Lymphatic System

Tissues organs, vessels and a fluid called lymph similar to interstitial fluid

Diffuse lymphatic tissue Tonsils, mucosa associated lymph

tissue and red bone marrow Lymph Organs

thymus spleen lymph nodes

Lymphocytes for Immunity

Functions of the Lymphatic System

Draining excess interstitial fluid & plasma proteins from tissue spaces

Transport of some nutrients and hormones

Immunity –specific defense recognize microbes or abnormal cells &

responding by killing them directly or secreting antibodies that cause their destruction

Formation & Flow of Lymph

Some fluid & proteins Filtered from blood capillaries are collected by lymphatic capillaries & returned to the blood

Muscle contraction and breathing promote flow of lymph

Lymphatic vessels empty into subclavian veins in shoulders

Lymph Circulation

Lymph capillariesCapillaries are closed-ended tubes in

tissuesHave one-way minivalvesPickup fluid (lymph) from Tissues

(interstitial fluid)

Lymph Capillaries

Comparison of Lymph and Blood Capillaries

Minivalve

Lymph Circulation

Lymphatic Vessels (lymphatics) Lymph passes from capillaries

into lymph vessels Resemble veins with thin walls

& valves Afferent lymphatics carry lymph

to nodes Efferent lymphatics carry lymph

from nodes

Lymph Circulation

Afferent, Efferent Lymphatics and Valves

Lymph Circulation

Lymph trunks drain lymph into ductsLymph ducts - largest lymph channels

Two ducts drain lymph into subclavian veins

Larger thoracic duct drains most of bodySmaller right duct drains right side head, right

shoulder and right arm into right subclavian vein

Lymph Ducts

Right Lymphatic Duct

Thoracic Duct

Lymph circulation

Drainage Pattern of Lymphatic Ducts

Summary of Lymphatic Flow

Interstitial fluid Lymph Capillaries

Afferent Lymphatics Lymph Nodes

Efferent Lymphatic Lymphatic Trunks

Lymphatic Ducts Subclavian Veins of cardiovascular system (CVS)

Which are the larger lymphatic structures?

(A) lymphatics

(B) trunks

(C) capillaries

(D) ducts

Question

Lymph Tissues

Lymphatic nodules – MALT (Mucosa Associated Lymph Tissues) lymphatic nodules within the digestive and

respiratory systems Small intestine Appendix Bronchi of respiratory tract

Lymph Tissues

Tonsils Located in and around throat Tonsilar crypts

Functions Crypts Trap microbes such as bacteria Mount immune response against inhaled and ingested

microbes

Lymph Organs

Lymph nodes Structure Location

Throughout body but concentrated in groin, neck, armpit

Functions Filter lymph Provide immunity

Lymph Node Distribution

Cervical Nodes

Inguinal Nodes

Axillary Nodes

Vessels that enter lymph nodes are called ______ lymphatics.

(A) efferent

(B) afferent

(C) enter

(D) endo

Question

Lymph OrgansThymus

Located in mediastinum above heart

Large in infants atrophying with age

FunctionThymosin hormones for

T-cell lymphocyte maturation

Spleen

Located in upper left quadrant to left of stomach

Functions Filters blood Provides

immunity Stores iron and

platelets

Question

(A) tonsils

(B) lymph nodes

(C) thymus glands

(D) MALT

Which of the following are located within the intestinal lining?

What lymphatic structure contains hormones for T-cell lymphocyte maturation?

(A) Tonsils

(B) Thymus gland

(C) Spleen

(D) MALT

Question

Defense

Non-specific DefenseFirst Line Defense: External

SkinMucous MembranesTearsSaliva Stomach acid

Non-specific Defense

Second Line Defense: InternalAntimicrobial proteins

Interferons – antiviral Complement – immunity and inflammation

Natural killer (NK) cells Lymphocytes Kill microbes and tumor cells

Phagocytes Wandering phagocytes Fixed phagocytes

Internal Defense

InflammationMast cells and basophils release chemicals

including histamineArterioles vasodilate – more blood to site Increased capillary permeability – more fluid

into tissues

Internal Defense

Results inRednessHeatSwelling (edema)PainHealing

Question

Which of the following is a first-line of non-specific defense?

(A) Interferons

(B) mucous membranes

(C) NK cells

(D) Inflammation

(E) none of the above

Specific Defense: Immunity

Study of immunity is immunologyImmunity versus non-specific defense

Specificity: responds to specific invadersDestroys invaders by various means such

as: ___________________________Memory: Second exposure to antigen

causes a stronger response

AntigensForeign (non-self) cells or chemicals that

produce an immune response (stimulate antibody production)

Are microbes, parts of microbes, blood cells, transplant tissues, and a variety of chemicals

Immunity

B-cell and T-cell lymphocytes responsible for immunity

Two types of immune responsesCell mediated immunity: T-cells respond

to intracellular antigens such as virus infected cells and tumor cells

Antibody mediated immunity: B-cells respond to extracellular antigens

Antibodies combat the antigen

Cell Mediated Immunity T-cells originate in the red bone marrow and

are processed (undergo maturation) in the thymus gland

Matured T-cells then pass into other lymph tissues where they are ready to respond to antigens

Immunity

Two types of T-cell lymphocytes CD8 cells

Activated by contact with virus infected body cell Onr type develops into killer T-cells and memory cells

CD4 cells Activated when antigen presented by antigen presenting

cell (APC) cell Develops into helper T-cells and memory cells Helper T-cells must activate CD8 cells before they can

become fully activated killer T’s

Cell Mediated Immunity continued

Killer T’s leave lymphatic tissue to search for and destroy virus infected cells, tumor cells and tissue transplant cells on contact

Cell Mediated Immunity Diagram

Question

Which of the following activate Killer T-cells?(A) B-cells(B) plasma cells(C) Helper T-cells(D) antibodies(E) none of the above

Antibody Mediated Immunity

Antigen causes production of antibodies B-cell lymphocytes stay in lymph tissues Antigen enters lymph tissue and binds to B-

cell receptors B-cells become activated

B-cells divide (clone) to form identical plasma cells and memory cells

Helper T-cells bind to antigen on compatible B-cells and “help” stimulate plasma cell and memory cell formation

Antibody Mediated Immunity

Plasma cells secrete various types of antibodies

Antibodies then bind to the specific antigen that activated its parent B-cells

Antibodies then cause the destruction of the antigen in several ways

Antibody Mediate Immunity Diagram

Question

Which cells secrete most of theantibodies?(A) Plasma cells(B) T-cells(C) B-cells(D) NK cells(E) none of the above

Antibody Mediated Immunity

Antibodies destroy antigens byNeutralizing antigens such as toxinsAgglutinating (clumping) and precipitating

(removing from solution) antigen bearing cells

Activating the complement proteins that destroy the antigen by various means

Enhancing phagocytosis by covering a microbe with antibodies

Antibody Mediated Immunity

There are five classes of antibodies IgG, IgM, IgA, IgE and IgDThe IgG antibody is most commonStudy Table 22-1, page 807 in text and earn

some extra credit on exam by learning the functions for each type.

What does the Ig stand for?

Summary of Immunity

Immunological Memory

What is meant by the terms primary response and secondary response?

What causes the secondary response?

Question

What does the Ig in the antibody symbolstand for?(A) Interferon globulin(B) Immunoglobin(C) Immunogenic(D) Immunoglobulin(E) none of the above

Disorders of the Immune System

To earn extra credit on your exam, study “Immune Disorders” on pages 815-817 in your text.