lymphatic Flashcards
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