The Lymphatic and Immune SystemsCHAPTER 6

Functions of the Lymphatic System

•1. Absorb fats and fat-soluble vitamins through the lacteals of the small intestine•2. Remove waste products from the tissues•3. Cooperate with the immune system in destroying pathogens•4. Return filtered lymph to the veins at the base of the neck

Absorption of fats and fat soluble vitamins

Food is digested (broken down) in the small intestines which are lined with villi (finger-like projections). These villi have lacteals and blood vessels inside them Lacteals absorb the fats that can’t be transported by the bloodstream

The blood vessels absorb nutrients/fats/fat-soluble vitamins directly into the blood stream

Interstitial fluid and lymph creation•Interstitial fluid AKA intercellular fluid: Plasma from arterial blood that flows out of the arterioles/capillaries and into the spaces between the cells of the tissues•It delivers nutrients, oxygen and hormones•When it leaves the cells, it brings back waste products and proteins created within the cells•90% returns to the bloodstream•The other 10% is lymph

Lymph…

•Is a clear watery fluid •Collects proteins made by the cells•Removes dead cells/debris/pathogens/cancer cells•Is collected by very small lymphatic capillaries in the tissues and flows toward increasingly larger vessels near the neck•Cooperates with the immune system

Flow of lymph•From lymphatic capillaries to…•Lymphatic vessels

• Have valves that prevent the lymph from flowing backward

•Lymphatic ducts• Right lymphatic duct

• Right side of head/neck, upper right quadrant of body & right arm

• Empties into right subclavian vein• Thoracic duct (largest)

• Left side of head/neck, upper left quadrant of body, lower trunk and both legs

• Empties into left subclavian vein

Lymphatic Circulation AKA Secondary Circulatory SystemLYMPHATIC CIRCULATORY SYSTEM

1. Lymph flows in only one direction. Once it enters a lymphatic capillary, it moves one-way toward the neck

2. Pumped through body by the motion of the muscles

3. Filtered by the lymph nodes

4. Lymph is clear so the lymphatic vessels are not easily seen

BLOOD CIRCULATORY SYSTEM

1. Circulates thru entire body in a loop

2. Pumped by the heart

3. Filtered by the kidneys and waste products are excreted by the urinary system

4. Blood is red and so arteries/veins are easy to see

Lymph Nodes

•Small and bean shaped•Half in the abdomen along the larger lymphatic vessels. Rest are in groups

• Cervical lymph nodes (sides of neck)• Axillary lymph nodes (arm pits)• Inguinal lymph nodes (inguinal *groin* area of the lower abdomen)

•Contains lymphocytes that can destroy pathogens and malignant cells•Filter the lymph•The “clean” lymph then continues on to become part of the bloodstream again

Cervical

Axillary

Inguinal

Tonsils•3 masses of lymphoid tissue around back of nose and upper throat•Prevent pathogens form entering the respiratory system•Palatine tonsils: on left and right sides of throat•Adenoids: AKA nasopharyngeal tonsils (upper pharynx)•Lingual tonsils: Base of tongue (can’t easily see them)

More lymphatic/immune structures•Thymus gland: Mass of lymphoid tissue above heart

• Biggest at puberty, then shrinks• Secretes a hormone that matures lymphocytes into T

cells

•Vermiform Appendix (the appendix): Hangs from the lower portion of the large intestine

•Spleen: Inferior to the diaphragm, posterior to the stomach• Filters microorganisms from blood• Forms white blood cells (leukocytes)• Hemolytic function: destroys worn-out erythrocytes• Stores extra erythrocytes

Click on picture above to link to the video

Functions of the immune system

•Maintain good health•Protect the body from harmful substances•Pathogens, allergens, toxins, malignant cells

•Prevents harmful things from entering body•BUT… if they do enter the body, they identify, attack and remember the threat•It must be able to differentiate “self” from “non-self”

Immunity•Natural – AKA passive immunity – Innate immunity• Present at birth or passed through

breast milk• Not dependent on exposure to an

antigen or disease

•Acquired - Adaptive• Obtained by having had a contagious

disease… and your body remembers how to fight it next time

• vaccines

First line of defense•Intact skin: physical barrier to prevent invading organisms from entering the body•Respiratory system: traps breathed in foreign matter with nose hairs and mucous membranes, tonsils, coughing and sneezing•Digestive system: acids and enzymes destroy invaders •Specialized leukocytes (white blood cells) destroy pathogens that do enter the body

Antigen-Antibody ReactionAKA immune reaction

•*** Involves binding antibodies to antigens. This labels the dangerous antigen so it can be recognized and destroyed by other immune system cells***•Antigen: Any substance that the body regards as foreign• Viruses, bacteria, toxins, transplanted tissues

•Antibody: Disease-fighting protein created by the immune system in response to the presence of a specific antigen• Immunoglobulins: Secreted by plasma cells; same as antibodies

•Tolerance: an acquire unresponsiveness to a specific antigen.• Mom tolerance to fetus/placenta; immune suppression for organ transplants, allergy shots

etc.

Phagocytes

•Are specialized leukocytes•Destroy antigens by surrounding and swallowing them•Monocytes – leukocytes that provide immune defense against infectious organisms • Macrophages –Come from monocytes. Surround and kill invading

cells, removes dead cells and stimulates other immune cells

The compliment system•Group of proteins that normally circulate in the blood in an inactive form, but when they are needed they complement (join to make complete) the ability of antibodies to fight off pathogens

Lymphocytes•Leukocytes that are formed in bone marrow, but mature and differentiate in lymphoid tissues thru body•3 types•B cells •T cells•Natural Killer Cells

• Important in killing cancer cells and cells infected by viruses

B cells (Mature in bone marrow)

•B cells: Produce antibodies •Antibodies are disease-fighting proteins created by the immune system in response to a specific antigen•Antigens are anything the body regards as being foreign.•Most effective against viruses and bacteria •When a B cell is confronted with the antigen that it is coded to destroy, it is transformed into a plasma cell•Plasma cells secrete large amounts of antibodies

T cells•Mature in the Thymus (“T” cell)

• NOTE: your book says they originate in the thymus, this is not true. They originate in the bone marrow, but mature in the thymus!

•Produce cytokines: group of proteins that act as intercellular signals that help to activate the immune system•Examples of cytokines: • interferon – produced to fight viruses or tumors by slowing their

multiplication, tell other cells to increase defenses• Interleukins – Direct B and T cells to multiply

Pathology of the Lymphatic system

•Lymphadenitis: AKA swollen glands, inflammation of the lymph nodes (Infection)•Lymphadenopathy: disease affecting a lymph node/s•Lymphangioma: benign tumor formed by a collection of lymph vessels (congenital malformation)

Before and After

Swiss Society of NeonatologyIntralesional injection therapy with OK-432 (Picibanil®) in a full term infant with multicystic lymphangioma colli

Lymphangiomas are congenital malformations of the lymphatic system originating during fetal development as a result of dysplastic sequestration of lymphatic tissue (1). They are present at birth in 50% of cases. The lesions consist of dilated endothelium-lined spaces that vary in size from microscopic channels (cavernous lymphangioma) to large cysts (cystic lymphangioma or cystic hygroma). Although histologically benign, these lesions may expand into surrounding tissues or vital structures similar to malignancies, sometimes causing life-threatening complications (2). Cystic lymphangiomas commonly appear in the neck (75%) and axillary region (20%), whereas cavernous lymphangiomas show a predilection for the tongue, cheek, thorax, extremities and retroperitoneal area (3).

More pathology and diagnostics

•Splenomegaly: Abnormal enlargement of the spleen d/t injury or infection•Lymphoscintigraphy: dx test for lymph system. Radioactive substance injected into lymph ducts, then scanned to show movement of the substance. Used to find a sentinel lymph node (first node to drain an area). In the case of cancer, these nodes are biopsied to see if the cancer has metastasized

Lymphedema•Is swelling of tissues due to an abnormal accumulation of lymph fluid within the tissues. (The lymph system is not functioning normally, and the lymph fluid is not draining properly)•Primary lymphedema: hereditary •Secondary: caused by damage to lymphatic vessels. Often d/t cancer treatment, surgery, trauma or burns.

Allergies•Allergic reactions: body’s immune system reacts to a harmless allergen such as pollen, food or animal dander as if it were dangerous.•Localized allergic response: AKA cellular response redness, itching and burning where the skin came into contact with an allergen. Reactions get worse with repeated exposures.• Poison ivy

•Systemic reaction: AKA anaphylaxis, AKA anaphylactic shock• Severe allergic reaction, can cause death within minutes

if not treated

Autoimmune disorders•A disease in which a person’s own immune system produces antibodies against its own tissues. •There appears to be a genetic component•Increased incidence for women during childbearing years•Examples: Rheumatoid arthritis, Crohn’s disease, multiple sclerosis

Immunodeficiency disorder

•Immune system compromised • (weakened, not working properly)

•HIV: Human immunodeficiency virus, bloodborne infection that damages T cells of the immune system. Advanced stage of infection is called AIDS (acquired immunodeficiency syndrome)• ELISA test screening test for HIV antibodies• Western Blot Test: More accurate than ELISA. Confirms diagnosis of HIV if the ELISA is

positive.

•Opportunistic infection: Caused by a pathogen that does not usually produce illness in healthy people, but is dangerous for those with weak immune systems

HIV/AIDS video clips.

Immunotherapy

•AKA biological therapy•Tx that involves either stimulating or repressing the immune system

• CA - Stimulate immune system to fight the malignancy• Allergies - Allergy desensitization is used to repress the immune system• Immunosuppressant: substance that prevents/reduces the normal immune

response (organ donation, autoimmune disorders)• Cytotoxic drug: kill or damage cells. Used as immunosuppressants or

antineoplastics (chemotherapy)

Pathogenic organisms: Bacteria

-One celled microscopic organisms. Most are not harmful… many are pathogenic (disease causing)-Bacilli: rod-shaped-Rickettsia: live in lice, fleas, ticks and mites – rocky mountain spotted fever-Spirochetes: long slender spiral-shaped bacteria. - Lyme disease from bite of an infected deer tick –

affects joints, heart and CNS- Syphilis - STD

More bacteria

•Staphylococci: 30+ kinds. Form irregular groups/clusters that resemble grapes•Staphyl/o – clusters of grapes, -cocci – spherical bacteria•Most are harmless and live on skin or mucous membranes. Others cause

serious infections (staph aureus… wound infections, toxic shock syndrome, food poisoning)

•Streptococci: Form a chain (strept/o – twisted chain, cocci – spherical bacteria)•Many are harmless, others cause strep throat, meningitis, endocarditis,

necrotizing fasciitis

Fungi•Simple parasitic organisms•Like warm wet places•Some harmless, some pathogenic•Tinea pedis (TIN-ee-ah): Athlete’s foot•Candidiasis (kan-dih-DYE-ah-sis): Yeast •Oral candidiasis – Thrush•Vaginal candidiasis

ParasitesYour book is confusing… not everything that is transmitted via an insect is a parasitic infection! The transmitting insect is a vector, not a parasite Lyme disease = bacterial, West Nile Virus = viral

•A plant/animal that lives on or in another living organism and harms it.•Malaria: lives in and is transferred by mosquitoes. Sx= fever, chills, headache, muscle aches, fatigue•Toxoplasmosis: pet feces to humans. •Especially harmful to a developing

fetus.

Viruses•Small infectious agents that reproduce by invading other cells. •Influenza: AKA “flu”, highly contagious respiratory infections often occurs seasonally. Fever, sore throat, muscle aches, cough runny nose and fatigue. Can lead to pneumonia. Vaccines are available for the most common strains•West Nile Virus: Spread by infected mosquitos

• Can be mild (flu-like) or severe affecting the spinal cord and brain

More Viruses•Rubella: AKA German Measles or 3-day measles. Fever, swollen glands, inflamed eyes, fine pink rash. Serious if caught in early pregnancy. (birth defects)•MMR: Measles, Mumps, Rubella vaccine

•Rabies: Transmitted by saliva of infected animal. Post-exposure treatment VERY important. Once symptoms begin in 30-90 days, it is nearly always fatal… no good treatments.

Herpesviruses•Cytomegalovirus: CMV found in most body fluids (50%-80% of all adults), often a silent infection, but if immune system becomes weakened or if transmitted to an unborn child, it is serious.•Varicella: Chickenpox – fever, and fluid-filled blister rash.•Herpes Zoster: Shingles – skin eruption that follow the route of an

inflamed nerve. Is caused by same virus as the chicken pox. Vaccine available.

•Infectious Mononucleosis: Epstein-Barr virus (EBV) fever, sore throat enlarged lymph nodes, splenomegaly, liver involvement.

Medications•Antibiotics: inhibits growth or kills bacteria• Bactericide – death of bacteria; penicillins• Bacteriostatic – slows/stops bacterial

growth; erythromycin, tetracycline

•Antifungal: Inhibits growth or kills fungi• Lotrimin for athlete’s foot

•Antiviral: treats viral infections or provide temporary immunity to the virus• Acyclovir

Tumors•Are abnormal growth of body tissues•Benign: not cancerous

• Myoma: benign tumor made of muscle tissue

•Malignant: cancerous• Myosarcoma: malignant tumor derived from

muscle tissue

*Angiogenesis: Tumor creates its own blood supply*Antiangiogenesis: Treatment that disrupts the blood supply to a tumor.

Cancer•Is a class of diseases characterized by the uncontrolled division of cells and the ability of these cells to invade other tissues. •Metastasize: Process by which cancer spreads from one place to another (verb)•A Metastasis: Is the new cancer site that results from the spreading process (noun)•Oncologist: physician who specializes in the dx and tx of malignant disorders such as tumors and cancer

Carcinoma vs. Sarcomas•Carcinoma: malignant tumor that occurs in epithelial (coverings… both inside and out) tissue•Can metastasize•Carcinoma in situ: malignant tumor in its original position that has

not invaded surrounding tissues

•Sarcoma: Malignant tumor in connective tissues•Hard-tissue sarcomas: bone or cartilage (osteosarcoma)•Soft tissue sarcomas: muscle, fat, blood and lymphatic vessels

• Example: synovial sarcoma is a tumor of the tissues surrounding a synovial joint•Liquid-tissue sarcomas: blood and lymph; leukemia

Lymphomas•Malignancies affecting lymphoid tissues•Hodgkin’s lymphoma•Presence of large cancerous lymphocytes•90% survive >10 years

•Non-Hodgkin’s lymphoma•All lymphomas except Hodgkin’s. •Many different kinds

Breast Cancer•Carcinoma that begins in the breast cells, but can spread to adjacent lymph nodes and other body sites•Ductal carcinoma in situ

• Earliest stage before the CA has broken thru the wall of the milk duct. Nearly 100% curable

• Infiltrating (invasive) ductal carcinoma• Starts in milk duct, goes thru the wall of the duct, invades fatty tissue. Most breast CA in

this category. • Inflammatory breast cancer

• Rare but very aggressive form of breast CA. Grows rapidly. Sx = pain, swelling, redness or a rash, swelling of nearby lymph nodes. Can only be detected with MRI.

Detection of Breast CA•Breast Self Exam (BSE): Pt. regularly checking for new lumps or changes in the breast•Mammography: Radiographic exam of breasts to find tumors or precancerous cells. •Ultrasound: follow-up test when mammogram is abnormal•Needle breast biopsy: X-Ray guided needle is used o remove small samples of tissue from the breast. •Surgical biopsy: Removal of a small piece of tissue for examination to confirm a diagnosis.•Sentinel node biopsy: Biopsy of the first lymph node to come into contact with cancer cells.

Surgical Treatment of Breast Cancer

•Lumpectomy: Removal of only the cancerous tissue and a margin of normal tissue•Mastectomy: Removal of the entire breast•Radical mastectomy: Surgical removal of the entire breast and many of the surrounding tissues•Modified radical mastectomy: Removal of the entire breast and all of the axillary lymph nodes.

Cancer Treatment•Surgery

• Remove the malignancy and a margin of normal tissue

•Chemotherapy• Chemical agents/drugs used to destroy malignant cells

and tissues

•Radiation: goal is to destroy only the CA and spare healthy tissues• Brachytherapy: Use of radioactive materials in contact

with or implanted into the tissues to be treated• Teletherapy: Administered at a distance from the body.

Uses 3D computer imaging to aim more precisely.