Lymphatic system

What are the two parts of the immune system

Ability to resist infection and disease

Responds to:

• Environmental pathogens

• Toxins and Foreign proteins

• Abnormal body cells including cancers

Includes lymphocytes (primary cells of the immune response)

Block or attack any potential infectious organism

• Cannot distinguish one attack from another

Carry lymph from peripheral tissues to the venous system

A fluid similar to plasma but has a lower amount of plasma proteins

What are the lymphoid organs (lymphocytes are produced here)

Functions of the lymphatic system

Differ from blood capillaries

• start as pockets rather than tubes

• Larger diameters but thinner walls

• basement membrane is incomplete or absent

• endothelial cells loosely bound together overlapping edges forming mini-valves

Absent in areas of the body with poor blood supply

One way valves attached by collagen fibers to the surrounding tissues

• allows fluids, solutes, viruses, bacteria, and cellular debris to enter

  • prevents return to intercellular space

special lymphatic capillaries in the small intestine

• transport lipids from digestive tract

travels from lymphatic capillaries to larger lymphatic vessels through one-way valves

• similar to valves in the venous system, but they are closer together

• Larger vessels are called collecting lymphatic vessels

Located in the subcutaneous layers of the skin, respiratory, urinary, and reproductive tracts

• Also within the areolar tissue of the digestive lining, pleural, pericardial and peritoneal cavities

Larger vessels that accompany arteries and veins

• within skeletal muscle, organs of the neck, limbs, trunk, and walls of visceral organs

Superficial and deep lymphatics unite to form ____ to drain large areas of the body

Trunks empty into what two major collecting vessels

Collects lymph from right jugular trunk, right subclavian trunk, right bronchomediastinal trunk

• empties into the right subclavian vein

collects lymph from the left side of the body and every region inferior to the diaphragm

• empties into the left subclavian vein

Thoracic duct expands into a sac-like structure called:

Where does cisterna chyli receive lymph from

Attack cells infected by viruses

• produce cell-mediated immunity

Respond to foreign substance

• remain in body to give immunity

Stimulate function of T and B cells

Inhibit function of T and B cells

Are helper and suppressor T cells

• Control immune response

Make up 10-15% of circulating lymphocytes

• differentiate into plasma cells which produce and secrete antibodies

What protects the body from antigens by producing antibodies

Act as targets that identify any pathogen or foreign compound

Bind to specific target antigen, initiating antibody-mediated immunity

A chain of events that destroys the target compound or organism

Make up 5-10% of circulating lymphocytes

Responsible for immunological surveillance

• attack foreign cells, virus-infected cells, and cancer cells

• Identify and attach to abnormal cell due to abnormal plasma membrane components

• Golgi apparatus in this cell forms perforin vesicles and release them through exocytosis

Phagocytize foreign substances

• activate T cells

capture antigens and bring them back to lymph ndoes

Act like fibroblasts creating reticular tissue that will support lymphoid organs and tissues

Dominates most lymphoid organs except the thymus

• macrophages reside in the reticular fibers

• starting place for lymphocytes to transfer between lymphatic and blood vessels

  • Allowing for constant surveillance

Loose arrangement of lymphoid cells and reticular fibers

• found in almost every body organ

Areolar tissue with densely packed lymphocytes

• Germinal center contains dividing lymphocytes

  • found in larger lymphoid organs, lymph nodes, spleen, tonsils, along digestive, urinary, and reproductive tracts

Lymph node functions

What carries lymph from peripheral tissues

Dense connective tissue covering lymph node

• bundles of collagen fibers extend from capsule into interior of lymph node making up the trabeculae

Inside capsule containing many germinal centers

• deeper in the cortex houses T cells in transit

Deep to the cortex

• contains B cells and plasma cells linked into medullary cords

Houses macrophages as they monitor lymph

What carries lymph to venous circulation

What is found below the diaphragm, lateral to kidney and posterior to the stomach

Functions of spleen

Located in mediastinum

• superior to the heart

  • divided into two lobes

Lymphocytes divide here

• Epithelial cells surround lymphocytes maintaining blood-thymus barrier

  • Keep T cells from activating early

    • Secrete thymic hormones that stimulate stem cell divisions and T cell differentiation

T cells migrate into this

• Thymic epithelial cells form concentric layers known as thymic corpuscles

  • Has no blood-thymus barrier

  • Mature T cells leave thymus by medullary blood vessels

Associated with digestive, respiratory, urinary, and reproductive systems

Forms a ring of lymphoid tissue around the throat

• gather and remove pathogens as they enter the pharynx or throat

Used for destroying intestinal bacteria, and creating lymphocyte memories for long term immunity

What contains a mass of fused lymphoid nodules

Type of defense:

• Always works the same way against any type of invading agent

  • Nonspecific resistance

Type of defense:

• protects against specific pathogens

• Depends on activities of lymphocytes

• Specific resistance

  • Develops after exposure to environmental hazards

Responds to specific antigens with coordinated action of T and B cells

Component of innate immunity:

• Outer layer of skin and hair

• Epithelial layers of internal passageways (mucous membranes)

• Physical obstruction

• Produce protective chemicals

  • Secretions that flush away unwanted materials

    • Sweat glands, mucus, and urine

  • Secretions that kill or inhibit microorganisms

    • Enzymes, antibodies, and acids

Component of Innate Immunity Internal defenses:

• Attacks and removes dangerous microorganisms pathogens and cellular debris

  • Chemotaxis

• Has 2 classes

• Responds to pathogens in several ways

  • Engulf pathogen and destroy it with lysosomal enzymes

  • Bind to pathogens so other cells can destroy it

  • Destroy pathogen by releasing toxic chemicals into interstitial fluid

    • Hydrogen peroxide, nitric oxide, and tumor necrosis factor

The release of chemicals in surrounding fluids may attract or repel phagocytes

What are the two classes of phagocytes

Type of phagocyte:

• Neutrophils and eosinophils

  • Leave the bloodstream and enter peripheral tissues to fight infections

Type of phagocyte:

• Large phagocytic cells derived from monocytes

  • Distributed throughout body tissues

What splits or lyse abnormal cells, cancer cells and cells infected with viruses

How do NK cells identify cancer cells as abnormal

What allows NK cells to identify and destroy infected cells to stop the spread of disease

Released by activated lymphocytes, macrophages, and infected tissue cells

• chemical messengers released by tissue cells

  • To coordinate local activities

  • Can act as hormones to affect whole body if necessary

Bind to adjacent cells, triggering the release of antiviral proteins

• Antiviral proteins do not kill viruses, but block replication within adjacent cells

What are the three types of interferons

Type of interferon:

• Produced by leukocytes and infected cells

  • Stimulate NK cells

Type of interferon:

• Secreted by fibroblasts

  • Slow inflammation

Type of interferons:

• secreted by T cells and NK cells

  • Stimulates macrophage activity

Helps with antibody action within the body through a series of cascade reactions

• plasma proteins that circulate in the blood in an inactive state

• Has two pathways that can be activated:

  • Classical and Alternative

Both pathways ends with the conversion of inactive protein C3 to active form C3b

Pathway of activating complement system:

• Protein CI binds to antibody molecules attached to antigen of foreign microorganism

• Bound protein acts as enzyme speeding up the chain reaction

Pathway of activating complement system:

• Factor P, Factor B, and Factor D interact in plasma after exposure to surface antigen of a microorganism

Effects of complement activation

Part of innate immunity internal defenses:

• Localized, tissue-level response that attempts to limit the spread of injury or infection

• Triggered by any stimulus that kills cells or injures tissue

  • Intense heat, physical trauma, irritating chemicals and infections

• Cardinal signs or symptoms

  • Swelling, redness, heat, pain and occasionally lost function

Effects of inflammation

What are inflammatory chemicals released by

What will release histamine, heparin and other chemicals

• stimulate neurons signaling pain in an area

• speed up blood flow through the area

  • clotting factors and antibodies will permeate the area

What are the products of inflammation

Local tissue destruction in area of injury

Mixture of debris and necrotic tissue

Pus accumulated in an enclosed space

Above what body temperature is considered a fever

Cause hypothalamus to raise body temperature

• Circulating pathogens, toxins, or antibody complexes created by macrophages

Benefits of fevers

provides cell-mediated immunity

• Defend against abnormal cells and pathogens inside cells

Provide antibody-mediated immunity

• Defend against antigens and pathogens in body fluids

• Attack antigens by producing specific antibodies

• Millions of populations, each with different antibody molecules

Properties of adaptive immunity:

Property of adaptive immunity:

• T or B cell responds only to a specific antigen and ignores all others

Property of adaptive immunity:

• Immunity is not restricted to the initial infection site

Property of adaptive immunity:

• The body produces many types of lymphocytes and antibodies

  • Each fights a different type of antigen

Property of adaptive immunity:

• Provides immunity against new exposure

  • Memory cells stay in circulation after initial exposure

Property of adaptive immunity:

• Immune system ignores antigens produced by the body

Any substance that can create or mobilize an immune response

• a contraction for “Antibody Generating”

  • Has 2 properties: immunogenicity and reactivity

Property of antigens:

• Stimulates specific lymphocyte to multiply

  • Antigenic determinants allow lymphocytes to recognize the antigen

Property of antigen:

• Reacts to activated lymphocytes and antibodies

As far as the body is concerned, any not body generated antigens are _____

Smaller molecules/incomplete antigens that must attach to proteins

• Immune system recognizes the combination as foreign

Where are lymphocytes created

Where do B cells mature