LYMPHATIC SYSTEM
ST120: Concorde Career College
Lymphatic System
Objectives:
 Define the term lymph.
 Describe the functions of the lymphatic system.
 List and identify the structures of the lymphatic
system and describe the function of each.
 Identify the origin of lymph.
Lymphatic System
Objectives:



Trace the flow of lymph through the body.
Describe the immune system and describe the
immune response.
Describe the mechanism by which the immune
system helps to maintain homeostasis.
Lymphatic System
Objectives:


Describe common diseases, disorders, and conditions
of the lymphatic system including signs and
symptoms, diagnosis, and available treatment
options.
Demonstrate knowledge of medical terminology
related to the lymphatic system verbally and in the
written form.
Lymphatic System
Functions of the Lymphatic System

Removal of impurities

Lymphocyte processing
Lymphatic System



The lymphatic system parallels
(same direction)the circulatory
system
Lymph vessels return tissue fluid
to the blood & protect the body
against foreign material
The lymphatic system includes:






Lymph fluid
Lymph vessels
Lymph nodes
Spleen
Thymus
And tonsils
Lymph Fluid
Lymph is the tissue fluid that enters and travels
through the lymphatic vessels


Plasma flows out of blood capillaries into tissue
spaces (interstitial fluid) – AKA Tissue fluid
Plasma diffuses out of the capillaries faster than it
is reabsorbed, the remaining interstitial fluid is
returned to the blood through the lymphatic system
Lymphatic Capillaries


Lymphatic Capillaries - Carry lymph and resemble
blood capillaries
Lacteals - Specialized lymphatic capillaries that
carry chyle
Lymph Vessels




Vessels of the lymphatic system start with the
smallest blind (dead-ended) lymph capillaries
The walls of the lymphatic capillaries are a thin
walled, single layer of loosely fit squamous
epithelial cells making them highly permeable
Lymphatic capillaries join larger lymphatic
arterioles that then join lymphatic arteries
Lymphatic vessels like the veins of the circulatory
system have valves
Lymph Flow
Lymphatic System
Relationship of Lymphatic
Vessels to Circulatory
System
Thoracic Duct


Lymph returns to the blood flow through the thoracic
duct and the left subclavian vein
Lymph from the lower body returns through the thoracic
duct




Cisterna chyli – dilation at the beginning of the thoracic
duct (pouch-like structure)
Lymph from a portion of the upper body also empties
into the thoracic duct superior to the cisterna chyli
Lymph from the upper left quadrant empties into the
subclavian vein
Two terminal vessels include: Right Lymphatic duct &
thoracic duct
Lymphahtic Drainage
Lacteal




Found in the villi of the small intestine
Responsible for absorbing fat-soluble nutrients
(fatty acids and vit. A,D,E & K)
Fats are absorbed by the lacteals as chylomicron
Chylomicron: combination of fatty acids and
glycerol to form triglycerides
Lacteal
Lymph nodes and nodules


Lymph Node: small ball shaped organs of the lymphatic system
Lymph Nodules: groups of lymph cells located beneath the
epithelial layer of mucus membranes (ex. Respiratory tract and
digestive tract)





Peyer’s patches: lymphatic nodules of the ileum
Filters pathogens and foreign material before returning to blood
Monitor the level of body fluid
Hematopoietic function – produce lymphocytes, macrophages, and
monocytes
Located throughout the body



Cervical
Axillary
Inguinal
Regional Lymph Nodes
Lymph node
Hilus
Afferent vessels x4
pg.261 A&P
Efferent vessels x1
Capsule
Germinal centers
Sinuses
Trabecula
Tonsils



Palatine Tonsils (throat) – located at each side of
the oropharynx
Pharyngeal (Adenoids) – located on the posterior
wall of the nasopharynx
Lingual Tonsils – located at the base of the tongue
Tonsils
Lymphedema


Abnormal accumulation of fluid in interstitial spaces
Causes:
 Obstruction
of a lymphatic vessel (tumors, inflammation)
 Increased capillary BP
 Abnormal uptake of fluid by the lymphatic capillaries
due to trauma or surgical wound (often seen after
mastectomy)
Lymphedema
Lymphedema
Terms



Lymphadenitis: inflammation of lymph
node/vessels
Metastasis: is the spread of a disease from one
organ or part to another non-adjacent organ or
part, causing a new cancer site
Lymphadenopathy: Any disease that usually
involves the lymph glands
Sentinel Lymph Node Biopsy









Method developed to determine if breast cancer has spread to lymph ducts
or nodes in the axilla
Prevents the patient from having to undergo a lymph node dissection
Sentinel Node: first node the breast drains to
Nuclear Medicine
A radioactive dye is injected into the area where the tumor is located as
well as around the areola
Hours later photos will reveal the pathway used to exit the breast, this will
reveal the sentinel node
OR
Surgeon injects a blue dye into the breast that assists in visual of the nodes
Small incision is made in the axilla
A special probe picks up signals form the radioactive dye and gets
“excited” when over an affected node
All blue and radioactive nodes are removed
Spleen







Highly vascular and friable (easily crumbled/delicate)
Located behind the stomach
Contains lymphoid nodules (white pulp)
Filters blood (red pulp) cleans out foreign
materials/microorganisms
Stores blood (approximately 200 ml) aids in
maintenance of BP during severe hemorrhage
Hematopoietic function: lymphocytes, monocytes,
leukocytes, fixed plasma cells
In a fetus the spleen produces erethrocytes
Spleen
Hilus
Splenic artery
Splenic vein
Spleen cont.


#1 organ injured in MVA’s (motor vehicle accidents)
despite being protected by the lower ribs
Splenectomy: surgical removal of the Spleen
Lymphatic System
Reticuloendothelial System


Responsible for destruction of obsolete RBCs,
bacteria, cancer cells, and other potentially harmful
foreign substances.
Utilizes monocytes distributed throughout the body
such as Kupffer’s cells located in the liver
Thymus




Located in the mediastinum
Composed of two lateral lobes bound by a
connective tissue capsule
Proper function dependent on thymosin
Produces T-cells important in cell mediated
immunity
Thymus
Lymphatic System
Lymphatic and Immune
Systems









Thymus
Bone marrow
Spleen
Tonsils
Lymph nodes
Lymph capillaries
Lymph vessels
Lymphocytes
Lymph
Lymphatic System
Immunologic Defenses

Provide the body with general defenses against
disease.
 Nonspecific
Defenses
 Specific Defenses
Lymphatic System
Nonspecific Defenses






Chemical and Mechanical Barriers
Phagocytosis
Natural Killer Cells
Inflammation
Fever
Interferon
Lymphatic System
Occurrence of Infection

Not every exposure to a pathogen results in
infection.
 Portal
of Entry
 Virulence
 Toxins
 Dose
 Predisposition
Lymphatic System
Barriers Against Infection

Chemical
 Body

secretions
Mechanical
 Skin
 Mucous
 Cilia
membranes
First Line of Defense

Our first line of defense against microbes include:
 Skin
 Mucous
membranes
 Secretions
Skin



Unbroken skin prevents microbes from entering the
body (keratin)
Broken skin such as Burns, Cuts, Scratches open the
doors for an invasion of microbes such as
Staphylococcus aureus
Sweat glands and Sebaceous gland secrete acids
that kill or inhibit the growth of bacteria on the skin
Mucous Membranes




Line tracts open to the exterior of the body (respiratory,
digestive, urinary)
Goblet cells secrete mucous to line the membranes and
“catch” microbes
Cilia catch and pass debris up to the pharynx to be
expelled
Glands in the stomach produce highly acidic gastric
juice that kills most bacteria

Helicobacter Pylori is an exception… can cause stomach
and duodenal ulcers
Second Line of Defense


If pathogens penetrate the 1st line of defense they
will encounter the body’s 2nd line of defense
Circulatory and chemical defenses
Circulatory Defenses:
Phagocytes
 Complement proteins
 Iron
 Fever
 Inflammatory response
 Interferons

Phagocytes

Leukocytes responsible for phagocytosis
Phagocytosis: the process of surrounding and ingesting
another microbe

Granulocytes





Neutrophils – motile and effective phagocytes
Eosinophils – attach to parasites and secrete peroxide ions which
kill them. Play a larger phagocytic role during allergic response
Basophils
Agranulocytes



Monocytes – enter body tissues and mature into stationary
macrophages or travel through blood to infection site (wandering
macrophages)
Kupffer cells (liver), microglia (brain)
Lymphocytes – are not phagocytes but are important in the
immune response
Phagocytosis



Chemotaxis – chemicals attract phagocytes to injured
tissues or bacteria
Adherence – antibody molecules secrete a serum
protein that can coat a bacterial cell and promote
attachment (opsonization)
Ingestion – phagocyte surrounds the microbe
Pseudopods: “false feet” that extent to cover a microbe
 The resulting sac is called a Phagosome


Digestion – phagosome is moved into the cytoplasm
(phagolysosome) and enzymes (from the lysosomes)
destroy the bacteria

Degranulation – digestion process
Complement proteins




Group of 25-30 serum proteins found in blood
plasma
Circulate inactive until needed in the antibodyantigen reaction
Activated Proteins: increase inflammatory response,
assist in lysis of antigen, attracts phagocytes
Complement cascade: sequence of proteins “bore”
holes into bacteria causing an accumulation of fluid
that eventually ruptures the cell
Iron


Virulence of bacteria increases when free iron is
present
Leukocytes: produce interleukin-1 (IL-1), stimulates
the liver to store iron depriving bacteria of
necessary free iron
Inflammatory response


Inflammation is a beneficial and necessary response to
injury
The four signs of inflammation include:
Pain
 Heat
 Redness
 Swelling


Three stages of inflammation include:
Vasodilatation
 Phagocyte migration
 Tissue repair

Inflammatory Response


Vasodilation: Increased blood flow to area and
increased permeability of blood vessels
Histamine, kinins, and prostaglandins: chemicals
released by damaged tissues responsible for
vasodilatation
Fever




An abnormally elevated body temperature
(controlled by hypothalamus)
Systemic response frequently caused by viral or
bacterial invasion
Symptoms include heat, shivering and increased
metabolism rate
Vasodilatation and sweating signify the
temperature falling “ fever breaking”
Interferons- produced by T-cells
Released to protect other cells by interferring with the
ability of the virus to reproduce as it moves from cell to
cell
 Proteins produced by leukocytes, T-lymphocytes, and
fibroblasts in response to infection “interfere with viral
replication”
 Proteins enter surrounding cells and inhibit the synthesis
of proteins needed by invading viruses for
multiplication
 They interfere with viral replication
Pg. 269 A&P

Third line of Defense



Immune response: lymphocytes secrete antibodies
that attach to microbes and inhibit or destroy them - Called humoral antibodies
Formation of antibodies is stimulated by the
presence of specific pathogens
Effective circulating antibodies gives us our immunity
Acquired Immunity
Active acquired immunity:
Immunity that develops after a person has had a disease



Natural – individual has an infection and produces antibodies
Artificial – vaccinations


Passive acquired immunity




Attenuation: process of weakening a pathogen
Natural – antibodies pass through the placenta or in colostrum
Artificial – antiserum (immune individual > susceptible individual)
Pasteur – rabies vaccine
Sabin – polio vaccine
Lymphatic System
Specific Defenses
Immunity
 Final defense against disease
 Inborn (Passive)
 Acquired
 Natural
(Active or Passive)
 Artificial (Active)
Lymphatic System
Inborn Immunity



Species
Racial
Individual
Lymphatic System
Acquired Immunity



Develops throughout the lifespan
May occur naturally
May be induced
Lymphatic System
Natural Acquired Immunity

Active
 Contraction
of the disease
 Antibodies
protect from recurrence
 May be long term or life long

Passive
 Mother
to fetus via placenta
 Mother to infant via breast milk
 May last six months or slightly longer
Lymphatic System
Artificial Acquired Immunity

Immunization
 Vaccines
 Live
 Weakened
(attenuated)
 Dead
 Toxoid
 Recombinant
DNA
 May be long term or life long

Humoral Immunity


Pg. 272 A&P
Cell-mediated Immunity
 Pg.
272 A&P
Antigens

Any substance that the body regards as foreign and
stimulates the production of antibodies aka is
immunogenic
Antibodies – A disease fighting protein created by the immune
system in response to the presence of that specific antigen



Immunoglobulins produced by B-lymphocytes
Bind to receptor site of specific antigen
B-lymphocytes mature into:
 Plasma
cells – produce antibodies in response to an
antigen (secretes them into blood)
 Memory cells – produces antibodies quickly when the
body is exposed to the same antigen again

Agammaglobulinemia: inability to produce
antibodies (have no gammaglobulin)

T-cells:
 Involved
in cell-mediated immune response
 Lymphoid stem cells that migrate to the thymus
 Cytotoxic T cell:
 Helper T cells:
 Memory T cell:
 Natural killer cell:

B-cells:
 Function
in Humoral immunity pg. 272 A&P
Organ Transplants



Tissue Rejection: cells of the recipient do not
recognize the tissue of the donor as self and
attack/destroy the transplanted tissue
To minimize chance of rejection recipients and
donors tissue should be antigenically similar. Close
family members are ideal donors
Immunosuppressive drugs: suppresses recipients
formation of antibodies/suppress the immune
system
Terms

Isograft: genetically identical twin

Allograft: close family member

Xenograft: different species, Pig
Anaphylactic Reaction


Anaphylaxis: severe allergic reaction that can be lifethreatening
Signs/Symptoms:
Itching, swelling, difficulty breathing, hives, urticaria
 Severe difficulty breathing, laryngeal edema,
bronchospasm


Treatment:
Epinephrine – bronchodilation, decrease laryngeal spasm,
^BP
 Steroid – inhibit reaction
 Levoped (vasopressor) - ^BP
 Ringer’s Lactate – Fluids
Box13-4

Latex Allergy



Many items used in the OR contain latex, daily
exposure can cause a latex-sensitivity
Latex allergic patients should be scheduled as the
first case of the day in an OR so there is not latex
dust in the room form previous surgeries
Examples of latex in the OR
 Tape,
elastic bandages, electrode pads, gloves,
tourniquets, endotracheal tubes,……….
Box 13-3
AIDS



Acquired immunodeficiency syndrome (AIDS)
Human immunodeficiency virus (HIV) has the most obvious
effect in certain types of T-cells – virus that causes AIDS
Characteristics:




Vulnerability to opportunistic infections
Major decrease in T-lymphocytes
Kaposi’s Sarcoma
Transmission:




Sexual contact
“dirty” hypodermic needles
mother > fetus
Blood transfusion
Hemolytic Transfusion Reaction

Occurs after a patient receives a transfusion of
mismatched blood

Agglutination: clustering and destruction of RBC’s

Box 13-5
Autoimmunity

Autoimmune disorder: the bodies immune system
regards normal body tissues as foreign. Can not
distinguish self from non-self
 Rheumatoid
arthritis
 Ulcerative colitis
 MS
Box 13-6