lymphatic system, open or closed
- open (moves one direction, tissues -> blood)
- slower flow than CV system (no pumping, relies on CV)
- Lymph vessels have valves that keep fluid moving in one direction (also travels from high to low pressure)
function
- conserving fluid and plasma that leak from capillaries, defends body against disease as part of immune system and absorbing lipids from intestinal tract.
- movement of lymph fluid within the cardiovascular system (maint. Of fluid balance…without drainage, fluid would build up in interstitial spaces because more fluid leaves capillaries than veins can absorb)
- filtration of fluid before it is returned to BS, filtering out substances that could be harmful to body and filtering out microorganisms from the blood
- phagocytosis: in LNs
- production of lymphocytes within the LNs, tonsils, adenoids, spleen and BM
- production of antibodies
- absorption of fat and fat soluble substances from the intestinal tract
- undesirable role: one pathway for spread of malignancy
– production of lymphocytes & antibodies
– phagocytosis
– absorption of fat and fat soluble substances in the gut
– movement of lymph fluid / drainage of interstitial space
– manufacture of blood when marrow is stressed
lymph
contains WBCs, usually lymphocytes (on occasion RBCs)
primary organs
- where lymphocytes are produced
- bone marrow and thymus
secondary organs
- where lymphocytes come in contact with antigens and mature into effector cells (things we are exposed to – allergens or antigens)
- tonsils/adenoids
- spleen
- lymph nodes
- peyers patches
bone marrow
-B lymphocytes (produce antibodies and area characterized by various arrangements of immunoglobulin’s on their surface
thymus
- thymus large in children and small in adults normally
- T lymphocytes: derived from marrow, flow to thymus
- thymus: superior mediastinum, extending up into lower neck
- child: primary site for production of T lymphocytes (cells responsible for cell mediated immunity reactions and the controlling agent for the humoral response generated by B lymphocytes)
tonsils/adenoids
- palatine tonsils = tonsils, rest are adenoids
- made of lymphoid tissue(follicles and crypts covered by mucous membranes)
- defensive responses to inhaled and intranasal antigens are activated in these tissues
spleen
- left UQ, highly vascular organ
- white pulp: made of lymphatic nodules and diffuse lymphatic tissue
- red pulp: venous sinusoids
- destroys old RBCs, produces antibodies, storing RBCs, filtering microorganisms from the blood
lymph nodes
- surrounded by capsule composed of connective tissue (usually in groups of nodes) -> storage of concentrated lymphocytes (fluid filters through each node, exposing circulation antigens to the waiting lymphocytes)
- usually less than 1 cm
- superficial nodes: in subcutaneous connective tissues
- deeper nodes: lie beneath fascia of muscles within the various body cavities
- filtrate and phago, aid in maturation of lymphocytes and monocytes
- lymphocytes: arise from LNs, tonsils, adenoids, spleen (primarily produced by BM
peyer patches
- small, raised areas of lymph tissue on mucosa of small intestine; made of many clustered lymphoid nodules
- important to immune surveillance in intestinal tract (facilitate an immune response when pathogenic microorganisms are detected)
humoral immunity
involved antibodies produced by B cells
cellular immunity
involving attacks on invaders by cells themselves
B cell lifespan
short
T cell lifespan
long
what does an increase in lymphocytes in blood mean
-mostly systemic response to viral infection (some bacterial infections)
virchow node
- L supraclavicular node:
- (VERY IMPORTANT in assessment of cancer because of L drainage area… specifically indicates abd or L thoracic malignancy)
is everything supplied by lymph tissue?
yes except brain and placenta
lymphatic drainage basics (capillaries and node itself)
- Pathway starts with highest pressure (pressure gradually decreases)
- *Blood capillaries–>Lymph from interstitial space–>Lymph Cap–>Lymph Veins–>Lymph Ducts–>Large circulatory veins
- Flow through node:
- *Interstitium–>Afferent lymphatic–>Capsule–>Cortex–>Medulla–>Efferent lymphatic–>either blood OR secondary lymphoid organs
Right drainage area
R lymphatic (trunk) duct–>R subclavian vein (drains right upper body)
Left drainage area
Thoracic duct–>L subclavian vein (rest of body)
what happens if lymph volume increases?
flows faster in response to mountain capillary pressure, greater perm of capillary walls of cardiovascular system, increased bodily or metabolic activity, and mechanical compression.
what happens if lymph volume decreases?
mechanical obstruction will slow or stop the movement of lymph, dilating system (if obstructed, lymph may diffuse into the vascular system or collateral connecting channels may develop)
assessing drainage
-Screening exam includes superficial lymph nodes and spleen
-Multiple locations of lymphadenopathy may indicate systemic inflammatory, infectious, or malignancy processes (TB, CA)
-Normal nodes may not be palpable
-Nodes enlarged from prior inflammation may be palpable and may or may not be significant
*Red streaking is lymph-related!
- Inspect above lymph nodes for:
o Color
o Erythema
o Enlargement
o Masses
-Certain nodes correspond to certain areas of the body, so it’s important to examine nodes that may be related to dz process
• Children under 12 years of age may have “shotty” facial, cervical and inguinal lymph nodes
