Lecture 6

Blood, Lymph and Immune Systems

Blood, Lymph and Immune Systems

Blood

• hem/o and hemat/o• plasma - 55%• formed elements - 45%• serum - plasma without

clotting proteins

Blood Cells

• RBC - erythrocytes - erythropoiesis• WBC - leukocytes - leukopoiesis• Platelets - thrombocytes -

thrombopoiesis

Erythrocytes

• erythr/o - red• cyte - cell• Hemoglobin - blood protein transports

oxygen• Reticulocyte - immature erythrocyte • RBCs produced by red bone marrow

Leukocytes

• leuk/o - white• Protect the body against invasion• Pass through capillary walls

• Granulocytes• neutrophils (phagocytosis)• eosinophils (allergies)• basophils (promote inflammation)

• Agranulocytes• lymphocytes (production of

circulating antibodies)• monocytes (macrophages)

• Collection of dead and living bacteria and leukocytes called pus, abscess.

Thrombocytes

• smallest formed element• made in bone marrow• essential to blood coagulation• In case of injury, blood comes in

contact with any tissue other than the lining of the vessels, platelets stick together, form plug, seals wound. Chemicals released, series of reactions, formation of clot.

Plasma

• plasma• 92% water• 8% plasma proteins

• albumin• globulin• fibrinogen

• serum - plasma without clotting proteins or fibrinogen

Functions of the Immune SystemFunctions of the Immune System

• To protect the entire body from a variety of harmful substances• pathogenic microorganisms• allergens• toxins• malignant cells

Structures of the Immune SystemStructures of the Immune System

• Unlike other body systems, Immune System is NOT contained within a single set of organs or vessels

• Action depends on structures from lymphatic, cardiovascular, and Integumentary systems

• Works primarily through antigen-antibody reaction

Lymphatic SystemLymphatic System

• Major structures• lymph vessels• lymph nodes• lymph fluid• tonsils

• Also• spleen• thymus

Functions of the Lymph SystemFunctions of the Lymph System

• lymph/o• drain fluid from tissue spaces and

return to it to the blood• transport materials (nutrients, hormones

and oxygen) to body cells• carry away waste products to the blood • transport lipids away from digestive

system• control of infection

Lymph SystemLymph System

• Lymph originates in blood plasma

• Interstitial fluid• cleans and nourishes body

tissues• collects cellular debris,

bacteria• return to blood or lymph

capillaries

Lymph NodesLymph Nodes

• located in lymph vessels• small round or oval

structures (filters)• depositories for cellular

debris• bacteria and debris

phagocytized

Lymph NodesLymph Nodes

• inside are masses of tissue which contain WBCs (lymphocytes)

• almost always grouped 2 or 3 to 100 • invading cells destroyed in nodes and

often swell as an indicator of the disease process

SpleenSpleen

• sac-like mass of lymphatic tissue• filter for lymph• phagocytic cells• hemolytic

ThymusThymus

• lymphatic tissue• mediastinum• primary role: changes

lymphocytes to T cells for cellular immunity

TonsilsTonsils

• masses of lymph tissue designed to filter tissue fluid, not lymph

• located beneath certain areas of moist epithelium exposed to outside and hence to contamination

• any or all may become so loaded with bacteria that the pathogens gain dominance

• should not be removed unless absolutely necessary.

Antigen-Antibody ReactionsAntigen-Antibody Reactions

• Antigen - any substance that the body regards as foreign (virus, bacterium, toxin)

• Antibody - a disease fighting protein developed by the body in response to the presence of an antigen

• Antigen-antibody reaction or immune reaction

WBCs for Immune ReactionsWBCs for Immune Reactions

• monocytes - type of lymphocytes • formed in bone marrow/transported where

needed by body• become macrophages

• macrophage - phagocytic cell that protects body by ingesting invading cells

• lymphocytes - major class of WBCs• formed in lymphatic tissue

Lymphocytes

• T cells or T Lymphocytes• mature in thymus gland• Cell mediated immunity

• B cells or B Lymphocytes• mature in bone marrow• antibody-mediated immunity

T Cell or T Lymphocyte(Cell Mediated Immunity)T Cell or T Lymphocyte(Cell Mediated Immunity)

• T Cell (cell mediated immunity)• circulating lymphocytes• produced in bone marrow• matures in thymus• live for years• primary function: coordinate

immune defenses and kill organisms

Lymphocyte: T CellsLymphocyte: T Cells

• helper T cells - essential to proper functioning of immune system

• Memory cells- remember antigens and stimulate a faster response if same antigen introduced at a later time

Blood Groups

• Four blood groups based on presence or absence of blood antigens (agglutinogens) on surface of RBCs

• A - A antigen• B - B antigen• AB - both AB antigens• O - no AB antigens

• Plasma does not contain the antibody against own antigen

• Antigens on the donor’s RBCs react with the antibodies in patients plasma and cause a transfustion reaction.

Rh Factor

• Rh factor is antigen present on RBC• Rh positive and Rh negative• Rh neg pregnant woman may develop

antibodies to the Rh protein of her Rh-positive fetus.

• hemolytic disease of the newborn• prevented with RhoGAM

ImmunityImmunity

• Immunity-state of being resistant or not susceptible to a specific disease

• Acquired immunity-any form of immunity NOT present at birth and obtained during life

Factors That Influence Immune SystemFactors That Influence Immune System

• Health• Age• Heredity

AnemiasAnemias

• Oxygen-carrying capacity of blood is reduced

• symptom of disease• erythropenia• hypochromasia• hematocrit

Acquired Immune Deficiency Syndrome (AIDS)

Acquired Immune Deficiency Syndrome (AIDS)

• Caused by HIV (Human Immunodeficiency Virus)

• HIV infects T-helper cells with often a long incubation of up to 10 years

• AIDS name applied during advanced stages of disease

• After immune system destroyed, opportunistic infections occur.

Autoimmune DisordersAutoimmune Disorders

Antigens stimulate development of antibodies that are unable to distinguish antigens of internal cells.

Body makes antibodies and T cells against itself and attacks own tissues.

Multisystemic involvement.

Myasthenia gravis, rheumatoid arthritis

Edema

• Hypoproteinemia• lowers osmotic pressure within blood

• large amounts of plasma pass out of blood

• poor lymph drainage• increased capillary permeability• congestive heart failure• localized edema, ascites

Hemophilia

• Hereditary blood clotting disorder• sex-linked, usually in men• lack factor VIII, essential for blood clotting• hematomas• hemarthrosis

Infectious MononucleosisInfectious Mononucleosis

• Acute infection caused by virus.• Fever, sore throat, swollen lymph glands,

atypical lymphocytes, splenomegaly, hepatomegaly, abnormal liver function, and bruising.

• transmitted by droplet infection• Infection confers permanent immunity• Treatment symptomatic

Oncology, the study of tumorsOncology, the study of tumors

• Metastasis, Metastasize• Carcinoma

• Malignant Melanoma• Adenocarcinoma

• Sarcoma (arises from bone, fat, muscle, etc.)• Osteocarcoma• Osteosarcoma• Myosarcoma

• Myeloma

Leukemia

• Major oncological disorder of blood-forming organs

• malignant cells replace health bone marrow cells

• acute myelogenous leukemia• acute lymphocytic leukemia

Hodgkin’s DiseaseHodgkin’s Disease

• Malignant disorder• Painless, progressive enlargement of

lymphoid tissue first evident in cervical lymph nodes; splenomegaly

• Anorexia, weight loss, pruritus, anemia, leukocytosis

Kaposi’s Sarcoma

• Malignancy associated with AIDS• lesions emerge as purplish-brown macules

and develop into plaques and nodules