The Lymphatic System & Immune Response Exercise 35 The Lymphatic System & Immune Response
Objectives Components & functions of lymphatic system Roles of B-cells, T-cells Structure & function of lymph nodes Localization of T-cells, B-cells, macrophages in lymph nodes Antigen vs. antibody Immunological memory, specificity, differentiation of “self vs. nonself”
Lymphatic System Cells, tissues, & organs responsible for defending the body against Environmental hazards (pathogens) Internal threats (cancers)
Lymphatic System Lymphocytes are primary cells responding to specific threats “specific defense” is the immune response
Lymphatic System Lymph (fluid c.t.) Lymphatic vessels Lymphoid tissues Tonsils Lymphoid organs Lymph nodes, thymus, spleen Fig. 22-1
Lymphatic System Functions Transports LYMPH to the blood (lymphatic capillaries pick up this “leaked” interstitial fluid from tissues & takes it to the veins) Fig. 22-2
Lymphatic System Functions Protects the body: Removes foreign material (i.e.: bacteria) from lymphatic system “Police” of the body fluids Replication/cell division of lymphocytes (T-cells, B-cells, etc.)
Lymphatic Vessels Right lymphatic duct SEE MODELS!!! Drains lymph from upper right extremity, head, thorax Into Rt Subclavian Vein Fig. 22-4
Lymphatic Vessels Thoracic duct Drains lymph from rest of the body Into L subclavian vein Fig. 22-4
Lymphatic Vessels Rt lymphatic & thoracic ducts Both empty lymph into venous circulation of blood One-way system—only TOWARD the heart Fig. 22-4
Lymphatic Vessels Cisterna chyli Enlarged inferior “end” of thoracic duct Receives lymph from the digestive viscera Fig. 22-4
Lymph Nodes Filter lymph as it’s transported through the lymphatic vessels 1000s throughout the body Macrophages inside—phagocytize bacteria, cancer cells, etc. in lymph before entering bloodstream Cervical, axillary, inguinal regions; Peyer’s patches in intestine
SEE MODELS!!! Fig. 22-1
clusters of lymph nodules in small intestine Peyer’s patches clusters of lymph nodules in small intestine SEE MODELS!!! uhaweb.hartford.edu/ BUGL/immune.htm
Structure of Lymph node Fig. 22-7
Peyer’s patch histology Collection of lymphoid nodules in mucosa of small intestine Peyer's Patches are largish, rounded areas located in the submucosa. They can be a bit difficult to spot: look for the slightly darker, purpler color and more speckled or grainy texture. Lumen of small intestine http://www.uky.edu/LCC/BSN/BIO/BiologyLabs/BSL111/111Lab6/Lab6DigestiveSlides.html
Lymph node histology http://science.nhmccd.edu/biol/lymphatic/lymph.htm
Lymphoid Tissue Tonsils Lingual Palatine Pharyngeal (adenoids) (2) Base of tongue Palatine L, R: posterior inferior palate Pharyngeal (adenoids) (1) posterior superior wall of nasopharynx Fig. 22-6 SEE MODELS!!!
Lymph Organs Thymus: primary lymphoid organ SEE MODELS!!! Fig. 22-8
Lymph Organs Spleen: secondary lymphoid organ SEE MODELS!!! Fig. 22-9
Lymphocytes: 2nd-most abundant WBCs Fig. 22-15
Stem Cells originate in bone marrow B cells Differentiate in bone marrow T cells Differentiate in thymus Then enter blood stream with specific things on cell’s surface, and are cloned in lymph organs
Fig. 22-15
Lymphocytes, continued: After cloned and made many more replicates, each can form memory cells or effector/regulatory cells
Lymphocytes, continued: B cell clones: Memory B cells Antibody-producing plasma cells “humoral immunity” (work indirectly through antibodies released into blood/lymphstreams
Lymphocytes: T cell clones: Memory T cells Cytotoxic T cells (directly attack virus-infected tissue cells) Helper T cells (activate B cells & cytotoxic T cells) Suppressor cells (can inhibit immune response) “cellular immunity” (act directly, attack bacteria/viruses/parasites/cancer cells)
“FILTER”: ~99% of antigens are removed before enters bloodstream Regions of T and B cells in lymph nodes Macrophages in Fig. 22-7
Antigen (Ag) vs. Antibody (Ab) Antigens Provoke an immune response ANTI body GEN erators Antibodies (immunoglobulins—Igs) Produced by sensitized B cells or plasma cells in response to antigen presence (proteins; IgM, IgG, IgD, IgA, IgE) Antigen-binding site is specific
Fig. 22-21
Important Immune Response Characteristics Immunological Memory Remembers foreign antigens it’s previously encountered, can react faster 2nd time (i.e.: chicken pox) Specificity Memory and antibodies very specific Differentiation of “self” and “non-self” Self = our own tissues, don’t alert immune response non-self = foreign antigens, triggers immune response
Important Immune Response Characteristics Just FYI--- Differentiation of “self” and “non-self” Can malfunction Autoimmune diseases (MS, Lupus, rheumatoid arthritis, juvenile diabetes, etc.)