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The Lymphatic The Lymphatic System & System &

Lymphoid TissueLymphoid TissueChapter 16Chapter 16

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The Lymphatic SystemThe Lymphatic System

A widespread system of tissues & A widespread system of tissues & vessels, scattered throughout the body vessels, scattered throughout the body

Services all regions of the body Services all regions of the body except:except:

Bone tissueBone tissue CartilageCartilage EpitheliumEpithelium Central Nervous SystemCentral Nervous System

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FunctionsFunctions

1.1. Fluid BalanceFluid Balance Clear fluid that circulates in the Clear fluid that circulates in the

lymphatic system is called LYMPH lymphatic system is called LYMPH (formed from blood plasma)(formed from blood plasma)

Excess fluid left in tissues is drained Excess fluid left in tissues is drained through LYMPHATIC VESSELSthrough LYMPHATIC VESSELS

2.2. Protection from InfectionProtection from Infection Important component of the immune Important component of the immune

systemsystem LYMPHOCYTES (a type of white blood LYMPHOCYTES (a type of white blood

cell) attack & destroy foreign organismscell) attack & destroy foreign organisms

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3.3. Absorption of FatsAbsorption of Fats Digested fats that are too large to Digested fats that are too large to

enter the blood capillaries are enter the blood capillaries are absorbed into the LYMPHATIC absorbed into the LYMPHATIC CAPILLARIESCAPILLARIES

Fats are then added to the blood when Fats are then added to the blood when lymph joins the bloodstreamlymph joins the bloodstream

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Lymphoid TissueLymphoid Tissue Distributed throughout the body and Distributed throughout the body and

makes up the specialized organs of the makes up the specialized organs of the LYMPHATIC SYSTEMLYMPHATIC SYSTEM

1.1. LYMPH NODESLYMPH NODES Designed to filter the lymph once it is Designed to filter the lymph once it is

drained from the tissuedrained from the tissue Small, rounded masses varying from Small, rounded masses varying from

pinhead size to as long as one inchpinhead size to as long as one inch Seldom isolated; they are massed together Seldom isolated; they are massed together

varying in number from 2 to 3 to well over varying in number from 2 to 3 to well over one-hundredone-hundred

Some are placed deeply, others Some are placed deeply, others superficiallysuperficially

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Main Groups of Lymph Main Groups of Lymph NodesNodes

Cervical NodesCervical Nodes

Located in the Located in the neckneck

Both deep & Both deep & superficial groupssuperficial groups

Become enlarged Become enlarged during upper during upper respiratory respiratory infectionsinfections

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Axillary NodesAxillary Nodes Located in the Located in the

armpitsarmpits May become May become

enlarged after enlarged after the infections the infections of the upper of the upper extremities & extremities & breastbreast

Breast cancer Breast cancer cells often cells often metastasize to metastasize to these nodesthese nodes

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TracheoBronchial NodesTracheoBronchial Nodes

Located near the TRACHEA and Located near the TRACHEA and around the large BRONCHIAL tubesaround the large BRONCHIAL tubes

People living in highly polluted areas People living in highly polluted areas may have these nodes filled with may have these nodes filled with carbon particles that actually carbon particles that actually resemble pieces of coalresemble pieces of coal

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Mesenteric NodesMesenteric Nodes Located near the Located near the

lining of the lining of the stomach cavitystomach cavity

Approximately Approximately 100 to 150 of 100 to 150 of these nodes in this these nodes in this area of the bodyarea of the body

Enlarged Enlarged mesenteric mesenteric lymph nodeslymph nodes indicated by the indicated by the arrowarrow

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Inguinal NodesInguinal Nodes

Located in the Located in the groin regiongroin region

May become May become enlarged after enlarged after infections of the infections of the lower extremitieslower extremities

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2. The Spleen2. The Spleen An organ containing An organ containing

lymphoid tissue designed lymphoid tissue designed to filter the bloodto filter the blood

Located in the upper left of Located in the upper left of the abdomen & is the abdomen & is protected by the lower protected by the lower part of the rib cagepart of the rib cage

Soft, purplish & somewhat Soft, purplish & somewhat flattenedflattened

Contains phagocytes & Contains phagocytes & lymphocyteslymphocytes

Cleanses blood of Cleanses blood of impuritiesimpurities

Destroys old, worn out red Destroys old, worn out red blood cellsblood cells

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3. The Thymus3. The Thymus The thymus gland is The thymus gland is

a pink-grey organ a pink-grey organ that lies beneath the that lies beneath the sternumsternum

Key role in immune Key role in immune system development system development before birth & first before birth & first few months of few months of infancyinfancy

Most active during Most active during early lifeearly life

After puberty, tissue After puberty, tissue shrinks in size & is shrinks in size & is replaced by replaced by connective tissue and connective tissue and fatfat

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4. The Tonsils4. The Tonsils

Masses of lymphoid Masses of lymphoid tissue located in the tissue located in the vicinity of the vicinity of the pharynx (throat)pharynx (throat)

Remove Remove contaminants from contaminants from materials that are materials that are inhaled or swallowedinhaled or swallowed

Located in three Located in three areas: palatine, areas: palatine, pharyngeal & lingualpharyngeal & lingual

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Palatine TonsilsPalatine Tonsils

Located on each Located on each side of the soft side of the soft palatepalate

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Pharyngeal TonsilsPharyngeal Tonsils

Commonly Commonly referred to as the referred to as the ADENOIDSADENOIDS

Located behind the Located behind the nose on the nose on the posterior wall of posterior wall of the upper pharynxthe upper pharynx

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Lingual TonsilsLingual Tonsils

Small mounds of Small mounds of tissue located at tissue located at the back of the the back of the tonguetongue

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Disorders of the Lymphatic Disorders of the Lymphatic System & Lymphoid TissueSystem & Lymphoid Tissue

1.1. LymphangitisLymphangitis – inflammation of the – inflammation of the lymphatic vesselslymphatic vessels

May start in the region of an infected May start in the region of an infected and/or neglected injuryand/or neglected injury

Can be seen as red streaks, meaning Can be seen as red streaks, meaning bacteria has spread to the lymphatic bacteria has spread to the lymphatic systemsystem

If lymph nodes are NOT able to stop If lymph nodes are NOT able to stop infection, pathogens enter the bloodstream infection, pathogens enter the bloodstream & cause SEPTICEMIA (blood poisoning)& cause SEPTICEMIA (blood poisoning)

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2. Lymphedema2. Lymphedema

Swelling due to obstruction of lymph Swelling due to obstruction of lymph flowflow

Causes include:Causes include: Infection of lymphatic vesselsInfection of lymphatic vessels Malignant growth blocking lymph flowMalignant growth blocking lymph flow Loss of vessels & nodes as a result of Loss of vessels & nodes as a result of

injury or surgeryinjury or surgery

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3. Lymphadenopathy3. Lymphadenopathy

Disease of the lymph nodesDisease of the lymph nodes Sometimes common in a number of Sometimes common in a number of

cancerous and infectious diseases:cancerous and infectious diseases: HIVHIV Infectious MononucleosisInfectious Mononucleosis

Enlarged lymph nodes are commonly Enlarged lymph nodes are commonly referred to as SWOLLEN GLANDSreferred to as SWOLLEN GLANDS

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4. Splenomegaly4. Splenomegaly

An enlargement of the spleenAn enlargement of the spleen Accompanies certain acute infections:Accompanies certain acute infections:

Scarlet Fever (caused by a strep infection in the Scarlet Fever (caused by a strep infection in the throat)throat)

Typhus Fever (disease spread by lice or fleas)Typhus Fever (disease spread by lice or fleas) Typhoid Fever (a bacterial infection - most Typhoid Fever (a bacterial infection - most

commonly caused by commonly caused by Salmonella; sSalmonella; spread by pread by contaminated food or water. Following ingestion, contaminated food or water. Following ingestion, the bacteria spread from the intestine via the the bacteria spread from the intestine via the bloodstream to the intestinal lymph nodes, liver, bloodstream to the intestinal lymph nodes, liver, and spleen via the blood where they multiply.and spleen via the blood where they multiply.

Syphilis (bacterial STD)Syphilis (bacterial STD)

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5. Lymphoma5. Lymphoma Any tumor, benign or malignant, that Any tumor, benign or malignant, that

occurs in lymphoid tissueoccurs in lymphoid tissue Malignant lymphoma includes:Malignant lymphoma includes:

1.1. Hodgkin’s DiseaseHodgkin’s Disease – a chronic, malignant – a chronic, malignant disease of lymphoid tissuedisease of lymphoid tissue

Cause unknown, but thought to involve a viral Cause unknown, but thought to involve a viral infectioninfection

Rises in 2 age groups: early 20’s among men & Rises in 2 age groups: early 20’s among men & women and again after age 50, primarily in menwomen and again after age 50, primarily in men

Painless enlargement of lymph nodes in the neck, Painless enlargement of lymph nodes in the neck, armpit, thorax or groinarmpit, thorax or groin

May spread if not treated earlyMay spread if not treated early Symptoms include: weight loss, fever, night Symptoms include: weight loss, fever, night

sweats, fatigue, anemia & decline of immune sweats, fatigue, anemia & decline of immune defensesdefenses

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2. Non-Hodgkin’s 2. Non-Hodgkin’s LymphomaLymphoma

More common than Hodgkin’sMore common than Hodgkin’s Appears mostly in older adults and patient’s Appears mostly in older adults and patient’s

with immune deficiencieswith immune deficiencies Enlarged cervical nodes may be an early signEnlarged cervical nodes may be an early sign More widespread through the lymphatic More widespread through the lymphatic

system than Hodgkin’s & spreads more system than Hodgkin’s & spreads more readily to other tissuesreadily to other tissues

May be related to a viral infectionMay be related to a viral infection Cure rate only 50% with chemotherapy & Cure rate only 50% with chemotherapy &

radiationradiation