Health Occupations

Lymphatic System

Functions of the Lymphatic System Works in conjunction with CV system

– Filters out organisms that cause disease– Produces WBCs– Makes antibodies– Drains excess fluids & protein so tissues

do not swell up

Lymphatic fluid Thin & watery Called interstitial fluid

– Forms when plasma diffuses into tissue spaces Composed of

– Water– Digested nutrients– Salts– Hormones– Oxygen– CO2– Lymphocytes– Metabolic wastes

Vessels & Organs of the Lymphatic System

Found in almost all tissues that have blood vessels

1. Lymphatic capillariesA. Tubes that reach into interstitial spacesB. Small, open-ended like drain pipesC. Lymph fluid contains waste products & foreign bodies from cellsD. Fluid moves from capillaries to lymph vessels

Vessels & Organs of the Lymphatic SystemLymphatic capillaries also have

LACTEALS – specialized capillariesfound in small intestine1. Pick up digested fats2. Lymph + Lipids = Chyle3. Transports chyle to bloodstream via thoracic duct

Vessels & Organs of the Lymphatic System

2. Lymphatic vesselsA. Similar to veinsB. Muscular contractions help to move lymph from

tissues to lymphatic trunksC. Valves prevent backflow of lymph so it moves in

only one direction, towards heartD. Fluid empties in lymphatic trunks which empty

into veins & then become part of the blood plasma

Vessels & Organs of the Lymphatic System3. Lymph nodes

A. Lie along lymph vesselsB. Small, round or oval massesC. Size of pinhead to almondD. Usually found in groups or clustersE. Job is to filter lymph & remove impurities like carbon, CA,

pathogens, dead blood cellsF. Also produce lymphocytes & antibodiesG. Purified lymph with lymphocytes & antibodies added

leave node via ONE lymphatic vesselH. Found in neck, armpit, chest, abdomen, elbows, groin,

knees

Vessels & Organs of the Lymphatic System4. Lymphatic ducts – all lymph vessels drain into these

A. Right lymphatic ductA. Short tube receiving all purified lymph from right side of head,

neck, right chest, & right armB. Drains into right subclavion vein

B. Thoracic ductA. Drains purified lymph from rest of bodyB. Empties into left subclavion veinC. Cisterna chili – enlarged pouch like structure @ start of thoracic

duct1. Serves as storage area for purified lymph before it returns to blood

stream2. Picks up chyle (digested lipids) from lacteals

Vessels & Organs of the Lymphatic System

5. TonsilsA. Masses of lymph tissue that are externalB. Filter interstitial fluid, not lymphC. If too much bacteria is filtered, pathogen can

overwhelm tonsils & they can become infectedD. 3 pairs of tonsils

1. Palatine tonsils – on each side of soft palate2. Pharyngeal tonsils – adenoids, in nasopharnyx3. Lingual tonsils – on back of tongue

Vessels & Organs of the Lymphatic System

6. SpleenA. Organ located beneath left side of diaphragm & behind upper stomachB. Filters microorganisms & wastesC. Makes lymphocytes & monocytesD. Destroys old erythrocytes & stores RBCs to release into bloodstream if there is excessive bleedingE. Destroys platelets

Vessels & Organs of the Lymphatic System

7. ThymusA. Mass of lymphatic tissue located in front of aorta

& behind sternumB. Stores lymphocytes to defend body only in

CHILDRENC. Atrophies after puberty & is replaced by fat &

connective tissueD. During childhood, makes lymphocytes &

antibodiesE. Function is taken over by lymph nodes in adults

Immunity

Lymph system helps body remove foreign & harmful substances1. Antigen – foreign matter that causes body to produce antibodies (poison, splinter, bacteria)2. Antibody – substance made by body to produce immunity to antigen

2 forms of immune response

1. Nonspecific – innate, provides general protection

A. Barrier of skin, mucous membranes, tears, leukocytes

1. Forms antibodies in response to antigens or foreign materialB. Inflammatory response - localized

1. Injured cells cause release of chemicals, causing vascular dilation & increased blood flow

2. Other molecules enter area, wall off injured tissue3. Bacteria are destroyed by WBCs4. Area is red, warm, painful, & often swollen with decreased

function

2 forms of immune response

C. Inflammatory response – systemic1. Affects entire body2. Same as localized, but with increased

neutrophils, fever, & fluid loss in tissues3. If not stopped, can lead to shock & death

2. Specific immunityA. Inherited – develops before birth, is genetic (example – humans don’t contract simian AIDS)

2 forms of immune response

B. Acquired 1. May be natural or artificial, depends

on how it was attaineda. Natural acquiredunintentional exposure likeimmunity from breast milkb. Artificial acquiredobtained intentionally like

immunization

Immune response may damage tissue1. With allergen exposure, plasma & memory cells

produced. The next exposure causes anaphylactic response

2. Cytoxic response when antibodies react with cells causing cellular destruction (RH incompatability)

3. Phagocytes released to remove antigen-antibody complexes & their actions cause by-products that can cause tissue damage

4. Delayed hypersensitivity – occurs more than 12 hours after exposure & results in tissue damage

Abnormal conditions

1. Lymphadenitis – inflammation or infection of lymph nodesA. Occurs when large amounts of harmful substances enter lymph nodesB. Symptoms – fever, swollen, painful nodesC. If untreated, nodal abscess may formD. Treatment – warm moist compresses, antibiotics, occasionally drain abscess

2. Hodgkin’s lymphoma Chronic, malignant disease of lymph nodes Most common form of lymphoma Symptoms

– Painful swelling of nodes– Fever– Night sweats– Weight loss– Fatigue– Pruritis (itching)

Treatment– Chemo & radiation

3. Lymphangitis Inflammation of lymph nodes, usually from infected

extremity Symptoms

– Red streak extending up an arm or leg from source of infection– Fever– Chills– Pain or tenderness

Treatment – Antibiotics– Rest & elevation– Warm, moist compresses

4. Lymphedema

Caused by lymphatic obstruction Commonly occurs after lymph node

removal Especially after mastectomy

5. Splenomegaly Enlargement of spleen Causes

– Abnormal accumulation of RBCs– Mononucleosis– Cirrhosis of liver

Symptoms– Swelling & abdominal pain

Can lead to anemia, leucopenia, thrombocytopenia If spleen ruptures, hemorrhage & shock, if untreated,

death May need to remove spleen

6. Tonsillitis Inflammation or infection of tonsils Usually pharyngeal or palatine tonsils Symptoms

– Throat pain– Dysphagia (difficult swallowing)– Fever– Exudate on tonsils– Swollen mandibular lymph glands

Treatment– Antibiotics– Warm saline irrigations– Analgesics– May remove with chronic infection or enlargement