complex network of channels for lymph to travel.
Nodes are often removed in procedures that remove cancerous cells from nearby tissues and organs.
Soft, bi-lobed gland enclosed in a capsule located behind the sternum Makes T-cells which aid in immunity. Larger in childhood and infancy. Shrinks throughout life.
Function: Filters blood Largest lymphatic organ. Looks like a large node. Two tissue types: › White pulp – nodules packed with lymphocytes › Red pulp – fills the rest of the space; RBC’s, lymphocytes, and macrophages.
Both work together to fight infections. Pathogens – disease-causing agents
General Responds quickly Protect against many kinds of pathogens. Species resistance, chemical barriers, mechanical barriers, natural killer cells, inflammation, phagocytosis, and fever. Precise Develops slowly Targets specific pathogens Provides adaptive defense/immunity. Innate (Nonspecific)Adaptive(Specific)
Type of DefenseDescriptionExample Species Resistance Mechanical Barriers Chemical Barriers Natural Killer (NK) cells Inflammation Phagocytosis Fever
First line of defense – mechanical barriers Second line – chemical barriers, NK cells, inflammation, phagocytosis, fever Third line - immunity
Antigens – large proteins and other molecules that invade the body. › The body recognizes and catalogues non-harmful substances before birth. Large and complex antigens are more likely to illicit a response. Hapten cells can aid in attacking the body; smaller; will not illicite a response on their own. The Enemy
Lymphocytes – T cells and B cells. T-Cells – Originally formed in red bone marrow and mature in the thymus. B-Cells – Formed and matured in red bone marrow. Both reside in lymphatic organs. The Remedy
Activation requires an antigen- presenting cell (macrophage or B cell.) T cells come in direct contact with cells (cellular immune response) 3 kinds › Helper cells – stimulate B cells to attack › Cytotoxic cells – Attack tumor and viral cells › Memory cells – Remain to attack already dealt-with cells with a quicker response.
B cells activate and produce clones of themselves. Most need helper T cells to activate. Some become plasma cells that release antibodies. Memory B cells – ready to respond to future encounters with the same antigen.
Antibodies/Immunoglobins – same thing! Antibodies do three things: › Directly attack antigens › Activate complement › Stimulate localized changes (inflammation)
Immunoglobin G (IgG) – fights bacteria, viruses, and toxins IgA – in breast milk, tears, nasal fluid, intestinal juice, urine, etc IgM – fights food antigens and bacteria IgD – mostly in infants; activates B cells Ig E – associated with allergic reactions
Active immunity – longer term Naturally acquired active immunity – when someone develops immunity based on their own body producing the antibodies needed. Artificially acquired active immunity – when someone develops immunity because of a vaccine
Passive Immunity – shorter term Artificially acquired passive immunity – individual receives a different individual’s antibodies Naturally acquired passive immunity – passed from mother to child during pregnancy
Immune response to a nonharmful substance Unlike normal responses, they can damage tissue Allergens – antigens that trigger an allergic response
Delayed-reaction allergy – due to long exposure › Household chemicals, cosmetics, poison ivy Immediate-reaction allergy – occurs within minutes › Tendency to overproduce IgE › Insect stings, penecillin
Occur after organ transplants Immunosuppressive drugs are used to avoid rejection Rejection can take place years after the organ is transplanted.
The body can begin to attack itself. About 5% of the population has an autoimmune disease › Diabetes, lupus, rheumatoid arthritis How? Viruses can take on part of an immune system’s antibodies. Other antibodies kill the viral cells and recognize it (even the good part) as an invader